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Introduction to Psychology By

Paul Bloom

Lecture 1 Professor Paul Bloom: I'd like to welcome people to this course, Introduction to Psychology. My name is Dr. Paul Bloom. I'm professor of this course. And what this is going to be is a comprehensive introduction to the study of the human mind. So, we are going to cover a very, very wide range of topics including brains, children, language, sex, memory, madness, disgust, racism and love, and many others. We're going to talk about things like the proper explanation for differences between men and women; the question of whether animals can learn language; the puzzle of what grosses us out; the problem of why some of us eat too much and what we could do to stop; the question of why people go crazy in groups; research into whether you could trust your childhood memories; research into why some of us get depressed and others don't.

The style of this is there'll be two lectures a week, as well as course readings. Now, to do well in the course, you have to attend both the lectures and do the readings. There will be some overlap. In some cases, the lectures will be quite linked to the readings. But there will be some parts of the readings that will not find their way into the lectures, and some lectures--some entire lectures that will not connect at all to the readings. So, to pursue this course properly you have to do both. What this means is that if you miss a class you need to get notes, and so you should get them from a friend or from the person sitting next to you. The slides are going to be made available online. So, one of the things you don't have to do is you don't have to write this down. You take notes any way you choose, but if you don't get anything on there it'll be available online. I'm going to post it in a format which will be black and white and easy to print out so you don't have to worry about this. But again, attending to the slides is not a substitute for attending class.

There's a textbook, Peter Gray's Psychology, 5th edition, and there's also a collection of short readings, The Norton Reader edited by Gary Marcus. It's an excellent textbook; it's an excellent collection, and you should get them both. They're available at Labyrinth bookstore on York Street or you get them online. I should note that last time I taught the course I used the Marcus Reader, and when Professor Marvin Chun taught his course last semester he used Peter Gray's 5th edition textbook. So, there may be a lot of used copies floating around. You should feel free to try to get one of those.

The evaluation goes like this. There is a Midterm and there is a Final. The Final will not be held in the exam period, because I like to take long vacations. It will be held the last day of class. The exams will be multiple choice and short answer, fill in the blank, that sort of thing. Prior to the exams I will post previous exams online, so you have a feeling for how these exams work and so on. There will also be review sessions.

Starting at the beginning of the third week of class – that is not next week but the week after – on each Monday I'm going to put up a brief question or set of questions, which you have to answer and your answers need to be sent to your teaching fellow. And you'll be given a teaching fellow, assigned one, by Friday. This is not meant to be difficult. It's not meant to be more than five, ten minutes of work, but the point of the question--15, 20 minutes of work, but the point of the question is to motivate people to keep up with the material and do the readings. These questions will be marked pass, fail. I expect most everybody could pass all of the questions but it's just to keep you on track and keep you going.

There is a book review, a short book review, to be written towards near the end of the class. I'll give details about that later on in the semester. And there's also an experimental participation requirement, and next week I'll hand out a piece of paper describing the requirement. The point of the requirement is to give you all experience actually seeing what psychological research is about as well as to give us hundreds of subjects to do our experiments on.

The issue sometimes comes up as to how to do well in the course. Here's how to do well. Attend all the classes. Keep up with the readings. Ideally, keep up with the readings before you come to class. And one thing I would strongly suggest is to form some sort of study groups, either formally or informally. Have people you could talk to when the--prior to the exams or--she's patting somebody next to her. I hope you know him. And in fact, what I'm going to do, not this class because it's shopping period. I don't know who's coming next class, or what but I'll set up a few minutes prior, at the beginning of the class, for people just to introduce themselves to the person next to them so they have some sort of resource in the class.

Now, this is a large class, and if you don't do anything about it, it can be very anonymous. And some of you may choose to pursue it that way and that's totally fine. But what I would suggest you do is establish some contact with us, either with me or with any of the teaching fellows, and I'll introduce the teaching fellows sometime next week. You could talk to us at the beginning or at the end of class. Unless there are special circumstances, I always try to come at least ten minutes early, and I am willing to stay late to talk to people. You could come by during my office hours, which are on the syllabus, and you could send me e-mail and set up an appointment. I'm very willing to talk to students about intellectual ideas, about course problems and so on. And if you see me at some point just on campus, you could introduce yourself and I'd like to meet people from this class. So, again, I want to stress you have the option of staying anonymous in this class, but you also have the option of seeking out and making some sort of contact with us. Okay. That's the formal stuff of the course.

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What's this course about? Unlike a lot of other courses, some people come to Intro Psychology with some unusual motivations. Maybe you're crazy and hope to become less crazy [laugher]. Maybe you want to learn how to study better, improve your sex life, interpret your dreams, and win friends and influence people [laugher]. Those are not necessarily bad reasons to take this course and, with the exception of the sex part, this course might actually help you out with some of these things. The study of scientific psychology has a lot of insights of real world relevance to real problems that we face in our everyday lives. And I'm going to try--and when these issues come up--I'm going to try to stress them and make you try to think about the extent to which the laboratory research I'll be talking about can affect your everyday life: how you study, how you interact with people, how you might try to persuade somebody of something else, what sort of therapy works best for you. But the general goals of this course are actually I think even more interesting than that.

What I want to do is provide a state of the art introduction to the most important topic that there is: us. How the human mind works, how we think, what makes us what we are. And we'll be approaching this from a range of directions. So, traditionally, psychology is often broken up into the following--into five sub-areas: Neuroscience, which is the study of the mind by looking at the brain; developmental, which is the area which I focus mostly on, which is trying to learn about how people develop and grow and learn; cognitive, which is the one term of the five that might be unfamiliar to some of you, but it refers to a sort of computational approach to studying the mind, often viewing the mind on analogy with a computer and looking at how people do things like understand language, recognize objects, play games, and so on. There is social, which is the study of how people act in groups, how people act with other people. And there is clinical, which is maybe the aspect of psychology that people think of immediately when they hear psychology, which is the study of mental health and mental illness. And we'll be covering all of those areas. We'll also be covering a set of related areas. I am convinced that you cannot study the mind solely by looking at the discipline of psychology. The discipline of psychology spills over to issues of how the mind has evolved. Economics and game theory are now essential tools for understanding human thought and human behavior--those issues connecting to philosophy, computer science, anthropology, literature, theology, and many, many other domains. So, this course will be wide ranging in that sense.

At this point I've been speaking in generalities so I want to close this introductory class by giving five examples of the sorts of topics we'll be covering. And I'll start with the topic that we'll be covering next week on Monday – the brain. This is a brain. In fact, it's a specific person's brain, and what's interesting about the brain is that little white mark there. It's her brain. It's Terri Schiavo's brain. You recognize her more from pictures like that. And what a case like this, where somebody is in a coma, is without consciousness as a result of damage to the brain, is a stark illustration of the physical nature of mental life. The physical basis for everything that we normally hold dear, like free will, consciousness, morality and emotions, and that's what we'll begin the course with, talking about how a physical thing can give rise to mental life.

We'll talk a lot about children. This is actually a specific child. It's my son, Zachary, my younger son, dressed up as Spider-Man, but it is Halloween. No, it's not Halloween. Oh. Well, there's more to say about that [laughter]. I study child development for a living and I'm interested in several questions. So, one question is just the question of development. Everybody in this room can speak and understand English. Everybody in this room has some understanding of how the world works, how physical things behave. Everybody in this room has some understanding of other people, and how people behave. And the question that preoccupies developmental psychologists is how do we come to have this knowledge, and in particular, how much of it is hard-wired, built-in, innate. And how much of it is the product of culture, of language, of schooling? And developmental psychologists use many ingenious methods to try to pull these apart and try to figure out what are the basic components of human nature.

There's also the question of continuity. To what extent is Zachary, at that age, going to be that way forever? To what extent is your fate sealed? To what extent could--if I were to meet you when you were five years old I could describe the way you are now? The poet William Wordsworth wrote, "The child is father to the man," and what this means is that you can see within every child the adult he or she will become. We will look and ask the question whether this is true. Is it true for your personality? Is it true for your interests? Is it true for your intelligence?

Another question having to do with development is what makes us the way we are? We're different in a lot of ways. The people in this room differ according to their taste in food. They differ according to their IQs; whether they're aggressive or shy; whether they're attracted to males, females, both or neither; whether they are good at music; whether they are politically liberal or conservative. Why are we different? What's the explanation for why we're different? And again, this could be translated in terms of a question of genes and environment. To what extent are things the result of the genes we possess? To what extent are our individual natures the result of how we were raised? And to what extent are they best explained in terms of an interaction? One common theory, for instance, is that we are shaped by our parents. This was best summarized most famously by the British poet Philip Larkin who wrote, They mess you up, your mum and dad. They may not mean to but they do. They fill you with the faults they had And add some extra just for you.

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Is he right? It's very controversial. You-- It's been a series of--a huge controversy in the popular culture to the extent of which parents matter and this is an issue which will preoccupy us for much of the course.

A different question: What makes somebody attractive? And this can be asked at all sorts of levels but a simple level is what makes for a pretty face? So, these are, according to ratings, very attractive faces. They are not the faces of real people. What's on the screen are computer generated faces of a Caucasian male and a Caucasian female who don't exist in the real world. But through using this sort of computer generation, and then asking people what they think of this face, what they think of that face, scientists have come to some sense as to what really makes a face attractive, both within cultures and across cultures. And that's something which we're going to devote some time to when we talk about social behavior, and in particular, when we talk about sex. Not all attractiveness, not all beauty of course, is linked to sex. So, pandas for instance, like this panda, are notoriously cute, and I don't have anything to say about it really. It's just a cute picture [laughter].

Morality is extremely central to our lives, and a deep question, which we will struggle with throughout most of the course, is the question of good and evil, evil and good. These three pictures exemplify different sorts of evil. What you could call institutional evil by somebody behaving cruelly toward somebody else, perhaps not due to malice but because of the situation that she's in. It has picture of Osama bin Laden, a mass murderer or driven by political cause? And then there's this guy on the bottom. Anybody know who he is? Ted Bundy. Who got that? Film that man [laughter]. No. Ted Bundy, exactly, and that's before we get into the technical stuff like crazy-evil, and we're going to have to come to terms with why some people are like that. And again, the same situation comes up. Is it part of your nature to be good or bad or is it largely due to the situation that you fall in? And there's a lot of some quite spectacular experiments that try to tease that apart.

If we're going to talk about evil, we should also talk about good. These are pictures of two notoriously good men, Oskar Schindler and Paul Rusesabagina, each who at different times in history saved the lives of many, many people at great risk to themselves. Schindler in the Holocaust, and then the other guy, in – and I can't pronounce his name – Rusesabagina, in Rwanda. And they both had real good movies made about them. But what's interesting with these cases is you couldn't have predicted ahead of time that they would be heroes. And one personal issue within any of us is what would we do in such situations?

Finally, throughout this course we will discuss mental illness. Now, towards the end of the class I want to devote a full week to discussing major disorders like depression and anxiety, because of their profound social importance. Such disorders are reasonably common in college students. Many people in this room are currently suffering from a mood disorder, an anxiety disorder or both, and I won't ask for a show of hands but I know a lot of people in this room are on some form of medication for this disorder. And we'll discuss the current research and why people get these disorders and what's the best way to make them better.

But I also have a weakness for the less common mental disorders that I think tell us something really interesting about mental life. So, when we talk about memory, for instance, we'll talk about disorders in memory, including some disorders that keep you from forming new memories as well as disorders of amnesia where you forget the past. And these are extraordinarily interesting for all sorts of reasons. Early in the course, in fact I think next week, we will discuss, no, later on in the course, in the middle of the semester, we will discuss an amazing case of Phineas Gage.

Phineas Gage was a construction worker about 100 years ago. Due to an explosion, a metal pipe went through his head like so. Miraculously, he was not killed. In fact, his friends--it went through his head, went--ended up 100 feet away, covered with brains and blood. And Phineas Gage sat down and went, "uh, oh." And then on the way to the hospital they stopped by a pub to have some cider. He was not blind, he was not deaf, he was not retarded, but something else happened to him. He lost his sense of right and wrong. He lost his control. He used to be a hard-working family man. After the accident he lost all of that. He couldn't hold a job. He couldn't stay faithful to his wife. He couldn't speak for five minutes without cursing. He got into fights. He got into brawls. He got drunk. He lost his control. He ended up on a circus sideshow traveling through the country with the big steel pipe that went through his head. And this is again an extraordinary example of how the brain can give rise to the mind, and how things that go wrong with the brain can affect you in a serious way.

We'll discuss cases of multiple personality disorder, where people have more than one personality. And also, discuss the debate over whether such cases are true or not; whether they could be taken as a real phenomena or a made-up phenomena, which is--there is a matter of a lot of controversy. And then, we'll even discuss some rarer cases like Capgras syndrome. Capgras syndrome is typically – there's hundreds of cases, not many – hundreds of cases. It's typically the result of some sort of stroke, and what happens to you is very specific. You develop a particular delusion, like it's getting dark [lights dim in the room, laughter follows]. And the delusion is that the people you love the most have been replaced. They've been replaced by aliens or robots [lights go on] – thank you – by Martians, by CIA agents, by trained actors and actresses. But the people--But the idea is, the people you care for the most you believe are gone. And this could lead to tragic consequences.

Capgras syndrome is associated with a very high level of violence. One man in Australia a couple of years ago was under the delusion that his father was replaced with a robot and cut off his head. A related disorder involving the very same parts of the brain is called Cotard's syndrome. And Cotard's syndrome is you believe that you're dead; you are persuaded that you're dead. You're walking around. You know you're walking around. And you know that there are people around, but

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you think that you're dead. And what's striking about these is--it's not--these are not just sort of big, screwy problems of messed up people. Rather, they're located--they're related at a pinpoint level to certain parts of your brain. And we're going to talk about the best modern theories as to why these syndromes occur.

Now, the reason to be interested in them, again, is not because they're frequent. They aren't. And it's not because of some sort of gruesome, morbid curiosity. Rather, by looking at extreme cases, they can help us best understand normal life. Often by looking at extremes it throws into sharp contrast things we naturally take for granted. The issue of psychopathy, of people who, either due to brain damage or because they are born that way, have no moral understanding, can help us cope with questions of free will and responsibility; of the relationship or difference between mental illness and evil. Multiple personality cases force us to address the question of what is a self. To what extent are all of us composed of multiple people, and to what extent are we a single unified person over time? Cases like Capgras are important because they tell us about how we see the world. They tell us for instance that there is a difference between recognizing something in the sense that you could name it, and knowing what it is. And so, by studying these abnormal cases we could get some insight into regular life. So, that's the end of the illustration of the example topics. The syllabus lists many more.

I'll end by telling you that there's a lot of stuff that we'll be talking about, that I want to talk about, that I am not expert in. And fortunately, there is a community at Yale of the best scholars and teachers on the planet. And so, it would be a shame for me not to use them to cover some of these issues. And so, I'm going to include four guest lecturers. The first one is Dr. Marvin Chun who teaches the Introduction to Psychology course in the fall and is my competition. And he's going to give an amazing lecture on cognitive neuroscience, especially the cognitive neuroscience of faces. Dr. Susan Nolen-Hoeksema is the world's authority on depression, and in particular, on sex differences and depression, and she's going to talk about this towards the end of the course. Kelly Brownell is going to talk--is head of the Rudd Center, focuses on obesity, eating disorders, dieting, and he'll talk about the psychology of food. And finally, Dr. Peter Salovey, Dean of Yale College, is going to come to us on Valentine's Day and tell us everything he knows about the mysteries of love. All of these details are in the syllabus and I'll stick around and answer questions. Hope to see you next week.

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Lecture 2 Professor Paul Bloom: We're going to begin the class proper, Introduction to Psychology, with a discussion about the brain. And, in particular, I want to lead off the class with an idea that the Nobel Prize winning biologist, Francis Crick, described as "The Astonishing Hypothesis." And The Astonishing Hypothesis is summarized like this. As he writes, The Astonishing Hypothesis is that: You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll's Alice might have phrased it, "you're nothing but a pack of neurons."

It is fair to describe this as astonishing. It is an odd and unnatural view and I don't actually expect people to believe it at first. It's an open question whether you'll believe it when this class comes to an end, but I'd be surprised if many of you believe it now. Most people don't. Most people, in fact, hold a different view. Most people are dualists. Now, dualism is a very different doctrine. It's a doctrine that can be found in every religion and in most philosophical systems throughout history. It was very explicit in Plato, for instance.

But the most articulate and well-known defender of dualism is the philosopher Rene Descartes, and Rene Descartes explicitly asked a question, "Are humans merely physical machines, merely physical things?" And he answered, "no." He agreed that animals are machines. In fact, he called them "beast machines" and said animals, nonhuman animals are merely robots, but people are different. There's a duality of people. Like animals, we possess physical material bodies, but unlike animals, what we are is not physical. We are immaterial souls that possess physical bodies, that have physical bodies, that reside in physical bodies, that connect to physical bodies. So, this is known as dualism because the claim is, for humans at least, there are two separate things; there's our material bodies and there's our immaterial minds.

Now, Descartes made two arguments for dualism. One argument involved observations of a human action. So, Descartes lived in a fairly sophisticated time, and his time did have robots. These were not electrical robots, of course. They were robots powered by hydraulics. So, Descartes would walk around the French Royal Gardens and the French Royal Gardens were set up like a seventeenth-century Disneyland. They had these characters that would operate according to water flow and so if you stepped on a certain panel, a swordsman would jump out with a sword. If you stepped somewhere else, a bathing beauty would cover herself up behind some bushes. And Descartes said, "Boy, these machines respond in certain ways to certain actions so machines can do certain things and, in fact," he says, "our bodies work that way too. If you tap somebody on the knee, your leg will jump out. Well, maybe that's what we are." But Descartes said that can't be because there are things that humans do that no machine could ever do. Humans are not limited to reflexive action. Rather, humans are capable of coordinated, creative, spontaneous things. We can use language, for instance, and sometimes my use of language can be reflexive. Somebody says, "How are you?" And I say, "I am fine. How are you?" But sometimes I could say what I choose to be, "How are you?" "Pretty damn good." I can just choose. And machines, Descartes argued, are incapable of that sort of choice. Hence, we are not mere machines.

The second argument is, of course, quite famous and this was the method. This he came to using the method of doubt. So, he started asking himself the question, "What can I be sure of?" And he said, "Well, I believe there's a God, but honestly, I can't be sure there's a God. I believe I live in a rich country but maybe I've been fooled." He even said, "I believe I have had friends and family but maybe I am being tricked. Maybe an evil demon, for instance, has tricked me, has deluded me into thinking I have experiences that aren't real." And, of course, the modern version of this is The Matrix.

The idea of The Matrix is explicitly built upon Cartesian--Descartes' worries about an evil demon. Maybe everything you're now experiencing is not real, but rather is the product of some other, perhaps malevolent, creature. Descartes, similarly, could doubt he has a body. In fact, he noticed that madmen sometimes believe they have extra limbs or they believe they're of different sizes and shapes than they really are and Descartes said, "How do I know I'm not crazy? Crazy people don't think they're crazy so the fact that I don't think I'm crazy doesn't mean I'm not crazy. How do I know," Descartes said, "I'm not dreaming right now?" But there is one thing, Descartes concluded, that he cannot doubt, and the answer is he cannot doubt that he is himself thinking. That would be self-refuting. And so, Descartes used the method of doubt to say there's something really different about having a body that's always uncertain from having a mind. And he used this argument as a way to support dualism, as a way to support the idea that bodies and minds are separate. And so he concluded, "I knew that I was a substance, the whole essence or nature of which is to think, and that for its existence, there is no need of any place nor does it depend on any material thing. That is to say, the soul by which I am, when I am, is entirely distinct from body."

Now, I said before that this is common sense and I want to illustrate the common sense nature of this in a few ways. One thing is our dualism is enmeshed in our language. So, we have a certain mode of talking about things that we own or things that are close to us – my arm, my heart, my child, my car – but we also extend that to my body and my brain. We talk about owning our brains as if we're somehow separate from them. Our dualism shows up in intuitions about personal identity. And what this means is that common sense tells us that somebody can be the same person even if their body undergoes radical and profound changes. The best examples of this are fictional. So, we have no problem understanding a

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movie where somebody goes to sleep as a teenager and wakes up as Jennifer Garner, as an older person. Now, nobody says, "Oh, that's a documentary. I believe that thoroughly true" but at the same time nobody, no adult, no teenager, no child ever leaves and says, "I'm totally conceptually confused." Rather, we follow the story. We can also follow stories which involve more profound transformations as when a man dies and is reborn into the body of a child.

Now, you might have different views around--People around this room will have different views as to whether reincarnation really exists, but we can imagine it. We could imagine a person dying and then reemerging in another body. This is not Hollywood invention. One of the great short stories of the last century begins with a sentence by Franz Kafka: "As Gregor Samsa woke one morning from uneasy dreams, he found himself transformed in his bed into a gigantic insect." And again, Kafka invites us to imagine waking up into a body of a cockroach and we can. This is also not modern. Hundreds of years before the birth of Christ, Homer described the fate of the companions of Odysseus who were transformed by a witch into pigs. Actually, that's not quite right. She didn't turn them into pigs. She did something worse. She stuck them in the bodies of pigs. They had the head and voice and bristles and body of swine but their minds remained unchanged as before, so they were penned there weeping. And we are invited to imagine the fate of again finding ourselves in the bodies of other creatures and, if you can imagine this, this is because you are imagining what you are as separate from the body that you reside in.

We allow for the notion that many people can occupy one body. This is a mainstay of some slapstick humor including the classic movie, All of Me--Steve Martin and Lily Tomlin – highly recommended. But many people think this sort of thing really happens. One analysis of multiple personality disorder is that you have many people inside a single body fighting it out for control. Now, we will discuss multiple personality disorder towards the end of the semester and it turns out things are a good deal more complicated than this, but still my point isn't about how it really is but how we think about it. Common sense tells us you could have more than one person inside a single body. This shows up in a different context involving exorcisms where many belief systems allow for the idea that people's behavior, particularly their evil or irrational behavior, could be because something else has taken over their bodies.

Finally, most people around the world, all religions and most people in most countries at most times, believe that people can survive the destruction of their bodies. Now, cultures differ according to the fate of the body. Some cultures have the body going to--sorry--the fate of the soul. Some cultures have you going to Heaven or descending to Hell. Others have you occupying another body. Still, others have you occupying an amorphous spirit world. But what they share is the idea that what you are is separable from this physical thing you carry around. And the physical thing that you carry around can be destroyed while you live on.

These views are particularly common in the United States. In one survey done in Chicago a few years ago, people were asked their religion and then were asked what would happen to them when they died. Most people in the sample were Christian and about 96% of Christians said, "When I die I'm going to go to Heaven." Some of the sample was Jewish. Now, Judaism is actually a religion with a less than clear story about the afterlife. Still, most of the subjects who identified themselves as Jewish said when they die they will go to Heaven. Some of the sampled denied having any religion at all--said they have no religion at all. Still, when these people were asked what would happen when they would die, most of them answered, "I'm going to go to Heaven."

So, dualism is emmeshed. A lot rests on it but, as Crick points out; the scientific consensus now is that dualism is wrong. There is no "you" separable or separate from your body. In particular, there is no "you" separable from your brain. To put it the way cognitive scientists and psychologists and neuroscientists like to put it, "the mind is what the brain does." The mind reflects the workings of the brain just like computation reflects the working of a computer. Now, why would you hold such an outrageous view? Why would you reject dualism in favor of this alternative? Well, a few reasons. One reason is dualism has always had its problems. For one thing, it's a profoundly unscientific doctrine. We want to know as curious people how children learn language, what we find attractive or unattractive, and what's the basis for mental illness. And dualism simply says, "it's all nonphysical, it's part of the ether," and hence fails to explain it.

More specifically, dualists like Descartes struggle to explain how a physical body connects to an immaterial soul. What's the conduit? How could this connection be made? After all, Descartes knew full well that there is such a connection. Your body obeys your commands. If you bang your toe or stub your toe you feel pain. If you drink alcohol it affects your reasoning, but he could only wave his hands as to how this physical thing in the world could connect to an immaterial mind.

Descartes, when he was alive, was reasonable enough concluding that physical objects cannot do certain things. He was reasonable enough in concluding, for instance, as he did, that there's no way a merely physical object could ever play a game of chess because--and that such a capacity is beyond the capacity of the physical world and hence you have to apply--you have to extend the explanation to an immaterial soul but now we know--we have what scientists call an existence proof. We know physical objects can do complicated and interesting things. We know, for instance, machines can play chess. We know machines can manipulate symbols. We know machines have limited capacities to engage in mathematical and logical reasoning, to recognize things, to do various forms of computations, and this makes it at least possible that we are such machines. So you can no longer say, "Look. Physical things just can't do that" because we know physical things can do a lot and this opens up the possibility that humans are physical things, in particular, that humans are brains.

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Finally, there is strong evidence that the brain is involved in mental life. Somebody who hold a--held a dualist view that said that what we do and what we decide and what we think and what we want are all have nothing to do with the physical world, would be embarrassed by the fact that the brain seems to correspond in intricate and elaborate ways to our mental life. Now, this has been known for a long time. Philosophers and psychologists knew for a long time that getting smacked in the head could change your mental faculties; that diseases like syphilis could make you deranged; that chemicals like caffeine and alcohol can affect how you think. But what's new is we can now in different ways see the direct effects of mental life.

Somebody with a severe and profound loss of mental faculties--the deficit will be shown correspondingly in her brain. Studies using imaging techniques like CAT scans, PET, and fMRI, illustrate that different parts of the brain are active during different parts of mental life. For instance, the difference between seeing words, hearing words, reading words and generating words can correspond to different aspects of what part of your brain is active. To some extent, if we put you in an fMRI scanner and observed what you're doing in real time, by looking at the activity patterns in your brain we can tell whether you are thinking about music or thinking about sex. To some extent we can tell whether you're solving a moral dilemma versus something else. And this is no surprise if what we are is the workings of our physical brains, but it is extremely difficult to explain if one is a dualist.

Now, so what you have is--the scientific consensus is that all of mental life including consciousness and emotions and choice and morality are the products of brain activities. So, you would expect that when you rip open the skull and look at the brain; you'd see something glorious, you'd see – I don't know – a big, shiny thing with glass tubes and blinding lights and sparks and wonderful colors. And actually though, the brain is just disgusting. It looks like an old meat loaf. It's gray when you take it out of the head. It's called gray matter but that's just because it's out of the head. Inside the head it's bright red because it's pulsing with blood. It doesn't even taste good. Well, has anybody here ever eaten brain? It's good with cream sauce but everything's good with cream sauce.

So, the question is, "How can something like this give rise to us?" And you have to have some sympathy for Descartes. There's another argument Descartes could have made that's a lot less subtle than the ones he did make, which is "That thing responsible for free will and love and consciousness? Ridiculous." What I want to do, and what the goal of neuroscience is, is to make it less ridiculous, to try to explain how the brain works, how the brain can give rise to thought, and what I want to do today is take a first stab at this question but it's something we'll continue to discuss throughout the course as we talk about different aspects of mental life. What I want to do though now is provide a big picture. So, what I want to do is start off small, with the smallest interesting part of the brain and then get bigger and bigger and bigger – talk about how the small part of the brain, the neurons, the basic building blocks of thought, combine to other mental structures and into different subparts of the brain and finally to the whole thing.

So, one of the discoveries of psychology is that the basic unit of the brain appears to be the neuron. The neuron is a specific sort of cell and the neuron has three major parts, as you could see illustrated here [pointing to the slide]. Neurons actually look quite different from one another but this is a typical one. There are the dendrites – these little tentacles here. And the dendrites get signals from other neurons. Now, these signals can be either excitatory, which is that they raise the likelihood the neuron will fire, or inhibitory in that they lower the likelihood that the neuron will fire. The cell body sums it up and you could view it arithmetically. The excitatory signals are pluses, the inhibitory ones are minuses. And then if you get a certain number, plus 60 or something, the neuron will fire and it fires along the axon, the thing to the right. The axon is much longer than the dendrites and, in fact, some axons are many feet long. There's an axon leading from your spinal cord to your big toe for instance. [the classroom lights accidentally go off] It is so shocking the lights go out.

Surrounded--Surrounding--To complete a mechanical metaphor that would have led Descartes to despair--[the classroom lights turn on] Thank you, Koleen. Surrounding the axon is a myelin sheath, which is actually just insulation. It helps the firing work quicker. So, here are some facts about neurons. There are a lot of them – about one thousand billion of them – and each neuron can be connected to around thousands, perhaps tens of thousands, other neurons. So, it's an extraordinarily complicated computing device. Neurons come in three flavors. There are sensory neurons, which take information from the world so as you see me, for instance, there are neurons firing from your retina sending signals to your brain. There are motor neurons. If you decide to raise your hand, those are motor neurons telling the muscles what to do. And there are interneurons which connect the two. And basically, the interneurons do the thinking. They make the connection between sensation and action.

It used to be believed, and it's the sort of thing I would--when I taught this course many years ago I would lecture on--that neurons do not grow back once you lose them. You never get them back. This is actually not true. There are parts of the brain in which neurons can re-grow.

One interesting thing about neurons is a neuron is like a gun. It either fires or it doesn't. It's all or nothing. If you squeeze the trigger of a gun really hard and really fast, it doesn't fire any faster or harder than if you just squeezed it gently. Now, this seems to be strange. Why? How could neurons be all or nothing when sensation is very graded? If somebody next to you pushed on your hand--the degree of pushing--you'd be able to notice it. It's not either pushing or not pushing. You can--Degrees of pushing, degrees of heat, degrees of brightness. And the answer is, although neurons are all or nothing, there are ways to code intensity. So, one simple way to code intensity is the number of neurons firing; the more neurons the

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more intense. Another way to increase intensity is the frequency of firing. So, I'll just use those two. The first one is the number of neurons firing. The second one is the frequency of firing in that something is more intense if it's "bang, bang, bang, bang, bang, bang" then [louder] "bang, bang, bang" and these are two ways through which neurons encode intensity.

Now, neurons are connected and they talk to one another and it used to be thought they were tied to one another like a computer, like you take wires and you connect wires to each other, you wrap them around and connect them. It turns out this isn't the case. It turns out that neurons relate to one another chemically in a kind of interesting way. Between any neurons, between the axon of one neuron and the dendrite of another, there's a tiny gap. The gap could be about one ten-thousandths of a millimeter wide. This infinitesimal gap--and this gap is known as a synapse--and what happens is when a neuron fires, an axon sends chemicals shooting through the gap. These chemicals are known as neurotransmitters and they affect the dendrites. So, neurons communicate to one another chemically. These--Again, the chemicals could excite the other neuron (excitatory) bring up the chances it will fire, or inhibit the other neuron (inhibitory).

Now, neurotransmitters become interesting because a lot of psychopharmacology, both of the medical sort and the recreational sort, consists of fiddling with neurotransmitters and so you could see this through some examples. There are two sorts of ways you could fiddle with neurotransmitters, and correspondingly two sorts of drugs. There are agonists. And what an agonist does is increases the effect of neurotransmitters, either by making more neurotransmitters or stopping the cleanup of neurotransmitters, or in some cases by faking a neurotransmitter, by mimicking its effects. Then, there are antagonists that slow down the amount of neurotransmitters, either because they destroy neurotransmitters or they make it hard to create more. Or in some cases they go to the dendrite of the neuron and they kind of put a paste over it so that the neurotransmitters can't connect. And it's through these clever ways that neurons can affect your mental life.

So, for instance, there is a drug known as Curare and Curare is an antagonist. It's a very particular sort of antagonist. It blocks motor neurons from affecting muscle fibers. What this does then is it paralyzes you because your motor neurons--You send the command to your arm to stand, to lift up. It doesn't work. You send the command to your leg to move. It doesn't work. The motor neurons are deactivated and then, because the way you breathe is through motor neurons, you then die.

There's alcohol. Alcohol is inhibitory. Now, this may be puzzling to people. It's mildly paradoxical because you may be thinking, "alcohol is not inhibitory. On the contrary, when I drink a lot of alcohol I lose my inhibitions and become a more fun person. I become more aggressive and more sexually vibrant and simply more beautiful. And so in what way is alcohol inhibitory?" Well, the answer is it inhibits the inhibitory parts of your brain. So, you have parts of your brain that are basically telling you now, largely in the frontal lobes, that are--"Okay. Keep your pants on. Don't hit me, buddy. Don't use bad words." Alcohol relaxes, shuts down those parts of the brain. If you take enough alcohol, it then goes down to inhibit the excitatory parts of your brain and then you fall on the floor and pass out.

Amphetamines increase the amount of arousal. In particular, they increase the amount of norepinephrine, a neurotransmitter that's responsible for just general arousal. And so, amphetamines include drugs like "speed" and "coke." There are--Prozac works on serotonin. When we discuss clinical psychology and depression we'll learn the extent to which neurotransmitter disorders are implicated in certain disorders like depression. And one problem is that – for depression – is that there's too little of a neurotransmitter known as serotonin. Prozac makes serotonin more prevalent and so in some extent might help alleviate depression. Parkinson's disease is a disease involving destruction of motor control and loss of motor control, difficulty moving. And one factor in Parkinson's is too little of a neurotransmitter known as dopamine. The drug L-DOPA increases the supply of dopamine and so there is something to alleviate, at least temporarily, the symptoms of Parkinson's.

So, you have neurons and they're clustered together and they fire and they communicate to one another. So, how does this all work to give rise to creatures who could do interesting things like talk and think? Well, again, it used to be believed that the brain is wired up like a computer, like a PC or a Mac or something like that, but we know this can't be true. It can't be true because there's two ways in which the brain is better than a computer. For one thing, the brain is highly resistant to damage. If you have a laptop and I persuade you to open it up for me and I take the pliers and kind of snip just about anywhere, your laptop will be destroyed but the brain is actually more resilient. You can take a lot of brain damage and still preserve some mental functioning. To some interesting sense, there's some sort of damage resistance built in to the brain that allows different parts of the brain to take over if some parts are damaged.

A second consideration is the brain is extremely fast. Your computer works on wires and electricity but your brain uses tissue and tissue is extremely slow. The paradox then is how do you create such a fast computer with such slow stuff? And you can't. If the brain was wired up like a personal computer, it would take you four hours to recognize a face but, in fact, we could do things extremely quickly. So, the question then is how is the brain wired up? And the answer is, unlike manys, unlike commercially generated computers, the brain works through parallel processing, massively parallel distributed processing.

There's a whole lot of research and this is research, some of which takes place outside psychology departments and in engineering departments and computer science departments, trying to figure out how a computer can do the same things brains can do. And one way people do this is they take a hint from nature and they try to construct massively distributed networks to do aspects of reasoning. So, there's a very simple computational network. That is interesting because

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it kind of looks to some extent like the way neurons look and this is often known as neural networks. And people who study this often claim to be studying neural network modeling to try to build smart machines by modeling them after brains. And in the last 20 years or so, this has been a huge and vibrant area of study where people are trying to wire up machines that can do brain-like things from components that look a lot like neurons and are wired up together as neurons are. One consideration in all of this is that this is a very young field and nobody knows how to do it yet. There is no machine yet that can recognize faces or understand sentences at the level of a two-year-old human. There is no machine yet that can do just about anything people can do in an interesting way. And this is, in part, because the human brain is wired up in an extraordinarily more complicated way than any sort of simple neural network. This is a sort of schematic diagram – you're not responsible for this – of parts of the visual cortex, and the thing to realize about this is it's extraordinarily simplified. So, the brain is a complicated system.

Now, so, we've talked a little bit about the basic building blocks of the brain – neurons. We've then talked about how neurons can communicate to one another; then, [we] turned to how neurons are wired up together. Now let's talk a little bit about different parts of the brain. Now, there's some things you don't actually need your brain to do. The study of what you don't need your brain to do has often drawn upon this weird methodology where--This was actually done in France a lot where they would decapitate people and when--After they decapitated people, psychologists would rush to the body of the headless person and sort of just test out reflexes and stuff like that. It's kind of gruesome but we know there are some things you don't need your brain for.

You don't need your brain for newborn sucking, limb flexation in withdrawal from pain. Your limbs will pull back even if your head is gone. Erection of the penis can be done without a brain. Vomiting also is done without a brain. Oh. I need a volunteer. Very simple. This will not involve any of--excellent--any of the above. Could you stand up just--Okay. This is a new shirt so I want to stay away. Just--No. This is--If you'll hold out your hand and--one hand flat. [The student holds his hand out flat] Excellent. [Professor Paul Bloom raises a book above the student's hand] That's the textbook, 5th edition. Now. [Professor Paul Bloom drops the book onto the student's hand. After succumbing to the weight of the book the student's hand automatically raises back up] Perfect. What you'll notice is--Thank you very much. What you'll notice is this hit and this hand went back up. This is something automatic, instinctive, and does not require your brain. So your brain isn't needed for everything.

What does your brain do? Well, some things that your brain does involve very low-level internal structures. And these are called subcortical structures because they're below the cortex. They're underneath the cortex. So, for instance, what we have here [gesturing toward the slides] is a diagram of the brain. The way to read this diagram is it's as if it were my brain and I am facing this way. My head gets cut in half down here and then you could see the brain. So, this is the front over here. That's the back. Some key parts are illustrated here. The medulla, for instance, is responsible for heart rate and respiration. It's very deep within the brain and if it gets damaged you could--you are likely to die. The cerebellum is responsible for body balance and muscular coordination. And to give you, again, a feeling for the complexity of these systems, the cerebellum contains approximately 30 billion neurons. The hypothalamus is responsible here for feeding, hunger, thirst, and to some extent sleep. And here is the same brain parts in close-up.

Now, all of these parts of the brains are essential and many of them are implicated in interesting psychological processes but where the action is is the cortex. Isn't this beautiful? The cortex is the outer layer and the outer layer is all crumpled up. Do you ever wonder why your brain looks wrinkled? That's because it's all crumpled. If you took out somebody's cortex and flattened it out, it would be two feet square, sort of like a nice--like a rug. And the cortex is where all the neat stuff takes place. Fish don't have any of that, so no offense to fish but it's--fish don't have much of a mental life. Reptiles and birds have a little bit about it--of it--and primates have a lot and humans have a real lot. Eighty percent of the volume of our brain, about, is cortex. And the cortex can be broken up into different parts or lobes. There is the--And, again, this is facing in profile forward. There is the frontal lobe, easy to remember. This part in front, the parietal lobe, the occipital lobe, and the temporal lobe.

And one theme we're going to return to is--this is half the brain. This is, in fact, the left half of the brain. On the other half, the right half, everything's duplicated with some slight and subtle differences. What's really weird--One really weird finding about these lobes is that they include topological maps. They include maps of your body. There is a cartoon which actually illustrates a classic experiment by some physiologists who for some reason had a dog's brain opened up and started shocking different parts of the brain. You could do brain surgery while fully conscious because the brain itself has no sense organs to it. And it turns out that the dog--When they zapped part of its brain, its leg would kick up.

And it took Dr. Penfield at McGill University to do the same thing with people. So, they were doing some brain surgery. He had a little electrical thing just on--I don't know how he thought to do this. He started zapping it and "boom." The person--Parts of their body would move. More than that, when he zapped other parts of the brain, people would claim to see colors. And he zapped other parts of the brain; people would claim to hear sounds; and other parts of the brain, people would claim to experience touch. And through his research and other research, it was found that there are maps in the brain of the body. There is a map in the motor part of the brain, the motor cortex, of the sort up on the left and the sensory cortex of the sort that you could see on the right and if you--and you could tell what's what by opening up the brain and shocking different parts and those parts would correspond to the parts of the body shown in the diagram there.

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Now, two things to notice about these maps. The first is they're topographical and what this means is that if two parts of the--two parts are close together on the body, they'll be close together on the brain. So, your tongue is closer to your jaw than it is to your hip in the body; so too in both the motor cortex and the somatosensory cortex. Also, you'll notice that the size of the body part represented in the brain does not correspond to the size of the body part in the real world. Rather, what determines the size in the brain is the extent to which either they have motor command over it or sensory control. So, there's a whole lot of sensory organs, for instance, focused along your tongue, and that's why that's so big, and an enormous amount on your face but your shoulder isn't even--doesn't even make it on there because, although your shoulder might be bigger than your tongue, there's not much going on. In fact, if you draw a diagram of a person, what their body is corresponding to the amount of somatosensory cortex, you get something like that [gesturing toward the slide]. That's your sensory body.

Now, so, you have these maps in your head but the thing to realize is--And these maps are part of your cortex, but the things to realize is that's an important part of what goes on in your brain but less than one quarter of the cortex contains these maps or projection areas. The rest is involved in language and reasoning and moral thought and so on. And, in fact, the proportion as you go from rat, cat, and monkey, humans--less and less of it is devoted to projection and there is more and more to other things. So, how do we figure out what the other parts of the brain do? Well, there's all sorts of methods. Typically, these are recent imaging methods like CAT scan and PET scan and fMRI which, as I said before, show parts of your brain at work. If you want to know which part of your brain is responsible for language, you could put somebody into a scanner and have them exposed to language or do a linguistic task or talk or something and then see what parts of their brain are active.

Another way to explore what the brain does is to consider what happens to people when very bad things happen to their brain. And these bad things could happen through lesions, through tumors, through strokes, through injury. For the most part, neuropsychologists don't like helmet laws. Neuropsychologists love when motorcyclists drive without helmets because through their horrible accidents we gain great insights into how the brain works. And the logic is if you find somebody--Crudely, if you find somebody with damage to this part of the brain right here and that person can't recognize faces for instance, there's some reason to believe that this part of the brain is related to face recognition.

And so, from the study of brain damage and the study of--we can gain some understanding of what different parts of the brain do. And so, people study brain damages--brain damage that implicates motor control such as apraxia. And what's interesting about apraxia is it's not paralysis. Somebody with apraxia can move, do simple movements just fine but they can't coordinate their movements. They can't do something like wave goodbye or light a cigarette.

There is agnosia and agnosia is a disorder which isn't blindness because the person could still see perfectly well. Their eyes are intact but rather what happens in agnosia is they lose the ability to recognize certain things. Sometimes this is described as psychic blindness. And so, they may get visual agnosia and lose the ability to recognize objects. They may get prosopagnosia and lose the ability to recognize faces. There are disorders of sensory neglect, some famous disorders. Again, it's not paralysis, it's not blindness, but due to certain parts of your--of damaged parts of your brain, you might lose, for instance, the idea that there's a left side of your body or a left side of the world. And these cases are so interesting I want to devote some chunk to a class in the next few weeks to discussing them.

There are disorders of language like aphasia. The classic case was discovered by Paul Broca in 1861. A patient who had damage to part of his brain and can only say one word, "tan," and the person would say, "tan, tan, tan, tan," and everything else was gone. There's other disorders of language such as receptive aphasia where the person could speak very fluently but the words don't make any sense and they can't understand anybody else. Other disorders that we'll discuss later on include acquired psychopathy, where damage to parts of your brain, particularly related to the frontal lobes, rob you of the ability to tell right from wrong.

The final--I want to end--We're talking about neurons, connection between neurons, how neurons are wired up, the parts of the brain, what the different parts do. I want to end by talking about the two halves of the brain and ask the question, "How many minds do you have?" Now, if you look at the brain--If you took the brain out and held it up, it would look pretty symmetrical, but it actually is not. There are actual differences between the right hemisphere and the left hemisphere. How many people here are right-handed? How many people here are left-handed? How many people here are sort of complicated, ambidextrous, don't know, "bit of the right, bit of left" people? Okay. Those of you who are right-handed, which comprises about nine out of ten people, have language in your left hemisphere. And, in fact, we're going to be talking about right-handed people for the most part, making generalizations in what I'll talk about now. Those of you who are left-handed are more complicated. Some of you have language in your right hemisphere, some in your left hemisphere, some God knows where. It's complicated.

Now, the idea is that some things are duplicated. So, if you were to lose half your brain, the other half can actually do a lot but some things are more prevalent and more powerful in one part of the brain than the other. And I want to show you a brief film clip from "Scientific American" that illustrates the differences between the hemispheres, but before doing that, I want to provide some introductory facts. Some functions are lateralized. So, typically, language in the left. Again, this is a right-handed centric thing but if you're right-handed – language on the left, math and music on the right. There is a crossover and this is important when we think about the studies that will follow but the crossover is that everything you see in the left

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visual field goes to the right side of your brain; everything in the right visual field goes to the left side of the brain, and similarly, there's a crossover in action. So, your right hemisphere controls the left side of the body. Your left hemisphere controls the right side of the body. Now, finally, the two halves are connected. They're connected by this huge web called the corpus callosum. And I'm just going to skip this because the movie illustration will go through some of this.

This is an excellent summary of a discussion of Michael Gazzaniga, who's one of the world's top neuroscientists and the leading expert on the two halves of the brain. The only flaw in this movie is people are just extremely pleased with themselves, so you have to ignore that while watching it. Is that working? Do you people hear it? [Professor Bloom plays a short video clip]

Now, I'll end on that happy note. This illustrates certain themes that are discussed in detail in the Gray book, concerning the lateralization of different parts of different mental capacities, some in the left hemisphere, some in the right hemisphere. But it also serves as a useful methodological development, which is a nice illustration as to how looking at people who are incredibly unusual, such as this man who had his brain bisected so his left hemisphere and his right hemisphere don't communicate with one another--how looking at such people, such extreme cases, can provide us with some understanding of how we normally do things. And this, again, is a theme we'll return to throughout the course.

This is generally the general introduction of the brain that I wanted to provide, giving the framework for what I'll be talking about later on throughout the course so that I might later on make reference to neurons or neurotransmitters or the cortex or the left hemisphere and you'll sort of have the background to understand what I'm talking about. But I want to end this first real class with a bit of humility as to what psychologists know and don't know. So, the idea behind a lot of psychology – particularly a lot of neuroscience and cognitive psychology – is to treat the mind as an information processor, as an elaborate computer. And so, we study different problems like recognizing faces or language or motor control or logic. The strategy then often is to figure out how, what sort of program can solve these problems and then we go on to ask, "How could this program be instantiated in the physical brain?" So, we would solve--We study people much as we'd study a computer from an alien planet or something. And I think--This strategy is one I'm very enthusiastic about but there still remains what's sometimes called the "hard problem" of consciousness and this involves subjective experience. What's it like? So, my computer can play chess. My computer can recognize numbers. It can do math. And maybe it does it kind of the same way that I do it but my computer doesn't have feelings in the same sense.

These are two classic illustrations. This [pointing at a picture on the slide] is from a very old "Star Trek" episode. It illustrates angst. I think a starship's about to go into the sun or something. And that's [pointing at a another picture on the slide] my older kid, Max, who's happy. And so the question is, "How does a thing like that give rise to consciousness and subjective experience?" And this is a deep puzzle. And although some psychologists and philosophers think they've solved it, most of us are a lot more skeptical. Most of us think we have so far to go before we can answer questions like Huxley's question. Huxley points out, "How it is that anything so remarkable as a state of consciousness comes about as a result of irritating nervous tissue, is just as unaccountable as the appearance of the Djinn…" – of the genie – "…when Aladdin rubs his lamp." It seems like magic that a fleshy lump of gray, disgusting meat can give rise to these feelings.

The second bit of humility we'll end the class on is I am presenting here, and I'll be presenting throughout this semester, what you can call a mechanistic conception of mental life. I'm not going to be talking about how beautiful it is and how wonderful it is and how mysterious it is. Rather, I'm going to be trying to explain it. I'm going to be trying to explain fundamental aspects of ourselves including questions like how do we make decisions, why do we love our children, what happens when we fall in love, and so on.

Now, you might find this sort of project in the end to be repellant. You might worry about how this, well, this meshes with humanist values. For instance, when we deal with one another in a legal and a moral setting, we think in terms of free will and responsibility. If we're driving and you cut me off, you chose to do that. It reflects badly on you. If you save a life at risk to your own, you're--you deserve praise. You did something wonderful. It might be hard to mesh this with the conception in which all actions are the result of neurochemical physical processes. It might also be hard to mesh a notion such as the purported intrinsic value of people. And finally, it might be hard to mesh the mechanistic notion of the mind with the idea that people have spiritual value.

Faced with this tension, there are three possibilities. You might choose to reject the scientific conception of the mind. Many people do. You may choose to embrace dualism, reject the idea that the brain is responsible for mental life, and reject the promise of a scientific psychology. Alternatively, you might choose to embrace the scientific worldview and reject all these humanist values. And there are some philosophers and psychologists who do just that, who claim that free will and responsibility and spiritual value and intrinsic value are all illusions; they're pre-scientific notions that get washed away in modern science or you could try to reconcile them. You could try to figure out how to mesh your scientific view of the mind with these humanist values you might want to preserve. And this is an issue which we're going to return to throughout the course. Okay. I'll see you on Wednesday.

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Lecture 3 Professor Paul Bloom: Okay. The last class we talked about the brain. Now we're going to talk a little bit about some foundations. So today and Monday we're going to talk about two very big ideas and these ideas are associated with Sigmund Freud and B. F. Skinner and are psychoanalysis and behaviorism. And I want to talk about psychoanalysis today and behaviorism next week.

Now, one of these things--One of the things that makes these theories so interesting is their scope. Most of the work we're going to talk about in this class--Most of the ideas are narrow. So, we're going to talk about somebody's idea about racial prejudice but that's not a theory of language acquisition. We'll talk about theories of schizophrenia but they're not explanations of sexual attractiveness. Most theories are specialized theories but these two views are grand theories. They're theories of everything, encompassing just about everything that matters, day-to-day life, child development, mental illness, religion, war, love. Freud and Skinner had explanations of all of these.

Now, this is not a history course. I have zero interest in describing historical figures in psychology just for the sake of telling you about the history of the field. What I want to tell you about though is--I want to talk about these ideas because so much rests on them and, even more importantly, a lot of these ideas have critical influence on how we think about the present. And that's there. [pointing at the slide]

Now, for better or worse, we live in a world profoundly affected by Sigmund Freud. If I had to ask you to choose a--no, name a famous psychologist, the answer of most of you would be Freud. He's the most famous psychologist ever and he's had a profound influence on the twentieth and twenty-first century. Some biographical information: He was born in the 1850s. He spent most of his life in Vienna, Austria, but he died in London and he escaped to London soon after retreating there at the beginning of World War II as the Nazis began to occupy where he lived.

He's one of the most famous scholars ever but he's not known for any single discovery. Instead, he's known for the development of an encompassing theory of mind, one that he developed over the span of many decades. He was in his time extremely well known, a celebrity recognized on the street, and throughout his life. He was a man of extraordinary energy and productivity, in part because he was a very serious cocaine addict, but also just in general. He was just a high-energy sort of person. He was up for the Nobel Prize in medicine and in literature; didn't get either one of them; didn't get the prize in medicine because Albert Einstein--Everybody loves Albert Einstein. Well, Albert Einstein really wrote a letter because they asked for opinions of other Nobel Prizes. He wrote a letter saying, "Don't give the prize to Freud. He doesn't deserve a Nobel Prize. He's just a psychologist." Well, yeah. Okay.

While he's almost universally acclaimed as a profoundly important intellectual figure, he's also the object of considerable dislike. This is in part because of his character. He was not a very nice man in many ways. He was deeply ambitious to the cause of promoting psychoanalysis, to the cause of presenting his view and defending it, and he was often dishonest, extremely brutal to his friends, and terrible to his enemies. He was an interesting character.

My favorite Freud story was as he was leaving Europe during the rise of the Nazis, as he was ready to go to England from, I think, either Germany or Austria, he had to sign a letter from the Gestapo. Gestapo agents intercepted him and demanded he sign a letter saying that at no point had he been threatened or harassed by the Gestapo. So he signs the letter and then he writes underneath it, "The Gestapo has not harmed me in any way. In fact, I highly recommend the Gestapo to everybody." It's--He had a certain aggression to him. He was also--He's also disliked, often hated, because of his views. He was seen as a sexual renegade out to destroy the conception of people as good and rational and pure beings. And when the Nazis rose to power in the 1930s he was identified as a Jew who was devoted to destroying the most sacred notions of Christianity and to many, to some extent, many people see him this way. And to some extent, this accusation has some truth to it.

Freud made claims about people that many of us, maybe most of us, would rather not know. Well, okay. What did he say? Well, if you ask somebody who doesn't like Freud what he said, they'll describe some of the stupider things he said and, in fact, Freud said a lot of things, some of which were not very rational. For instance, he's well known for his account of phallic symbols, arguing certain architectural monuments are subconsciously developed as penile representations. And related to this, he developed the notorious theory of penis envy. And penis envy is an account of a developmental state that every one of you who is female has gone through, according to Freud. And the idea is that you discovered at some point in your development that you lacked a penis. This is not--This is a catastrophe. And so, each of you inferred at that point that you had been castrated. You had once had a penis but somebody had taken it from you. You then turn to your father and love your father because your father has a penis, so he's a sort of penis substitute. You reject your mother, who's equally unworthy due to her penis lack, and that shapes your psychosexual development.

Now, if that's the sort of thing you know about Freud, you are not going to have a very high opinion of him or of his work, but at the core of Freud's declamation, the more interesting ideas, is a set of claims of a man's intellectual importance. And the two main ones are this. The two main ones involve the existence of an unconscious, unconscious motivation, and the notion of unconscious dynamics or unconscious conflict which lead to mental illnesses, dreams, slips of the tongue and so on.

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The first idea – the idea of unconscious motivation – involves rejecting the claim that you know what you're doing. So, suppose you fall in love with somebody and you decide you want to marry them and then somebody was asked to ask you why and you'd say something like, "Well, I'm ready to get married this stage of my life; I really love the person; the person is smart and attractive; I want to have kids" whatever. And maybe this is true. But a Freudian might say that even if this is your honest answer – you're not lying to anybody else –still, there are desires and motivations that govern your behavior that you may not be aware of. So, in fact, you might want to marry John because he reminds you of your father or because you want to get back at somebody for betraying you.

If somebody was to tell you this, you'd say, "That's total nonsense," but that wouldn't deter a Freudian. The Freudian would say that these processes are unconscious so of course you just don't know what's happening. So, the radical idea here is you might not know what--why you do what you do and this is something we accept for things like visual perception. We accept that you look around the world and you get sensations and you figure out there is a car, there is a tree, there is a person. And you're just unconscious of how this happens but it's unpleasant and kind of frightening that this could happen, that this could apply to things like why you're now studying at Yale, why you feel the way you do towards your friends, towards your family.

Now, the marriage case is extreme but Freud gives a lot of simpler examples where this sort of unconscious motivation might play a role. So, have you ever liked somebody or disliked them and not known why? Have you ever found yourself in a situation where you're doing something or you're arguing for something or making a decision for reasons that you can't fully articulate? Have you ever forgotten somebody's name at exactly the wrong time? Have you ever called out the wrong name in the throes of passion? This is all the Freudian unconscious. The idea is that we do these things--these things are explained in terms of cognitive systems that we're not aware of.

Now, all of this would be fine if your unconscious was a reasonable, rational computer, if your unconscious was really smart and looking out for your best interest. But, according to Freud, that's not the way it works. According to Freud, there are three distinct processes going on in your head and these are in violent internal conflict. And the way you act and the way you think are products, not of a singular rational being, but of a set of conflicting creatures. And these three parts are the id, the ego, and the superego and they emerge developmentally.

The id, according to Freud, is present at birth. It's the animal part of the self. It wants to eat, drink, pee, poop, get warm, and have sexual satisfaction. It is outrageously stupid. It works on what Freud called, "The Pleasure Principle." It wants pleasure and it wants it now. And that's, according to Freud, how a human begins – pure id. Freud had this wonderful phrase, "polymorphous perversity," this pure desire for pleasure.

Now, unfortunately, life doesn't work like that. What you want isn't always what you get and this leads to a set of reactions to cope with the fact that pleasure isn't always there when you want it either by planning how to satisfy your desires or planning how to suppress them. And this system is known as the ego, or the self. And it works on the "Reality Principle." And it works on the principle of trying to figure out how to make your way through the world, how to satisfy your pleasures or, in some cases, how to give up on them. And the ego – the emergence of the ego for Freud--symbolizes the origin of consciousness.

Finally, if this was all there it might be a simpler world, but Freud had a third component, that of the superego. And the superego is the internalized rules of parents in society. So, what happens in the course of development is, you're just trying to make your way through the world and satisfy your desires, but sometimes you're punished for them. Some desires are inappropriate, some actions are wrong, and you're punished for it. The idea is that you come out; you get in your head a superego, a conscience. In these movies, there'd be a little angel above your head that tells you when things are wrong. And basically your self, the ego, is in between the id and the superego.

One thing to realize, I told you the id is outrageously stupid. It just says, "Oh, hungry, food, sex, oh, let's get warm, oh." The superego is also stupid. The superego, point to point, is not some brilliant moral philosopher telling you about right and wrong. The superego would say, "You should be ashamed of yourself. That's disgusting. Stop doing that. Oh." And in between these two screaming creatures, one of you; one of them telling you to seek out your desires, the other one telling you, "you should be ashamed of yourself," is you, is the ego.

Now, according to Freud, most of this is unconscious. So, we see bubbling up to the top, we feel, we experience ourselves. And the driving of the id, the forces of the id and the forces of the superego, are unconscious in that we cannot access them. We don't know what--It's like the workings of our kidneys or our stomachs. You can't introspect and find them. Rather, they do their work without conscious knowledge.

Now, Freud developed this. This is the Freudian theory in broad outline. He extended it and developed it into a theory of psychosexual development. And so, Freud's theory is, as I said before, a theory of everyday life, of decisions, of errors, of falling in love, but it's also a theory of child development. So, Freud believed there were five stages of personality development, and each is associated with a particular erogenous zone. And Freud believed, as well, that if you have a problem at a certain stage, if something goes wrong, you'll be stuck there. So, according to Freud, there are people in this room who are what they are because they got stuck in the oral stage or the anal stage. And that's not good.

So, the oral stage is when you start off. The mouth is associated with pleasure. Everything is sucking and chewing and so on. And the problem for Freud is premature weaning of a child. Depriving him of the breast, could lead to serious

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problems in his personality development. It could make him, as the phrase goes, into an oral person. And his orality could be described literally. Freud uses it as an explanation for why somebody might eat too much or chew gum or smoke. They're trying to achieve satisfaction through their mouth of a sort they didn't get in this very early stage of development. But it can also be more abstract. If your roommate is dependent and needy, you could then go to your roommate and say, "You are an oral person. The first year of your life did not go well."

A phrase even more popular is the anal stage and that happens after the oral stage. And problems can emerge if toilet training is not handled correctly. If you have problems during those years of life, you could become an anal personality, according to Freud, and your roommate could say, "Your problem is you're too anal." And, according to Freud, literally, it meant you are unwilling to part with your own feces. It's written down here. I know it's true. And the way it manifests itself, as you know from just how people talk, is you're compulsive, you're clean, you're stingy. This is the anal personality.

Then it gets a little bit more complicated. The next stage is the phallic stage. Actually, this is not much more complicated. The focus of pleasure shifts to the genitals and fixation can lead to excessive masculinity in females or in males or if you're female a need for attention or domination. Now, at this point something really interesting happens called the "Oedipus Complex." And this is based on the story, the mythical story of a king who killed his father and married his mother. And, according to Freud, this happens to all of us in this way. Well, all of us. By "all of us," Freud meant "men."

So, here's the idea. You're three or four years old. You're in the phallic stage. So, what are you interested in? Well, you're interested in your penis and then you seek an external object. Freud's sort of vague about this, but you seek some sort of satisfaction. But who is out there who'd be sweet and kind and loving and wonderful? Well, Mom. So the child infers, "Mom is nice, I love Mom." So far so--And so this is not crazy; a little boy falling in love with his mother. Problem: Dad's in the way.

Now, this is going to get progressively weirder but I will have to say, as the father of two sons, both sons went through a phase where they explicitly said they wanted to marry Mommy. And me – if something bad happened to me that wouldn't be the worst thing in the world. So, there's this. But now it gets a little bit aggressive. So, the idea is the child determines that he's going to kill his father. Every three- and four-year-old boy thinks this. But then because children, according to Freud, don't have a good sense of the boundary between their mind and the world, which is a problem – the problem is they don't – they think their father can tell that they're plotting to kill him and they figure their father is now angry at them. And then they ask themselves, "What's the worst thing Dad could do to me?" And the answer is castration. So, they come to the conclusion that their father is going to castrate them because of their illicit love for their Mom. And then they say, "Dad wins" and then they don't think about sex for several years and that's the latency stage.

The latency stage is they've gone through this huge thing with Mom and Dad, "fell in love with Mom, wanted to kill my father, Dad was going to castrate me, fell out of love with Mom, out of the sex business." And then, sex is repressed until you get to the genital stage. And the genital stage is the stage we are all in – the healthy adult stage. Now that you're adults and you've gone through all the developmental stages, where do you stand? You're not out of the woods yet because unconscious mechanisms are still--Even if you haven't got fixated on anything, there's still this dynamic going on all the time with your id, your ego and your superego. And the idea is your superego--Remember, your superego is stupid. So, your superego isn't only telling you not to do bad things, it's telling you not to think bad things. So, what's happening is your id is sending up all of this weird, sick stuff, all of these crazy sexual and violent desires, "Oh, I'll kill him. I'll have sex with that. I'll have extra helpings on my dessert." And your superego is saying, "No, no, no." And this stuff is repressed. It doesn't even make it to consciousness.

The problem is Freud had a very sort of hydraulic theory of what goes on and some of this stuff slips out and it shows up in dreams and it shows up in slips of the tongue. And in exceptional cases, it shows up in certain clinical symptoms. So what happens is, Freud described a lot of normal life in terms of different ways we use to keep that horrible stuff from the id making its way to consciousness. And he called these "defense mechanisms." You're defending yourself against the horrible parts of yourself and some of these make a little bit of sense.

One way to describe this in a non-technical, non-Freudian way is, there are certain things about ourselves we'd rather not know. There are certain desires we'd rather not know and we have ways to hide them. So, for instance, there's sublimation. Sublimation is you might have a lot of energy, maybe sexual energy or aggressive energy, but instead of turning it to a sexual or aggressive target what you do is you focus it in some other way. So, you can imagine a great artist like Picasso turning the sexual energy into his artwork.

There is displacement. Displacement is you have certain shameful thoughts or desires and you refocus them more appropriately. A boy who's bullied by his father may hate his father and want to hurt him but since this would--this is very shameful and difficult. The boy might instead kick the dog and think he hates the dog because that's a more acceptable target.

There is projection. Projection is, I have certain impulses I am uncomfortable with, so rather than own them myself, I project them to somebody else. A classic example for Freud is homosexual desires. The idea is that I feel this tremendous lust towards you, for instance, and--any of you, all of you, you three, and I'm ashamed of this lust so what I say is, "Hey. Are you guys looking at me in a sexual manner? Are you lusting after me? How disgusting," because what I do is I take my own

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desires and I project it to others. And Freud suggested, perhaps not implausibly, that men who believe other men--who are obsessed with the sexuality of other men, are themselves projecting away their own sexual desires.

There is rationalization, which is that when you do something or think something bad you rationalize it and you give it a more socially acceptable explanation. A parent who enjoys smacking his child will typically not say, "I enjoy smacking my child." Rather he'll say, "It's for the child's own good. I'm being a good parent by doing this."

And finally, there is regression, which is returning to an earlier stage of development. And you actually see this in children. In times of stress and trauma, they'll become younger, they will act younger. They might cry. They might suck their thumb, seek out a blanket or so on. Now, these are all mechanisms that for Freud are not the slightest bit pathological. They are part of normal life. Normally, we do these things to keep an equilibrium among the different systems of the unconscious, but sometimes it doesn't work. Sometimes things go awry and what happens is a phrase that's not currently used in psychology but was popular during Freud's time: hysteria.

Hysteria includes phenomena like hysterical blindness and hysterical deafness, which is when you cannot see and cannot hear even though there's nothing physiologically wrong with you – paralysis, trembling, panic attacks, gaps of memory including amnesia and so on. And the idea is that these are actually symptoms. These are symptoms of mechanisms going on to keep things unconscious. It's a common enough idea in movies. Often in movies what happens is that somebody goes to an analyst. They have some horrible problem. They can't remember something or they have some sort of blackouts and so on. And the analyst tells them something and at one point they get this insight and they realize what--why they've blinded themselves, why they can't remember, and for Freud this is what happens. Freud originally attempted to get these memories out through hypnosis but then moved to the mechanism of free association and, according to Freud, the idea is patients offer resistance to this and then the idea of a psychoanalyst is to get over the resistance and help patients get insight.

The key notion of psychoanalysis is your problems are--actually reflect deeper phenomena. You're hiding something from yourself, and once you know what's going on to deeper phenomena your problems will go away. I'm going to give you an example of a therapy session. Now, this is not a Freudian analysis. We'll discuss later on in the course what a Freudian analysis is, but this is not a pure Freudian analysis. A Freudian analysis, of course, is lying on a couch; does not see their therapist; their therapist is very nondirective. But I'm going to present this as an example here because it illustrates so many of the Freudian themes, particularly themes about dreams, the importance of dreams, about repression and about hidden meaning.

So, this is from a television episode and the character's--Many--Some of you may have seen this. Many of you will not have. The character is suffering from panic attacks. [Professor Paul Bloom plays a short episode from the Sopranos]

Freud's contributions extend beyond the study of individual psychology and individual pathology. Freud had a lot to say about dreams as you could see in this illustration. He believed that dreams had a manifest content, meaning; "manifest" meaning what you experience in your dream. But dreams always had a latent content as well, meaning the hidden implication of the dream. He viewed all dreams as wish fulfillment. Every dream you have is a certain wish you have even though it might be a forbidden wish that you wouldn't wish to have, you wouldn't want to have. And dreams had--and this is an idea that long predated Freud. Dreams had symbolism. Things in dreams were often not what they seemed to be but rather symbols for other things. Freud believed that literature and fairy tales and stories to children and the like carried certain universal themes, certain aspects of unconscious struggles, and certain preoccupations of our unconscious mind. And Freud had a lot to say about religion. For instance, he viewed a large part of our--of the idea of finding a singular, all-powerful god as seeking out a father figure that some of us never had during development.

What I want to spend the rest of the class on is the scientific assessment of Freud. So, what I did so far is I've told you what Freud had to say in broad outline. I then want to take the time to consider whether or not we should believe this and how well it fits with our modern science. But before doing so, I'll take questions for a few minutes. Do people have any questions about Freud or Freud's theories? Yes. Student: [inaudible] Professor Paul Bloom: So, that's some question. The question is: The conflicts in psychosexual development that Freud describes is--always assumes that a child has a mother and a father, one of each, in a certain sort of familial structure. And the question then is, "What if a child was raised by a single parent, for example?" What if a child was never breast fed, but fed from the bottle from the start? And Freudians have had problems with this. Freud's--Freud was very focused on the family life of the people he interacted with, which is rather upper class Europeans, and these sort of questions would have been difficult for Freud to answer. I imagine that what a Freudian would have to say is, you would expect systematic differences. So, you would expect a child who just grew up with a mother or just grew up to be a father--with a father to be in some sense psychologically damaged by that, failing to go through the normal psychosexual stages. Yes. Student: [inaudible] Professor Paul Bloom: The issue--The question is, "Do modern psychoanalysts still believe that women do not have superegos?" Freud was--As you're pointing out, Freud was notorious for pointing, for suggesting that women were morally immature relative to men. I think Freud would say that women have superegos, they're just not the sort of sturdy ones that

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men have. I think psychoanalysts and psychoanalytic scholars right now would be mixed. Some would maintain that there really are deep sex differences. Others would want to jettison that aspect of Freudian theory. Yes. Student: Do you define sublimation as being displacement? Does that make it sort of a subgroup of displacement? Professor Paul Bloom: Well, what sublimation is--A lot of these--It's a good question. The question is sort of, what is sublimation? How does it relate to the other defense mechanisms? A lot of defense mechanisms involve taking a desire and turning it. Now, what displacement does is it takes it from you to her. I'm angry at you but maybe that's forbidden for some reason, so I'll be angry at her. What projection does is takes a desire from me and then puts it on somebody else heading outwards. And what sublimation does is it just gives up the details and keeps the energy. So, you stay up--Your roommate stays up all night working and you say to your roommate, for instance, "That's just because you haven't had sex in a long time and you want to have sex so you devote all your energy to your math exam." And then you say, "That's sublimation. I learned that in Intro Psych." And your roommate would be very pleased. One more question. Yes. Student: What kind of evidence is there for cross-cultural variation? Professor Paul Bloom: The question is, which is related to the issue--extending the issue of the two-parent versus one-parent family is, "To what extent are these notions validated cross-culturally?" And that's such a good question I'm going to defer it. I'm going to talk about it in a few minutes because that's actually--That speaks to the issue of the scientific assessment of Freud so I'm going to try to get to your question in a little bit.

Freudian theory is now, at this point of time, extremely controversial and there is a lot of well-known criticisms and attacks on Freud. This is just actually an excellent book on The Memory Wars by Frederick Crews, which--and Frederick Crews is one of the strongest and most passionate critics of Freud. And the problems with Freud go like this. There are two ways you could reject a theory. There are two problems with the scientific theory. One way you could reject a theory is that it could be wrong. So, suppose I have a theory that the reason why some children have autism, a profound developmental disorder, is because their mothers don't love them enough. This was a popular theory for many years. It's a possible theory. It just turns out to be wrong but another way--And so one way to attack and address a scientific theory is to view it as just to see whether or not it works. But there's a different problem a theory could have. A theory could be so vague and all encompassing that it can't even be tested. And this is one of the main critiques of Freud. The idea could be summed up by a quotation from the physicist Wolfgang Pauli. And Pauli was asked his opinion about another physicist. And Pauli said this: "That guy's work is crap. He's not right. He's not even wrong." And the criticism about Freud is that he's not even wrong.

The issue of vagueness is summarized in a more technical way by the philosopher Karl Popper who described--who introduced the term of falsifiability. The idea of falsifiability is that what distinguishes science from non science is that scientific predictions make strong claims about the world and these claims are of a sort that they could be proven wrong. If they couldn't be proven wrong, they're not interesting enough to be science. So, for example, within psychology the sort of claims we'll be entertaining throughout the course include claims like, damage to the hippocampus causes failures of certain sorts of memory, or everywhere in the world men on average want to have more sexual partners than women, or exposure to violent television tends to make children themselves more violent. Now, are they true or are they false? Well, we'll talk about that, but the point here is they can be false. They're interesting enough that they can be tested and as such they go to--they might be wrong but they graduate to the level of a scientific theory.

This should be contrasted with nonscientific programs and the best example of a nonscientific program is astrology. So, the problem with astrological predictions is not that they're wrong. It's that they can't be wrong. They're not even wrong. I did my--I got my horoscope for today on the web. [reading from a slide] "A couple of negative aspects could make you a little finicky for the next few days." Okay. I'm going to watch for that. "The presence of both Mars and Venus suggests you want to box everything into a neat, ordered, structured way but keeping a piece of jade or carnelian close will help you keep in touch with your fun side." And starting this morning I got from my wife a little piece of jade and I have been sort of in touch with my fun side. The problem is, a few days aren't going to go by and say, "God. That was wrong." It can't be wrong. It's just so vague. I got a better horoscope from The Onion actually: "Riding in a golf cart with snow cone in hand, you'll be tackled by two police officers this week after matching a composite caricature of a suspected murderer." Now, that's a good prediction because "wow." If it turns out to be true, I'm going to say, "Those guys really know something." It's falsifiable.

Arguably, Freud fails the test because Freudian theory is often so vague and flexible that it can't really be tested in any reliable way. A big problem with this is a lot of Freudian theory is claimed to be validated in the course of psychoanalysis. So, when you ask people, "Why do you believe in Freud?" they won't say, "Oh, because of this experiment, that experiment, this data set and that data set." What they'll say is, "It's--The Freudian theory proves itself in the course of psychoanalysis – the success of psychoanalysis." But it's unreliable. The problem is, say, Freud says to a patient, "You hate your mother." The patient says, "Wow. That makes sense." Freud says, "I'm right." The patient--Freud says, "You hate your mother," and the patient says, "No, I don't. That's titillating. That's disgusting." Freud says, "Your anger shows this idea is painful to you. You have repressed it from consciousness. I am right."

And the problem is the same sort of dynamic plays itself out even in the scientific debate back and forth. So Freud--Freudian psychologists--I'm putting Freud here but what I mean is well-known defenders of Freud will make some claims like: adult personality traits are shaped by the course of psychosexual development; all dreams are disguised wish fulfillment; psychoanalysis is the best treatment for mental disorders. Scientists will respond, "I disagree. There's little or no

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evidence supporting those claims." And the Freudian response is, "Your rejection of my ideas shows that they are distressing to you. This is because I am right." And this is often followed up, seriously enough. "You have deep psychological problems."

And now, I don't want to caricature Freudians. A lot of Freudians have tried and made a research program of extending their ideas scientifically, bringing them to robust scientific tests. But the problem is, when you make specific falsifiable predictions they don't always do that well. So, for instance, there's no evidence that oral and anal characteristics, the personality characteristics I talked about – about being needy versus being stingy – relate in any interesting way to weaning or toilet training.

And there's been some efforts cross-culturally, to go back to the question this young man asked before – looking at cross-cultural differences in toilet training and weaning, which are really big differences, to see if they correspond in any interesting way to personality differences. And there's been no good evidence supporting that. Similarly, Freud had some strong claims about sexuality, for why some people are straight and others are gay. These have met with very little empirical support. And the claim that psychoanalysis proves itself by being--by its tremendous success in curing mental illness is also almost certainly not true. For most--Maybe not all, but for most psychological disorders, there are quicker and more reliable treatments than psychoanalysis. And there's considerable controversy as to whether the Tony Soprano method of insight, where you get this insight and there's discovery, "Oh, now I know," makes any real difference in alleviating symptoms such as anxiety disorders or depression.

This is why there's sort of--often sort of a sticker shock when people go to a university psychology department where they say, "Look. Hey. Where is--So I'm in Psych. How could I take classes on Freud? Who's your expert on Freud?" And the truth is Freudian psychoanalysis is almost never studied inside psychology departments. Not the cognitive or developmental side, not the clinical side. There are some exceptions but, for the most part, even the people who do study Freud within psychology departments do so critically. Very few of them would see themselves as a psychoanalytic practitioner or as a Freudian psychologist.

Freud lives on both in a clinical setting and in the university but Freud at Yale, for instance, is much more likely to be found in the history department or the literature department than in the psychology department. And this is typical enough but, despite all of the, sort of, sour things I just said about Freud, the big idea, the importance of the dynamic unconscious, remains intact. We will go over and over and over again different case studies where some really interesting aspects of mental life prove to be unconscious.

Now, there's one question. I'm actually going to skip over this for reasons of time and just go to some examples of the unconscious in modern psychology. So, here's a simple example of the unconscious in modern psychology: Language understanding. So, when you hear a sentence like, "John thinks that Bill likes him," in a fraction of a second you realize that this means that John thinks that Bill likes John. If you heard the sentence--Oops--"John thinks that Bill likes himself," in a fraction of a second you would think that it means "John thinks that Bill likes Bill." And as we will get to when we get to the lecture on language, this is not conscious. You don't know how you do this. You don't even know that you are doing this but you do it quickly and instinctively.

So much of our day-to-day life can be done unconsciously. There are different activities you can do – driving, chewing gum, shoelace tying – where if you're good enough at them, if you're expert enough at them, you don't know you're doing them. I was at a party a few years ago for a friend of mine and we ran out of food so he said, "I'll just go pick up some food." An hour later he was gone--still gone and it was around the corner. And we called him up on his cell phone and he said, "Oh. I got on the highway and I drove to work." Yeah. He works an hour away but he got on the highway "drive drive drive." And these--some version of these things happen all of the time.

Maybe more surprising, Freud's insight that our likes and dislikes are due to factors that we're not necessarily conscious of has a lot of empirical support--a lot of empirical support from research into social psychology, for example. So, here's one finding from social psychology. If somebody goes through a terrible initiation to get into a club, they'll like the club more. You might think they'd like it less because people do terrible things to them. But actually, hazing is illegal but a remarkably successful tool. The more you pay for something the more you like it and the more pain you go through to get something the more you like it. From the standpoint of politics for instance, if you want loyal people in a political campaign, do not pay them. If you pay them, they'll like you less. If they volunteer, they'll like you more. And we'll talk about why. There's different theories about why, but my point right now is simply that people don't necessarily know this but still they're subject to this.

Another example is some weird studies done in a discipline of social psychology known as terror management which involves subliminal death primes. The idea of subliminal death primes is this. You sign up for your human subjects requirement and then you--they put you in front of a computer screen and then they tell you, "Oh, just sit in front of the computer screen and then we'll ask you some questions." And then the questions come out and they're questions like, "How much do you love your country?" "What do you think of Asians?" "What do you think of Jews?" "What do you think of blacks?" "What do you think of vegetarians?" "What do you think of people's political views different from yours?"

Here's the gimmick. What you don't know is on that computer screen words are being flashed like that but they're being flashed so fast it looks like that--You don't see anything--words like "corpse," "dead," "dying." The flashing of these subliminal words, "subliminal" meaning – a fancy term meaning below the level of consciousness, you don't know you're

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seeing them – has dramatic effects on how you answer those questions. People exposed to death primes become more nationalistic, more patriotic, less forgiving of other people, less liking of other races and people from other countries. Again the claim--the explanation for why this is so is something which we'll get to in another class. The point now is simply to illustrate that these sort of things can have--that things you aren't aware of can have an effect on how you think.

The final example I'll give of this is a short demonstration. To do this, I'm going to cut the class in half at this point so you'll be on this side of the class, the right side, my right, and this will be on the left side, and I simply want everybody to think about somebody you love. So, think about somebody you love, your girlfriend, your boyfriend, your mom, your dad. Think about somebody you love. Just think. Okay. Now, on this screen is going to be instructions but I want to give the instructions to this half of the class [pointing to his right]. I'm going to ask everybody in this half of the class [pointing to his left] please either turn your head or shut your eyes. Okay? Teaching fellows too. Okay. And everybody on this half obey [pointing to his right]. Okay. Has everybody read that [pointing to the slide]? Okay. Now, turn your head, this group [pointing to his right]. Now this group [pointing to his left]: Look at this [pointing to instructions on the slide] and take a moment. You don't have to do it on paper but take a moment to do it in your head. You--Each group had instructions. Some people might have seen both instructions. Follow the instructions you got for you.

Now, this was research done by Norbert Schwarz and here's the question I want you to ask yourself, "How much do you like this person?" And here's the effect: Half of you were asked to list three features of the person. Half of you were asked to list ten. The finding, which is not a subtle finding, is that liking goes up in the three group and liking goes down in the ten group. And here is why. I have to think about three positive features of somebody so I think about my girlfriend. I have a girlfriend. I think about my girlfriend, "but oh, she's smart, she's beautiful and she's kind. Good. How much do--What do I think of her? "Pretty, good, smart, beautiful, kind, smart, beautiful, oh, yeah." But the problem--;Now, Schwarz is clever though. He says, "List--" The other group gets ten positive features, "smart, beautiful, kind… really nice… good cook… punctual, smart… No, I mentioned that." The problem is nobody has ten positive features! And the effect of being asked to do ten positive features is people find this hard. And then those people, when asked, "How much do you like this person?" say, "Couldn't really make it that ten. I guess I don't like them very much."

Now, the point of this illustration, again, is that it shows that you don't know this. Subjects who were asked to do ten positive features and then later ranked the person lower and then asked, "Why did you rank the person lower?" Don't say, "'Cause you told me to list ten." Typically, we are oblivious to these factors that change our points – what we like and what we dislike – and this is, in fact, a substantial and an important part of the study of psychology, and particularly, for instance, the study of racial and sexual prejudice. Where--One of the big findings from social psychology, and we'll devote almost an entire lecture to this, is that people have strong views about other races that they don't know about and that they don't know how to control their actions.

So, to some extent, this rounds out Freud because to some extent the particulars of Freud are--for the most part have been rejected. But the general idea of Freud's actually been so successful both in the study of scientific psychology and in our interpretation of everyday life that, to some extent, Freud's been a victim of his own success. We tend to underestimate the importance of Freudian thought in everyday life because he's transformed our world view to such an extent that it's difficult for us to remember if there's any other way to think about it. So, to some extent, he's been the victim of his own success.

We have time for some further questions about Freud and about scientific implications of Freud. I took a class once on how to teach when I was a graduate student. And I just remember two things from this class. One thing is never grade in red pen. Those--People don't like that. The second thing is never ask any questions, because presumably it is very frightening to ask, "Any questions?" and people find it's intimidating. I'm supposed to ask, "What are your questions?" So, what are your questions? Yes, in back. Sorry. Student: Did Freud believe in [inaudible] Professor Paul Bloom: Did Freud believe in [inaudible] Student: Medication Professor Paul Bloom: Medication. Freud had an--It's a good question. The question was, "Does--did Freud believe in medication?" Medication, of course, being a major theme of how we deal with certain disorders now, particularly depression and anxiety disorders. On the one hand, Freud made his start as a neuroscientist. Freud studied the mind and the brain and was intensely interested in the neural basis of thought and behavior. But the answer to your question in the end is, "no." Although Freud was very sensitive to the brain basis of behavior, Freud was totally convinced that the method through which to cure disorders like depression and anxiety would not be medication but rather through the sort of talk therapy and insight. Moreover, modern therapists, including some people who aren't psychoanalytically defined, will say, "Look. These drugs are all well and good but what they do is they mask the symptoms." So, if you have panic attacks, say, it's true that drugs might make the panic attacks go away, but the panic attacks are actually not your real problem. And by making them go away you don't get to the root of your problem. So, the answer is both Freud and modern day psychoanalysts would think that medications are substantially overused in the treatment of mental disorders. Yes. Student: Are there any [inaudible]

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Professor Paul Bloom: The question is, "What about research on dreams?" "Dreams" is such a fun topic that I'm going to devote half a class to sleeping and dreams. So, for instance, I will answer the question "What is the most common dream?" I will also answer the question "Who thinks about sex more in dreams, men or women, and what proportion of--" Oh. There's so many great questions I will answer. Dreams from a Freudian standpoint. There's been some evidence that dreams do, and some often do, have some relationship to what you're thinking about and worrying about through the day. But the strong Freudian view about symbolism and wish fulfillment has not been supported by the study of dreams. What are your other questions? Yes, whoever Erik is pointing to. Professor Paul Bloom: Purple shirt. Yes. Student: [inaudible]--Electra complex? Professor Paul Bloom: The Electra complex? The Electra complex is the penis envy story. Freud developed--This is a crude summary, but Freud developed the Oedipal complex, "Mom, I love Mommy, Dad." And then it's as if somebody reminded him, "Sigmund, there are also women." "Oh, yeah." And that story I told you with the penises and the penis envy and the replacement is sort of a very shortened version of the Electra complex. I think it's fair to say that the Electra complex was a sort of add-on to the main interest of Freud's Oedipal complex. One more, please. Yes. Student: [inaudible] Professor Paul Bloom: According to Freud, the--there's not a fixation in the stage, in the same sense as an oral or anal stage, but yes. The claim that Freud would make is that the woman's discovery that she lacks the penis plays a fundamental role later on determining her allegiances in life and in fact her own sexual preferences and interests. So, it's not the sort of thing that affects her just for a short period.

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Lecture 4 Professor Paul Bloom: I actually want to begin by going back to Freud and hitting a couple of loose ends. There was a point in my lecture on Wednesday where I skipped over some parts. I said, "We don't have time for this" and I just whipped past it. And I couldn't sleep over the weekend. I've been tormented. I shouldn't have skipped that and I want to hit--Let me tell you why I skipped it. The discussion I skipped was the discussion of why we would have an unconscious at all. So, I was talking about the scientifically respectable ideas of Freud and I want to talk about some new ideas about why there could be an unconscious.

Now, the reason why I skipped it is I'm not sure this is the best way to look at the question. As we will learn throughout the course, by far the vast majority of what our brains do, the vast majority of what our minds do, is unconscious and we're unaware of it. So the right question to ask may not be, "Why are some things unconscious?" but rather, why is this tiny subset of mental life--why is this conscious? On the other hand, these claims about the utility of unconsciousness, I think, are provocative and interesting. So I just wanted to quickly share them with you.

So, the question is, from an evolutionary standpoint, "Why would an unconscious evolve?" And an answer that some psychologists and biologists have given is deception. So, most animals do some deception. And deception defined broadly is simply to act or be in some way that fools others into believing or thinking or responding to something that's false.

There's physical examples of deception. When threatened, chimpanzees--their hair stands up on end and that makes them look bigger to fool others to thinking they're more dangerous than they are. There's an angler fish at the bottom of the ocean that has a rod sticking up from the top of its head with a lure to capture other fish – to fool them in thinking that this is something edible and then to themselves be devoured. But humans, primates in general but particularly humans, are masters of deception. We use our minds and our behaviors and our actions continually to try to trick people into believing what's not true. We try to trick people, for instance, into believing that we're tougher, smarter, sexier, more reliable, more trustworthy and so on, than we really are. And a large part of social psychology concerns the way in which we present ourselves to other people so as to make the maximally positive impression even when that impression isn't true.

At the same time, though, we've also evolved very good lie detection mechanisms. So not only is there evolutionary pressure for me to lie to you, for me to persuade you for instance, that if we're going to have a--if you are threatening me don't threaten me, I am not the sort of man you could screw around with. But there's evolutionary pressure for you to look and say, "No. You are the sort of man you could screw around with. I can tell." So how do you become a good liar? And here's where the unconscious comes in. The hypothesis is: the best lies are lies we tell ourselves. You're a better liar, more generally, if you believe the lie that you're telling.

This could be illustrated with a story about Alfred Hitchcock. The story goes--He hated working with child actors but he often had to. And the story goes--He was dealing with a child actor who simply could not cry. And, finally frustrated, Hitchcock went to the actor, leaned over, whispered in his ear, "Your parents have left you and they're never coming back." The kid burst into tears. Hitchcock said, "Roll ʻem" and filmed the kid. And the kid, if you were to see him, you'd say, "That's--Boy, he's--he really looks as if he's sad" because he was. If I had a competition where I'd give $100,000 to the person who looks the most as if they are in pain, it is a very good tactic to take a pen and jam it into your groin because you will look extremely persuasively as if you are in pain. If I want to persuade you that I love you, would never leave you, you can trust me with everything, it may be a superb tactic for me to believe it. And so, this account of the evolution of the unconscious is that certain motivations and goals, particularly sinister ones, are better made to be unconscious because if a person doesn't know they have them they will not give them away. And this is something I think we should return to later on when we talk about social interaction and social relationships.

One other thing on Freud--just a story of the falsification of Freud. I was taking my younger child home from a play date on Sunday and he asked me out of the blue, "Why can't you marry your mother or your father?" Now, that's actually a difficult question to ask--to answer for a child, but I tried my best to give him an answer. And then I said--then I thought back on the Freud lecture and so I asked him, "If you could marry anybody you want, who would it be?" imagining he'd make explicit the Oedipal complex and name his mother. Instead, he paused for a moment and said, "I would marry a donkey and a big bag of peanuts." [laughter] Both his parents are psychologists and he hates these questions and at times he just screws around with us. [laughter]

Okay. Last class I started with Freud and now I want to turn to Skinner. And the story of Skinner and science is somewhat different from the story of Freud. Freud developed and championed the theory of psychoanalysis by himself. It is as close as you could find in science to a solitary invention. Obviously, he drew upon all sorts of sources and predecessors but psychoanalysis is identified as Freud's creation. Behaviorism is different. Behaviorism is a school of thought that was there long before Skinner, championed by psychologists like John Watson, for instance. Skinner came a bit late into this but the reason why we've heard of Skinner and why Skinner is so well known is he packaged these notions. He expanded upon them; he publicized them; he developed them scientifically and presented them both to the scientific community and to the popular community and sociologically in the 1960s and 1970s. In the United States, behaviorism was incredibly well known and so was Skinner. He was the sort of person you would see on talk shows. His books were bestsellers.

Now, at the core of behaviorism are three extremely radical and interesting views. The first is a strong emphasis on learning. The strong view of behaviorism is everything you know, everything you are, is the result of experience. There's no

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real human nature. Rather, people are infinitely malleable. There's a wonderful quote from John Watson and in this quote John Watson is paraphrasing a famous boast by the Jesuits. The Jesuits used to claim, "Give me a child until the age of seven and I'll show you the man," that they would take a child and turn him into anything they wanted. And Watson expanded on this boast,

Give me a dozen healthy infants, well-formed and my own specified world to bring them up and I'll guarantee to take any one at random and train them to become any type of specialist I might select--doctor, lawyer, artist, merchant, chief, and yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations and race of his ancestors.

Now, you could imagine--You could see in this a tremendous appeal to this view because Watson has an extremely egalitarian view in a sense. If there's no human nature, then there's no sense in which one group of humans by dint of their race or their sex could be better than another group. And Watson was explicit. None of those facts about people will ever make any difference. What matters to what you are is what you learn and how you're treated. And so, Watson claimed he could create anybody in any way simply by treating them in a certain fashion.

A second aspect of behaviorism was anti-mentalism. And what I mean by this is the behaviorists were obsessed with the idea of doing science and they felt, largely in reaction to Freud, that claims about internal mental states like desires, wishes, goals, emotions and so on, are unscientific. These invisible, vague things can never form the basis of a serious science. And so, the behaviorist manifesto would then be to develop a science without anything that's unobservable and instead use notions like stimulus and response and reinforcement and punishment and environment that refer to real world and tangible events.

Finally, behaviorists believed there were no interesting differences across species. A behaviorist might admit that a human can do things that a rat or pigeon couldn't but a behaviorist might just say, "Look. Those are just general associative powers that differ" or they may even deny it. They might say, "Humans and rats aren't different at all. It's just humans tend to live in a richer environment than rats." From that standpoint, from that theoretical standpoint, comes a methodological approach which is, if they're all the same then you could study human learning by studying nonhuman animals. And that's a lot of what they did.

Okay. I'm going to frame my introduction--my discussion of behaviors in terms of the three main learning principles that they argue can explain all of human mental life, all of human behavior. And then, I want to turn to objections to behaviorism but these three principles are powerful and very interesting. The first is habituation. This is the very simplest form of learning. And what this is is technically described as a decline in the tendency to respond to stimuli that are familiar due to repeated exposure. "Hey!" [shouting, then pausing] "Hey!" [shouting again] The sudden noise startles but as it--as you hear it a second time it startles less. The third time is just me being goofy. It's just--It's--You get used to things. And this, of course, is common enough in everyday life. We get used to the ticking of a clock or to noise of traffic but it's actually a very important form of learning because imagine life without it. Imagine life where you never got used to anything, where suddenly somebody steps forward and waves their hand and you'd go, "Woah," [as if surprised] and then they wave their hand again and you'd go, "Whoah," [as if surprised again] and you keep--[laughter]

And there's the loud ticking of a clock and you say, "Hmmm." [acting as if he's interested in the sound of a clock ticking] And that's not the way animals or humans work. You get used to things. And it's actually critically important to get used to things because it's a useful adaptive mechanism to keep track on new events and objects. It's important to notice something when it's new because then you have to decide whether it's going to harm you, how to deal with it, to attend to it, but you can't keep on noticing it. And, in fact, you should stop noticing it after it's been in the environment for long enough. So, this counts as learning because it happens through experience. It's a way to learn through experience, to change your way of thinking through experience. And also, it's useful because harmful stimuli are noticed but when something has shown itself to be part of the environment you don't notice it anymore.

The existence of habituation is important for many reasons. One thing it's important for is clever developmental psychologists have used habituation as a way to study people, creatures who can't talk like nonhuman animals, and young babies. And when I talk on Wednesday about developmental psychology I'll show different ways in which psychologists have used habituation to study the minds of young babies.

The second sort of learning is known as classical conditioning. And what this is in a very general sense is the learning of an association between one stimulus and another stimulus, where stimulus is a technical term meaning events in the environment like a certain smell or sound or sight. It was thought up by Pavlov. This is Pavlov's famous dog and it's an example of scientific serendipity. Pavlov, when he started this research, had no interest at all in learning. He was interested in saliva. And to get saliva he had to have dogs. And he had to attach something to dogs so that their saliva would pour out so he could study saliva. No idea why he wanted to study saliva, but he then discovered something. What he would do is he'd put food powder in the dog's mouth to generate saliva. But Pavlov observed that when somebody entered the room who typically gave him the food powder, the dog--the food powder saliva would start to come out. And later on if you--right before or right during you give the dog some food – you ping a bell – the bell will cause the saliva to come forth. And, in fact, this is the apparatus that he used for his research.

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He developed the theory of classical conditioning by making a distinction between two sorts of conditioning, two sorts of stimulus response relationships. One is unconditioned. An unconditioned is when an unconditioned stimulus gives rise to an unconditioned response. And this is what you start off with. So, if somebody pokes you with a stick and you say, "Ouch," because it hurts, the poking and the "ouch" is an unconditioned stimulus causing an unconditioned response. You didn't have to learn that.

When Pavlov put food powder in the dog's mouth and saliva was generated, that's an unconditioned stimulus giving rise to an unconditioned response. But what happens through learning is that another association develops – that between the conditioned stimulus and the conditioned response. So when Pavlov, for instance--Well, when Pavlov, for instance, started before conditioning there was simply an unconditioned stimulus, the food in the mouth, and an unconditioned response, saliva. The bell was nothing. The bell was a neutral stimulus. But over and over again, if you put the bell and the food together, pretty soon the bell will generate saliva. And now the bell--When--You start off with the unconditioned stimulus, unconditioned response. When the conditioned stimulus and the unconditioned stimulus are brought together over and over and over again, pretty soon the conditioned stimulus gives rise to the response. And now it's known as the conditioned stimulus giving rise to the conditioned response. This is discussed in detail in the textbook but I also--I'm going to give you--Don't panic if you don't get it quite now. I'm going to give you further and further examples.

So, the idea here is, repeated pairings of the unconditioned stimulus and the conditioned stimulus will give rise to the response. And there's a difference between reinforced trials and unreinforced trials. A reinforced trial is when the conditioned stimulus and the unconditioned stimulus go together. You're--and to put it in a crude way, you're teaching the dog that the bell goes with the food. An unreinforced trial is when you get the food without the bell. You're not teaching the dog this. And, in fact, once you teach an animal something, if you stop doing the teaching the response goes away and this is known as extinction.

But here's a graph. If you get--They really count the number of cubic centimeters of saliva. The dog is trained so that when the bell comes on--Actually, I misframed it. I'll try again. When the bell comes connected with food, there's a lot of saliva. An unreinforced response is when the bell goes on but there's no food. So, it's--Imagine you're the dog. So, you get food in your mouth, "bell, food, [making panting sound] bell, food, [another panting sound]" and now "bell [panting]." But next you get "bell, bell, bell." You give it up. You stop. You stop responding to the bell. A weird thing which is discussed in the textbook is if you wait a while and then you try it again with the bell after a couple of hours, the saliva comes back. This is known as spontaneous recovery.

So, this all seems a very technical phenomena related to animals and the like but it's easy to see how it generalizes and how it extends. One interesting notion is that of stimulus generalization. And stimulus generalization is the topic of one of your articles in The Norton Reader, the one by Watson, John Watson, the famous behaviorist, who reported a bizarre experiment with a baby known as Little Albert. And here's the idea. Little Albert originally liked rats. In fact, I'm going to show you a movie of Little Albert originally liking rats. See. [pointing to video] He's okay. No problem. Now, Watson did something interesting. As Little Albert was playing with the rat, "Oh, I like rats, oh," Watson went behind the baby--this is the--it's in the chapter--and banged the metal bar right here [simulating a banging motion]. The baby, "Aah," screamed, started to sob. Okay. What's the unconditioned stimulus? Somebody. The loud noise, the bar, the bang. What's the unconditioned response? Crying, sadness, misery. And as a result of this, Little Albert grew afraid of the rat. So there--what would be the conditioned stimulus? The rat. What would be the conditioned response? Fear. Excellent.

Moreover, this fear extended to other things. So, this is a very weird and unpersuasive clip. But the idea is--the clip is to make the point that the fear will extend to a rabbit, a white rabbit. So, the first part, Little Albert's fine with the white rabbit. The second part is after he's been conditioned and he's kind of freaked out with the white rabbit. The problem is in the second part they're throwing the rabbit at him but [looking at the video] now he's okay. [laughter] [Speaking to a teaching assistant] Is the mic on? Oh. This is fine.

This is one of a long list of experiments that we can't do anymore. So, classical conditioning is more than a laboratory phenomena. The findings of classical conditioning have been extended and replicated in all sorts of animals including crabs, fish, cockroaches and so on. And it's been argued to be an extension of--it's argued to underlie certain interesting aspects of human responses.

So, I have some examples here. One example is fear. So, the Little Albert idea--The Little Albert experiment, provides an illustration for how phobias could emerge. Some proportion of people in this room have phobias. Imagine you're afraid of dogs. Well, a possible story for the--for why you became afraid of dogs is that one day a dog came up and he was a neutral stimulus. No problem. And all of a sudden he bit you. Now the pain of a bite, being bit, and then the pain and fear of that is an unconditioned stimulus, unconditioned response. You're just born with that, "ow." But the presence of the dog there is a conditioned stimulus and so you grew to be afraid of dogs.

If you believe this, this also forms the basis for ways for a theory of how you could make phobias go away. How do you make conditioned stimulus, conditioned response things go away? Well, what you do is you extinguish them. How do you extinguish them? Well, you show the thing that would cause you to have the fear without the unconditioned stimulus. Here's an illustration. It's a joke. Sorry. [pointing towards a slide containing a comic of a man trapped in a small booth, filled with snakes, dangling from the top of a building] He's simultaneously confronting the fear of heights, snakes, and the dark

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because he's trapped in that thing and the logic is--the logic of--the logic is not bad. He's stuck in there. Those are all the--his conditioned stimulus. But nothing bad happens so his fear goes away. The problem with this is while he's stuck in there he has this screaming, horrific panic attack and then it makes his fear much worse.

So, what they do now though, and we'll talk about this much later in the course when we talk about clinical psychology--but one cure for phobias does draw upon, in a more intelligent way, the behaviorist literature. So, the claim about a phobia is that there's a bad association between, say dog and fear, or between airplanes or snakes and some bad response. So, what they do is what's called, "systematic desensitization," which is they expose you to what causes you the fear but they relax you at the same time so you replace the aversive classical conditioned fear with something more positive. Traditionally, they used to teach people relaxation exercises but that proves too difficult. So nowadays they just pump you full of some drug to get you really happy and so you're really stoned out of your head, you're [makes "sick" noise] and this isn't so bad. It's more complicated than that but the notion is you can use these associative tools perhaps to deal with questions about fear, phobias and how they go away.

Hunger. We'll spend some time in this course discussing why we eat and when we eat. And one answer to why we eat and when we eat is that there's cues in the environment that are associated with eating. And these cues generate hunger. For those of you who are trying to quit smoking, you'll notice that there's time--or to quit drinking there's times of the day or certain activities that really make you want to smoke or really make you want to drink. And from a behaviorist point of view this is because of the associative history of these things.

More speculatively, classical conditioning has been argued to be implicated in the formation of sexual desire, including fetishes. So a behaviorist story about fetishes, for instance, is it's straightforward classical conditioning. Just as your lover's caress brings you to orgasm, your eyes happen to fall upon a shoe. Through the simple tools of classical conditioning then, the shoe becomes a conditioned stimulus giving rise to the conditioned response of sexual pleasure. This almost certainly is not the right story but again, just as in phobias, some ideas of classical conditioning may play some role in determining what we like and what we don't like sexually. And in fact, one treatment for pedophiles and rapists involved controlled fantasies during masturbation to shift the association from domination and violence, for instance, to develop more positive associations with sexual pleasure. So the strong classical conditioning stories about fetishes and fears sound silly and extreme and they probably are but at the same time classical conditioning can be used at least to shape the focus of our desires and of our interests.

Final thought actually is--Oh, yeah. Okay. So, what do we think about classical conditioning? We talked about what habituation is for. What's classical conditioning for? Well, the traditional view is it's not for anything. It's just association. So, what happens is the UCS [unconditioned stimulus] and the CS [conditioned stimulus], the bell and the food, go together because they happen at the same time. And so classical conditioning should be the strongest when these two are simultaneous and the response to one is the same as the response to the other. This is actually no longer the mainstream view. The mainstream view is now a little bit more interesting. It's that what happens in classical conditioning is preparation. What happens is you become sensitive to a cue that an event is about to happen and that allows you to prepare for the event. This makes certain predictions. It predicts that the best timing is when the conditioned stimulus, which is the signal, comes before the unconditioned stimulus, which is what you have to prepare for. And it says the conditioned response may be different from the unconditioned response.

So, move away from food. Imagine a child who's being beaten by his father. And when his father raises his hand he flinches. Well, that's classical conditioning. What happened in that case is he has learned that the raising of a hand is a signal that he is about to be hit and so he responds to that signal. His flinch is not the same response that one would give if one's hit. If you're hit, you don't flinch. If you're hit, you might feel pain or bounce back or something. Flinching is preparation for being hit. And, in general, the idea of what goes on in classical conditioning is that the response is sort of a preparation. The conditioned response is a preparation for the unconditioned stimulus.

Classical conditioning shows up all over the place. As a final exercise, and I had to think about it--Has anybody here seen the movie "Clockwork Orange"? A lot of you. It's kind of a shocking movie and unpleasant and very violent but at its core one of the main themes is right out of Intro Psych. It's classical conditioning. And a main character, who is a violent murderer and rapist, is brought in by some psychologists for some therapy. And the therapy he gets is classical conditioning. In particular, what happens is he is given a drug that makes him violently ill, extremely nauseous. And then his eyes are propped open and he's shown scenes of violence. As a result of this sort of conditioning, he then – when he experiences real world violence – he responds with nausea and shock; basically, training him to get away from these acts of violence.

In this example--Take a moment. Don't say it aloud. Just take a moment. What's the unconditioned stimulus? Okay. Anybody, what's the unconditioned stimulus? Somebody just say it. The drug. What's the unconditioned response? Nausea. What's the conditioned stimulus? Violence. What's the conditioned response? [nausea] Perfect.

The third and final type of learning is known as operant conditioning or instrumental conditioning. And this is the thing, this is the theory championed and developed most extensively by Skinner. What this is is learning the relationships between what you do and how successful or unsuccessful they are, learning what works and what doesn't. It's important. This is very different from classical conditioning and one way to see how this is different is for classical conditioning you don't do anything. You could literally be strapped down and be immobile and these connections are what you appreciate and you

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make connections in your mind. Instrumental conditioning is voluntary. You choose to do things and by dint of your choices. Some choices become more learned than others.

So, the idea itself was developed in the nicest form by Thorndike who explored how animals learn. Remember behaviorists were entirely comfortable studying animals and drawing extrapolations to other animals and to humans. So, he would put a cat in a puzzle box. And the trick to a puzzle box is there's a simple way to get out but you have to kind of pull on something, some special lever, to make it pop open. And Thorndike noted that cats do not solve this problem through insight. They don't sit in the box for a while and mull it over and then figure out how to do it. Instead, what they do is they bounce all around doing different things and gradually get better and better at it.

So, what they do is, the first time they might scratch at the bars, push at the ceiling, dig at the floor, howl, etc., etc. And one of their behaviors is pressing the lever. The lever gets them out of the box, but after more and more trials they stopped scratching at the bars, pushing at the ceiling and so on. They just pressed the lever. And if you graph it, they gradually get better and better. They throw out all of these behaviors randomly. Some of them get reinforced and those are the ones that survive and others don't get reinforced and those are the ones that go extinct.

And it might occur to some of you that this seems to be an analogy with the Darwinian theory of natural selection where there's a random assortment of random mutations. And sexual selections give rise to a host of organisms, some of which survive and are fit and others which aren't. And in fact, Skinner explicitly made the analogy from the natural selection of species to the natural selection of behavior. So this could be summarized as the law of effect, which is a tendency to perform – an action's increased if rewarded, weakened if it's not. And Skinner extended this more generally.

So, to illustrate Skinnerian theory in operant conditioning I'll give an example of training a pig. So here is the idea. You need to train a pig and you need to do so through operant conditioning. So one of the things you want to do is--The pig is going to do some things you like and some things you don't like. And so what you want to do, basically drawing upon the law of effect, is reinforce the pig for doing good things. Suppose you want the pig to walk forward. So, you reinforce the pig for walking forward and you punish the pig for walking backward. And if you do that over the fullness of time, your reinforcement and punishment will give rise to a pig who walks forward.

There's two--One technical distinction that people love to put on Intro Psych exams is that the difference between positive reinforcement and negative reinforcement. Reinforcement is something that makes the behavior increase. Negative reinforcement is very different from punishment. Negative reinforcement is just a type of reward. The difference is in positive reinforcement you do something; in negative reinforcement you take away something aversive. So, imagine the pig has a heavy collar and to reward the pig for walking forward you might remove the heavy collar.

So, these are the basic techniques to train an animal. But it's kind of silly because suppose you want your pig to dance. You don't just want your pig to walk forward. You want your pig to dance. Well, you can't adopt the policy of "I'm going to wait for this pig to dance and when it does I'm going to reinforce it" because it's going to take you a very long time. Similarly, if you're dealing with immature humans and you want your child to get you a beer, you can't just sit, wait for the kid to give you a beer and uncap the bottle and say, "Excellent. Good. Hugs." You've got to work your way to it. And the act of working your way to it is known as shaping.

So, here is how to get a pig to dance. You wait for the pig to do something that's halfway close to dancing, like stumbling, and you reward it. Then it does something else that's even closer to dancing and you reward it. And you keep rewarding it as it gets closer to closer. Here's how to get your child to bring you some beer. You say, "Johnny, could you go to the kitchen and get me some beer?" And he walks to the kitchen and then he forgets why he's there and you run out there. "You're such a good kid. Congratulations. Hugs." And then you get him to--and then finally you get him to also open up the refrigerator and get the beer, open the door, get the--and in that way you can train creatures to do complicated things.

Skinner had many examples of this. Skinner developed, in World War II, a pigeon guided missile. It was never actually used but it was a great idea. And people, in fact--The history of the military in the United States and other countries includes a lot of attempts to get animals like pigeons or dolphins to do interesting and deadly things through various training. More recreational, Skinner was fond of teaching animals to play Ping-Pong. And again, you don't teach an animal to play Ping-Pong by waiting for it to play Ping-Pong and then rewarding it. Rather, you reward approximations to it.

And basically, there are primary reinforcers. There are some things pigs naturally like, food for instance. There are some things pigs actually automatically don't like, like being hit or shocked. But in the real world when dealing with humans, but even when dealing with animals, we don't actually always use primary reinforcers or negative reinforcers. What we often use are things like--for my dog saying, "Good dog." Now, saying "Good dog" is not something your dog has been built, pre-wired, to find pleasurable. But what happens is you can do a two-step process. You can make "Good dog" positive through classical conditioning. You give the dog a treat and say, "Good dog." Now the phrase "good dog" will carry the rewarding quality. And you could use that rewarding quality in order to train it. And through this way behaviorists have developed token economies where they get nonhuman animals to do interesting things for seemingly arbitrary rewards like poker chips. And in this way you can increase the utility and ease of training.

Finally, in the examples we're giving, whenever the pig does something you like you reinforce it. But that's not how real life works. Real life for both humans and animals involved cases where the reinforcement doesn't happen all the time but actually happens according to different schedules. And so, there is the distinction between fixed schedules versus ratios –

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variable schedules and ratio versus interval. And this is something you could print out to look at. I don't need to go over it in detail. The difference between ratio is a reward every certain number of times somebody does something. So, if every tenth time your dog brought you the newspaper you gave it hugs and treats; that's ratio. An interval is over a period of time. So, if your dog gives you--if your dog, I don't know, dances for an hour straight, that would be an interval thing. And fixed versus variable speaks to whether you give a reward on a fixed schedule, every fifth time, or variable, sometimes on the third time, sometimes on the seventh time, and so on.

And these are--There are examples here and there's no need to go over them. It's easy enough to think of examples in real life. So, for example, a slot machine is variable ratio. It goes off after it's been hit a certain number of times. It doesn't matter how long it takes you for--to do it. It's the number of times you pull it down. But it's variable because it doesn't always go off on the thousandth time. You don't know. It's unpredictable. The slot machine is a good example of a phenomena known as the partial reinforcement effect. And this is kind of neat. It makes sense when you hear it but it's the sort of finding that's been validated over and over again with animals and nonhumans. Here's the idea. Suppose you want to train somebody to do something and you want the training such that they'll keep on doing it even if you're not training them anymore, which is typically what you want. If you want that, the trick is don't reinforce it all the time. Behaviors last longer if they're reinforced intermittently and this is known as "the partial reinforcement effect."

Thinking of this psychologically, it's as if whenever you put something in a slot machine it gave you money, then all of a sudden it stopped. You keep on doing it a few times but then you say, "Fine. It doesn't work," but what if it gave you money one out of every hundred times? Now you keep on trying and because the reinforcement is intermittent you don't expect it as much and so your behavior will persist across often a huge amount of time. Here's a good example. What's the very worst thing to do when your kid cries to go into bed with you and you don't want him to go into bed with you? Well, one--The worst thing to do is for any--Actually, for any form of discipline with a kid is to say, "No, absolutely not. No, no, no, no." [pause] "Okay." And then later on the kid's going to say, "I want to do it again" and you say no and the kid keeps asking because you've put it, well, put it as in a psychological way, not the way the behaviorists would put it. The kid knows okay, he's not going to get it right away, he's going to keep on asking. And so typically, what you're doing inadvertently in those situations is you're exploiting the partial reinforcement effect. If I want my kid to do something, I should say yes one out of every ten times. Unfortunately, that's the evolution of nagging. Because you nag, you nag, you nag, the person says, "Fine, okay," and that reinforces it.

If Skinner kept the focus on rats and pigeons and dogs, he would not have the impact that he did but he argued that you could extend all of these notions to humans and to human behavior. So for an example, he argued that the prison system needs to be reformed because instead of focusing on notions of justice and retribution what we should do is focus instead on questions of reinforcing good behaviors and punishing bad ones. He argued for the notions of operant conditioning to be extended to everyday life and argued that people's lives would become fuller and more satisfying if they were controlled in a properly behaviorist way. Any questions about behaviorism? What are your questions about behaviorism? [laughter] Yes. Student: [inaudible]--wouldn't there be extinction after a while? [inaudible] Professor Paul Bloom: Good question. The discussion was over using things like poker chips for reinforcement and the point is exactly right. Since the connection with the poker chips is established through classical conditioning, sooner or later by that logic the poker chips would lose their power to serve as reinforcers. You'd have to sort of start it up again, retrain again. If you have a dog and you say "Good dog" to reward the dog, by your logic, which is right, at some point you might as well give the dog a treat along with the "Good dog." Otherwise, "Good dog" is not going to cut it anymore. Yes. Student: [inaudible] Professor Paul Bloom: As far as I know, Skinner and Skinnerian psychologists were never directly involved in the creation of prisons. On the other hand, the psychological theory of behaviorism has had a huge impact and I think a lot of people's ways of thinking about criminal justice and criminal law has been shaped by behaviorist principles. So for instance, institutions like mental institutions and some prisons have installed token economies where there's rewards for good behavior, often poker chips of a sort. And then you could cash them in for other things. And, to some extent, these have been shaped by an adherence to behaviorist principles.

Okay. So, here are the three general positions of behaviorism. (1) That there is no innate knowledge. All you need is learning. (2) That you could explain human psychology without mental notions like desires and goals. (3) And that these mechanisms apply across all domains and across all species. I think it's fair to say that right now just about everybody agrees all of these three claims are mistaken.

First, we know that it's not true that everything is learned. There is considerable evidence for different forms of innate knowledge and innate desires and we'll look--and we'll talk about it in detail when we look at case studies like language learning, the development of sexual preference, the developing understanding of material objects. There's a lot of debate over how much is innate and what the character of the built-in mental systems are but there's nobody who doubts nowadays that a considerable amount for humans and other animals is built-in.

Is it true that talking about mental states is unscientific? Nobody believes this anymore either. Science, particularly more advanced sciences like physics or chemistry, are all about unobservables. They're all about things you can't see. And it

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makes sense to explain complex and intelligent behavior in terms of internal mechanisms and internal representations. Once again, the computer revolution has served as an illustrative case study. If you have a computer that plays chess and you want to explain how the computer plays chess, it's impossible to do so without talking about the programs and mechanisms inside the computer.

Is it true that animals need reinforcement and punishment to learn? No, and there's several demonstrations at the time of Skinner suggesting that they don't. This is from a classic study by Tolman where rats were taught to run a maze. And what they found was the rats did fine. They learn to run a maze faster and faster when they're regularly rewarded but they also learn to run a maze faster and faster if they are not rewarded at all. So the reward helps, but the reward is in no sense necessary. And here's a more sophisticated illustration of the same point. [Professor Bloom plays video] Professor Paul Bloom: And this is the sort of finding, an old finding from before most of you were born, that was a huge embarrassment for the Skinnerian theory, as it suggests that rats in fact had mental maps, an internal mechanism that they used to understand the world – entirely contrary to the behaviorist idea everything could be explained in terms of reinforcement and punishment.

Finally, is it true that there's no animal-specific constraints for learning? And again, the answer seems to be "no." Animals, for instance, have natural responses. So, you could train a pigeon to peck for food but that's because pecking for food is a very natural response. It's very difficult to train it to peck to escape a situation. You can train it to flap its wings to escape a situation but it's very difficult to get it to flap its wings for food. And the idea is they have sort of natural responses that these learning situations might exploit and might channel, but essentially, they do have certain natural ways of acting towards the world.

We know that not all stimuli and responses are created equal. So, the Gray textbook has a very nice discussion of the Garcia effect. And the Garcia effect goes like this. Does anybody here have any food aversions? I don't mean foods you don't like. I mean foods that really make you sick. Often food aversions in humans and other animals can be formed through a form of association. What happens is suppose you have the flu and you get very nauseous and then at the same point you eat some sashimi for the first time. The connection between being nauseous and eating a new food is very potent. And even if you know intellectually full well that the sashimi isn't why you became nauseous, still you'll develop an aversion to this new food.

When I was younger – when I was a teenager – I drank this Greek liqueur, ouzo, with beer. I didn't have the flu at the time but I became violently ill. And as a result I cannot abide the smell of that Greek liqueur. Now, thank God it didn't develop into an aversion to beer but-- [laughter] Small miracles. But the smell is very distinctive and for me--was new to me. And so, through the Garcia effect I developed a strong aversion.

What's interesting though is the aversion is special so if you take an animal and you give it a new food and then you give it a drug to make it nauseous it will avoid that food. But if you take an animal and you give it a new food and then you shock it very painfully it won't avoid the new food. And the idea is that a connection between what something tastes and getting sick is natural. We are hard wired to say, "Look. If I'm going to eat a new food and I'm going to get nauseous, I'm going to avoid that food." The Garcia effect is that this is special to taste and nausea. It doesn't extend more generally.

Finally, I talked about phobias and I'll return to phobias later on in this course. But the claim that people have formed their phobias through classical conditioning is almost always wrong. Instead, it turns out that there are certain phobias that we're specially evolved to have. So, both humans and chimpanzees, for instance, are particularly prone to develop fears of snakes. And when we talk about the emotions later on in the course we'll talk about this in more detail. But what seems likely is the sort of phobias you're likely to have does not have much to do with your personal history but rather it has a lot to do with your evolutionary history.

Finally, the other reading you're going to do for this part--section of the course is Chomsky's classic article, his "Review of Verbal Behavior." Chomsky is one of the most prominent intellectuals alive. He's still a professor at MIT, still publishes on language and thought, among other matters. And the excerpt you're going to read is from his "Review of Verbal Behavior." And this is one of the most influential intellectual documents ever written in psychology because it took the entire discipline of behaviorism and, more than everything else, more than any other event, could be said to have destroyed it or ended it as a dominant intellectual endeavor.

And Chomsky's argument is complicated and interesting, but the main sort of argument he had to make is--goes like this. When it comes to humans, the notions of reward and punishment and so on that Skinner tried to extend to humans are so vague it's not science anymore. And remember the discussion we had with regard to Freud. What Skinner--What Chomsky is raising here is the concern of unfalsifiablity. So, here's the sort of example he would discuss. Skinner, in his book Verbal Behavior, talks about the question of why do we do things like talk to ourselves, imitate sounds, create art, give bad news to an enemy, fantasize about pleasant situations? And Skinner says that they all involve reinforcement; those are all reinforced behaviors. But Skinner doesn't literally mean that when we talk to ourselves somebody gives us food pellets. He doesn't literally mean even that when we talk to ourselves somebody pats us on the head and says, "Good man. Perfect. I'm very proud." What he means, for instance, in this case is well, talking to yourself is self-reinforcing or giving bad news to an enemy is reinforcing because it makes your enemy feel bad.

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Well, Chomsky says the problem is not that that's wrong. That's all true. It's just so vague as to be useless. Skinner isn't saying anything more. To say giving bad news to an enemy is reinforcing because it makes the enemy feel bad doesn't say anything different from giving bad news to an enemy feels good because we like to give bad news to an enemy. It's just putting it in more scientific terms.

More generally, Chomsky suggests that the law of effect when applied to humans is either trivially true, trivially or uninterestingly true, or scientifically robust and obviously false. So, if you want to expand the notion of reward or reinforcement to anything, then it's true. So why did you come--those of you who are not freshmen--Oh, you--Why did you come? All of you, why did you come to Yale for a second semester? "Well, I repeated my action because the first semester was rewarding." Okay. What do you mean by that? Well, you don't literally mean that somebody rewarded you, gave you pellets and stuff. What you mean is you chose to come there for the second semester. And there's nothing wrong with saying that but we shouldn't confuse it with science. And more generally, the problem is you can talk about what other people do in terms of reinforcement and punishment and operant conditioning and classical conditioning. But in order to do so, you have to use terms like "punishment" and "reward" and "reinforcement" in such a vague way that in the end you're not saying anything scientific.

So, behaviorism as a dominant intellectual field has faded, but it still leaves behind an important legacy and it still stands as one of the major contributions of twentieth century psychology. For one thing, it has given us a richer understanding of certain learning mechanisms, particularly with regard to nonhumans. Mechanisms like habituation, classical conditioning and operant conditioning are real; they can be scientifically studied; and they play an important role in the lives of animals and probably an important role in human lives as well. They just don't explain everything. Finally, and this is something I'm going to return to on Wednesday actually, behaviorists have provided powerful techniques for training particularly for nonverbal creatures so this extends to animal trainers. But it also extends to people who want to teach young children and babies and also want to help populations like the severely autistic or the severely retarded. Many of these behaviorist techniques have proven to be quite useful. And in that regard, as well as in other regards, it stands as an important contribution.

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Lecture 5 Professor Paul Bloom: So, most of what we do these days – our methods, our theories, our ideas – are shaped, to some extent, by Piaget's influence. And so, what I want to do is begin this class that's going to talk about cognitive development by talking about his ideas. His idea was that children are active thinkers; they're trying to figure out the world. He often described them as little scientists. And incidentally, to know where he's coming from on this, he had a very dramatic and ambitious goal. He didn't start off because he was interested in children. He started off because he was interested in the emergence of knowledge in general. It was a discipline he described as genetic epistemology – the origins of knowledge. But he studied development of the individual child because he was convinced that this development will tell him about the development of knowledge more generally. There's a very snooty phrase that--I don't know if you ever heard it before. It's a great phrase. It's "Ontogeny recapitulates phylogeny." And the idea of this--What that means is that development of an individual mimics or repeats development of the species. Now, it's entirely not true, but it's a beautiful phrase and Piaget was committed to this. He was very interested in saying, "Look. We'll figure how a kid develops and that will tell us about the development of knowledge more generally."

So, Piaget viewed the child as a scientist who developed this understanding, these schemas, these little, miniature theories of the world. And they did this through two sorts of mechanisms: assimilation and accommodation. So, assimilation would be the act of expanding the range of things that you respond to. Piaget's example would be a baby who's used to sucking on a breast might come to suck on a bottle or on a rattle. That's changing the scope of things that you respond to. Accommodation is changing how you do it. A baby will form his mouth differently depending on what he's sucking on. And so, these processes where you take in--I'm giving this in a very physical way, but in a more psychological sense you have a way of looking at the world. You could expand it to encompass new things, assimilation. But you could also change your system of knowledge itself – accommodation. And Piaget argued that these two mechanisms of learning drove the child through different stages. And he had a stage theory, which was quite different from the Freudian stage theory that we have been introduced to. So his methods were to ask children to solve problems and to ask them questions. And his discoveries that--they did them in different ways at different ages led to the emergence of the Stage Theory.

So, for Piaget, the first stage is the sensorimotor stage or the sensorimotor period. For here the child is purely a physical creature. The child has no understanding in any real way of the external world. There's no understanding of the past, no understanding of the future, no stability, no differentiation. The child just touches and sees, but doesn't yet reason. And it's through this stage that a child gradually comes to acquire object permanence.

Object permanence is the understanding that things exist when you no longer see them. So those of you in front, you're looking at me and I go [ducks behind lectern]. It occurred to me it'd be a great magic trick if I then appeared in back. But no, I'm just here. That's object permanence. If I went under here and then the people said, "Where the hell did he go? Class is over," that would show a lack of object permanence. So, adults have object permanence. Piaget's very interesting claim is that kids don't. Before six-month-olds, Piaget observed, you take an object the kid likes like a rattle, you hide it, you put it behind something, it's like it's gone. And he claimed the child really thinks it's just gone. Things don't continue to exist when I'm not looking at them anymore. And so he noticed they--they're surprised by peek-a-boo. And Piaget's claim was one reason why they're surprised at peek-a-boo is you go--you look at a kid, the kid's smiling and go, "Oh, peek-a-boo," and you close--and you cover your face and the kid says, "He's gone." "Peek-a-boo." "Oh, there he is. He's gone." And you really--That's the claim.

Piaget also discovered that older children fail at a task that's known as the A-not-B task. And Peter Gray in his psychology textbook refers to it as the "changing hiding places" problem, which is probably a better name for it. And here's the idea. You take a nine-month-old and for Piaget a nine-month-old is just starting to make sense of objects and their permanence. You take an object and you put it here in a cup where the kid can't see it, but it's in the cup. So the kid, if you were the kid, will reach for it. You do it again, reach for it. You do it again, reach for it. That's point A. Then you take--you move it over here. Piaget observed kids would still reach for this. It's like they're not smart enough to figure out that it's not there anymore, even if they see it move. And this was more evidence that they just don't understand objects, and that this thing takes a lot of time and learning to develop.

The next stage is the preoperational stage. The child starts off grasping the world only in a physical way, in a sensorimotor way, but when he gets to the preoperational period the capacity to represent the world, to have the world inside your head, comes into being. But it's limited and it's limited in a couple of striking ways. One way in which it's limited is that children are egocentric. Now, egocentrism has a meaning in common English which means to be selfish. Piaget meant it in a more technical way. He claimed that children at this age literally can't understand that others can see the world differently from them. So, one of his demonstrations was the three mountains task. We have three mountains over there. You put a child on one side of the mountains and you ask him to draw it, and a four- or five-year-old can do it easily, but then you ask him to draw it as it would appear from the other side and children find this extraordinarily difficult. They find it very difficult to grasp the world as another person might see it.

Another significant finding Piaget had about this phase of development concerns what's called "conservation." The notion of conservation is that there's ways to transform things such that some aspects of them change but others remain the same. So, for instance, if you take a glass of water and you pour it into another glass that's shallow or tall, it won't change the

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amount of water you have. If you take a bunch of pennies and you spread them out, you don't get more pennies. But kids, according to Piaget, don't know that and this is one of the real cool demonstrations. Any of you who have access to a four- or five-year-old, [laughter] a sibling or something--Do not take one without permission, but if you have access to a four- or five-year-old you can do this yourself. This is what it looks like. The first one has no sound. The second one is going to be sound that's going to come on at the end [plays video]. But there's two rows of checkers. She asks the kid which one has more. The kid says they're the same. Then she says--Now she asks him which one has more, that or that. So that's really stupid. And it's an amazing finding kids will do that and it's a robust finding.

Here's another example. So, they're the same [tape playing]. So, it's a cool finding of that stage, suggesting a limitation in how you deal and make sense of the world. The next phase, concrete operations, from seven to twelve, you can solve the conservation problem, but still you're limited to the extent you're capable of abstract reasoning. So the mathematical notions of infinity or logical notions like logical entailment are beyond a child of this age. The child is able to do a lot, but still it's to some extent stuck in the concrete world. And then finally, at around age twelve, you could get abstract and scientific reasoning. And this is the Piagetian theory in very brief form.

Now, Piaget fared a lot better than did Freud or Skinner for several reasons. One reason is these are interesting and falsifiable claims about child development. So claims that--about the failure of conservation in children at different ages could be easily tested and systematically tested, and in fact, there's a lot of support for them. Piaget had a rich theoretical framework, pulling together all sorts of observations in different ways, wrote many, many books and articles and articulated his theory very richly. And most of all, I think, he had some really striking findings. Before Piaget, nobody noticed these conservation findings. Before Piaget, nobody noticed that babies had this problem tracking and understanding objects.

At the same time, however, there are limitations in Piaget's theory. Some of these limitations are theoretical. It's an interesting question as to whether he really explains how a child goes from a concrete thinker to an abstract thinker, or how he goes from not having object permanence to understanding object permanence. There's methodological limitations. Piaget was really big into question and answer, but one problem with this is that children aren't very good with language, and this might lead you to underestimate how much they know. And this is particularly a problem the younger you get.

Methodology is going to loom heavy in the discussion of any science and that includes psychology. Often 90% of the game is discovering a clever method through which to test your hypotheses. We're going to talk a little bit about that regarding babies. I'll give you another example from a very different domain. There was a set of scientists interested in studying tickling. So, when you tickle somebody, under what circumstances will they laugh? Where do you have to tickle them? Can you tickle yourself? Does it have to be a surprise, and so on? It turns out very difficult to study this in a lab. You're not going to have your experimental credit. You come into the lab and say, "Okay. I'm the graduate student. Ha, ha, ha." And [laughter] in fact, an example of a methodological attempt was done by Henry Gleitman at University of Pennsylvania, who built a tickle machine, which was this box with these two giant hands that went "r-r-r-r." This was a failure because people could not go near the tickle machine without convulsing in laughter. But we will discuss when we have a lecture on laughter a bit of the tickle sciences.

And finally there's factual. What do infants and children really know? It's possible that due to the methodological limitations of Piaget, he systematically underestimated what children and babies know. And in fact, I'll present some evidence suggesting that this is in fact--that this is the case.

So, I want to introduce you to the modern science of infant cognition. Infant cognition has been something studied for a very long time. And there was a certain view that has had behind it a tremendous philosophical and psychological consensus. And it's summarized in this Onion headline here. And the idea is that babies are stupid, that babies really don't know much about the world. Now, the work that this Onion headline is satirizing is the recent studies, which I'm going to talk about, suggested that on the contrary, babies might be smarter than you think. And to discover the intelligence of babies we have to ourselves be pretty smart in developing different techniques.

To study what a baby knows, you can't ask your questions. Babies can't talk. You could look at what it does but babies are not very coordinated or skilled so you need to use clever methods. One clever method is to look at their brain waves [laughter]. This child on the right died during testing. It was a tragic--It was crushed by the weights [laughter] of the electrodes. He's happy though. You could study their brain waves. One of the few things babies can do is they could suck on a pacifier. And you might think, well, how could you learn anything from that? Well, for instance, you could build machines that when babies suck on a pacifier they hear music or they hear language, and then you could look at how much they suck on the pacifier to determine what they like.

But undeniably we know most of our--we got most of our knowledge about babies from studies of their looking times. That's one thing babies can do. They can look. And I have up here--This is a picture of Elizabeth Spelke, who is a developmental psychologist who's developed the most research on looking at babies' looking times and what you could learn from them. And I have here two ways you could learn from looking. One is preference. So for instance, suppose you want to know, for whatever reason, do babies like the looks of dogs or cats? Well, you could put a baby down, have a picture of a dog here, a picture of a cat here, and see which one the baby looks at. Babies can move their eyes and that could tell you something. Do babies distinguish pretty faces from ugly faces? Well, put a pretty face here, an ugly face here, see if the baby

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prefers to look at the pretty one. You could also do habituation and surprise. And much of the studies I'm going to talk about here involve habituation and surprise.

Habituation is a fancy word for boredom. What you do is you show a baby something over and over again. Now, remember from behaviorism the baby will learn this isn't very interesting. Then you show the baby something different. If the baby really sees it as different, the baby will look longer, and you could use that as a measure of what babies find different. For instance, suppose you want to know if the baby can tell green from red. Well, you could show the baby a green patch, a green patch, a green patch, a green patch; the baby'll get bored, then a red patch. If they all look the same to the baby, the baby will just continue to tune out, but if the red looks different the baby will perk up. And this is, in fact, one way they study color vision in babies.

Surprise is related to this. You could show babies something that shouldn't happen. If babies are like--If babies also think it shouldn't happen, they might look longer, and essentially what happens is scientists do magic tricks to explore this very thing. And to start with some real examples, a lot of this infant research has gone back to the Piagetian question of object permanence, asking, "Is it really true babies don't know that objects remain even when they're out of sight?" So one very simple study by Spelke and Baillargeon: Have babies shown a block with a bar going back and forth like that. So the bar just goes back and forth. Now, there's something you do that's so obvious you probably don't even know you're doing it. When you see a display like that, what you assume is there's a bar there, and what that means is there's something in the middle that you've never seen before. But of course, if you were a simple perceptual creature, you would just see that there'd be a bar on top and a bar on the bottom. You wouldn't expect anything in the middle because you never saw anything in the middle. So, what you do then is you show babies this and then you show them either B or C and if we do this with adults you expect B, C is almost a joke. And, in fact, babies respond the same way. Babies expect there to be an entire, complete bar and are surprised and look longer at the broken bar.

Other studies, some of them--Well, here's another study by Rene Baillargeon looking at the same thing in a different way. You show the baby, say a six-month-old, a stage with a block on it. Then a screen rises and obscures the block. Now, if the babies expect the block to still be there, they should think the block should stop the screen. On the other hand, if out of sight out of mind, they should expect the screen to keep going. So, what you do is you set up a couple of displays, one where the block is stopped, the other one where you take this away with a trap door and it keeps going. And, as you see, the baby screams when this happens. That doesn't really happen, but they do look longer.

One final example of an object permanence study. Some of this work's been done at Yale in Karen Wynn's lab, where they look at babies' understanding of addition and subtraction. And a lot of it is done with real objects, but there's also animated versions so here is an animated example [tape playing]. Babies are surprised. They expect 2 - 1 = 1 and when 2 - 1 = 2 or 3 or 0, they look longer, indicating surprise. And even six-month-olds are sensitive to these rudimentary facts of arithmetic, telling us something about their mathematical knowledge, but also telling us something about that they expect things to remain when they're out of sight.

Now, this research suggests that infants' understanding of the physical world is there from the very start, but at the same time not entirely. We know there are certain things babies don't know. Here's an example. Suppose you show babies this. You have a block here and then you have something above there floating in mid air. Babies find this surprising. Even six-month-olds find this surprising. It violates gravity, but six-month-olds aren't smart enough to know that a block just stuck over here is also surprising. Twelve-month-olds will think that it should fall. Six-month-olds don't, and even 12-month-olds don't find anything weird about this, while adults are sophisticated enough to understand that that's an unstable configuration and should fall over. So, although some things are built in, some things develop.

And this raises the question of, "How do we explain development?" How do we explain when babies come to know things that they didn't originally know? Well, one answer is neural maturation, growth of the brain. Most of the neurons you have now in your head, right now, you had when you were in your mother's uterus. What happens in development isn't for the most part the growth of new neurons. It's for the most part pruning, getting rid of neurons. So, the neural structures change radically as babies kind of get rid of excess neurons through development. At the same time though, connections between neurons grow like crazy and they--and this process of synaptic growth where there are the connections across different synapses peaks at about two years. Finally, remember myelination, where you sort of get this fatty sheath over your neuron to make it more effective? That also happens through development, and in fact, it goes through development and even teenagers are not fully myelinated. In particular, they're not fully myelinated in their frontal lobes. Recall that frontal lobes are involved in things like restraint and willpower. And so, it could be the problem is the baby's brain doesn't develop yet.

Another possibility is there's problems with inhibition. This is related, again, to the frontal lobes and this comes out with the A, not B error. So, remember the baby reaches, reaches, reaches. It's moved, reach, follow, keeps reaching the same place. And it could be that babies don't know anything about objects. But another possibility is once you do something it's kind of hard to stop. It takes a bit of control to stop. And there's all sorts of independent evidence that babies lack this control. The part of their brain that could control certain behaviors is just not active yet.

There's a very nice illustration of inhibitory problems from a "Simpsons" episode that actually sort of covers anything you might want to know about developmental differences. So it goes like this [tape playing]. And that basically may sum up

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much of developmental psychology. That the child essentially--he does A, A, A. It's moved. You go, "doh!" and he keeps going for it. And there's some evidence that's true. Adele Diamond who studies this finds that although kids reach for A, they look for B, as if they know it's there but they can't stop themselves from reaching. And we'll continue this theme a little bit later.

Finally, it might be kids don't know things. Some things you've got to learn. And this is true in all sorts of domains – in the social world, in the economic world, in the political world – and it's true as well in the physical world. In fact, there's some things even adults don't know. So, here's a study by Michael McCloskey with college students. Here's the idea. You have a tube, a transparent--a tube--a hollow tube, and at the top of the tube you throw a ball through so it whips through the tube and it comes out. The question is, "What happens to it?" Does it go in the path of A, or does it go in the path of B? Without looking around, who votes for A? Who votes for B? Here's the weird thing. Whenever I do this at Yale everybody gets the damn thing right [laughter]. At Johns Hopkins, 50/50, [laughter] for A and B. I got to get a better demo. But anyway, college students not here, show systematic biases of incorrect physical intuitions. Here's a twist, and if you found people who were less wonderful than you all, and asked them you'd get a lot of people saying the curving thing. But here's a twist. Ask somebody, "What if you took a tube and you squirted water through it? Where would the water go?" Nobody chooses B. Everybody knows the water would continue in a straight line, suggesting that when you have experience that helps you out, but in absence of experience you're kind of lost.

We've talked about the physical world. What about the social world? What about the world of people? Well, there's a lot of research on this as well. Babies start off with some social preferences. If you take newborn babies--It's very hard to do research with newborn babies actually because of the consent procedure and everything, so most of this work is done in France [laughter], where they have no laws at all. They just rush in to--Women give birth and they rush in and they say, "We are psychologists," and then we do experiments on the babies, and it's terrific. And this is one of them where they compare babies looking at this versus this. Babies like the one that looks like a face. These are newborns. There are some preferences with humans and with other primates to favor faces. Babies are also social animals too, so they're natural mimics.

Andrew Meltzoff, for instance, has found that if you go to a newborn baby, and if you find a newborn baby, this is the first thing you should do. Stick your face right up to the newborn baby and go like this and stick your tongue out. And Meltzoff finds that babies more often than not stick their tongues out back, suggesting some sort of social connection from one person to another, and then later on babies are mimics. Babies more often than not will copy the face next to them. Now, these--the nature of these responses, this preferring faces, this sort of mimicry, is a matter of debate, and there's a lot of research going on asking how smart are babies. Can we see--use some of the same methods that we've looked at for the physical world to look at the social world?

And to illustrate one of the studies, I'll tell you about a study that I did with Valerie Kuhlmeier and Karen Wynn. And so, what we tested was nine-month-olds and twelve-month-olds, and we showed them movies. So, they're sitting down and they're seeing a movie where one character's going to help a ball achieve a goal, and another character's going to hinder the ball. And then we're going to see whether they expect the ball to approach the one that helped it versus the one that hindered it. So, this is what a baby would see. This is literally the same movie a baby would see in the experiment. The thing is for these sorts of experiments there is a lot of control, so something that's a square in one movie will be a triangle in another movie; something that's on the top in one movie will be on the bottom in another movie. So, this is an example movie but this is what babies would see. [video playing]

And they'd see this over and over again and the question is would they expect babies--would babies expect the one to approach the one that helped it or approach the one that hindered it? And what we find is, statistically, babies look longer when shown a movie where it approaches the one that hindered it versus helped it. And this we take as preliminary evidence that they have a social interpretation. They see this movie as you see this movie in terms of helping and hindering, and somebody going to somebody that helped it versus hindered it. You could then ask--This makes a prediction that babies should themselves prefer the creature who's the helper versus the hinderer, and to explore this, a graduate student in this department, Kiley Hamlin, has started a series of studies where they show babies three-dimensional scenes and then give them the characters and see which one they reach for. So, here's video so you could see how this experiment is done. [video playing]

Now, the next trial is from a different study. A different thing we use, and the baby is given a choice. One thing to know methodologically is the person giving a choice is blind to the study. And blind here is a technical term meaning she had no idea what the baby saw, and the point about this is to avoid either intentional or unintentional sort of trying to get the answer you want. She couldn't do that because she didn't know what the right answer is. So, here's what the baby would see. [video playing]

So, this suggests that some social understanding may be there from the very start. This evidence is tentative, very controversial. But now, I want to raise a huge developmental puzzle and the puzzle is there are some ways in which babies are--not just babies, but young children are very clueless when it comes to people. And so, I have a film clip here of two very nice studies

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showing babies' ignorant--sorry, young children's ignorance of other people. I'll show you the studies and then we'll briefly discuss what they mean. Uh oh. [video playing] Professor Paul Bloom: Before discussing that example in a little bit more detail, any questions? What are your questions? Yes, in back. Student: [inaudible] Professor Paul Bloom: Typically--I don't know for those particular children, but typically on those tasks three-year-olds and young four-year-olds tend to fail, and around the age of four or five kids tend to succeed. There's sort of a period around the age of four, four and a half, where kids make the transition from failure to success. The question, by the way, was when do children--in that video when were the--what were the ages of the children who failed and who passed? Yes. Student: [inaudible] Professor Paul Bloom: The question of whether discriminant conditioning has been used with babies to explore what sort of concepts they have. I don't know. Does anybody--It has been-- Graduate Student: --It's not as effective-- Professor Paul Bloom: Koleen answered and said that it's not as effective as other methods. Part of the problem with using operant conditioning with babies is it's difficult to get them to behave in any systematic way. So, the looking-time measures tend to be more subtle. Any other questions? Oh. Yes. Student: [inaudible] Professor Paul Bloom: Oh. The question of why they chose--the baby--the kids chose the rocket ship one as opposed to the Rafael one. It wasn't what they were interested in in the experiment. And my bet is when they chose the stickers they had a pretty good sense of why, of which ones the boys would prefer in those studies. The question of why a boy might prefer one sort of sticker, and you might get a different response with a girl, is going to come up later when we discuss different theories of sex differences. But that was something I think they were just assuming in the study to get it off the ground. Okay.

There's a huge debate over what's going on there. And if you listened at the end to the psychologist summarizing the data, the psychologist had a very good and very clear and strong idea of what was going on. It was that children need to know more about minds. The children don't know about that you can do something with the intent to deceive. They don't understand that somebody could choose what you chose in a malicious way. This is possible. This is one respectable theory, but the alternative is they have the right knowledge, but they suffer from problems with inhibition.

So, consider both studies. The first study, the one with the deceptive dolls with the big shoes and little shoes, is actually fairly difficult. And it's possible that children kind of got overwhelmed with it, and when asked what would the mother think, who the mother would think stole the food, responded with who really stole the food. And that there's some pull towards the right answer that makes this task difficult.

The second one--the second study illustrates this issue even more clearly. Take the boy who kept failing. He kept pointing to the rocket ship and mean monkey kept taking it away. It's possible that he genuinely didn't know what to do, that he wasn't smart enough to understand that he needed to point to the other one. But it's also possible that it's a Homer Simpson-like effect, where when asked to point to what he wants, he just couldn't help but point to the one he wanted. And that the extra work it takes to lie was beyond him. And, in support of the second alternative, even adults find these tasks involving lying and deception more difficult. They were slower at them. We make more mistakes than tasks that don't involve lying and deception. So, I'm raising this not to solve the problem. You'll read more about it in the Peter Gray textbook and more about it in The Norton readings on development, but just to raise this as an interesting area of debate.

Another interesting area of debate is, "What's the relationship between different sorts of development?" So, I started off with Piaget, and Piaget, like Freud, believed in general, across the board changes in how children think. An alternative, though, is that there's separate modules, and this is a view developed, again, by Noam Chomsky, and also by the philosopher of mind Jerry Fodor, who claimed that the whole idea of a child developing as a single story is mistaken. What you get instead is there are separate pre-wired systems for reasoning about the world. These systems have some built-in knowledge, and they have to do some learning, but the learning pattern varies from system to system and there's a separateness to them. Why should we take this view seriously? Well, one reason is that there are developmental disorders that seem to involve damage to one system but not to another. And the classic case of this is a disorder known as autism. And autism is something I've always found a fascinating disorder for many reasons. It's actually why I entered psychology. I started off working with children with autism. And it could be taken as a striking illustration of how the social part of your brain is distinct from other parts of your brain.

So, what autism is is a disorder that strikes about one in a thousand people, mostly boys. And the dominant problems concern--consist of a lack of social connectedness, problems with language, problems dealing with people, and more generally, a problem of what the psychologist, Simon Baron-Cohen has described as "mind blindness." In that autistic people show no impairments dealing with the physical world, they show no impairments on--they don't necessarily show any impairments on mathematical skills or spatial skills, but they have a lot of problems with people. Now, many autistic children have no language; they're totally shut off from society. But even some of them who'd learned language and who managed to get some sort of independent life, nevertheless will suffer from a severe social impairment. And this could be shown in all sorts of ways.

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A simple experiment developed by Simon Baron-Cohen goes like this. You show this to three- and four-year-olds. There's four candies there, and you say, "This is Charlie in the middle. Which chocolate will Charlie take?" For most children and most of you, I hope, the answer's pretty clear: This one. Autistic children will often just shrug, say, "How could I know?" because they don't instinctively appreciate that people's interests and desires tend to be attuned to where they're looking.

Another sort of task, which is a task that's been done hundreds, perhaps thousands of times, is known as "the false-belief task" and here's the idea. You show the child the following situation. There's a doll named Maxie and Maxie puts the ball in the cupboard. Maxie leaves and a second doll enters. The second doll takes the ball out of the cupboard and puts it under the bed. Maxie comes back and the question is, "Where will Maxie look for the ball?" Now, this is a question about your understanding about minds. The question of where is the ball really is a question about the physical world. Everyone can solve it, but this question is hard. The right answer is Max will--Maxie will look in the cupboard, even though it's not really there because Maxie has a false belief about the world. Three-year-olds find this difficult. Two-year-olds find this difficult. Four-year-olds and five-year-olds are able to pass this task. Normal adults are able to pass this task. Children with autism have serious problems. And often, people with autism who are otherwise very high functioning will fail this task. They'll say, "Oh, he must think it's not--He'll--He's going to check under the bed." Any questions about autism? Yes. Student: [inaudible] Professor Paul Bloom: Good question. It isn't. They're both experiments designed to tap an appreciation of false belief. The deception one with the shoes and everything looked at it in the course of deception. Can you understand that the mother might think it's that person even though it's really that person? And our kid failed. This is a sort of stripped-down version without all the fanciness but it tests exactly the same thing. Yes. Student: [inaudible] Professor Paul Bloom: Nobody knows, but there's a theory which won't answer your question but will put it into a broader context. Simon Baron-Cohen argues that there are certain abilities that tend to be more sequestered for males, and other abilities that are more sequestered, more focused on females. Social abilities, he argues, tend to be more female than male. So, the way Baron puts it, provocatively, is to be a man is to suffer from a very mild form of autism [laughter]. The idea is then that autistic individuals suffer from what he calls extreme male brains, and as such, it stands to reason that they'd be more sampled from the male population than the female population. That's such an interesting issue, that again, when we return to talk about sex differences we'll look at that in a little bit more detail to see if it's supported by the evidence. Yes. Student: [inaudible] Professor Paul Bloom: I'm sorry. Tell me the--Is the severity of autism… Student: [inaudible] Professor Paul Bloom: It's an interesting question. The question is, "How do you think about the severity of autism with regard to developmental stages?" And sort of surprisingly, autism can't really be thought of in that way. So, it's not like an adult with autism is like a three-year-old or a two-year-old. In some ways, somebody with autism isn't like any child at all, any normally developing child at all. So, it's not really a developmental delay in the way that it might make sense to think about certain forms of retardation. On the other hand, when we think about how severe autism is we do look at things like how much language does the person have, and in that sense, it is related to development. Yes. Student: What are the chances that someone who's autistic would be able to overcome their deficiencies? Professor Paul Bloom: The majority of people with autism. It's a good question. The question is, "What are the chances that somebody with autism will be able to overcome their deficiencies?" Autism is a funny disorder in that there's a lot of media publication and media presentation. Often the people who are showcased in the media tend to be very exceptional. So, there's a woman, Temple Grandin, who's autistic and--Has anybody here heard of Temple Grandin? She wrote some wonderful books about her experience as an autistic person, but she's very unusual. So a lot depends, to answer your question, how one defines autism, and whether one includes Asperger syndrome, which is a limited, a more mild syndrome, as a form of autism. The answer is that the majority of people with autism have severe problems, and will not, and at this stage, with this level of therapy, will not lead a normal life. Student: More specifically, what I meant was, when you showed the example of Rain Man, ere they exceptional [inaudible] Professor Paul Bloom: Right. The question is about so-called autistic savants. So, Rain Man, the character played by Dustin Hoffman, had extraordinary mathematical abilities. And some people with autism have extraordinary artistic abilities or mathematical abilities or musical abilities and these are amazing. It's an amazing question why they have it but this is a very small minority. This is a very--It's fascinating that it happens at all, that you have severe damage but compensated with some powerful skill. Now, I know I'm answering your question I think in a better way, but it's actually very rare. Most people with autism do not have any exceptional abilities that go along with it.

Another question is if you believe in modules--If there are modules, what are they? And so far when reviewing the developmental data we've talked about two of them: physics and people. An object module and a social module. But other people have argued that there is a special module in your brain for dealing with artifacts, that is, things like tables and chairs and cars and forks. Some people have argued there's a module for sociology, for dealing with human groups, races and classes and so on. Some have even argued that there is an intuitive biology, a common-sense biological understanding of the world that's separate from your understanding of people and physics. And, in fact, the most dominant proponent of the

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view is our very own Frank Keil, Master of Morse College at Yale, who has strongly defended the notion of an intuitive biological module.

Final question, just to raise: I've talked in terms of the modular view but there might also be profound general differences between children and adults, not just specific to how you think about objects or how you think about people or how you think about this or how you think about that, but rather more general. And one claim, which we're going to return to briefly next class when we talk about language, is that there's a very, very big difference between a creature that doesn't have language and a creature that does. And part of the claim is that learning a language, learning to speak, reconfigures the human brain in such a way that is really exceptional. And that has no parallel in any other species. And this is an interesting claim and one we'll talk about.

Finally, I want to end with an example from Stephen Jay Gould. Suppose you hate development; you hate developmental psychology; you hate babies; you hate children; they're not cute; they're ugly; you don't want to have them; you don't want to study them; you're annoyed that we have to discuss them. Fine. But there are reasons to study development even if you are not interested in children because sometimes developmental studies and developmental data and developmental science can inform questions about adults.

And Stephen Jay Gould has a very nice example of this. He asked the question "Is a zebra a black animal with white stripes or a white animal with black stripes?" Now, you could look at adult zebras all day long and you're never going to figure this out. But if you want to know the answer, and I knew it, but I forget what it is--It doesn't matter. But if you wanted to know it you could. You would look at development and you'd watch the embryological development of a zebra and that's how you would learn the answer to your question. In fact, I'll end with a nice quote. This is by the famous biologist, D'Arcy Thompson, who wrote the book On Growth and Form, and it's sort of the model of many developmental psychologists and many evolutionary psychologists so I'll end with this: "Everything is the way it is because it got that way." Okay. I'll see you next week.

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Lecture 6 Professor Paul Bloom: This class today is about language. And language is, to a large extent, where the action is. The study of human language has been the battleground over different theories of human nature. So, every philosopher or psychologist or humanist or neuroscientist who has ever thought about people has had to make some claim about the nature of language and how it works. I'm including here people like Aristotle and Plato, Hume, Locke, Freud and Skinner. I'm also including modern-day approaches to computational theory, cognitive neuroscience, evolutionary theory and cultural psychology. If you hope to make it with a theory of what people are and how people work, you have to explain and talk about language. In fact, language is sufficiently interesting that, unlike most other things I'll talk about in this class, there is an entire field devoted to its study, the field of linguistics that is entirely devoted to studying the nuances and structures of different languages.

Now, I'll first, before getting into details, make a definitional point. When I'm talking about language I'm meaning systems like English and Dutch and Warlpiri and Italian and Turkish and Urdu and what we've seen and heard right now in class in the demonstration that preceded the formal lecture. [Before class started, Professor Bloom had several bilingual students give demonstrations of non-English speech.] Now, you could use language in a different sense. You could use the term "language" to describe what dogs do, or what chimpanzees do, or birds. You could use language to describe music, talk about the--a musical language or art, or any communicative system, and there's actually nothing wrong with that. There's no rule about how you're supposed to use the word "language." But the problem is if you use the word "language" impossibly, incredibly broadly, then from a scientific point of view it becomes useless to ask interesting questions about it. If language can refer to just about everything from English to traffic signals, then we're not going to be able to find interesting generalizations or do good science about it.

So, what I want to do is, I want to discuss the scientific notion of language, at first restricting myself to systems like English and Dutch and American sign language and Navajo and so on. Once we've made some generalizations about language in this narrow sense, we could then ask, and we will ask, to what extent do other systems such as animal communication systems relate to this narrower definition. So we could ask, in this narrow sense, what properties do languages have and then go on to ask, in a broader sense, what other communicative systems also possess those properties.

Well, some things are obvious about language so here are some; here are the questions we will ask. This will frame our discussion today. We'll first go over some basic facts about language. We'll talk about what languages share, we'll talk about how language develops, and we'll talk about language and communication in nonhumans.

I began this class with a demonstration of--that illustrates two very important facts about language. One is that languages all share some deep and intricate universals. In particular, all languages, at minimum, are powerful enough to convey an abstract notion like this; abstract in the sense that it talks about thoughts and it talks about a proposition and spatial relations in objects. There's no language in the world that you just cannot talk about abstract things with. Every language can do this. But the demonstration [before class] also illustrated another fact about language, which is how different languages are. They sound different. If you know one language, you don't necessarily know another. It's not merely that you can't understand it. It could sound strange or look unusual in the case of a sign language. And so, any adequate theory of language has to allow for both the commonalities and the differences across languages. And this is the puzzle faced by the psychology and cognitive science of language.

Well, let's start with an interesting claim about language made by Charles Darwin. So, Darwin writes, "Man has an instinctive tendency to speak, as we see in the babble of our young children, while no child has an instinctive tendency to bake, brew or write." And what Darwin is claiming here, and it's a controversial and interesting claim, is that language is special in that there's some sort of propensity or capacity or instinct for language unlike the other examples he gives. Not everything comes natural to us but Darwin suggests that language does.

Well, why should we believe this? Well, there are some basic facts that support Darwin's claim. For one thing, every normal--every human society has language. In the course of traveling, cultures encounter other cultures and they often encounter cultures that are very different from their own. But through the course of human history, nobody has ever encountered another group of humans that did not have a language. Does this show that it's built in? Well, not necessarily. It could be a cultural innovation. It could be, for instance, that language is such a good idea that every culture comes across it and develops it. Just about every culture uses some sort of utensils to eat food with, a knife and a fork, chopsticks, a spoon. This probably is not because use of eating utensils is human nature, but rather, it's because it's just a very useful thing that cultures discover over and over again. Well, we know that this probably is not true with regard to language. And one reason we know this is because of the demonstrated case studies where a language is created within a single generation. And these case studies have happened over history.

The standard example is people involved in the slave trade. The slave trade revolving around tobacco or cotton or coffee or sugar would tend to mix slaves and laborers from different language backgrounds, in part deliberately, so as to avoid the possibility of revolt. What would happen is these people who were enslaved from different cultures would develop a makeshift communication system so they could talk to one another. And this is called a "pidgin," p-i-d-g-i-n, a pidgin. And this

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pidgin was how they would talk. And this pidgin was not a language. It was strings of words borrowed from the different languages around them and put together in sort of haphazard ways.

The question is what happens to the children who are raised in this society. And you might expect it that they would come to speak a pidgin, but they don't. What happens is, in the course of a single generation, they develop their own language. They create a language with rich syntax and morphology and phonology, terms that we'll understand in a few minutes. And this language that they create is called a "creole." And languages that we know now as creoles, the word refers back to their history. That means that they were developed from pidgins. And this is interesting because this suggests that to some extent the ability to use and understand and learn language is part of human nature. It doesn't require an extensive cultural history. Rather, just about any normal child, even when not exposed to a full-fledged language, can create a language.

And more recently, there's been case studies of children who acquire sign language. There's a wonderful case in Nicaragua in sign language where they acquire sign language from adults who themselves are not versed in sign language. They're sort of second-language learners struggling along. What you might have expected would be the children would then use whatever system their adults use, but they don't. They "creolized" it. They take this makeshift communication system developed by adults and, again, they turn it into a full-blown language, suggesting that to some extent it's part of our human nature to create languages.

Also, every normal human has language. Not everybody in this room can ride a bicycle. Not everybody in this room can play chess. But everybody possesses at least one language. And everybody started to possess at least one language when they were a child. There are exceptions, but the exceptions come about due to some sort of brain damage. Any neurologically normal human will come to possess a language.

What else do we know? Well, the claim that language is part of human nature is supported by neurological studies, some of which were referred to in the chapters on the brain that you read earlier that talk about dedicated parts of the brain that work for language. And if parts of these brains--if parts--if these parts of the brain are damaged you get language deficits or aphasias where you might lose the ability to understand or create language. More speculatively, there has been some fairly recent work studying the genetic basis of language, looking at the genes that are directly responsible for the capacity to learn and use language. And one bit of evidence that these genes are implicated is that some unfortunate people have point mutations in these genes. And such people are unable to learn and use language. So, in general, there is some support, at least at a very broad level, for the claim that language is in some sense part of human nature. Well, what do we mean by language? What are we talking about when we talk about language? We don't want to restrict ourselves, for instance, to English or French. What do all languages share? Well, all languages are creative and this means a couple of things.

One meaning is the meaning emphasized by Rene Descartes. When Rene Descartes argued that we are more than merely machines, his best piece of evidence for him was the human capacity for language. No machine could do this because our capacity for language is unbounded and free. We could say anything we choose to say. We have free will. And in fact, language allows us to produce a virtual infinity of sentences. So, we could create and understand sentences that we never heard before. And there are a lot of sentences. So, if you want to estimate how many grammatical sentences under twenty words in English, the answer is, "a lot." And what this means is that any theory of language use and language comprehension cannot simply appeal to a list. When you understand a sentence I said you have to have the capacity to understand a sentence even if you've never heard it before. And this is because we could effortlessly produce and understand sentences that no human has ever said before on earth.

Would anybody volunteer to say a sentence, non obscene, non derogatory, that has never been spoken before on earth, ever? Here. I'll start. "It's surprisingly easy to get a purple tie on eBay if you don't care much about quality." I could imagine no one else in the world has said this before. "I am upset that one cannot easily download 'Buffy the Vampire Slayer' through iTunes." Now, it's possible somebody said both these sentences before, but you probably have not heard them. But you understand them immediately. So, how do you do it? Well, you have rules in your head. You've learnt what the words mean, but you have abstract and unconscious rules that take these words, figure out the order, and in a fraction of a second, give rise to understanding. And that's the sort of thing linguists study. So, take some standard examples from the linguistic study of English. And bear in mind the rules we're talking about here are not rules you explicitly know. They're automatic rules of the same sort we're going to talk about in the context of visual perception in that they're implicit and unconscious and not accessible to explicit understanding. So for instance, immediately you read "The pig is eager to eat" versus "The pig is easy to eat" and in a fraction of a second you know there's an important difference. "The pig is eager to eat" means the state of affairs that we're talking about is when the pig does the eating. "The pig is easy to eat" is when the pig is being eaten.

You would see a sentence like "Bill knew that John liked him" and you know, without even knowing how you know, that this could mean that Bill knew that John liked Bill or it could mean that Bill knew that John liked Fred. But it can't mean that Bill knew that John liked John. The natural interpretation, in fact, is that Bill knew that John liked Bill. The two words co-refer. Contrast that with "Bill knew that John liked himself," which only has the meaning Bill knew that John liked John. And this is what linguists do for a living so if you hear me talking about this and say, "I want to spend the next forty years of my

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life studying that," you should become a linguist. But that's the sort of--those are the sort of phenomena that we're interested in.

Now, it gets more complicated. Those are examples from syntax, but language has many structures. Language has structures going from the bottom to the top. All languages--All human languages have phonology, which is the system of sounds or signs; morphology, which is the system of words or morphemes, basic units of meaning; and syntax, which refer to rules and principles that put together words and phrases into meaningful utterances. And I want to talk briefly about each of these three parts of language before looking at some other issues. I'm indebted here to Steven Pinker's excellent book The Language Instinct which provides, I think, a superb discussion of these phenomena. And I'm going to steal some of my examples from Pinker.

So, phonology. Phonology is the system of sounds that languages have. There's a subset. There's a list, a finite list, of possible sounds that language can use. I'm going to put aside for the moment the question of sign languages and how they work. I'm going to talk about them in a little bit. The idea is that English has about forty of these phonemes. So, if you're a native monolingual speaker of English you hear speech and each sound you hear is categorized as falling into one of those forty morphemes--sorry, phonemes. So, for example, English has a phoneme of "lu," "l," and a phoneme of "r." And so, an English speaker can hear the difference between "lip" and "rip" and that corresponds to two different words in English. Other languages don't have that distinction and so those distinctions are very difficult for non-native English speakers to learn.

So, part of what goes on when you learn, is you have to learn the language--the phonemes that your language has. Another part of the problem of learning language is you have to figure out what the boundaries are between the words. You have to use sound signals to figure out the boundaries between the words. Now that--If the only language you've ever heard is English, that's going to seem like a really weird example of a problem because you're listening to me speak and in between each of my words you're hearing a pause. You don't have to be very smart to figure out where one word begins and one word ends. But the pause is a psychological illusion. If you were to just talk into an oscilloscope that measured your sound vibrations, there are no pauses between the words. Rather, the pauses are inserted by your mind as you already know where one word begins and another one ends. And you insert a pause at that point.

You could see this when you hear a language you don't already know. So, for those of you who have never heard French before, when you hear somebody say, "Je ne sais pas" you could say, "Remarkable! French has no pauses between words." And you-- And now a French speaker, of course, hears "Je ne sais pas." For Hebrew, I know one sentence in Hebrew: "Sleecha, eypho ha-sheeruteem" which I think is a request for the bathroom. But if you don't know Hebrew there's no pauses. And the truth is, when you each gave your demonstrations, nobody spoke properly because nobody spoke--Here's the sentence: "Glorp [pause] fendel [pause] smug [pause] wuggle." Rather, you all sounded like, "blublublublublub" without any pauses because I don't know your languages.

Children come into the world without knowing any specific language and so they have to learn pauses. They have to learn to interpret sounds in context and sometimes they make mistakes. They get problems of segmentation. And there are some illustrations. You could see their mistakes if they're trying to repeat back something that's already known within a society. So, songs are a good example. These are excerpts from children. [misunderstood lyrics from songs] "I'll never be your pizza burnin'." Anybody know--figure out what that corresponds to? Student: [I'll never be your] Beast of burden? Professor Paul Bloom: "Beast of burden." Very good. [reading another misunderstood song lyric off of the slide] "A girl with colitis goes by." Somebody? Student: "A girl with kaleidoscope eyes." Professor Paul Bloom: "The ants are my friends; they're blowin' in the wind." And [laughter] this is a religious one. "Our father with Bart in heaven; Harold be they name… Lead us not into Penn Station…" Now, phonological understanding illustrates all sorts of aspects of language processing and, in fact, of consciousness. Because remember I said that, typically, when you hear a sentence you make--you manufacture in your mind gaps between the words. Typically, when there's something which is unclear you'll fill in the gap and figure out what the word is. And you'll hear it that way. So, the few examples--The best examples, again, are for when it goes wrong.

So, a classic example is from the song "Super Freak" by Rick James. I got a big lecture about copyright laws and this is going to violate most of them. Rick James is going to be sitting on the--at--staring at the web two years from now saying, "Hey. That's my thing." Okay. So, I want you to listen to this line. I'm sure most of you have heard this before but I want you to listen closely. [music playing] What was that last line? [laughter] "The kind of girl you read about--" Well, it turns out that nobody really knows. And it sounds to many people who do top-down interpretation as--to me as well, that "she's the kind of girl you read about in Newsweek magazine." But that makes no sense at all given that you don't want to "bring home to Mama." [referring to a song lyric] And she's--and it's not the--and in fact, if you check the notes on the song, she's in fact, "the kind of girl you read about in new wave magazines." Now, when you listen to it then, again, knowing that, you hear it that way. [music playing]

Now, this top-down--This is known as "top-down" processing. Top-down processing is an example of when you know what something is you hear it that way. And this is extremely useful when it comes to filling in gaps in sounds. In normal conversation, if I'm to say "s-- [coughs] entence" you won't hear that as "s-- [cough] entence." Rather, you hear

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"sentence." You fill in the gap. This can lead to problems. The problem it's led to in my life revolves around the song "Get Crunk" [laughter] because I've heard "Get Crunk" and my children asked me if I would buy them "Get Crunk" from iTunes. My children are eight and ten. And now "Get Crunk," as I was aware from having heard it before, involves the consistent refrain of "get crunk" extremely bad word, "get crunk" extremely bad word, and so I said "no." And then they said, "Well, there's a clean version of it." So, I downloaded the clean version. Unfortunately, knowing what the clean version--knowing what the word is means to me the clean version is not very clean. Now, I will add, [laughter] before people write letters and stuff, this is the clean version. [The music plays, but even though the expletives are censored out you still perceive them as being there] [laughter] Thank goodness they took away that obscene word. [laughter]

Okay. So, top-down processing affects how we hear things, usually, almost always, for the better. And in fact, this is a theme we're going to return to next class when we talk about vision because the same thing is going to happen there. How we see the world is often confusing and befuddled but what we know can clear things up. Same with sound.

Morphology is the next level up. Phonology is sounds. Morphology is words. And human language uses this amazing trick described by Ferdinand de Saussure, the great linguist, as "the arbitrariness of the sign." And what this means is we can use--take any arbitrary idea in the world, the idea of a chair or a story or a country, and make a sound or a sign to connect to it. And the link is arbitrary. You might choose to use a word for "dog" as "woof woof" because it sounds like a dog but you can't use a word for "country" that sounds like a country. You could use a sign language thing for "drink" that looks sort of like the act of drinking but you can't use a sign language word for "country" that looks like a country, or for "idea" that looks like an idea.

So, the way languages work is it allows for arbitrary naming. It allows for this map between a symbol, say a spoken word, and any sort of thought we want to use. And those arbitrary mappings, as we come to learn them, make up the vocabulary of a language. I'm talking about words but the more technical term is "morpheme." And what a morpheme is is the smallest meaningful unit in a language. Now often, this is the same thing as a word. So, "dog" is a word. And "dog" is also a morpheme, but not always because there are single morphemes and then there are words that are composed of many morphemes. So, "dogs" and "complained" are one word, but two morphemes and what this means is that you make the word by putting together two morphemes. To put it differently, in order to know what "dogs" means, you never had to learn the word "dogs." All you had to know is the word "dog" and the plural morpheme 's' and you could put them together to create a word.

How many morphemes does the average speaker know? The answer is fairly startling. The average speaker knows, as a low-ball estimate, about 60,000 words. I think the proper estimate is closer to 80,000 or 100,000. What this means, if you average it out, is that since children start learning their first words at about their first year of life, they learn about nine new words a day. And it's not a continuous nine words every day. It goes up and down depending on the age. But still, the amount of words we know is staggering. How many of you know more than one language pretty fluently? Those of you who know other languages might have in your heads 200,000 words or 300,000 words and you're accessing them in a fraction of a second. It is--could legitimately be seen as one of the most astonishing things that people do.

Finally, syntax. So, we have the sound system of a language, the phonology. We have the words of a language, the morphology, but all that gives you is "dog," "cup," "chair," "house," "story," "idea." That won't allow us to communicate complicated ideas. So, the final step in the story is syntax. And syntax refers to those rules and principles that allow us to combine words into phrases and phrases into sentences. And syntax uses another neat trick and this is defined by Wilhelm von Humboldt as the "infinite use of finite media." So, here's the question. Your vocabulary is finite. There are just so many words. You have to learn them one by one, but you could produce a virtual infinity of sentences. How can you do that? How can you go from a finite list of symbols to an infinite number of sentences? And the answer is you have a combinatorial system.

Now, language is not the only thing in culture or nature that has this sort of combinatorial system. Music also has a combinatorial system. There's a finite number of notes but a limitless number of musical compositions. DNA also has this sort of combinatorial system where you have a finite number of, I guess, bases or amino acids that could combine to a possible infinity of strings, of DNA strings. So, how does this happen? Well, the infinity mechanism, and many of you will be familiar with this from mathematics or computer science, is recursion. And there's a lot to be said about this but it could be pretty simply illustrated in language.

So, here's an example of a simple language. It's not--It's actually close to how linguists describe normal languages, but it's very simple. It has three nouns, "Fred," "Barney" and "Wilma," and two verbs, "thinks" and "likes." A very simple language. And one rule. And the way to read this rule is you make a sentence by taking a noun, any noun, putting a verb after it, and then following that verb with a noun. Now, when you do this, how many--And then so, for instance, you get the sentence "Fred likes Wilma." When you do this, how many possible sentences are there?

Let me just take a second. Okay. Any guesses? Eighteen. The sentences are "Fred likes Fred," "Fred likes Barney," "Fred likes Wilma," "Fred thinks Fred," "Fred thinks Barney," "Fred thinks Wilma," and so on. The three nouns followed by any of the two verbs followed by any of the three nouns. That is not a very interesting language. But now, take a more complicated language--same vocabulary, the same three nouns, the same two verbs, the same sentence, but now one other sentence. This sentence expands to a noun followed by a verb followed by a sentence and there you get recursion. You

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have one rule invoking another rule and then you can get a sentence like "Fred thinks Barney likes Wilma." And here you get a potential infinity of sentences.

And this is obviously a toy example but you could see the use of recursion in everyday life and in everyday use of language. You could say, "John hates cheese," "My roommate heard a rumor that John hates cheese," "It disturbed Mary when I told her that my roommate heard a rumor that John hates cheese," "I was amazed that it disturbed Mary when I told her that my roommate heard a rumor that John hates cheese," "Professor Bloom had devoted way too much of his lecture talking about how I was amazed [laughter] that it disturbed Mary when I told her that my roommate heard a rumor that John hates cheese," "It really bothered me that--" and there's no limit. There's no longest sentence. You could keep producing a sentence deeper and deeper embedded until you die. And this is part of the power of language.

Now, the syntactic rules are complicated. And one of the puzzles of syntactic rules, or one of the issues of them, is that different rules can conspire to create the same sentence. So, you take a sentence like--This is a classic line from Groucho Marx: "I once shot an elephant in my pajamas. How it got into my pajamas I'll never know." And the humor, such that it is, revolves around the ambiguity of rules that generate it, like this versus like this. Often, to illustrate the issues of ambiguity, people have collected poorly thought-out headlines in newspaper reports that play on--that inadvertently have ambiguity. "Complaints about NBA referees growing ugly." So, that's the beauty of that structure. "Kids make nutritious snacks." "No one was injured in a blast which was attributed to the buildup of gas by one town official." Last summer I was in Seoul visiting the--visiting Korea University and the big headline there on the front page was "General arrested for fondling privates." [laughter]

Now, there actually is--The ambiguity is actually quite difficult to avoid in the construction and understanding of sentences. It's one of the ways in which it's often difficult to write clearly, and in fact, there's a whole sub-field of the law involving the use of linguistic theory to disambiguate sentences both in the Constitution, in legislation, as well as in some criminal cases.

And there was, several years ago, a very serious criminal case that rested on a sentence. And here's what happened. There were two brothers, one of them retarded, and they get into a robbery. And a police officer sees them and points the gun at them. And one of the brothers points a gun at the police officer. The police officer shouts for the brother, the non-retarded brother, to drop the gun. Actually, he said, "Give me the gun." The retarded brother shouted, "Let him have it," whereupon the brother shot and killed the police officer. Now, the brother who did the shooting was plainly a murderer. What about that brother who shouted, "Let him have it"? Well, it depends on what he--on how you interpret that sentence because the sentence is beautifully ambiguous. It could mean "shoot him, let him have it," or it could mean "give him the gun, let him have it." And in fact, the trial, which I think somebody could--If people out there know about this, please send me an e-mail. My understanding was he was found guilty but a lot to turn on the ambiguity of a sentence. I want to shift now and talk about where does all this knowledge come from but I'll stop and answer any questions about the material so far. What are your questions? Yes. Student: How does syntax differ from grammar or are they exactly the same? Professor Paul Bloom: Syntax--The question is, "How is syntax different from grammar?" They're exactly the same. Syntax is a more technical term but it means the same thing as grammar. Yes. Student: You said that every normal human being that's born uses at some point or another some kind of language. Aren't there people who weren't born within a culture and grew up and who never really spoke a language though they were physically normal?

Professor Paul Bloom: Yes. I'm glad you actually asked me about that because, as I said it, I realized it wasn't quite right. The point that was just raised here is I had said before that everybody who's neurologically normal comes to acquire and learn a language. But what about people who are neurologically normal but they don't have language around them? And in fact, there have been, historically, some cases of this. There's been, probably apocryphal, stories about children who are raised by wolves or by dogs. There are stories, horrible stories, some in the twentieth century, about children who are locked away by insane or evil parents and have never learned to speak. There are stories of deaf people who are within certain societies where nobody signs to them, and so they're what's known as linguistic isolates. And they themselves never learn to speak. And those cases are the dramatic exception and they do tell you something.

They tell you that it's not enough to have a brain for language. Somebody does have to use it with you. Interestingly, it doesn't have to be that many people. So, Susan Goldin-Meadow has studied deaf children that nobody signed to but what she studies is deaf children with deaf siblings and these children don't just sit there. They create their own language. It's not a full-blown language like American sign-language or langue des signes quebecoise but it's a language nonetheless, with words and syntax and phonology. It's an interesting question. Any other questions? Yes. Student: Could it be argued that there are inherent limits to grammar? Professor Paul Bloom: It's a good question. The question is, "Are there inherent limits in our abilities to come up with grammars?" And most linguists would argue "yes," that languages are highly constrained in how they do things. So, for instance, one example is there's no language in the world that ever constructs a question by switching the order of words around in a sentence. There's no language in the world that has a rule that says the fifth word has to be a verb. And linguists have all of these conditions they say, "no language in the world works this way." Now this is--;So, these are constraints on

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grammar and they're really interesting because they tell us what's a humanly natural language versus what's not a humanly natural language. But notice, even if there is incredible constraints on grammars, still--we could still produce an infinite number of sentences. It's just like if you restrict me to only a subset of numbers, only the odd numbers, still there's an infinity of odd numbers. So, grammar can be restricted but still give rise to an infinity of possible sentences.

Well, there's a radical claim about the origin of language associated with the guy who we met when we talked about behaviorism who wrote A Review of Verbal Behavior, the linguist Noam Chomsky. And Chomsky makes this radical claim. And this is that we shouldn't view language learning as learning at all. Instead, we should view it as something similar to growth. So he says,

No one would take seriously the proposal that a human organism learns through experience to have arms rather than wings, or that the basic structure of particular organs results from accidental experience. [Language] proves to be no less marvelous and intricate than these physical structures. Why, then, should we not study the acquisition of a cognitive structure like language more or less as we study some complex bodily organ?

So, you might learn to play baseball, you might learn about the American Civil War, but if Chomsky is right you didn't learn to speak English. Rather, what happened is you heard English and--but the capacity grew in your head and something a lot more similar to the development of arms or legs or a visual system.

Well, should we believe this? We know there has to be some effect of the environment shaping language, obviously, because in order to know English you have to have heard English, in order to know Dutch you have had to heard, to--had to have learned and heard Dutch. And in fact, languages differ in all the ways that we were talking about. Some languages like English has a--have a distinction between ʻl' and ʻr.' Other languages do not. For a language like English, that creature there is referred to with the morpheme "dog." That's a historical accident of English. In French it's chien and in Greek it's something else. And each of those 6,000 languages and people in the room who know another language would say, "Yeah, in Vietnamese it's this," "In Urdu it's this," "In Czech it's that."

Finally, there is syntax. So, English is what's known as a subject-verb-object language. That means if you want to convey the idea that Bill hit John, you would say, "Bill hit John." But not all languages work that way. In fact, the majority of languages, more languages, are actually subject-object-verb languages. So, you would say, if you wanted to convey that Bill was the hitter and John was hit, "Bill John hit." All of this has to be learned. And all of this has to be learned through exposure to language users.

On the other hand, there is considerable evidence that the development of these language skills, in some way, is similar to growth in the way that Chomsky suggests. So, here are some basic facts about language development. One is something which I had mentioned before. All normal children learn language. There can be specific impairments of language. Now, again, we spoke about them before when talking about the brain. Some of these impairments could be due to trauma, the aphasias. Trauma, a blow to the head, a stroke can rid you of your language. But, also, there are genetic disorders, some falling under the rubric of what's known as "specific language impairment," where children are born without the same ability as the rest of us to learn to speak. And these are interesting in many ways.

One reason that they're interesting is that they illustrate something about human language. It is not--It would not be unreasonable for you to think before listening to his lecture, "Look. All you need to have to learn a language is to be smart" or "All you need to have to learn a language is to want to communicate" or "All you need to have to learn a language is to be a social person wanting to--having the ability to understand others and deal with others." But the cases of specific language impairments suggest that all of that is wrong, because there are children in this world right now who are plenty smart, who really want to communicate, and who are entirely social creatures but they can't learn language. And this suggests that the ability to learn language and understand language is to some extent separate from these other aspects of mental life.

Continuing on this theme, we also know that language is learnt without any sort of feedback or training. There are many Americans who believe that they need to teach their children language. And there's a huge industry with DVDs and flash cards and all sorts of things designed to teach your children language. And I think many parents believe that if they didn't persist in using these things their children would never learn to speak. But we know that that's not true. We know that this isn't true because there are communities where they don't speak to their kids. They don't speak to their kids because they don't believe it's important to speak to their kids. Some linguists would interview--Linguists would interview adults in these communities and say, "Why don't you speak to your babies?" And these adults would respond, "It'd be ridiculous to speak to a baby. The baby has nothing to say. You might as well just speak to your dog." And then the American linguist would say, "Yeah. We speak to our dogs." [laughter] Americans and Europeans speak to everything and everybody. Other cultures are more picky and they don't talk to their children until their children themselves are talking. This doesn't seem to make much of a difference in language learning.

Some studies have, motivated by Chomsky's work in expressed--sorry, motivated by Chomsky's critique of Skinner'sVerbal Behavior, have asked even in-- "What if we just looked at children within the United States? Don't these children get feedback?" And the answer is yes and no. So your average highly educated Western parent does give their children feedback--do give their children feedback based on what they say. But they don't typically give feedback based on the syntax or grammaticality of what they say.

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The example given by Brown and Hanlon in the classic study in the 1970s is they did all of these studies looking at what children say and how parents responded, and it turns out parents respond not to the grammatical correctness but to the affect or cuteness or sociability of the utterance. So for instance, if a child says to his mother, "I loves you, Mommy," it's a very unusual parent who would say, "Oh, no. The verb agreement is mistaken. [laughter] You've added a redundant ʻs.' It's not appropriate." Similarly, if a child is to say, "I hate your guts, Mother," it's an unusual mother, "That's wonderful. There's a subject, verb, object. The whole thing's structurally fine." We respond to our kids like we respond to each other based on the message that's conveyed, not the grammaticality of the utterances. Children make grammatical mistakes all the time but then they go away and they go away without correction. So those are some basic facts.

What do we know about the time course of language? Well, early on children start off and they prefer the melody of their own language. These studies were done in France with four-day-old babies. And what they did was they used a sucking method. Remember, there's a limited number of things babies can do. One of the things they can do is suck, and these babies would suck on a pacifier to hear French. And they would prefer to hear French than to hear Russian. And these investigators claimed this is because they had been exposed to French in the first four days of their lives. Reviewers, mostly from France, objected and said, "No. Maybe French just sounds better. Everybody's going to like French." So, they re-did the study in Russia. Russian kids sucked harder to hear Russian than they did to French.

And what they're listening to isn't the words. They don't know words yet. They don't know of syntax yet. It's the rhythm of the language. For you, French and Russian sound different. Even if you're like me and you don't know a word of either language, they still sound different. They sound different to babies too. And a baby being raised in France or a baby being raised in Russia knows enough to tell what's his language and what isn't.

Early on, children are sensitive to every phoneme there is. So, English-speaking children, for instance, can--English-speaking babies – babies who are born in the United States – can distinguish between English phonemes like "lip" and "rip" but they could also distinguish between phonemic contrasts that are not exemplified in English, such as phonemic contrasts in Czech or Hindi. Yes. Student: I'm wondering if you can say the wrong things to them--to infants based on what you were saying before. Because I was in France one summer and I had some neighbors there. I hated these neighbors, I thought they were stupid. Not because they were French, but they had a baby and it would gaggle and coo and they would respond in similar terms. Professor Paul Bloom: They would gaggle and coo back at the baby. Student: [inaudible] And I hate these people. [inaudible] So I don't know if it--Does it matter what you say to babies as long as you say something. Professor Paul Bloom: There's a lot going on in your question. [laughter] Some raising--Well, there's a lot going on in your question. The answer to the question-- The question was, "your baby's going to coo and 'ga ga, goo goo,' does it matter if you coo and 'ga ga, goo goo' back?" No, it doesn't make a difference. Your hatred towards them was unmotivated. You can be relieved of that debt, or now you know you feel bad now, I guess. [laughter] If you speak to your children in perfect English, it's very strange. Nobody speaks to their babies in, "Hello, Son. It's time--Oh. You want to change your diaper right now so stay still." That's bad parenting. It sounds kind of silly. More--What most people do is, "Oh. You're such a cute little baby." And it probably--One--There's--Evolutionary psychologists debate the function of why we talk funny to babies. And some people have argued that it does help their language learning. And some people have argued instead that what it does is it calms them. They like to hear the music of a smooth voice and so on. But whether or not you do so doesn't seem to make a big difference.

It is very difficult to find any effect of how parents talk to their kids on how their kids learn language, particularly when it comes to babies. So, early on babies can--are sensitive to all phonemes and then that goes away. Around twelve months of age it goes away. This is one thing you were much better at when you were a baby than you are now. When you were a baby you were a multilingual fool. You could understand the sound differences of every language on earth. Now, if you're like me, you could barely understand English. [laughter] You narrow down until you're sensitive just to the language you hear. And this narrowing down is largely in place by about twelve months of age. Around seven months is babbling. And I want to stop at this point to go back to the issue--I promised you I would turn a bit to sign language and I want to describe now a very elegant--I want to show a little film now of a very elegant series of experiments looking at the question of whether babies who are exposed to a sign language, babble. [film plays]

One of the real surprising findings in my field over the last ten/twenty years has been that the acquisition of sign languages has turned out to be almost exactly the same; in fact, as far as we know, exactly the same as the acquisition of spoken languages. It didn't have to be that way. It could have been just as reasonable to expect that there'd be an advantage for speech over sign. That sign languages may be full-blown languages but they just take--they're just harder to learn because the brain and the body have adapted for speech. It turns out that this just isn't the case. It turns out that sign and--the developmental milestones of sign languages and the developmental milestones of spoken languages are precisely the same. They start babbling at the same point. They start using first words, first sentences, first complicated constructions. There seems to be no interesting difference between how the brain comes to acquire and use the spoken language versus a sign language.

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Around twelve months of age, children start using their first words. These are words for objects and actions like "dog" and "up" and "milk." They start showing some sensitivity to the order of words. So they know that "dog bites cat" is different from "cat bites dog." Around eighteen months of age, they start learning words faster. They start producing little, miniature sentences like "Want cookie" or "Milk spill" and the function morphemes, the little words, "in," "of," "a," "the," and so on start to gradually appear. Then the--Then there's the bad news. Around seven years of age going up through puberty, the ability to learn language starts to go away. The best work on this has been done by Elissa Newport and Sam Supalla who have studied people who have been in the United States for many, many years – 30, 40 years – and seeing how well they have come to speak English. And it turns out the big determinant of how well you speak English as an immigrant isn't how smart you are. It's not how many family members you have when you're here. It's not your motivation. It's how old you were when you started.

It turns out that if you start learning a language – a second language is where most of the work's been done – within the first few years of life you're fine. You'll speak like a native. But then it starts getting worse and worse. And once you hit puberty, suddenly there's huge variation in the abilities you have to learn language. It is very rare, for instance, for somebody who has learned English past puberty to speak without an accent. An accent is very hard to shake and it's not just an accent. It's also other aspects of phonology, syntax, and morphology. It's like the part of the brain that's responsible for language learning is only around early in development and if you don't get your language by then it'll just run out.

I want to begin next class with this question, the question of animals. And that will shut down the language learning part. But one thing I'll put up here is your second reading response. So, I'll also put this up on Wednesday, and by Wednesday you might have a bit of a better--be in a better position to answer this question. But I'll continue with language on Wednesday and then we'll also talk about vision, attention, and memory. I'll see you then.

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Lecture 7 Professor Paul Bloom: Two follow-ups on yesterday's--I'm sorry, on Monday's lecture. One is that somebody came up after class and asked when the preference for your own language emerges in development and fortunately, [A graduate teaching assistant] studies pretty much exactly this sort of infant understanding. She knew the answer. There's been studies looking at newborn babies finding that pretty much the moment they pop out they favor their own language over other language--over other languages. And this suggests that they are listening while in utero, while in the womb, to the rhythms of their language and developing a preference for it.

A second issue is, I talked very briefly about a court case in which the person was--said at a moment where someone else was pointing a gun at a police officer, "Let him have it!" and a police officer was killed. And that person was charged with murder but I admitted I didn't actually know how things turned out and [a graduate teaching assistant] was kind enough to do extensive research. Well, he went to Wikipedia and [laughter] found out the answer. The answer is he was tried and found guilty for murder. He was then subsequently pardoned. In fact, he was pardoned in 1988, which is really nice except he was executed in 1957. But they did it into a movie. So, it's a movie.

Okay. So, I want to do today, for the first part of the lecture, is continue the language lecture and then move to perception, attention, and memory. And what we had spoken about was--We first talked about universals of language, then moved to some detail about the different aspects of language including phonology, morphology, and syntax. We discussed the ways in which language does the amazing things it does, including the fact that language has used arbitrary science or sounds to convey concepts, and that languages exploit a combinatorial system including recursion to put together these symbols into a virtually limitless set of meaningful sentences. We then talked about development and made some remarks about the developmental time course – talking about the emergence of language from babies to – where babies are really good at learning language to you who are not, whose brains have atrophied, whose language capacities are dead.

Final issue is to shift to animals. Now that we know something about language, we could then ask do animals use--possess the same sort of language? And if not, can they learn it? Now, there is absolutely no doubt at all that nonhuman animals possess communication systems. This has been known forever and is not a matter of controversy. And if you want to use the term "language" to mean "communication," then the answer is obviously "yes." Dogs and bees and monkeys have language. If you want to use language though in the more technical, narrow sense as anything that has the properties that we discussed earlier, using English and ASL and Spanish and so on as our background, the answer's almost certainly "no."

Animal communication systems fall into sort of one of three categories. Either there is a finite list of calls, so vervet monkeys, for instance, have a small list of calls to convey different warnings like "attack from a snake" or "attack from a leopard." There is a continuous analog signal. So, bee dance, for instance, works on this way. Bee dance communicates the location of food sources but doesn't do it in any syntactically structured way. Rather, the intensity of the dance corresponds to the richness of the food source. And then, you get things like random variation on a theme such as birdsong. But what you don't find in any real sense is phonology, morphology, syntax, combinatorial systems or arbitrary names.

Now, this much is not particularly controversial. There gets to be a lot of controversy though. This is the summary about nonhuman communication systems. It gets more controversial when we get to famous cases of primates trained by humans such as Kanzi, Nim Chimpsky, and other famous primates that you may well have seen on the Discovery channel and other venues. And this is fairly controversial. If you read the Gray textbook, while nothing in it is particularly inaccurate, I think Gray is actually a little bit too credulous, too believing in the claims that have been made about the abilities of the animals. So many scientists argue, for instance, that animals like Kanzi, even if they can be said to be learning words at all, learn very few of them. And it takes them extensive years of training to learn, unlike a normally developing child who could learn a word in a day or a word in an hour. The utterances often have order but this order tends to be very limited and lacks the recursive properties. And in fact, the lack of recursion is not controversial.

Finally, the utterances of chimpanzees--trained chimpanzees are extremely repetitive so what you often see on TV and in documentaries is sort of a sampling. And the sampling could often be very impressive but if you take just what they say at random it tends to look like this. This is typical chimpanzee utterances just taken at random: "Nim eat, Nim eat. Drink, eat, me Nim. Me gum, me gum. Tickle me, Nim play. Me eat, me eat. Me banana, you banana, me you give. Banana me, me eat. Give orange, me give, eat orange, me eat orange." Lila Gleitman once commented that if any normally developing child spoke like this, his parents would rush him screaming to a neurologist.

There's a broader question here, which is, "Why would we ever expect a chimpanzee to learn a human language?" We don't normally expect one species to have the capacities associated with another species. So, bats use echolocation to get around and some birds navigate by the stars, but there's not an active research program seeing if cats can use echolocation or dogs could navigate by the stars. And I think one reason why you might be tempted to think, "well, of course chimps must be able to learn language" is because you might be caught in the grips of some bad ideas about language.

So, one idea is you might say, "Look. Chimps should use language because chimps are so smart." But the response to this is, "they are smart but we know that smart isn't enough." We know that the human capacity for language is not totally a result of smartness. There are smart children who, due to some deficit in their language capacity, don't speak or understand a language. So, the smartness of chimpanzees does not in itself demonstrate that they should be able to learn language.

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You might also point out correctly that chimps are our nearest evolutionary relatives, which is right, so you--one would expect on the face of it--it's not unreasonable to expect us to share a lot of abilities with them. On the other hand, we split from them a long time ago and plainly humans are different from chimps. And there was five million years either way and that's more than enough time for a language capacity to evolve.

Now, none of this is to say that the study of nonhuman communication systems isn't interesting. From my own--This is my personal opinion I'll raise here. From my own opinion, the study of the attempts to try to teach chimpanzees, or gibbons, or gorillas, a human language like ASL are misguided. It would be as if a team of monkeys kidnapped a human child and tried to train him how to hoot like a monkey. It might be enjoyable but it does not seem to give us any rich insights. What I think is a lot more interesting is the study of these animal communication systems in the wild. There's a linguistics of human language that has delineated the principles that underlie all human languages. It would be as extraordinarily interesting to attempt the same linguistic program to the other communication systems used in the wild such as the cries of vervet monkeys and bee dance.

So, this brings the section on language to a close but I want to tell you a few things we didn't talk about. One of the problems with an Intro Psych course is we have to whip through a lot of topics very fast. So, if you were to take a course that focused directly on language you might learn, for instance, more about language in the brain, something touched about very briefly in the textbook but something that has a large literature associated with it. Similarly, and related to this, there's language disorders, disorders like aphasias and disorders like specific language impairment and dyslexia. There is the study of language perception and production. How is it that we do this amazing feat of understanding and producing words in a fraction of a second? Where does that ability come from?

There is the study of reading which is, in many ways, different from the study of a language. Remember when Darwin described language as an instinct. He carefully distinguished it from other things that don't come natural to us including reading. And in fact, reading is difficult. Reading is a cultural invention, not every human has it. And unlike language, reading is acquired with tremendous difficulty over many years. On the other hand, reading plainly intersects with language. It's a new way of conveying language, moving out from speech to writing. And the psychology and neuroscience of reading is thus very interesting.

There's bilingualism and multilingualism. The questions people in this room typically are going to be interested in is does it matter for how well you learn language whether you're learning one or two or three or four. How is it that a multilingual encodes all these different languages inside a single brain? And so on. Finally, a very hot issue is that of the relationship between language and thought and I'm actually--A few years ago I taught an entire seminar called "Language and Thought" devoted to precisely this question. And it's a cool question and it could break up into two very general questions. One is, "Is language necessary for abstract thought?" And one way to answer that question is to look at creatures without language like babies and chimpanzees and see how smart they are. It might be that they're not--that they're very smart, in which case it would suggest you don't need language for abstract thought. On the other hand, it might be that they have certain cognitive limitations, which would suggest that language is essential for abstract thought.

Then there's the related question. Even once you know a language, does the structural properties of the language that you know affect the way you think? And the claim that the language you know affects how you think is sometimes described as linguistic relativity or the Sapir-Whorf hypothesis. So for instance, there's a lot of research looking at speakers of different languages such as English versus Korean and seeing whether structural differences in these languages affect how you think. Now, some of this work is discussed in the readings, the book--the Gray textbook, and the selections from The Norton Anthology. And this makes up--again, I've showed this to you on Monday--your reading response where you have to address this question and take your best shot at answering it. What are your questions about language? Yes. Student: [inaudible] Professor Paul Bloom: The question was raised, "Some people learn languages easier than others and how do we explain this?" And the answer is you could ask the question both with regard to first language learning – so some children learn language very quickly, some are very slow – and also with regard to second language learning. Some of you are breezing through your second language requirement here at Yale. Others are struggling and miserable. And there's considerable variation. There's the story of Einstein who was very slow to learn language and didn't speak at all until he was four. And in fact, he was a--He said his first words when all of a sudden he was having supper with his parents and he put down the spoon and he said, "The soup is too hot." And his parents stared in astonishment and said, "You've never spoken before." And he said, "Well, up to now everything's been fine." [laughter] It's not a true story. [laughter]

The question of why and where these differences come from, nobody really knows and it's surprisingly hard. There's a slight advantage for being female. Girls are slightly more advanced in language than boys but it's not a big one and you need a hundred people to just see it statistically. There's a big genetic factor. If your parents learned language quickly and learned other languages quickly, you are more likely to. But an understanding of the brain bases of these differences or the cognitive bases or the social bases is just--is largely an open question. Yes. Student: What happens when parents [inaudible] Professor Paul Bloom: This is actually more the norm around the world than the situation in the United States where kids are exposed to a single language. What happens is children learn both languages. Children are very good, as adults are, of

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distinguishing different languages on the basis of their sound system and their rhythms so they don't typically confuse them. And then they just learn more than one language. And that's actually more the average state of affairs around the world. Yes. Student: You said that people who are right-handed learn languages [inaudible] Professor Paul Bloom: The question is about the hemispheric specialization for language. And I don't have actually much more to say than what I said before, which I agree is deeply unsatisfying. If you're right-handed, language is probably in the left side of your brain. How many people here are left-handed? For you we don't know. It varies. Some of you have it in the left side. Some of you have it in the right side. For some of you it's kind of diffuse. Now, why is this? And in fact, why are some people right-handed and others left-handed in the first place? Those are really good questions. Yes. Student: [inaudible] Professor Paul Bloom: Yes. I'll--Yes, that's--I'll answer that question. And unfortunately, it's going to be the last one and then I'll go to vision. The question is, "Does learning more than one language cause you to learn them slower than just learning one language?" And it would stand to reason that it would. There's a finite amount of mental resources. If I'm just learning English, I use all of it for English. And if I'm learning English and Spanish I kind of got to split. And you'd expect them to be each learned slower. It's one of the surprises of the study of language development that that common-sense view does not appear to be true. Children learning more than one language seem to show no deficit relative--in each of their languages, relative to a child learning just one language. In other words, if I am just learning English and I'm a kid and you're learning English and Spanish and you're a kid, you'll reach the milestones in English the same time I will. Your extra learning of Spanish doesn't seem to affect you. There doesn't seem to be any detriment for learning multiple languages.

Another question which comes up is, "Is there any cognitive deficit?" In other words, some people have argued that learning multiple languages sometimes harms children in certain ways. This is a claim that's been made in Quebec, for instance, over the debate over how children should be taught English and French. It does not appear to be the case. There appears to be, as far as we know, no down side to learning many languages when you're young. Does that answer your question?

I want to move now to the topic that will take us through today and through the beginning of next week – perception, attention, and memory. And I'm putting them together instead of treating them as separate lectures because there's a sense in which they're the same story. You see a scene. You see this scene and you're looking at it and you're perceiving it. It's coming through your eyes and you're interpreting it and you see something. You see a man and you see a house. If you were to shut your eyes, you could still hold that scene in memory. And a week later, if I'm to ask you about that, "What season was it?" you would do pretty well. This is the story I want to talk about – how we do this.

And in the course of this I want to make a series of claims that go something like this. For perception, I want to first persuade you the problem of perception's hard and that successful perception involves educated and unconscious guesses about the world. For attention, I want to suggest that we attend to some things and not others and we miss a surprising amount of what happens in the world. For memory, there are many types of memory. The key to memory is organization and understanding. And you can't trust some of your memories.

How many of you remember where you were at 9/11? Many of you are wrong. And I am never going to persuade you of this because you have certain memories. And you could tell the story. Everybody could tell the story where they were when the towers went down. But clever psychologists on September 12 said, "Let's do a study." And they asked people, "Where were you yesterday when you heard the news?" And they told them. And then they went back to them later, a year later, two years later, and said, "Tell me about what happened September 11." And they said, "I remember totally where I was. I have a very--" And then--And often the story was wrong. There is a lot like that which we're going to talk about. And the biggest moral then--so, I put it really, in really big print--We are often wrong about our experiences, both of the present and of right now. So, let's start with perception.

There is a story--I went to graduate school at MIT and there was a story there about Marvin Minsky who is the A.I. [artificial intelligence] guru. He--If you've heard the words--the phrase "artificial intelligence," that was him. And if you heard the claim that people are nothing more than machines made of meat--also him. Well, there's a story where he was doing work on robotics and he was interested in building a robot that could do all sorts of cool things that's like a robot. And the story goes the robot had to among--had to write--had to see the world. It had to be able to pick up things and recognize people and see chairs and navigate its way and Minsky said, "That's a tough problem. It's going to take a graduate student a whole summer to figure it out." And he assigned it to a graduate student for a summer project.

Visual psychologists, perception psychologists, love that story because the study of computer vision and robotics vision and the attempts to make machines that can identify and recognize objects has been a profound failure. There is, at this point, no machine on earth that could recognize people and objects and things at the level of a really dumb one-year-old. And the reason why is that it's a much harder problem than anybody could have expected. Well, what makes it such a hard problem?

Well, one reason why you might think it's an easy problem is you say, "Okay. We have to figure out the problem of how people see. Well, here's what we do." [pointing to a slide that caricatures the inside of a person's head as containing a little man, the real "you," sitting in a control room watching a television monitor that is connected to the larger-head's eyeballs] You're in--You're over there and here's your eye. And somehow it has to get to this television monitor and then you

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look at it and that'll solve the problem of how you see. So, sometimes people say, "Hey. I hear the eye flips things upside down. I guess this guy [the guy in your head] is going to have to get used to looking at things upside down. That's an interesting problem." No. That's not the way to look at it because that doesn't answer any questions. That just pushes the question back. Fine. How does "he" see? We're not answering anything.

Similarly, although the Terminator's [the cyborg assassin from the movie "The Terminator"] view of the world may correspond to that [showing a slide of what vision looks like to the Terminator – a series of gauges and numbers], that doesn't solve any problem of how he actually sees. So, he has all these numbers shooting out there. Well, he has to read the numbers. He has to see this. This [pointing to some icons at the edge of his slide] is my iTunes. [laughter] That's inadvertent.

Here's the right way to think about perception. You got the eye, which is very ugly and bloody, and then around here you have the retina. And the retina is a bunch of nerve cells. And the nerve cells fire at--for some stimulus and not others. And from this array of firings, "firing… not firing… firing… not firing," you have to figure out what the world is. So, a better view is like this. The firings of the neurons could be viewed as an array of numbers. You have to figure out how to get from the numbers to objects and people, and to actions and events. And that's the problem. It's made particularly a difficult problem because the retina is a two-dimensional surface and you have to infer a 3D world from a two-dimensional surface. And this is, from a mathematical point of view, impossible. And what this means is that there--For any two-dimensional image there is an indefinite number of three-dimensional images that correspond to it.

So for instance, suppose you have this on your retina, an array of light shaped like that [referring to a slide portraying a square and an irregular polygon that could be a square that is tilted backwards in space]. What does that correspond to in the world? Well, it could correspond to a thing just like that that you're looking for or it could correspond to a square that's tilted backwards. And so, you have to figure out which is which. And the way we solve this problem is that we have unconscious assumptions about how the world works. Our minds contain certain assumptions about how things should be that enable us to make educated guesses from the two-dimensional array on to the three-dimensional world.

And I purposefully did not make the slides available for this class ahead of time because I don't want people to cheat, but there are several points where you could look at the slides and confirm that some of the things I'm going to tell you are actually true. And I want to give you three examples. One is color. And I'm going to conflate here color and brightness. The other is objects. The other is depth. First, the problem of color. How do you tell a lump of coal from a snowball? Well, that's a lump of coal and that's a snowball, and it's from Google images. How do you know which is which? Well, a lump of coal you say is black and a snowball is white. How do you know? Well, maybe you have on your retina--Your retina responds to sort of color that hits it. It's oversimplified, but let's assume that this is true. So, this is black coming out and that's white and that's how you tell. But in fact, that can't be right. It can't be right because objects' color is not merely a matter of what material they're made of but of the amount of light that hits it. So, as I walk across the stage I fall into shadow and light, and none of you screams out, "Professor Bloom is changing colors!" Rather, you automatically factor out the change in illumination as this is happening.

And this could actually be quite striking. So, you see this display over here. Take a look at those two blocks. [a slide portrays two blocks of different luminance, one under a table, one in the middle of a lit room.] I take it you see this one [the object under the table] as lighter than that one. You do. You might imagine this is because this strip [the block under the table] is lighter than this [the block out in the open] but it isn't. They're the same. And you won't believe me until you actually print it out and take a look, but they are in fact the same. I'll show it to you. And you could say I'm tricking you but this is the way it works. There's the close-up. So, remember we're comparing this and this [the two blocks]. Now, let's take away other parts of the environment and you'll see they're the same. [As Professor Bloom covers the background surrounding both of the blocks they suddenly appear to be the same color as one another.]

Now you say, "But hold it. This can't be the same as this" but the answer is--goes like this. We know shadows make surfaces darker. We don't know this like "Here's something I know." Rather, we know this in that it's wired up in our brains. So when we see a surface in shadow we automatically assume that it's lighter than it looks, and we see it as lighter. And you could show this by removing the cues to the shadow. And you see it as it really is. And this is an illustration of how the information to your eyes is just one bit of information; the degree of light coming from a single source is one bit of information that you use to calculate certain assumptions and come to a conclusion. Here's a different kind of example: Objects. You see this [a picture of a man walking down a path, in front of his house] and you automatically and intuitively segment it into different objects. You segment it into a man and a house and birds and trees. How do you do this? It turns out, to program a computer to segment a scene into different objects is hugely difficult and the question of how we do it is, to some extent, unknown. But one answer to this question is there are certain cues in the environment that are signals that you're dealing with different objects. And these cues are often described as Gestalt principles.

So, one example is "proximity." When you see things that are close to each other, you're more likely than not to assume that they belong to the same thing. There's "similarity." That display [a group of many objects that are all the same shape, but all the objects on one side have a different texture than those on the other side] could correspond to an indefinite number of objects but you naturally tend to see it as two. You do one with one texture pattern, the other with the other texture pattern. "Closure." The fact that this is a closed square here suggests it's a single object [referring to a line drawing of a

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square overlapping a circle]. "Good continuation." If you had to judge, this [referring to a picture of two overlapping lines, line AB and line CD] could just as well be two shapes, one that runs from A to C, the other one that runs from D to B. But you don't tend to see it that way. Rather, you tend to see it as one that runs from A to B, the other one that runs from C to D. "Common movement." If things move together they're a single object. And "good form." You see the object over there [two overlapping and perpendicular rectangles]. In the absence of any other information, you might be tempted to say that's a single thing, a plus sign maybe. This [pointing to two overlapping but non-perpendicular rectangles], because it has lousy form, you're more tempted to say it's two things, one thing lying on top of each other.

And these are the sort of cues, expectations; none of them are right. There's cases where they could all fool you. But these are useful cues that guide our parceling of the world, our segmenting of the world into distinct objects. Here they are summarized [pointing to a slide showing all the cues on the same page]. And here's a case where they fool you [pointing to a slide showing a Kanizsa Triangle, an illusory triangle induced by three incomplete circles]. So you might think, if you're suggestible, that there is a triangle here. And this is a case where there are certain cues driving you to think that there's a triangle here. There is, however, no triangle here. If you cover up these little Pacmen here, the triangle goes away. Similarly, there is no square in the middle [referring to a picture of a Kanizsa Square]. There is no square. It's very Matrix. And these are illusions because these are cues that there should be a square there, the regularity of form.

Finally, "depth." You see this [the picture of the man walking away from his house] and you don't--You see it on one level as a flat thing. Another level you look inside the picture and you see, for instance, the man is in front of the house. You look at me and you see the podium. And if you have a terrible neurological disorder you see this strange creature that's half podium leading on to a chest and up to a head that's sort of--the top of him is wiggling and the podium staying still. If you are neurologically normal, you see a man walking back and forth behind a podium. How do you do that? Well, this is really a problem because, I could give you a technical reason why vision is hard, but crudely, you got a two-dimensional retina and you have to figure out a three-dimensional world. How do you do it? And the answer once again is assumptions or cues. There are certain assumptions the visual system makes that aren't always right and in fact, in cases of visual illusions, can be wrong but will guide you to perceive the world in a correct and accurate way.

So for example, there is binocular disparity. This is actually a sort of interesting one. This is the only depth cue that involves two eyes. If I look at you [a student sitting in the front row] pretty close, the image I get here [pointing to his right eye] and the image I get here [pointing to his left eye] are somewhat different while--or I have to focus my eyes together to get the same image. If I look at you in back, they're almost identical because the further away, given the two eyes that are static, the closer the images look. And it's not, again, that you say to yourself, "Oh. Back there an orange. It's the same image in my right eye and my left eye. You must be far away." Rather, unconsciously and automatically you make estimations on how far people are in depth based on binocular disparity.

There is "interposition." How do you know I'm in front of the podium and the podium's not in front of me? No. How do you know the podium's in front of me? Well, from where I'm standing it's right. How do you know the podium is in front of me? Well, because I'm walking here and then it cuts into me. And unless I'm going through a grotesque metamorphosis, what's happening is it makes sense to say I'm moving behind the podium. Interposition. You take the guy. How do you know the guy is standing in front of the house? Well, because there is--you see all of him and he's blocking a lot of the house.

There's relative size. How far away am I? Well, if you looked at me and you had to estimate how far away I am, part of the way you'll figure that out is you know how tall a human's supposed to be. If you thought that I was fifty feet tall, you would assume I'm further away than I am. And so, your judgments on size dictate your judgments about distance. Usually, this cue isn't necessary but if you look at the Empire State Building--If you go into a field and you see a tower and you look, your judgment of how far away the tower's going to be depends on your knowledge of how tall a tower should be. If it's this tall, you say, "Oh. It must be--" And then you'd be surprised. There's texture gradient, which I'll explain in a second, and linear perspective, which I'll also explain in a second.

Texture gradient goes like this. Remember the problem we had before. How do you know if that thing [a spotted rectangle that's tilted backwards] is this object [a spotted rectangle standing upright] or an object in and of itself? Well, the answer is things with textures will show themselves because the textures will get smaller from a distance. Now, logically, this could still be a single thing standing upright with just dots going up smaller. But the natural assumption is the reason why the dots recede in this regular fashion is because it's receding in depth.

Classic illusion – the Mueller-Lyer illusion. People will see this as longer than this [referring to one of two arrow-like lines, one with both ends pointing inward, the other with both ends pointing outward]. It's not. If you don't believe me, print it out and measure it. Related to the Ponzo illusion, once again people see this one [showing a picture of two gradually converging lines crossed by several horizontal lines, like a train-track receding in the distance] as--you get illusions named after you when you discover these--this one [a horizontal line at the top] as longer than this [a horizontal line at the bottom]. Again, it's not.

What's going on here? Well, the top line looks longer even though it isn't. And one explanation for why is, these other lines in the scene cause your visual system to make guesses about distance. And then you correct for distance by making assumptions about size. If you have two lines--You'll get--We'll get in more detail in a second, but if you have two lines and they take up the same amount of space on your retina, but you believe that one is 100 feet away and the other's 50

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feet away, the one that's 100 feet away you will see as bigger because your brain will say, "Well, if it takes up just this much space but it's further away, it must be bigger than something that's closer and takes up that much space." And that's what goes on here.

For the top line, for the Mueller-Lyer illusion, we assume that this is further away and this is closer based on the cues to distance. And the cue is factored in. And because we assume that this is further away, we assume it must be bigger to take up the same space as this which is closer. Similarly for the Ponzo illusion. There's linear perspective. Parallel lines tend to recede in distance. If this top one is further away than this but they take up the same size in your eye, this one must be bigger and you see it as bigger. And the book offers more details on how these illusions work.

I'm going to end with an illusion that I'm not even going to bother explaining. I'll just show it to you because you should be able to, based on thinking about these other illusions, figure it out. It was developed by Roger Shepard. Well, you know that. And they are called Shepard tables [pointing to a picture of what looks like two simple dining tables, or desks. One that looks longer and skinnier than the other]. And the thing about it is, these look like two tables. If you ask people--You don't frame in terms of here's a lecture on visual perception. You ask people, "Which of these tables would be easier to get through a door if you have a thin door?" People would say the one on the left. This one looks sort of thicker and harder to get through. This one looks longer and leaner. In fact, they're the same size. What I mean by that is that this [rectangle] is exactly the same as this [rectangle].

Now, I'm going to prove it to you by showing you something which took me--on the computer which took me about seven hours to do. And nobody's going to believe it because I could have faked it. But if you want, print it out and do it yourself. You just take a piece of paper, put it on here. Then you move it [he demonstrates that a piece of paper, cut to be the same size as one of the tables, fits perfectly over the other table] and [they're] the same. I showed it to somebody and they called me a liar. Anyway, you could do it yourself in the privacy of your own home or study. But what I'd really like you to do after you do it is say, "Okay. Fine. Why does this one look longer and thinner than this one?" And the answer is the same answer that will explain the Mueller-Lyer illusion and the Ponzo illusion, having to do with cues to depth and the way your mind corrects the perception of depth. And that's all I have to say at this point about perception.

I want to move now to attention and memory and I'm going to treat attention and memory together. We are fascinated with memory and, in particular, it's particularly interesting when memory goes wrong. It's particularly fascinating what happens in cases of amnesia. So for example, I need a volunteer who is willing to do a little bit of acting, a very little bit, an incredibly little bit. [a student volunteers] Excellent. Okay. So well, you just stay there. So pretend you have amnesia. Okay? What's your name? Student: I don't know. Professor Paul Bloom: Perfect. I'm really glad you said that. That's the wrong answer because you don't have total amnesia. You still remember English. Okay. It's very clever. Okay. So you couldn't have lost all your memories. You have English. You [pointing to a different student]--So we'll do you. What's your name? Oh. He looks puzzled but he still maintains bowel and bladder control so he hasn't forgotten everything. [laughter] Now, I always lose the third volunteer in that demo.

So, what I'm saying is that memory is a hugely broad concept. It includes autobiographical memory, which is what we standardly think. That's a perfectly rational response. When I say somebody's losing their memory, "Oh. I have a movie about somebody losing their memory," you don't imagine a person in diapers. You imagine the person walking around, having sex with cool people and saying, "Where am I?" And [laughter] so what you imagine is you imagine them losing their autobiographical memory, their sense of self. But of course, knowing English is part of your memory and knowing how to stand and knowing how to chew and swallow are all things that you've learned, that you've--that have been molded by experience.

There's another distinction which is going to come in regarding amnesia, which is there's broadly two types of amnesia. They often run together, but one type of amnesia is you lose your memory of the past. Another type of amnesia--That's the Matt Damon amnesia. Another type of amnesia though is you lose the ability to form new memories. And here's a film of a man who had exactly this problem. [film playing]

He was a world-renowned choir director and he suffered viral encephalitis which led to brain damage which destroyed most of his temporal lobes, his hippocampus, and a lot of his left frontal lobe. It could be--It could have been worse in that he retains the ability to talk. He seems to be--He's not intellectually impaired. He just can't form new memories and so he lives in this perpetual "now" where just nothing affects him and he feels--This has not always happened. There's more than one of these cases and it doesn't always happen like this, but he feels continually reborn at every moment. And we'll return to this and then ask what's going on here. But there's a few themes here.

I want to, before getting into detail about memory, I want to review some basic distinctions in memory when we talk about memory. So crudely, you could make a distinction between sensory memory, short-term memory, which is also known as working memory, and long-term memory. Sensory memory is a residue in your senses. There's a flash of lightning. You might see an afterimage. That afterimage is your sensory memory. There's somewhat of a longer echoic memory for sounds. So as somebody is talking to you even if you're not paying attention you'll store a few seconds of what they're saying, which is sometimes, when somebody's talking to you and you're not listening to them and they say, "You're not listening to me."

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And you say, "No. You were talking about--" and pick up the last couple of seconds from echoic memory. There's short-term memory.

Anybody remember what I just said? If you did, that's short-term memory--spans for a few minutes. And then there's long-term memory. Anybody know who Elvis is? Do you know your name? Do you know where you live? Your long-term memory store that you walk around with and you're not going to lose right away. When we think about amnesia in the movie sense, we think of a certain loss of long-term memory associated with autobiographical personal events.

There is a distinction between implicit and explicit, which we'll talk about it in more detail. But explicit, crudely, is what you have conscious access to. So, what you had for dinner last night. You could think back and say, "I had this for dinner last night." Implicit is more unconscious. What the word--what certain word--what the word "had" means, how to walk, how to ride a bicycle, that you might not be able to articulate and might not even be conscious of but still have access to.

There's a distinction between semantic memory and episodic memory. Semantic memory is basically facts, what a word means, what's the capital of Canada, and so on. Episodic is autobiography, is what happened to you. That Yale is in New Haven is semantic. That you went on vacation away from New Haven last week, it would be episodic. There is encoding stores and retrieval, which refers to different levels of what happens in memory. Encoding is getting the memory in, as when you study for a test or you have an experience. And storage is holding the memory. And retrieval is getting the memory out.

Finally, retrieval is often broken, conveniently, into recall versus recognition, where recall is when you just pull it out of memory and recognition is when you recognize what corresponds to something in the past. Anybody remember what color tie I had on two days ago? Oh. Okay. Well, that would be impossible to remember but if I asked you, "Is it purple or is it orange?" that would be much easier. [laughter] Now, you could break up, crudely, the memory into stages. So you start that sensory memory is just the stuff that comes in leading to short-term memory, leading to long-term memory. And this stage theory is something which we'll discuss in more detail. But this leads us to the issue of attention.

How do you get memory from your sensations, from what you're hearing? I'm speaking to you. You're hearing me. How does it ever get in to the other systems? What decides what's remembered and what's not? There's all sorts of things happening to you now. The seat of your chair is pressing against your butt. You wouldn't say, "Oh. I want to remember this forever. The seat's pressing against my butt." [laughter] Your neighbor is exuding a certain sort of smell. You're thinking about something. Your eyes follow him. Not everything gets in memory. You'd go mad if you tried to remember everything. You can't. So, what determines what gets into memory? Well, one answer is "attention does."

And attention is--could be crudely viewed as a flashlight, a spotlight on experience that willingly zooms in on something and makes it memorable. Attention has certain properties. Some things come from attention--to attention effortlessly and automatically. Here's an example. You're going to see an array of letters here. One of them's going to be green. When you see the green one, please clap. [laughter] No, not this green one. [laughter] There's going to be another slide. Okay. You're ready now. [students quickly find the one green "x" amongst a background of black "x"s. Okay. Now find--Not that "o" [laughter] but there's going to be an "o." When you see it clap. [students quickly find the "o" amongst a background of "x"s] Okay. Sometimes it's work. Find the red "o." [students are much slower at finding the red "o" amongst a background of black "o"s and red "x"s] [laughter] It's harder.

Sometimes attention is involuntary. I need a volunteer. And all I want to do is I want to show you colors on the screen and I'd like you to name the colors as they come out. [pointing at a student] Do you want this? Student 1: I'm colorblind. Professor Paul Bloom: Oh. [laughter] The first one is easy. See. This is--You have to just go down the colors [on the slide are a series of different colored rectangles. The student must name the colors]. Anybody? Okay. Student 2: Red, green, blue, black, green, blue, red, blue, black, red. Professor Paul Bloom: Excellent. [applause] Okay. Now these. These will be words but just name--Okay, you. Just name the colors. [this slide contains color words that are written in the same color that they spell. Again, the student must name the color of the font] Student 3: Green, red, blue, black, blue, red, green, black, red, blue. Professor Paul Bloom: Perfect. Now, we'll go back to you, same deal, words. [now the slide contains a list of color words that are written in a different colored font then what they spell. The student must name the font color.] Student 4: Red, blue, green -- Professor Paul Bloom: No, no, no. Huh uh. Don't--I know you can read. The colors. Student 4: Okay. Sorry. Okay. Blue, green, red, green, black, green, blue, black, red, [laughter] blue, black, red, black. [the student struggles to name the color of the font without accidentally saying the name that is written] Professor Paul Bloom: Very good actually. [laughter] That's known as the Stroop effect. Being an expert reader, as you are, your knowledge of reading, your attention to what the words meant, subverted your desire to do the task. You couldn't make that go away even if you wanted to. If somebody gave you $1,000 to read this as fast as you read this, and as fast as you read this, you'd be unable to. You can't block it.

There is some work--There are some interesting discoveries about attention. I have a demonstration here. I'd like people actually--It's important--Some of you may have seen this before. It's important for you to be silent throughout it. What you're going to see is you're going to see two teams of basketball players. One of them is going to have white T-shirts. The

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other one will have black T-shirts. They'll be passing balls back and forth. What I'd like you to do is count in your head how many passes the white team does with the ball. [the video shows several people passing a basketball back and forth while, at one point, a person in a gorilla suit walks across the scene] [laughter] What number did people get? Okay. Did anybody notice anything unusual? [laughter] Did anybody not notice anything unusual? Okay. Some people did not notice anything unusual. Those who didn't see anything unusual, watch this again and just watch it. [laughter] About 50% of people when counting, who have never seen this before don't notice anything. But then when you're not counting it's kind of obvious what you're missing. [laughter] And this is one demonstration among many of the fact that when you're attending to something you have a very small window of attention and you lose the focus on other things.

Here's another different example. I'd like people to watch a movie and pay attention very closely to what happens in the movie and try to remember this. [The movie shows a conversation between two people. Each time the camera cuts from one angle to the next something about the scene changes.] How many of you noticed something odd in that movie? How many of you didn't? Okay. Now, everybody look at the scarf, the color of the plates and the food, among other things. [the same movie plays again] The phenomena, in general, has been called "change blindness." And what it is is we tend to be--when there's a focus of attention focused in a certain way, we tend to be oblivious to other things that go on in the environment. Often it is, in fact, quite difficult when there's a change in scene to notice what changes and what stays the same.

So, in this final demo, there's just going to be two pictures flicking. Could you clap when you see what's different between the two pictures? [applause] [laughter] I myself am terrible at these and so I have a lot of sympathy. How many people never saw it? [laughter] Good. That's very impressive. [laughter] One more time with a different one. [applause] Did anybody not see it? Be honest. I'll give you another try. [applause] Okay. I'll put you out of your misery. [laughter] This is work by Dan Simons and it's part of an extraordinarily interesting body of work on what's known as "change blindness." And what this means is, the phenomena is, we have a very narrow focus of attention and huge changes can happen that we are oblivious to. This is why, in movies, there are so many--so much difficulty with continuity changes.

Dan Simons is also famous for having brought this outside of the laboratory in some classic experiments and I'm trying to get the film corresponding to them. What he did was that he did this great study in the Cornell campus where he was--where what happened is they would get some unsuspecting person walking through campus and some guy would come over and say, "Excuse me, Sir. I'm lost. Could you help me with directions?" And have a map and then the person would say, "Sure." And then there'd be two construction workers holding a door. And these guys were going to rudely bump between these two characters and then the experimenter gets switched with another guy. So now, when these two guys walk away, the subject is standing there with an entirely different person. [laughter] What's interesting is nobody notices. [laughter] They notice if the person changes sexes. "Didn't you used to be a woman?" [laughter] And they notice if the experimenter changes races, but most other changes they're oblivious to.

There's another experiment. I think Brian Scholl did this one but it may have been Dan Simons where what happens is a subject comes in to the lab. They say, "If you're going to do an experiment with us, you need to sign the human subject form." Hands him the form, the experimenter. The subject signs the form. The experimenter takes the form and says, "Thank you. I'll put it down here." Goes down here and then a different person pops up. [laughter] People don't notice. And there's a certain level on which we're oblivious to changes. What's weird is we don't see--we don't think we are. We think we see the world as it is and we don't know--notice that when we're attending to something; everything else gets blanked out.

And so about 50% of people who have never seen this demo before, the gorilla demo, they don't notice the gorilla. And there's--you couldn't imagine anything more obvious. The gorilla study was actually done a very long time ago. And it was originally done in a different way but I'll show it to you just because this is the original study and now that you all know what to expect--Oh, not that one. Oops. [demo playing] Nope. [demo playing] That's actually--If you looked at that quickly, it's a current Yale professor. Oh. I'm never going to get my DVD back. Anyway, I'll show you the other demo on--next week. I will. [laughter] Any questions about attention and memory at this point? Yeah. Student: [inaudible] Professor Paul Bloom: Yeah. Why does it work that way? Why is it--Why do things that become very practiced become automatic and involuntary? It's a good question. I don't know. We know that they do. We know that once you--that you can't not read once you know how to read. You also can't not listen. If I'm talking to you and I'm extremely boring, but I'm talking to you, it's very hard not to listen. You can't shut off your ears. You could put your fingers in them but you can't shut off your--You also can't shut your eyes without actually shutting them. You can't say, "This is a disgusting movie. I'm not going to attend to it." [laughter] So, that's not answering your question. It's just saying that your observation is a right one and a more general one. When you're good at something and you're over-practiced, it becomes involuntary and you cannot stop it. Okay. Well--Oh. One more in back. Yes. Student: [inaudible] Professor Paul Bloom: What now? Sorry. Over there. Yeah. Student: [inaudible] right before his accident?

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Professor Paul Bloom: Did he remember things before his accident? Yes. He had some amnesia of events before his accident but he did remember things. He knew his name and he knew other things about his life. Okay. I'll see you next week.

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Lecture 8 Professor Paul Bloom: I'll begin the class officially with a different sort of demonstration. I want to just show you one of the change-blindness studies that has been done in the real world. And these videotapes are not available publicly. We get them from the web and see them as little Java scripts. So, this is one of the first studies done by Dan Simons when he was at Cornell. And his adviser at the time was our Frank Keil, who's now in our department. So, here's the study. [The videotape shows a student who is walking outside on a college campus and stops and asks an older man for directions. Their conversation is interrupted when two construction workers carrying a door walk in between them. At that point the student surreptitiously swaps places with one of the men carrying the door. Remarkably, the conversation about directions resumes without the older man ever noticing that he is speaking to a completely different person.] [laughter] And you don't notice it.

Change blindness is one of the more striking phenomena discovered by laboratory scientists and by psychologists. But it's important to realize, to get away from the sort of surprise of the gorilla and the fact that it's hard to see the flickering--the object that's flickering, and appreciate the big moral of this, because the big moral of this is actually, I think, striking and quite important. You think right now that you're perceiving the world. I look down on you and I think I have a whole sense of where everybody is. I can't see everybody perfectly in back. You're kind of far away and blurry but there's a sense in which I have a world around me. Similarly, if I'm to close my eyes for a second, everything just remains and I could sort of remember some of the things that are there. That's really good sound localization by me [responding to a noise he heard from the video screen].

So you're looking up and you think you have a sense of the world both in perception and memory. The change-blindness experiment suggested this isn't true. The change-blindness experiment suggests that if you look at me for a second and during that second all of your classmates change positions, including those next to you, you are extremely unlikely to notice. The change-blindness experiment suggests that if you turn your eyes away from me towards there for a second and turn back, and I'm dressed entirely differently, you wouldn't notice. The exceptions would be if you told yourself consciously, "Remember what this guy is wearing; he's wearing this, that and the other." But if you don't do it consciously you'll lose it, and usually this is okay.

Usually, it's okay because your memory and your visual system exploits a basic fact about the universe, which is that most things stay the same most of the time. I don't have to explicitly remember that you're over there when I turn my head for a second because you'll be over there in any case. You don't need to hold precise representations of the world. And so you only notice it in certain clever circumstances. One sort of clever circumstance is when psychologists change reality as in the change-blindness studies. A second sort of circumstance is in movies. So, one of the big surprises when people started making movies involving cuts was it is extremely difficult to get everything continuously right. And you need to work very hard to notice. So, there's all of these continuity errors that creep up into movies and you have to be a film buff or writing it down to even notice this. And the overall moral here then is that your perception of reality is a lot more sparse, a lot more limited, than you might think it is.

So, this is where we were at the end of last class. We were talking about the different sorts of memories: Sensory memory, which is the sort of fraction of a second of sensory residue of what you're hearing and what you're seeing, working memory, short-term memory, and then long-term memory. And we talked last class about how things get into sensory memory, into working memory, the role of attention. And in fact, the change-blindness studies are actually just studies of how something gets from your senses to your consciousness and what does and what doesn't.

Now I want to move to the distinction between working memory, short-term memory, and long-term memory. Now, the obvious distinction is actually just in fact--is storage differences. So, long-term memory or "LTM" has a huge storage capacity. This is your memory like the hard drive of your computer. This is the memory you walk around with. It includes all the words in English, just for example, 60 to 80,000 words. It includes everybody you've ever met, languages, faces, stories, locations, nursery rhymes, songs, TV programs. Nobody knows the storage. It is not true that you remember everything that has ever happened to you. There's no reason to believe that this is true. At the same time though, you have a huge amount stored in your brain in long-term storage and nobody actually--It has to be limited because it's a finite, limited brain. But nobody knows how big it is. Nobody knows how many terabytes you carry around in your brain and--but it's a lot.

Compare this to working memory – the short-term memory, which is actually very limited. Your memory of what you could store on--in--where you could hold in consciousness right now is quite limited. Here is an exercise. Do not write these things down. I want you to remember them. I'm just going to give you a few numbers: 14, 59, 11, 109, 43, 58, 98, 487, 25, 389, 54. Please write them down. View this as an IQ test if that would relax you. How many of you who decided to participate in this experiment got three or less? Good. Good. Four, five, six, seven, eight, nine or more? Anybody get all eleven? This is a particularly difficult memory task. The numbers are meaningless. And I told--and I forgot to tell you to get your pen and pencil ready, so some of you just glared at me. But [laughter] under normal circumstances the cognitive psychologist George Miller said that this sort of suggested that the standard memory storage of short-term memory is seven, plus or minus two. And what that means is anywhere from five to nine roughly.

Some of you, I bet, can beat that. Some of you on a not-so-good day maybe won't make it that much. Now "seven plus or minus two" is what you--;so, that's what you hold in consciousness. I can tell you 14, 21. You walk around, "Oh, yeah,

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14, 21." You hold that in consciousness with no problem. But I throw eleven numbers at you, you can't. Some dribble out. You can't hold that in your conscious window in your short-term memory.

Now, this raises the question "seven plus or minus two" what? And the answer seems to be what George Miller calls "chunks." And a chunk is a basic memory unit, something you think of as a single, individual entity. So, suppose you see the string of letters "L, A, M, A, I, S, O, N." If you don't know--If you can't form these into words and you have to remember them, these are eight chunks. You have to just pick them up separately. On the other hand, if you break them up into four words you could just remember it as four chunks. And if you break it up into two words in French, "la maison," "the house," it could just be one or two. How much you know depends--affects how much you memorize--how much you could store in memory because it affects what counts as a basic unit of memory.

And there's all sorts of examples of this. If I tell you "1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0," those of you who don't know binary numbers might have to remember that as "1, 1, 0, 0," whatever I said. Those of you who are computer scientists or mathematicians or, for whatever reason, know binary numbers could convert it into a single binary number. Anybody know what the number is? No, I cannot say it again. [laughter] Some number, 24, or not 24--to some number, 24, and then you remember "24." It's easier. Suppose you see a chessboard and the chessboard is set up and you don't know how to play chess. It is murderously hard to remember that. They've done the experiments. They've taken people in a lab who don't know how to play chess. They set up a chessboard and then they say, "Okay. Look at this for five minutes." Then they take it away, set it up again, and it's murderously hard. "There is a horse-y thing on the side there and everything." But if these chess pieces are set up in some way that's logical for a chess player, then a chess master could look at it and remember it in a glance, "Oh. It's the Fibonacci defense" or something like that [laughs], and then immediately recover it.

Similarly, football coaches have been tested on their memories of football diagrams. And they have a photographic memory for football diagrams because it corresponds to things that make sense. Architects could have a photographic memory, a perfect memory for floor plans because it makes sense to them. They understand it. And so the way you store things in memory, and this is a theme we're going to return to when we get to long-term memory, depends in a large extent on how much you understand it. And this shows up in expertise effects.

Now, this is what's happening so far in short-term memory, how much you hold in there. The question is how do you get it into long-term memory? So, you have long-term memory, your major storage system. How does information get from your consciousness to long-term storage? Well, there's one thing--there's one way which sort of works sometimes but not very well. And it's called "maintenance rehearsal."

Suppose I said you have to remember this number, this string of numbers. And if you remember it in twenty minutes you will get one thousand dollars. And the string is my phone number when I was a kid. I'll include the area code: 514-688-9057. Now, if you tell that to a four-year-old, well, the four-year-old will say, "I'll remember it." And then you ask them, "What did I just say?" "Well, I don't know." If you tell it to an--because you know something--If a lot depended on it, you would know to do something. What you would do is you'd say to yourself, "514-688-9057, 514-688-9057, 514-688 --" You'd rehearse it in your head over and over again. The problem is you could hold it as long as you can do that. It's like these movies. You see this all the time, like an episode of 24: "Jack, call CTU and tell them Agent 11 is trapped in a--" And I can't even remember this but the way to remember it is you hold--you've just got to repeat it over and over again in your head. But this will not typically get things into long-term memory.

To get things into long-term memory, rehearsal is usually not enough. You need to do other things. Typically, what you need is structure and organization. And one way to demonstrate this was in a classic "depth of processing" experiment which nicely illustrates the fact that the more you structure something, the deeper you think about it, the better it gets entrenched in the long-term memory.

So, in this study what they did was they asked people--they told people that there's going to be words flashed on a screen. And all of the subjects saw the same strings of words. There were forty-eight words. They were not told to memorize the words. One third of the subjects was told, "Look. Some of these words are going to come out in capital letters, some of them not capital letters. Press a button for capitals, non-capitals." "Sure." The other group was told, "Some of these words will rhyme with 'train,' Others won't. Press a button if it rhymes in 'train'." The third group was told, "Does it fit into the sentence ʻThe girl placed the blank on the table'? Press a button if it does. Press a button if it doesn't." Then they were asked as a surprise, "What words did you see?" And the findings looked like this. When they were asked to focus on just what the word looked like, memory was very poor, the sound better, the meaning better. If you want to remember something, the best way to remember it is to give it meaning, to give it sense.

This is illustrated through a very ancient technique, which is that the way to remember things that are otherwise arbitrary is to give them some organization through memory tricks, through vivid imagery or songs or poetry. And there's a lot of examples of this. Do you know how to remember that the hippocampus--There's a part of the brain called the hippocampus. This is the worst memory trick ever but it will stick with you for twenty years. The hippocampus is involved in spatial memory. It's involved in finding your way around. Think to yourself, "The way I find my way around campus is through the hippocampus." And you think, "Well, that's stupid," but you'll never forget now that the hippocampus is in charge of spatial memory. It's going to be all you retain from this course.

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Memory books on how to remember people's names usually try to exploit this sort of thing when you try to get poetry or dramatic images. So, the memory books always typically involve somebody--like you meet somebody with very spiky hair and they say, "My name is Mr. Fish" and then you remember--you think of their--of a big fish impaled on their hair. And then whenever you see them you remember their name. It only really works for names like "Fish" but [laughter] the idea is you try to generate vivid imagery. When stuck with a situation where you have to remember ten letters, turn it into a song where--or a dirty poem where each of the letters is the first words of it. When having to remember something that seems totally arbitrary, try to figure out a grand and obscene image that will come to mind easily. And this is how--these are one way to get things into memory.

At a deep level though, the way to get things into memory, and this applies to this course no less than anything else, is by understanding the--understanding it. I'm going to read you something and I want you to try your best to remember what I tell you. These are not going to be strings of numbers. These are going to be--This is going to be a series of sentences: "A newspaper is better than a magazine. A seashore is a better place than the street. At first it is better to run than to walk. You may have to try several times. It takes some skill but it's easy to learn. Even young children can enjoy it. Once successful, complications are minimal. Birds seldom get too close. Rain, however, soaks in very fast. Too many people doing the same things can also cause problems. One needs lots of room. If there are no complications, it can be very peaceful. Finally, a rock will serve as an anchor. If things break loose from it, however, you will not have a second chance."

And here is what I said [pointing to the written sentences on the overhead slide]. This is murderously hard to remember. Now try it. [Pointing to a slide that reads, "This paragraph is about flying a kite."] Knowing what this is about, being able to put a context to it helps the memory and helps it come to mind. [laughter]

Okay. So, this is about how to get memory--how to get information into your memory. How do you get information out? So, it's exam period. You got the stuff presumably into your head. You have to get it out. You have to retrieve it. There is a court case. You have to figure out--You have to recount the crime that you witnessed. You see somebody and you want to know his or her name. And you heard it; you just have to get it out. Well, how do you do that? Well, there's "retrieval cues." Retrieval cues make sense. Retrieval cues are just things that have been associated with what you--what you're trying to remember. If I have to remember to replace the windows, when I walk in to my living room and see that a window is cracked that will remind me to replace the windows. If I had a lunch date with you and forgot about it, when I see you, "Oh, yeah. We were supposed to get together to have lunch."

Retrieval cues bring things back but it's a little bit more complicated than that. There's a more general relationship between encoding and retrieval called the "compatibility principle." And what this means is you're much better to remember something in the context in which you have learned it. And this is also known as "context-dependent memory" and "state-dependent memory." It's illustrated by one of the strangest experiments in the history of psychology where they had people on a boat and then they had them scuba dive underwater. And they taught them things either on the boat or underwater with things that they held up. And then they tested them later. And it turns out that you'll remember it better if you're tested on it in the context in which you learned it. And it might be because then the retrieval cues help bring it back. But it's more general than that. If you have to remember something you learned in this class, you will do better if you try to think about the room in which you learned it in. You will do better on your final exam if you were to take it in this room than if you were to take it in another room because being in this room will bring back the cues.

It's not just the environment. People who learn things when they're stoned remember them better--keeping stoned at a sort of a low-level that doesn't disrupt other mental activities--remember them better when they're sort of stoned again [laughter] than if they're non-stoned. Similarly--So, if you study while you drink you should tipple a little bit before coming in to the Final exam. [laughter] It's sort of like the "what happens in Vegas stays in Vegas" sort of result. And so, similarly, it even applies to moods in that if you learn something when depressed you have a slightly better recovery of it when you're in that same mood of depression than when you're elated. And the idea is that part of what memory is--part of what recovering memory is is getting back your original context in which you learned it.

"Elaborative rehearsal" and retrieval involves the connections between different things. Elaborative rehearsal is that the more you think about something the easier it is to remember. If you have to think about--If you have to remember something, try to connect it to as many things as possible. Think of an image. Make a joke out of it. Imagine how you would explain it to somebody else. Imagine how the world--what the world would be like if it wasn't so. And the idea is that this sort of thinking about it makes connections in your memory from that thing you have to learn, to other memories. And so it makes it easier to recover.

"Elaborative retrieval" refers to a finding that when you want to get something back out of memory people tend to give up too soon. It turns out that there's a lot of stuff that's in your memory but it needs work to extract; it needs various sort of searching strategies. One study asked people who were considerably older than you to remember their high school classmates. And in the first pass people were terrible. Maybe they had a couple of friends they kept in touch with. Otherwise, pretty bad. And this is a good experiment because you could use high school yearbooks to judge whether or not they get it right. But then what you do is you tell the person, "Look. Keep trying. Were you--What sort of--Who was your teacher? What sort of clubs did you belong to? What sort of sports you--did you participate in? How did you get to school? How did you get from school? What did you do during lunch? What did you do during break?" And you keep ask--"Do you know--have any

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friends whose letter--whose last name began with ʻB,' with ʻC,' with ʻD'?" And you keep pushing and pushing and pushing. And over the span of time things come back. Again, it's not true that you never forget. There is honest to God forgetting but sometimes you think you forget and it's because you haven't looked long enough. There's a real physical notion of searching for the right answer.

We've talked about retrieval. Oh. Every class I've given somebody asks either in class or by e-mail what about déjà vu? And déjà vu is a feeling that an event has happened before. So, you're looking at me and I'm lecturing and you say, "I've heard this before. I know this before." You see somebody and say, "I've been in this situation before." This is not evidence for psychic powers, [laughter] which many people say it is, but nobody really knows why this exists. We know, and this is a clue, it's worse with frontal lobe damage. If you get damage to this part of the brain, you get a lot more déjà vu experiences. I asked some experts in memory, including Marcia Johnson who is chair of our department, what the best explanation for déjà vu is. And the answer she gave, the--say one big theory, goes like this. Déjà vu is a feeling that it's happened before. The answer is it has happened before. It's happened half a second ago. And so what happens is sometimes there is a glitch, a disturbance in the force. I don't know. There's a glitch [laughter] and you are talking and then something happens to you and you put it in your memory. But it's as if you don't put the stamp on it of what time and what date. So, you're talking to me and then you store it in memory but you don't store it in memory as happening right now. Then half a second goes by and you're talking to me and you say, "This is strangely familiar." And that's one theory of what goes on in déjà vu.

Okay. So far, there's the sort of good news – remembering – but then there's bad news – forgetting. How many people can remember, without looking down at your notes, at least two of the numbers I gave you earlier? How many people can remember at least four? Oh, impressive. If I asked you in an hour, the number would go down. These are sort of statistics in a similar experiment [pointing to an overhead slide]. And this graph illustrates that people forget. Over time, you'll forget.

Why do you forget? Why is there forgetting at all? Well, there's different explanations for this. One explanation is your brain's a physical thing, it's a physical piece of meat, and it kind of goes bad. Physical things decay. And so, the memory traces that are laid onto your brain will just decay over time. A second answer is interference. So, remember those numbers? Here's a few more: 114, 81, 66, 42. Well, the more information that comes in that's similar to the stuff you're trying to remember, it blocks your recovery of original information. So your ability to remember something can be impaired by learning more things which are related to it because they get confused in memory. Finally, and maybe this is most interesting, there are changes in retrieval cues. So, the more time goes by the more the world changes. And if your memory is to some extent dependent on cues bringing it back to life, then the change in retrieval cues can make it more difficult to recall certain things.

This leads to a puzzle where there's considerable scientific debate over the case of childhood amnesia. And the case of childhood amnesia is--doesn't refer to when a child gets brain damage and gets amnesia. What it refers to is people have a difficult time recovering very early memories. I want people to just take a second and try to think back on what your first memory is and roughly how old you were. How many people don't think you have a first memory until you were about five years old or older? Okay. How many people think you have the first memory of around age four or younger? How many people think you have the first memory of around age three or younger? Two or younger? How many of you think you have the first memory when you were about one years old or younger? And I'm not asking about past lives but that [laughs] happened last year. How old is your--roughly your first memory do you think? [pointing towards a student] How old? Student: Between one and two. Professor Paul Bloom: Between one and two? Anybody think they could beat that? Same guy? Yeah. Student: One. Professor Paul Bloom: One. [laughter] Anybody else? The literature is unclear on this because it's very difficult to test people's recollections of their first memories. If I'm to ask people about their first memories, they'll often say, "Oh, yeah. I remember I was in this room and there was a crib and I'm going ʻGa ga, goo goo' [laughter] and I was on the potty. I was walking. I was so cute. I remember it." It's very difficult to tell and, as we'll discuss in some detail, there are a lot of reasons to distrust people when they--not that they're lying but to distrust the accuracy of people's memories.

We also know from studies about trauma where people have terrible experiences when they're one or two. Typically, this trauma is not remembered later on. People know of trauma because they're told about it but they don't typically remember it with any accuracy. Even children--older children don't remember back beyond that age. Nobody knows why childhood amnesia occurs. Nobody knows why it's very difficult to recover memories before about the age of three. One theory is that the retrieval cues change radically. I had a friend of mine who's a clinical psychologist and he suggested a new form of therapy where they make these giant tables and chairs and then they bring you in to the office and you're standing there with these giant tables and chairs [laughter] and all these memories of being a baby would come flooding back. [laughter] And he dropped out of the field and-- [laughter] Really, but it's such a cool idea.

Some people think language is to blame. So a child, a baby, starts out with no spoken or signed language. Language comes to be learned at around one, two, and three, and it might be that the learning of a language reformats your memory. And once the memory is reformatted it can't go back to the previous state prior to language in the end. It could be

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neural maturation. It could be that those memory parts of the brains grow around age two or three that just weren't there prior to that. And nobody really knows. It's a fascinating research area why--about memory changes early on.

Another case of memory failure is brain damage. And brain damage comes in a couple of flavors. There is retrograde amnesia; "retro" for past. Retrograde amnesia is when you lose some memory of the past. This could be in a case where you get some sort of head trauma and you lose memory of your entire episodic memory. But typically, if you have any sort of serious accident that involves you losing consciousness you'll have a blackout of some period prior to that, say, blow to the head. And the reason for this is as you're having these experiences now they need to kind of get consolidated into your brain. Your brain needs to rewire and catch up to the experiences you're having. A sudden blow to the head will knock you unconscious and then the memories that have happened immediately prior will not get consolidated and they'll be lost forever.

Another sort of memory is anterograde amnesia and this was the case of--This happens in Korsakoff's syndrome. It happens to a very famous patient known as H.M. who actually lives in Hartford, Connecticut. And it happened to Clive Wearing, the film you saw last class. And this sort of amnesia is a sort of amnesia where you lose the ability to form new memories. And so you live in a perpetual present, unable to accumulate new memories.

But it's actually a little bit more complicated than that. What happens is--And this was an exciting discovery about these patients that led to some real insights about normal memory--What happens is--And this is the brain damage in these cases, the temporal lobe and the hippocampus, very useful for spatial memory you'll know. One discovery made about people who couldn't form new memories is that they could form new memories, but of certain types. So for example, this is a task here involving filling in a star while looking in to a mirror. And if I asked you to do it you'd find it pretty difficult. It's just kind of difficult to do. You'd be clumsy at it. You bring in an amnesic who can't form new memories and you say, "Hey. I want you to try something new. I want you to try this star game." He'd say, "Okay. I've never seen it before but I'll do it." Tries it. Does very badly. You bring him in and over and over again--Each time he does it he starts off by saying, "I've never seen this before. I'll--I'm sure I'll give it a try" but he gets better and better at it. And this is known as implicit memory.

The claim is that in these sorts of cases you lose the abilities to form explicit conscious memories that you're aware of, that you understand. But some sorts of memories persist and you are able to form them. This has actually been illustrated in a couple of dramatic movies, one of them a very bad dramatic movie [laughs] where Drew Barrymore loses the ability to form new memories and somehow falls in love with Adam Sandler. [laughs] Definitely don't watch that. But a very good movie called "Memento," which is about a character who loses his ability to form new memories while trying to track down his wife's killer. "Memento" is a movie which is fascinating because it's told backwards. But throughout "Memento" there's another story told forwards. And I like this story because it very dramatically illustrates what does, and what is and is not impaired in cases of severe memory damage. So, I'm going to show you a couple of clips that illustrate the disassociation from "Memento." [clip playing]

Now, the next scene is actually modeled after real experiments. [clip playing] Those of you who have seen the movie know that this ends up quite tragically for Sammy. I highly recommend the movie. We've dealt right now with two sorts of failures of memory. One is everyday failure of memory when you forget. How many of you remember three or more of the numbers I originally presented? Yeah? Go ahead. Student: [inaudible] Professor Paul Bloom: Fourteen, 59, 11. Is that right? [laughs] Fine. [laughter] All right. I'm going to ask you again in a month. [laughter] Well, people are supposed to forget [laughter] and some things will--you will forget. That's normal forgetting.

A second case is forgetting due to brain damage. Forgetting due to brain damage is exotic and unusual but it's interesting in that it illustrates some more general themes about how the mind works. Remember one theme of this course is we're going to look at exotic cases like the case of Clive Wearing, not just because they're interesting in their own right but sometimes by looking at the extremes we could learn something about how normal people's normal, intact minds and brains work.

The third case of forgetting is more interesting and it actually--Well, I want to do a little trial here. What I want to do is I want to--You to listen to three children describe an event that happened. I want you to come to some--your own guess. Imagine you were a judge, you were a childcare worker, you wanted to see--I want you to be--come to your own guess about who you believe and what you think happened. [audio playing] [inaudible] [laughter]

You've heard three children. Who do you believe? Who believes--There's three of them, one, two, three. Who believes the first one? Who believes the second one? Who believes the third one? Sort of an even split. Twenty-three hundred experts were shown these films and asked about the different actions, whether or not the person ripped the book, messed up the bear, tossed the book in the air and, as you could see, the majority thought that he did. This is work done by Steve Ceci who was gracious enough to lend me the film to use for teaching purposes.

It turns out the second girl was right. Absolutely nothing happened. [laughter] The teacher said, "There is somebody named Sam Stone who's going to come in." A guy walks in and says, "Hi," walks around and leaves. [laughter] The first and third children had their memories implanted, not through any sort of science fiction means. They had their memories implanted--Well, they had their memories implanted like this. Some of the children would just ask questions. The interviewer,

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by the way, was herself unaware of what happened so the interviewer was a perfectly naïve interviewer. And it turns out if you just interview children and you ask them questions about whether the book was ripped, "Did you see him? Did he really do it?" they don't say anything. They didn't see anything and they won't say anything.

Other children were told about Sam Stone. They were told a stereotype about Sam Stone – that he's very clumsy and he tends to rip things and he trips and he breaks things and he spills things. And in fact, the third child mentioned that in passing. He said, "He always does that." Just knowing this about Sam Stone tends to raise the proportion of kids who say, for instance, that he ripped the book.

Other children were given suggestions. They were given suggestive questioning. They were a series of leading questions like, "Oh. Sam Stone came in? Did he rip a book while he was there?" And still more children got both. And in fact, the children you saw were from this group. They heard Sam Stone being described as a clumsy fellow and they were given a series of suggestive questionings. In this condition they were given several suggestive questionings over the period of several months. These children, like the first child and the third child, are not lying. They honestly believe that Sam Stone came in and did these things. Also they believe it and they're so convincing in their belief that experts, including police officers and child caseworkers and judges and lawyers, find these children to be extremely believable. And I think they probably find them to be extremely believable because the children are not lying. They really believe they saw what they saw. But these memories were implanted. And Ceci, and many other investigators, study how memories can be implanted in people's minds through suggestion and through leading questions.

It turns out that the same sort of experiments and the same sort of research has been done with considerable success in implanting false memories in adults. There are dramatic cases of people remembering terrible crimes and confessing to them when actually, they didn't commit them. And this is not because they are lying. It's not even because they're, in some obvious sense, deranged or schizophrenic or delusional. Rather, they have persuaded themselves, or more often been persuaded by others, that these things have actually happened.

Psychologists have studied in the laboratory how one could do this, how one can implant memories in other people. And some things are sort of standard. Suppose I was to tell you a story about a trip I took to the dentist or a visit I took to--or a time when I ate out at a restaurant and I'm to omit certain details. I omit the fact that I paid the bill in a restaurant, let's say or I finished the meal and then I went home. Still, you will tend to fill in the blanks. You'll tend to fill in the blanks with things you know. So, you might remember this later saying, "Okay. He told me he finished eating, paid the bill and left," because paying the bill is what you do in a restaurant.

This is benign enough. You fill in the blanks. You also can integrate suppositions made by others. And the clearest case of this is eyewitness testimony. And the best research on this has been done by Elizabeth Loftus who has done a series of studies, some discussed in the textbook, showing how people's memories can be swayed by leading questions. And it can be extremely subtle. In one experiment, the person was just asked in the course of a series of questions--shown a scene where there's a car accident and asked either, "Did you see a broken headlight?" or "Did you see the broken headlight?" The ʻthe' presupposes that there was a broken headlight and in fact, the people told--asked, "Did you see the broken headlight?" later on are more likely to remember one. It creates an image and they fill it in.

In another study, she would show film segments and then ask, "Did you see the children getting on the school bus?" Now, there was no school bus but people who hear that question later on when asked, "Did you see a school bus in the film?" are more likely to say yes. In another study, she would show people film segments and ask them either, "How fast were the cars going when they hit each other?" or "How fast were the cars going when they smashed into each other?" A week later she'd bring people back in to the laboratory and ask, "Did you see any broken glass?" Those who hear a smash tend to see the broken glass more than those who hear a hit because the question has changed their memory, making it more of a dramatic event.

Hypnosis is the clearest case where there's a sort of reconstructive effort led by--led as a result of leading and probing questions. Some of you are readily hypnotizable and you can be hypnotized. And what we would learn about a past event from hypnotizing you will not necessarily then be inaccurate. What hypnotizing does is it makes people very willing to cooperate. Unfortunately, it isn't as if there is a memory storage there where you could just go through and look as in the movies where you just say, "What's the license plate?" The person's hypnotized and then the flashback comes in and then they zoom in on the license plate. Memory doesn't work that way. What happens is--What somebody will do in a hypnotizable state is they'll be very eager to please the hypnotist. And so they'll make stuff up.

And people under hypnosis just make stuff up. And they do very enthusiastically and very believably make stuff up. This is particularly the case with hypnotic regression when we ask you to go back to your sixth birthday party, for instance. And what's great as a developmental psychologist is if I ask you to go back to your fourth birthday party and you're hypnotizable you'll be oh, just like a four-year-old except you won't be like a real four-year-old. What you'll be like is an adult's notion of what a four-year-old is supposed to be. In fact, this has happened in the extreme case with hypnotic regression where people claim to speak languages like from ancient Egypt. And linguists love these studies because you don't--of course you don't really sound like you're speaking a language from ancient Egypt. What you sound is like a North American who believes he's speaking a language from ancient Egypt so they're, "nonsense sounds." [laughter] And so what it makes

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you is--Hypnotism brings out the actor in you. It makes you want to give a persuasive account of what happened. And so hypnotism is just an extreme form of what normally happens in eyewitness testimony.

Repressed memories. We could devote a class--We could devote a semester to the very heated debate in the United States mostly about repressed memories. There are many adults who have claimed to have experienced traumatic sexual abuse. In some cases, this is unexceptional from a memory point of view. People know this happened to them. They've always known it happens to them and then they tell people about it. But there's a subset of cases where people have had no memory up to a point of what happened to them. Then they go to a psychologist or a psychiatrist; they undergo questioning, often using hypnotic techniques; and then they recover a memory of past traumatic sexual abuse. And what this is--what makes this so debatable, and there is a debate about this. I don't want to try to preclude it one way or another. What makes this debatable is some psychologists believe that, in at least some cases, these memories are real and they have been repressed through a Freudian mechanism – that they're too terrible to bring to consciousness, and the therapy brings them out into real life. But most psychologists believe that these memories cannot be trusted, that these memories are created through the actions of the therapist.

And so, there's actually considerable psychological and legal battles over the veracity of the therapists where women who have claimed to have sexual--be sexually abused, for instance, have pressed criminal charges against their fathers on the basis of false memories. Similarly, people who have been accused of sexual abuse have pressed criminal charges against psychiatrists claiming that these psychiatrists have implanted the memories into their sons and daughters. It is controversial whether memories are ever repressed. What isn't controversial is that, for at least some cases, you can implant false memories in people, not because you're a sinister or evil person but because you really believed something happened. And you talked to them about it and then you caused these memories to come into being.

A final case is flashbulb memories. I asked this early in the semester. I'll ask it again. How many of you remember where you were on September 11, 2001? Is there anybody who doesn't remember where they were on September 11, 2001? It would be interesting. It was a socially relevant event, but here's the problem with these flashbulb memories. Flashbulb memories are the idea that these memories being so vivid, and they are vivid for many of us--exactly where we stood, what happened; well, they can't really be trusted. And here is why not. Because they are such important events, I bet many of you have actually heard the question before, "Where were you on September 11th?" and talked about it. What happens in these conversations is stories change. I have my--I knew where I was on September 11th. My wife knew where she was. But I spent as much time listening to her talk about it as I spent time me talking about it. And now maybe my memory is actually of her experience and not mine.

It's not--For all of these cases, the temptation you have to resist is saying, "Yes. I know memories can be swayed. I know they could be distorted and everything but, you see, I really am sure that happened." You have to resist that temptation because there are so many cases we know, including the tape of the girls that we just saw, where people are entirely sure things happened. And we know full well that they didn't exist. Being sure is no guarantee that a memory isn't false, reconstructed or even implanted.

So, this part of memory has three main morals. There are many types of memories. I talked about short-term memory, long-term memory. I talked about implicit memory and explicit memory. These are sort of separable sort of memories. You could break one while having the other one impaired. Arguably, there are brain systems dedicated to memory for faces, memory for everyday objects, memory for spatial locations. The key to remembering is organization and understanding. Introduction to "X" courses, including Introduction to Psychology courses, are among the hardest courses at Yale. And the reason why is there is just a lot of material that is diverse and you have to command each aspect separately. The easiest courses at Yale tend to be highfalutin seminars where you kind of have enough of a background that everything is--can be clear and understandable. The more you understand something, the easier you'll remember it.

And finally, you can't trust some of your memories. Your reading response for this week is you have to use your powers for good and not for evil, [laughter] though if you manage to succeed at this I will be very impressed. [laughter] But you have to describe, based on the lecture materials and the readings, how to implant a false memory. We have a few minutes. Any questions on memory. Yes. Student: [inaudible] Professor Paul Bloom: Uh huh. Hey. Please-- Student: [inaudible] Is that long-term sensory memory? Professor Paul Bloom: The example is, "What sort of memory is it when you know how to play the piano?" And it's a very good question. It is long-term memory because you might know how to do a concerto or a song and then you have it stored in your head and you carry it around with you. You'll remember it a year from now, two years from now. It is long-term memory but it is also an excellent example of implicit memory because you know how to do it but you could do it unconsciously without attending to it. It's not sensory but it's as if, put it crudely, that your fingers know and not your mind. We have time for one more question. Yes. Student: [inaudible] Professor Paul Bloom: The question is about photographic memory. There are a lot of claims about photographic memory. My understanding is they do not tend to be substantiated. Sometimes photographic memory, and this came up when we

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talked about autism a few classes ago, is linked with savant-like skills. People who have severe impairments in some ways may have photographic memories in others. I am not convinced that photographic memory in the sense that you see something, you take a picture of it, you hold it in memory really exists. I think there may be one or two case studies that suggest it might be real but I think it's controversial. Okay. We have a guest lecturer on Wednesday. Dean Peter Salovey will talk to us about love.

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Lecture 9 Professor Paul Bloom: I'm delighted to introduce the first guest lecturer for this Introduction to Psychology course, Dean Peter Salovey. Peter is an old friend and colleague. Many of you--I think everybody here knows of him through his role as Dean of Yale College. I'll just, in this context of this introduction, mention two other things about him. One is prior to being dean and in fact, still as a dean, he's an active scientist and in particular, a social psychologist actively involved in studying health psychology, the proper use of psychological methods to frame health messages, and also is the founder and developer of the idea of emotional intelligence, an idea he's done a huge amount of research on. Secondly, Peter is or was an active and extremely well-known teacher at Yale College. He taught at one point, the largest course ever in Yale College – a course on Psychology in Law which broke every record ever had here. And before that, during that, and after that, he was a legendary Introduction to Psychology teacher. And I think--and he had some reason for why he was so legendary with his lecture today on the topic of love. [applause] Dean Peter Salovey: Thanks very much. Okay. Thank you very much, Professor Bloom. It really is a pleasure to come and lecture to you today on Valentine's Day on the topic of love. My main area of research is human emotion. And love is an emotion. It's not one that I study personally, at least not in the lab, and--but it is fun to talk about. And it is a topic that lends itself to many social psychological phenomena. It's also great to be able to come in and guest lecture. One of the things I very much miss since serving as dean is the opportunity to teach Psychology 110. And although I love being dean, I do miss teaching Introductory Psychology, the feeling of exposing people to ideas that maybe you hadn't heard before.

Well, I suspect some of the ideas in this talk you'll have not heard before and for a variety of reasons. A couple of the things you'll notice is that some of the experiments I'll talk about today are not the kinds of experiments that can be done anymore. They're not considered ethically acceptable but they were done in the ʻ50s and ʻ60s and early ʻ70s when ethical standards were different and so we can teach them. We just can't give you the same experiences that some of the college students that we'll talk about today in these studies had. The other thing I will mention is that there is a certain androcentric and heterosexual quality to much of the social psychological research on romantic love. You'll see that in the experiments. Usually, the participants are men and usually the targets are women in these experiments. I'm not endorsing this as the only way to study love. It just happens to be the way these experiments were done and so I mention this caution right from the beginning. We'll have to think about--One of the things you should think about is do you think these experiments generalized to other kinds of dyadic relationships. And that's a question that I think you can ask throughout this lecture.

Okay. So let's get started. And to start things off I think what we need to do is consider a definition. I'm going to define what love is but then most of the experiments I'm going to talk about are really focused more on attraction than love--who finds each other of romantic interest that might then develop into a love relationship. But let's start with a definition of love. And I'm going to pick a definition from a former colleague, Robert Sternberg, who is now the dean at Tufts University but was here on our faculty at Yale for nearly thirty years or so. And he has a theory of love that argues that it's made up of three components: intimacy, passion, and commitment, or what is sometimes called decision commitment. And these are relatively straightforward. He argued that you don't have love if you don't have all three of these elements.

Intimacy is the feeling of closeness, of connectedness with someone, of bonding. Operationally, you could think of intimacy as you share secrets, you share information with this person that you don't share with anybody else. Okay. That's really what intimacy is, the bond that comes from sharing information that isn't shared with other--with many other people. Second element is passion. Passion is what you think it is. Passion is the--we would say the drive that leads to romance. You can think of it as physical attraction or sex. And Sternberg argues that this is a required component of a love relationship. It is not, however, a required component of taking a shower in Calhoun College. [a Yale dormitory] [laughter]

The third element of love in Sternberg's theory is what he calls decision or commitment, the decision that one is in a love relationship, the willingness to label it as such, and a commitment to maintain that relationship at least for some period of time. Sternberg would argue it's not love if you don't call it love and if you don't have some desire to maintain the relationship. So if you have all three of these, intimacy, passion and commitment, in Sternberg's theory you have love. Now what's interesting about the theory is what do you have if you only have one out of three or two out of three? What do you have and how is it different if you have a different two out of three? These are--What's interesting about this kind of theorizing is it give--it gives rise to many different permutations that when you break them down and start to look at them carefully can be quite interesting. So what I've done is I've taken Sternberg's three elements of love, intimacy, passion and commitment, and I've listed out the different kinds of relationships one would have if you had zero, one, two or three out of the three elements.

And I'm using names or types that Sternberg uses in his theory. These are really from him. Some of these are pretty obvious. If you don't have intimacy, if you don't have passion, if you don't have commitment, you don't have love. Sternberg calls this non-love. That's the technical term. And [laughs] essentially what he's saying is the relationship you now have to the person sitting next to you, presuming that you're sitting next to a random person that you didn't know from your college, is probably non-love. If it's something else, we could talk about it at the end of the lecture or perhaps when I get to it in a moment.

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Now let's start to add elements. Let's add intimacy. This is sharing secrets, a feeling of closeness, connectedness, bonding. Let's say we have that with someone but we don't have passion, that is, no sexual arousal, and no commitment to maintain the relationship. This is liking. Sternberg calls it liking. And liking is really what is happening in most typical friendships, not your closest friendship but friendships of a casual kind. You feel close, you share certain information with that person that you don't share with other--many other people, but you're not physically attracted and there's no particular commitment to maintaining this for a long period of time.

Now, what if you're not intimate, you're not committed, but you're passionate; you feel that sexual arousal. This is what Sternberg would call infatuation. And that term probably works for you too, infatuated love, and this is love at first sight. "I don't know you, we've never shared any secrets because I don't know you, I'm not committed to defining this as anything, I'm not committed to the future. In fact, I'm not thinking about the future. I'm thinking about right now but boy, am I attracted." Right. That's infatuation and that's what Sternberg means by infatuated love.

The third kind of one-element relationship is there's no intimacy, right, no bonding, no closeness, no secrets, no physical attraction, no sexual arousal, but by gosh, we are going to maintain this relationship, we are committed to it for all time. Sternberg calls that "empty love." Empty love is kind of interesting. It's often the final stage of long-term relationships that have gone bad. "We don't share information with each other anymore so there's no intimacy. We don't feel physically attracted to each other anymore, there's no passion, but we'd better stay together for the kids, right? Or we've got to stay together for appearance's sake or we'd better stay together because financially it would be a disaster if we don't" or all of the reasons other than intimacy and passion that people might commit to each other. That's what Sternberg calls empty love.

Now what's interesting is in societies where marriages are arranged this is often the first stage of a love relationship. These two people who have maybe never seen each other before, who have never shared secrets so there's no intimacy, who have never--don't know if they're physically attracted to each other or on their wedding day revealed to each other and committed legally and sometimes religiously to each other. Right? The commitment is there but at that moment nothing else might be there. What's interesting of course is that such relationships don't seem to have any greater chance of ending in divorce than people who marry for love. But there's a big confound, there's a big problem in studies of those kind of relationships. What might it be? Anybody. What might be the problem in the statement I just made that these kind of relationships are just as likely to survive as people who marry for love? Yes. Student: [inaudible] Dean Peter Salovey: Yeah. So they may occur; they're more likely to occur in societies that frown on divorce. They make it very costly, socially costly, to divorce, so then they stay together for all kinds of reasons, not always such good ones.

All right. Now who was it who sang the song "Two Out of Three Ain't Bad"? Was that Meat Loaf? Who was it? It was Meat Loaf. All right. Professor Bloom says it was Meat Loaf. It was Meat Loaf. You're all saying, "there was a singer called Meat Loaf?" Meat Loaf sang the song "Two Out of Three Ain't Bad." Let's see if two out of three ain't bad. What if you have intimacy, "we share secrets, passion, we feel physically attracted to each other but we're not making any commitments here." Sternberg calls that "romantic love." This is physical attraction with close bonding but no commitment, Romeo and Juliet when they first met. This is often the way relationships start: "We like each other, I'm physically attracted to each other, I--to you, I enjoy spending time with you but I'm not making any long-term commitments. So I'm not even willing to use the ʻL' word in describing what it is we have." Right? Many of you might have been in relationships of this sort. That's romance. That's romantic love.

Now, what if you have intimacy, "we share secrets with each other, but there's no particular physical attraction but we are really committed to this relationship." This is what Sternberg calls "companionate love." This is your best friend. "We are committed to sharing intimacy, to being friends forever," but physical attraction is not part of the equation here. This is sort of the--maybe the Greek ideal in relationships of some kind.

All right. What if we have passion, "I'm sexually attracted to you," but no intimacy. "I don't want to really know that much about you, I don't want to really share anything of me with you, but I am committed to maintaining this physical attraction to you" [laughter] Well, that's what Sternberg calls "fatuous love." It's a whirlwind courtship. It's a Hollywood romance. It might lead to a shotgun wedding. Maybe you find yourself in Las Vegas and you get married for a day and a half and then realize that this wasn't such a good idea. And maybe your name is Britney and you're a singer. [laughter]

Well, anyway, you've got the idea. That's fatuous love. "We are basically committed to each other for sex" but it's very hard to make those relationships last a long time because we might not have anything in common, we might not share anything with each other, we might not trust each other, we are not particularly bonded to each other. On the other hand, if you have all three, intimacy, passion, commitment, this is "consummate love" according to Sternberg – complete love. This is how he defines love. Okay. So now you have a definition of love and you can now, as a homework assignment, sit down tonight and make a list of every person you know by the three elements of love and just start putting the check marks in the boxes and tallying up your personal love box score. And we don't want to collect those. We don't even want to see those but you can have fun with that. Then you can ask the other people to do it too and you can compare with each other. [laughter] And if you all survive this exercise you'll be better for it. [laughter] What doesn't kill you makes you stronger. That's the idea behind that exercise.

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All right. Now the social psychology of love really has been a social psychology of attraction. What makes people find each other attractive? What makes them want to be intimate? What makes them physically desirable to each other? What might lead to a commitment, a decision to make a commitment to make the relationship last? This is just so nice. I'm giving this lecture on love and the two of you are holding hands here in the front row. It's really-- [laughter] And-- [applause] All three elements present, intimacy, passion, and-- [laughter] Yeah. Okay. [laughter] Good. Just checking. [laughter] Okay.

So what's interesting about the social psychology of attraction is it has focused on seven variables. And I've divided these into two groups, the big three and the more interesting four. And I call them the big--The big three are three variables that the effects are so powerful that they almost don't need to be discussed in much detail. The more interesting four are the ones I'm going to focus on in this lecture because they're a bit more subtle and they may be things that you've never heard of before. But let's quickly talk about the big three.

The way to understand the big three is with the phrase "all other things being equal." All other things being equal, people who find themselves in close spatial proximity to each other, like sharing an armrest in a lecture, will be more likely to be attracted to each other and form a romantic relationship. Okay, all other things being equal. Now this has been tested in lots of interesting ways. Studies have been done in the city of New York where you can--if you live in Manhattan you can actually get a very nice metric of how far apart people live from each other in city blocks. Right? You have a nice grid pattern and you can use a city block metric to add up the number of blocks between people's doors. And people who live more closely together are more likely to end up in romantic relationships with each other. It seems kind of obvious. Right? This even works on college campuses. We can measure in feet the distance between the door to your room and the door to every other room of a student on campus and there will be a correlation between the likelihood of--it's a negative correlation--the likelihood of getting into a romantic relationship with a person and the number of feet between your door and that person's door. The fewer feet, the more likely a romantic relationship, all other things being equal.

Now, all other things being equal is a big qualifier. Right? But if we could statistically control for every other variable, all I'd need to do is measure the distance from your door to everybody else's door on campus and I could chart out who's going to fall in love with whom on the Yale campus. Now, this idea in a way is--I don't know. Maybe it's a little counterintuitive. There is a kind of cultural myth around the stranger, the person you don't know, who you will--who you fall in love with. And that is not likely to be the case if it's the person who is nearby. Right? And you'll see as we go through the other big--the other two "big three" that there is a kind of repetition of this theme. It isn't the stranger you fall in love with.

All right. Let's continue down. Similarity. You've probably heard the phrase "Birds of a feather flock together" and that's true when it comes to romance. On any dimension that psychologists have measured in these kinds of studies, when people are more similar they are more likely to find each other attractive. This could be obvious things like height or age but it also could be things like attitudes toward capital punishment, preference for the Red Sox over the Yankees. Right? All of these are dimensions of similarity. All things being equal, the more similar the more likely you'll find each other attractive. So, opposites don't really attract. Birds of a feather may flock together but opposites don't really attract each other.

Now, usually at this point somebody in the lecture hall raises their hand and says, "Well, my boyfriend or my girlfriend and I are complete opposites and how do you account for that, Professor Salovey?" And I usually look at them and I say, "Good luck." [laughter] And of course all things might not be equal. There may be other variables at play but, all things being equal, similarity does not breed contempt. Similarity breeds attraction. Okay? Isn't it interesting? We have all of these common sayings that contradict each other and then empirically, some of them turn out to have more evidence supporting them than others. So "opposites attract?" Not much evidence. "Similarity breeds contempt?" Not much evidence. "Birds of a feather flock together?" Yeah, there's some evidence for that anyway.

Finally, familiarity. Familiarity--We tend to fall in love with people in our environment with whom we are already familiar. The idea that some enchanted evening we will see a stranger--Where are The New Blue [a Yale a cappella group that sings for couples on Valentine's Day] when you need them? [laughter] "Some enchanted evening you will see a stranger across a crowded room." Right? What musical is that from? "South Pacific." Very good. You will see a stranger across a crowded room. That's kind of a cultural myth. Of course it happens, but much more common is somebody you already know, somebody you have seen repetitively you suddenly find attraction--attractive and a relationship forms. Okay?

So the big three: People who are similar to you, people who are already familiar to you, people who are nearby in space. These are the people, all things being equal, that you will find attractive. Okay? So those are the big three. Those are big main effects. Those are big, easy to observe in various ways in the lab. By the way, the familiarity idea doesn't just work for people. I can show you words in a language that you don't speak and I can flash those words to you very quickly and I can later repeat some of those words and mix in some new ones that you've never seen before and I can say, "I don't know--I know you don't know what any of these words mean. I know you can't read these characters but just, if you had to tell me, which ones do you like and which ones don't you like or how much do you like each one?" The ones you will like are the ones you saw earlier, the ones that you already have familiarity. Even if you don't remember having seen them, even if that familiarity was generated with such quick exposures that you don't remember even having seen anything, you will get that familiarity effect. Okay? Good.

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The more interesting four. These are more interesting because they're a little bit complicated, a little bit subtle. Let's start with actually the one that is my favorite. This is "competence." Think about other people in your environment. Think about people who are competent. Generally--And think about people who are incompetent. Generally, we are more attracted to people who seem competent to us. Now, that isn't very interesting. And it turns out that's not really the effect. Yes, we're more attracted to people who are competent than people who we think are incompetent but people who are super competent, people who seem competent on all dimensions, they're kind of threatening to us. They don't make us feel so good about ourselves. Right? They make us feel a bit diminished by comparison. So, what we really like--The kind of person we're really attracted to is the competent individual who occasionally blunders. And this is called the Pratfall Effect, that our liking for the competent person grows when they make a mistake, when they do something embarrassing, when they have a failure experience. Okay?

You can see this with public figures. Public figures who are viewed as competent but who pratfall, who make a mistake, sometimes they are even more popular after the mistake. Okay? I think of Bill Clinton when he was President. His popularity at the end of his term, despite what everyone would agree, whether you like Bill Clinton or not, was a big mistake with Monica Lewinsky, his popularity didn't suffer very much. A lot of people in the media would describe him, "Well, he's just--It just shows he's human." He makes mistakes like the rest of us, even though that was a pretty big mistake. Right? And you could see this even with smaller pratfalls. Sometimes public figures are liked even more after their pratfall.

Now, the classic experiment, the classic pratfall experiment, is just a beautiful one to describe. It's a work of art. So, let me tell you a little bit about it. You're in this experiment. You're brought to the lab and you're listening to a tape recording of interviews with people who are described as possible representatives from your college to appear on a quiz show. The quiz show is called "College Bowl," which I don't think is on anymore but was on when I was in college. And you're listening to interviews with possible contestants from Yale who are going to be on "College Bowl." You have to decide how much--What you're told is you have to decide who should be chosen to be on "College Bowl." And you listen to these interviews. Now what's interesting is there's two types of people, the nearly perfect person and the mediocre person. The nearly perfect person answered 92% of the questions correctly, admitted modestly to being a member of the campus honor society, was the editor of the yearbook, and ran varsity track. That's the nearly perfect person. The mediocre person answers only 30% of the questions correctly, admits that he has only average grades, he worked on the yearbook as a proofreader, and he tried out for the track team but didn't make it. So, you see, they're keeping a lot of the elements consistent but in one case he's kind of an average performer and in the other case nearly perfect.

Now, which of these two people do you find more attractive in listening to the tape? So, when they ask you questions about which person should be on the quiz show, people say the more competent person. But they also ask questions like, "How attractive do you find this person?" Now, you're only listening to an audiotape. How attractive do you find this person? And the results are pretty obvious. The competent person is rated as much more attractive, considerably more attractive, than the mediocre person. Okay? If this were the end of the story though, it would be a kind of boring story and it's not the end of the story.

Now, what happens is half of the participants in the experiment who have listened to each of these tapes--You only get to listen to one tape. Half of them are assigned to the blunder condition. And what happens in the blunder condition is the tape continues and what you hear is the clattering of dishes, a person saying--the person saying, "Oh, my goodness. I've spilled coffee all over my new suit." Okay? That's the blunder. That's the pratfall. Now you're asked, "Who do you find more attractive?" And look what happens. Your rating of the attractiveness of the competent person grows even higher. The competent person who blunders, this is the person that I love. Unfortunately, the mediocre person who blunders, you now think is even more mediocre. [laughter] Right? This is the sad irony in these experiments. The effect works both ways so the mediocre become even more lowered in your esteem, in your regard.

Now, I'll tell you a little personal story about my coming to Yale that relates to this experiment. This is one of the most famous experiments in the history of social psychology. I wouldn't quite put it up there. You'll hear maybe later about, or maybe you've already about Milgram and maybe Asch conformity and maybe Robber's Cave. Those are even better known than this, but this is right up there. This is a top five experiment. What--So--And it was done by Elliot Aronson who has retired now, but for many years taught at the University of California at Santa Cruz. The name is not one that you need to know.

In any case, I came to Yale in 1981 as a graduate student and I was looking for an adviser and I was kind of interviewing with a faculty member at Yale at the time named Judy Rodin. Some of you may know that name because she went on later to become the President of the University of Pennsylvania and now is the President of the Rockefeller Foundation. But I was interviewing with her and set up a meeting. And what I was trying to persuade her in this meeting was to take me on as one of her students, to let--to be my adviser. And it's about my third or fourth week of graduate school and I'm pretty nervous about this. And she could be intimidating to a first-year graduate student.

And I remember I was holding this mug of coffee and I was pleading with her, trying to convince her to take me on as her student, and I was saying, "Judy, I'll get a lot done. I'll work really hard. I can analyze data. I can write." And I'm talking about myself and I'm swinging--I'm using my hands as I talk. I'm swinging this cup of coffee around. And fairly soon into the conversation I demonstrated some principle that you've probably learned in your physics class having to do with an object at rest remaining at rest unless acted upon by a force. Well, the object at rest was the coffee in the cup and when I pulled the

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coffee cup out from under the coffee it landed right on her desk and began--I watched in slow motion as this wave of coffee just moved from my side of the desk to her side of the desk.

She jumped up and jumped back and started moving papers around and really was giving me this look like "Why don't you just leave?" So, I was trying to save the moment as best as I could, and I looked at her and I said, "Judy, do you remember that old experiment that Elliot Aronson did [laughter] on attractiveness?" [laughter] She looked at me kind of out of the corner of her eye and I said, "Well, that was my blunder. [laughter] Now you're going to like me even more." [laughter] And she just shook her head and she said, "Peter, Peter, Peter. You know that effect only works if I think you're competent first." [laughter] Anyway, that was my introduction to Yale, graduate school at Yale. [laughter]

All right. So blundering. Only blunder if you're competent first and it will make you more attractive. That is the Pratfall Effect. Let's move on and I'm going to move a little bit quickly through all this because I want to leave time for a few questions at the end of the lecture. Let's talk about physical attractiveness as number two of the more interesting four. Now physical attractiveness is one that really bothers us. We don't like to believe that physical attractiveness accounts for much in life. It seems unfair. Except at the margins, there isn't much we can do about physical attractiveness. And when we're not pictured in The Rumpus [a satirical Yale newspaper that publishes a list of the best looking people on campus] it can really hurt. [laughter] So, we all like to believe that physical attractiveness matters. And the interesting thing is if you do surveys of college students and you say to them, "Rate how important different characteristics are in relationships that you might be involved in," they will say that warmth is important, sensitivity is important, intelligence is important, compassion is important, a sense of humor is important, and they'll say that looks aren't important. But if you measure all of those things--Let's do it in a different order. If you send everybody out on a blind date and then you look at, after the blind date, how many of those people who are matched up blindly actually go on a second date, actually get together again, what predicts who gets together again? Was it the rating of warmth? No. Sensitivity? No. Intelligence? No. Compassion? No. Sense of humor? No. What was it? Looks. So we believe that looks don't matter and unfortunately they do.

Now, the good news in all of this is the studies that looked at physical attractiveness in this way were just looking at what predicts a second date after a first date. Obviously, what predicts a long-term relationship are probably things less superficial than looks, or at least other things in addition to looks. But it is a great predictor of a second date. And college students year after year say, "But it's not important." And it's one of those classic disassociations between what we think is unimportant and what empirically turns out to be more important. Alright well, there are very interesting studies that have been done with physical attractiveness. At the University of Minnesota, a computer algorithm paired people up. It couldn't have been a very complicated algorithm because it basically paired people up randomly on the campus. But the computer--but a lot of data about all the students on campus were--was collected--were collected and people were then randomly paired up and sent to the dance. And then they were tracked over time. And just as in the thought experiment I just gave you, the University of Minnesota students acted in the same way. If the computer--If they rated their partner as attractive, the randomly assigned partner, they were more likely to continue the relationship.

Now it's interesting to ask, "why?" And we have to start to look at other experiments to try to get at what is it about physical attractiveness that makes people want to pursue the relationship? And once again Elliot Aronson, the person who did the blunder experiment, the "Pratfall" experiment, he did some nice work on attractiveness as well. And in one experiment, which many people know as the "Frizzy Wig" experiment, he did the following. He invited a confederate, a graduate student who was working with him in his lab--Psychologists--Social psychologists always call people who are in the employ of the experimenter "confederates." It doesn't mean that they grew up south of the Mason-Dixon Line or wave a certain kind of flag or--but the older term for it was "stooge." They would say, "We hired a stooge to act in the following role in the experiment." But I think a certain generation of college students thought stooges were only named Moe, Larry, and Curly and so they started to use the phrase "confederate." Now, they'll usually just say, "We hired an actor."

But anyway, the confederate that they hired was a woman who was naturally attractive in most people's view but they made her look either more attractive or less attractive by giving her kind of frumpy clothes, bad make-up, and a frizzy wig. And it was the frizzy wig that everybody remembers from this experiment. And what she does in the experiment is she poses as a graduate student in clinical psychology who is interviewing male participants – only men in this experiment. And at the end of the interview she gives them her own personal clinical evaluation of their personality. Okay? So, that's all it is. They have this interview with this woman. She's either made to look very good or she's made to look kind of ugly with this frizzy wig and they talk to her. She gives them an evaluation of their personality. Half of the subjects receive a favorable personality assessment. Half of them receive a kind of unfavorable evaluation.

How do they respond? Well, when she was made to look attractive they were delighted when she gave them positive feedback about themselves. When she was made to--When she gave--When she was made to look attractive but gave them unfavorable information about themselves, they were really upset about it. When she was made to look unattractive they didn't really care what kind of information she gave. It didn't really matter whether it was positive or not. It didn't really make any difference. It was interesting. In the condition where she was made to look attractive but gave you bad

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feedback about yourself, often the subjects in that condition would look for an opportunity to interact with her in the future, obviously to try to prove that her evaluation was wrong. It mattered that much to them. So there's kind of this idea that attractive people, their feedback to us has more impact. I'm not saying this is fair, I'm not saying it's rational, I'm not endorsing it, but empirically-- [coughs] excuse me--empirically we can see it, that somehow the attractive--the feedback from the attractive person matters more to us.

Okay. Number three of the more interesting four. Gain, loss. This is really a general idea in psychology that we are in a way wired up to be more sensitive to change than to steady states. And you could imagine why that might be true. Change often signals danger or opportunity and if we are especially tuned-in to change, it helps us survive and it helps us pass along our genes. Okay? So we're more sensitive to change.

How does that play out in love? Well, in love we are--what is very powerful to us is not just that someone always is positive toward us, "I love you, I love you, I love you, I love you, I love --" Right? It wears out its welcome. What's more powerful is the person who was not that positive to us but over time becomes more positive. The first derivative of their regard for us is positive. Okay? Aronson calls this the "Gain Effect." We are really attracted to people whose regard for us is gaining momentum over time. Okay? And even if over a period of time the average amount of their regard is lower because they started lower and then got higher than someone who was always high, it's the ones who were first lower who then went up that capture our attention. The first derivative is more important than just the position of their regard for us, getting better and better.

Now, what's interesting is there is also a loss effect. People who really hurt us are not the people who have always been negative. The person who every time they sees you hates you, says they hate you and accompanies it with an obscene gesture--after a while this person can't hurt you. Right? There's a country song that Ricky Skaggs sings that has the phrase in it "Nothing can hurt you like the person you love." That's what hurts, the person who always was positive who now--whose regard starts to fade. Oh. You can only hurt the one you love. Right? You can only hurt the one you love because you are expecting positive feedback from the one you love. And when that turns negative, it's a blow. It's a blow to the solar plexus. Right? So you can only hurt the one you can love but the one who always loves you sometimes has trouble showing you that they love you. The one who didn't really love you that much but then starts to show you that they love you, that person is a powerful influence on your behavior.

Okay. The last--Oops. Come back. The last set of studies--Have you talked about Schacter, Singer's "Emotions"? Okay. So let me describe to you this phenomenon. This is a phenomenon about the misattribution for the causes of arousal. You feel physiologically aroused but you're not completely sure why, and you have to make up an explanation for it. I think what I want to do--And sometimes that explanation is accurate, but the ones that are interesting here are the ones where you misattribute the cause of the arousal--you make a mistake and think it's love when it might be due to something else.

So, let's do a thought experiment. I'm a Yale college student, for the purposes of this thought experiment and I live in Pierson because I need to walk a great distance to Chapel Street, to the Starbuck's on Chapel Street. And I have a friend who I don't know that well, somebody who was sitting next to me in class a few weeks in a row. And I said, "Would you like to go see The New Blue in concert and then get coffee after it Friday night?" And she says to me, "Sure. I would do that." And so The New Blue concert takes place in the Pierson-Davenport Theater in the basement there – what used to be a squash court is now a little theater – and we enjoy ourselves at the concert and then I say, "Let's go to Starbuck's and get a coffee."

And so, we walk that distance from Pierson College down to the York Street Gate, over to Chapel Street, make the left on Chapel Street, another block down to High, walk into the Starbuck's. And she says to me, "You know, I'd better have a decaf because it's kind of late and I want to be able to sleep." And I say, "That's fine. Whatever you want." She says, "Yeah. So I'll have a decaf double espresso mocha skinny with a--" What? What other dimensions are there? [laughter] Right? "A double espresso mocha skinny frothed." [laughter] And I say, "Okay. Fine. I'll have a coffee." [laughter] And I go up there and I order the drinks. "I'll have a small coffee please and a double espresso mocha skinny frothed" except the barista makes a mistake. Did the word "barista" exist before Starbuck's? [laughter] I don't think so. The barista makes a mistake. The barista uses caffeinated coffee in the drink instead of decaf, doesn't tell anybody, doesn't tell me. I don't see it. I just come back with my black coffee and my double espresso mocha latte skinny frothed, except it isn't espresso. It's got two shots of caffeinated espresso. I'm sorry. It isn't decaffeinated. It's got two shots of caffeinated espresso in it. And I put it down on the table and we're having this nice conversation and we're drinking our beverages and it's about 12:30/1:00 now and Starbuck's is closing and it's time to walk back to Pierson. And we're walking back to Pierson and we leave the Starbuck's, we make a left on Chapel Street, we're walking up to York, I'm getting a little sleepy, but my friend looks at me and says, "Huh. I feel a little funny." What's actually happening? Her heart is beating a little faster, [sound of heartbeat] her palms are beginning to sweat, her breath is coming a little shorter than it otherwise would. "I don't know. Is it warm in here?" And she said, "I don't think I've felt this way in a very long time. [laughter] "Gee. It couldn't be the coffee. I ordered decaf. What could this be? What.." And she turns and she looks at me [laughter] and she says, "What a day this has been. What a rare mood I'm in. Why, it's almost like being in love." [laughter]

And it is almost like being in love except what it really is is two shots of caffeinated espresso [laughter] causing a rapid heart rate, an increase in respiration, sweaty palms, but I don't realize--she doesn't realize that's what it is. She turns to

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the most salient--and this is the way social psychologists would say it--turns to the most salient object in her immediate social environment--that would be me--and [laughter] says she's in love.

That's the idea of misattribution--aroused due to something else, "don't know what that is." It's best if you don't know what that is or even if you do mistakenly attribute it, misattribute it, to physical attraction, romance, intimacy, passion and commitment, it's love. All right. Now, I don't necessarily recommend that you do this thought experiment in vivo this weekend, although if you're lonely you might want to try it but [laughter] we can go--we can take this idea right--We can actually do research on this. We could take it into the lab. But before I tell you about lab experiments let me tell you about the most famous field experiment on this idea.

We call this the "Rickety Bridge" experiment. And there is a bridge at the University of British Columbia that crosses a river that runs through campus and the rickety--There's actually two bridges. The rickety bridge is one that's kind of a rope bridge. It's hundreds of feet above the river. It sways in the breeze. It's only about three feet wide. You kind of hold on to it carefully and you cross the river. It's a pretty scary way to cross that river. Has anybody been--seen this bridge? It's still there. Yes. You know this bridge. Okay. There's another way to cross the river. It's on a low bridge near the water, solid wood planks, nice and wide, hand railings made out of solid wood, and you can cross the bridge that way.

So, what two investigators at the University of British Columbia did is they simply positioned, once again, an attractive actor or confederate on one side of the bridge. She was a woman and she met men crossing the bridge. And she would intercept them as they came across the rickety bridge, or the low bridge, and she would ask them a few questions and conclude with, "Can you write me a story? You would help me out with my experiment if you'd just write a little story right now." Then she would collect their story and she would say, "If you have any questions about this experiment, here is my phone number." Actually, this happens when you're in experiments. You get the phone number of the experimenter.

What happens? Well, the men, male students, who cross the rickety bridge, they wrote these sexy stories with interesting content, with kind of little bit ribald themes. And the people on the solid bridge, they just wrote pretty boring stories. The people who crossed the rickety bridge were more likely to call her up later and say, "Yeah. I'd like to talk about that experiment I was in. Could we meet at the Starbuck's? [laughter] You drink decaf, don't you?" Right? And the people on the low bridge were much less likely to call her up. Okay? What was going on? Well, this was interpreted as misattributed arousal. On the rickety bridge you're swaying in the breeze hundreds of feet above the water, the bridge seems unstable. Maybe you'll make it. Maybe you won't. Your heart is beating, your palms are sweating, you're breathing harder. You meet this person and she seems more attractive because you're feeling all these things. And you attribute it to the attraction.

Now, there's a reason why this study is bad science. There's a major flaw in this study. The clue to the flaw is that you can't even call this study an experiment. What's the flaw? Anybody. Yes. Student: The people who would take the rickety bridge might be more likely to be more [inaudible] Dean Peter Salovey: People who take the rickety bridge might be the kind of people who are more looking for adventure than the people who take the solid bridge. Right. Another way of saying it is there isn't random assignment of the subjects to the two conditions in the study. That's no random assignment; it's not an experiment. You--By not randomly assigning people to these two conditions, you may be capturing just individual differences in the kind of person who, when there's a perfectly stable, safe, low bridge, says, "Huh uh. I won't want to go on that bridge. I want to go on the bridge where I have to risk my life to get to class." [laughter] And then should it surprise us that that's the kind of person who would call a perfect stranger on the telephone and write a sexy story and give it to them? [laughter] Right? We're not so surprised. So what we have to do, of course, is take it in to the lab and do this in a more systematic way with random assignment. And this is how I'll want to finish up today. We have until 2:45, 3:45? Okay. Great. I'll take about five more minutes to finish up and that'll give us some time for questions.

So how do you do this in the lab? Well, you can bring people in to the lab and I can present you with a confederate who--Let's say you are all in condition one, everybody on this side of the room, and I can say to all of you, "Please wait here. We'll begin the experiment in a moment. While you're waiting please fill out this form." And the form includes how attractive--how attracted you are to the experimenter, to me. I can do the same thing over here. I can give you the form and ask you to rate how attractive you think I am and I can give you the same instruction with a crucial difference: "Please wait here. We will begin the painful shock experiment in a moment. Please fill out these forms while you wait."

What happens? The people who got the painful shock instruction are more likely to find the confederate attractive. [laughter] Why? While they're sitting there thinking about painful shock it's making their heart beat faster, [sound of heartbeat] it's making their palms sweat, it's making them breathe harder maybe. And even though it's fairly obvious what's doing that, they still misattribute that arousal to "I must be falling in love," even with that obvious a--even with that obvious an instruction.

You can do this in other ways. You can bring--Here is one of my favorite ones. You bring people in the lab. We'll make them the control group this time. We bring you in the--to the lab and we say to this group of people, "Please wait here. We'll begin the experiment in a moment. You can fill out these forms in the meantime." The forms ask how attracted you are to the experimenter. You're now in the experimental group and I say, "Please wait here. We'll begin the experiment in a

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moment. I'm going to ask you to fill out some forms but first, to get ready for this experiment, I'd like you to get on this treadmill and run for ten minutes." So you've run on the treadmill. You've just sat around. The people who've run on the treadmill, even when that arousal is fairly obvious, you've got--you--doing a little bit of aerobic exercise, you still find the experimenter more attractive. Okay? This is why the fourth floor of Payne Whitney Gym is such a dangerous place [laughter] and I urge you as your dean to be very careful there. [laughter] Okay? It's that combination of aerobic exercise and spandex [laughter] that leads to trouble.

All right. Now, here's the final experiment and I apologize for this. It is a bit sexist in 2007 context, but let me explain. And we could never do this--and one could never do this experiment today but let me go through it with you and you'll apologize for its--some of its qualities. In this experiment male subjects were brought in to the lab and they were asked to look at centerfolds from Playboy magazine. So, these are essentially photographs of naked women. And they are wearing headphones that amplify their heartbeat and they are asked among other things how attracted are they to the centerfold photograph that they're looking at. So, maybe--I don't remember how many they look at. Maybe it's about 10.

So, these slides are coming up. They've got the headphones on. The headphones are amplifying their heartbeat and the slides are moving one after another for a few seconds each slide and they're listening to their heartbeat. [sound of heartbeat] Slide one. Slide two. Slide three. Slide four. Slide five. Slide six. And then they're asked which one did you find most attractive, which one are you most attracted to? "Oh, slide five, absolutely. She's the woman I want to marry." [laughter] Right? And what has happened is they're using this bodily cue of their heartbeat to infer that that's who they find more attractive.

Now, here is the twist. They're not actually listening to their heartbeat. They're listening to a tape recording of a heartbeat. And the experimenter is back there with the speed knob [laughter] and at random intervals he just speeds up the tape of their heart [laughter] and then slows it down. And it doesn't matter which slide he speeds up the tape of the heartbeat on, that's the one the subject is more likely to think is the person of their dreams, the person they're attracted to. So even you can misattribute real arousal. You can even misattribute phony arousal, arousal that isn't even coming from your body. It's just coming--It's just being played to you randomly. You can even misattribute that.

Okay. I think these experiments are cute and I think there's an interesting phenomenon there. And it says something, in a way, about how easily we can be misled as to what things in our environment, even things coming from our own body, mean. But there's also some very serious implications of this kind of work. One of them has to do with domestic violence. So think about domestic violence situations and why people stay in them. Why do people stay in relationships that are violent? Now the number one reason, and we have to acknowledge it up front, is usually economically there's no alternative or people believe there's no alternative. "I can't leave because if I leave I'd be homeless. If I leave I will starve, if my--if I leave my kids will starve or there'll be danger to my kids." And that keeps people trapped in abusive relationships but--And that's number one, but what else might be going on?

Sometimes people don't realize that the relationship they're in is abusive--it's psychologically or emotionally abusive. They get into these fights and screaming matches and name-calling and such even if it's not physical violence. And they feel a certain arousal when that happens and they misattribute it. "Well, he wouldn't be yelling and screaming at me if he didn't love me." Right? They misattribute that, what might be anger, what might even be aggression and violence, to an expression of love.

I have a friend who's a social psychologist who told me a story once that really made me very nervous, although she's fine. She said, "When I was dating my husband"--this is thirty years ago--"we were having a tough time. We were in many, many arguments--We got into many, many arguments and one time something happened where he came up to my car in a parking lot and he was yelling at me through the window. And I rolled up the window and before you know it he had punched out the window." And yelling at her and punched out the window. He didn't touch her. And he--she said to me, "That's when I knew he really loved me." And I thought that's scary and I--and, all joking aside, that's scary but that's misattributed arousal. "I'm feeling--when he did that I felt something and I assumed it was love. What she was misattributing as love--Well, she was misattributing his aggressive response as love. She was misattributing her own fear as mutual attraction, as "And I must love him." So, although we joke about these kinds of experiments, and they are fun to talk about because they are unusual and cute, there is also some serious implications of this kind of work that one might think about. And you might think about other possible implications as well. Okay. Let me stop there and see what kinds of questions we might have. [applause] Dean Peter Salovey: Thank you. Thanks very much. That's very kind of you. Because we are on tape I'll repeat any questions that come in. Yeah. Student: [inaudible] Dean Peter Salovey: Right. So the question is in experiments like the painful shock experiment if you are told in advance, like you all are, through a consent form or by the experimenter, "This is an experiment involving painful shock," will you still rate the experimenter as more attractive or will you not be able to misattribute the arousal? It is true. The more salient we make the source of the arousal, the less likely you can get the effect. If in my thought experiment I say to my friend, "Well, I know why you're feeling that way. The reason why you're feeling that way is ʻcause the barista made a mistake and gave you

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caffeinated espresso when you asked for decaf or maybe you just love me." Right. The person is not likely to say, "Oh, I bet it's love." They're more likely to think oh, caffeine, yeah. That's the parsimonious explanation here." So it is true. The more salient you make the cause of the arousal, the less likely you'll get the effect but you can see even in experiments where the cause of the arousal is somewhat obvious, at least to us, you can still get a misattribution effect. Other questions. Yes. Student: [inaudible] Dean Peter Salovey: Yeah. So the question is are any of these factors, particularly the big three, proximity, familiarity, and similarity--Do they affect the maintenance of relationships or just the initial attraction? It's interesting. My guess is they affect both initial and maintenance over time but the literature mostly focuses on initial attraction, much richer data on that initial attraction and those initial stages of the relationship in part because it's a little hard to follow couples over time. Imagine the sort of Heisenberg-esque problems we would get carefully following romantic couples over time and interfering with them to ask questions and make observations. It would be hard to let this couple naturally--this relationship naturally unfold. So, we really get--So, really the focus of many of these experiments is on initial attraction. That's why I always say my lecture is on love, the definition of terms is about love, but the experiments really are much more about attraction than about love. Another question. Yes. Student: Can someone feel consummate love for more than one person? Dean Peter Salovey: Oh. Can someone feel consummate love for more than one person? That's a very good question. It's actually a question that's debated in the literature. I didn't get into it at all in this experiment--in this lecture--but there's an interesting debate going on about love and many other emotions between people who take a kind of evolutionary perspective on these states versus people who take what might be called a more socially constructed perspective. And these aren't necessarily so incompatible but the evolutionary perspective I think would argue that you can feel that kind of love for more than one person or at least it would facilitate the passing on of your genetic material to a larger array of the next generation. So I think the evolutionary explanation is not a problem but we have constructed a world where in most societies, except for very unusual polygamist societies, the belief is that you can't love more than one. Right. And so you've got this tension between what might be evolutionarily wired impulses and the kind of social constraints that say this isn't good, this isn't appropriate, this is taboo. And my guess is the result is yes, you could but you're not going to feel un-conflicted about it and it's because these two are conflicting each other at the same time. How about one more question and then we'll let you go? I'm sorry. I saw him first. Student: Wouldn't natural selection favor the people who learn all these things and then practically try to apply them? Dean Peter Salovey: So he's making the evolutionary argument. Wouldn't natural selection favor the people who take introductory psychology, come to my Valentine's Day lecture, listen carefully to the big three and the more interesting four, and then go out there and put them into practice? It feels a little bit like the--like we're trying to pass on an acquired characteristic, which is a little bit counter to Darwinian theory but if somehow you could design a proclivity for learning this kind of material, evolution might indeed favor it. I can tell you this much. It would make the several thousands social psychologists in this world very happy and proud of their field, if that turned out to be true. Anyway, thank you all very much. Happy Valentine's Day! Thanks!

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Lecture 10 Professor Paul Bloom: We began the course by talking about one of the foundational ideas of modern psychology. This is what Francis Crick described as "The Astonishing Hypothesis," the idea that our mental life, our consciousness, our morality, our capacity to make decisions and judgments is the product of a material physical brain. What I want to talk about today and introduce it, and it's going to be a theme that we're going to continue throughout the rest of the course, is a second idea which I think is equally shocking, perhaps more shocking. And this has to do with where mental life comes from, not necessary its material nature, but rather its origin. And the notion, this other "astonishing hypothesis," is what the philosopher Daniel Dennett has described as Darwin's dangerous idea. And this is the modern biological account of the origin of biological phenomena including psychological phenomena.

Now, people have long been interested in the evolution of complicated things. And there is an argument that's been repeated throughout history and many people have found it deeply compelling, including Darwin himself. Darwin, as he wrote The Origin of Species, was deeply persuaded and moved by this argument from--in the form presented by the theologian William Paley. So, Paley has an example here. Paley tells--gives the example of you're walking down the beach and your foot hits a rock. And then you wonder, "Where did that rock come from?" And you don't really expect an interesting answer to that question. Maybe it was always there. Maybe it fell from the sky. Who cares? But suppose you found a watch on the ground and then you asked where the watch had come from. Paley points out that it would not be satisfying to simply say it's always been there or it came there as an accident. And he uses this comparison to make a point, which is a watch is a very complicated and interesting thing.

Paley is--was a medical doctor and Paley goes on to describe a watch and compare a watch to the eye and noticing that a watch and the eye contain multitudes of parts that interact in complicated ways to do interesting things. In fact, to change and to update the analogy a little bit, an eye is very much like a machine known as a camera. And they're similar at a deep way. They both have lenses that bend light and project an image onto a light-sensitive surface. For the eye the light-sensitive surface is the retina. For the camera it's the film. They both have a focusing mechanism. For the eye it's muscles that change the shape of the lens. For a camera it's a diaphragm that governs the amount of incoming light. Even they're both encased in black. The light-sensitive part of the eye and part of the camera are both encased in black. The difference is--So in fact, the eye and a camera look a lot alike and we know the camera is an artifact. The camera has been constructed by an intelligent--by intelligent beings to fulfill a purpose.

In fact, if there's any difference between things like the eye and things like a camera, the difference is that things like the eye are far more complicated than things like the camera. When I was a kid I had this incredible TV show called "The Six Million Dollar Man." Anybody here ever seen it or heard of it? Oh. Anyway, the idea is there's a test pilot, Steve Austin, and his rocket jet crashes and he loses his--both legs, his arm and his eye, which sounds really bad but they replace them with bionic stuff, with artificial leg, artificial arm and an artificial eye that are really super-powered. And then he fights crime. [laughter] It was [laughs] really the best show on. It was really good, [laughter] but the thing is this was in 1974. It's now over thirty years later and it's true then and it's true now, this is fantasy. It doesn't make it to the level of science fiction. It's fantasy. We are impossibly far away from developing machines that could do this. We are impossibly far away from building a machine that can do what the human eye does. And so somebody like Paley points out, "Look. The complexity of the biological world suggests that these things are complicated artifacts created by a designer far smarter than any human engineer. And the designer, of course, would be God."

I went to Goggle Images. That--I don't mean that to be sacrilegious [laughter] in any sense. You could try this. I went to "Google Images" and typed in "God" and this [a picture of an old-bearded man wearing a crown] is what showed up right in the middle so--And this, Paley argued, and it was--has been convincing throughout most of history, is a perfectly logical explanation for where these complicated things come from. It also has the advantage of being compatible with scripture and compatible with religious beliefs, but Paley made the point this stands on its own. If you find complicated things that--complicated artifacts, you don't assume they emerged by accident. You assume that they were created by an intelligent being.

Now, this view has always had problems. This view, you could call it "creationism," which is that biological structures were created by an intelligent being, has always had problems. One problem is it pushes back the question. So you ask, "Where did that intelligent being come from?" And this is a particularly serious problem from the standpoint of the evolution of psychological structures. So, we want to know, "how is it that creatures came across--upon this earth with the ability to reason and plan and do things?" And then the answer is "well, another creature with that ability created us." That doesn't necessarily mean it's wrong, but it means it's unsatisfying. You immediately want to get an explanation for where that other creature comes from.

More to the point, there's always been evidence for evolution. And what I mean by evolution here isn't necessarily a specific mechanism, but merely the fact that body parts like the eye didn't emerge all of a sudden, but rather have parallels both within other existing animals and across human and biological history. This evidence comes in different forms. There is fossil evidence for different body parts suggesting that they have evolved from more rudimentary form. There is vestigial characteristics. And what this means is there are characteristics that human bodies have that are somewhat inexplicable, like

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the human tailbone or goose-bumps, unless you view them--the human body in its current form as modifications from a previous form.

There are parallels with other animals. And this is clear in psychology. So, a human brain is different from the rat, cat, and monkey brain but at the same time you see them following a sort of common plan and common structures. And one rational inference from this is that they're linked through evolutionary descent.

Finally, there is occasional poor design. So, Paley rhapsodized about the remarkable powers of the human body and the different body parts, but even Paley admitted that there are some things which just don't work very well. Your eye contains a blind spot because of how the nerves are wired up. In the male urinary system the urethra goes through the prostate gland instead of around it, which leads to many physical problems in men later on in life. And so you're forced to either argue that these are really good things or that God is either malicious or incompetent. And those are difficult arguments to make.

So, these are problems with the creationist view. But still, for the longest time in human intellectual history there was no alternative. And in fact, Richard Dawkins, the most prominent evolutionary--one of the most prominent evolutionary biologists alive and one of the most staunchest critics of creationism, has written in The Blind Watchmaker saying, look, anybody 100 years ago or 150 years ago who didn't believe that God created humans and other animals was a moron because the argument from design is a damn good argument. And in the absence of some other argument you should go--defer to that. You should say, "Well, there are all of these problems but humans and other biological forms must have divine creation because of their incredible rich and intricate structure." What changed all that of course was Darwin. And Darwin--Darwin's profound accomplishment was showing how you get these complicated biological structures, like the eye, emerging through a purely non-intentional, non-created process, a purely physical process. And this could be seen as equal in importance to the claim that the Earth revolves around the Sun and that we're not the center of the universe. And in fact, some scholars have made a suggestion which seems plausible, that the idea of natural selection is the most important idea in the sciences, period.

So, this is not a course in evolution and I expect people to have some background. If you don't have a background in it, you could get your background from external readings but also from--the Gray textbook and the Norton readings will both--will each provide you with enough background to get up to speed. But the general idea is that there are three components to natural selection. There is variation. And this variation gives rise to different degrees of survival and reproduction and gets passed on from generation to generation and gives rise to adaptations, what Darwin described as "that perfection of structure that justly excites our imagination."

And the biological world has all sorts of examples. You look at camouflage. Prior to Darwin one might imagine that some intelligent creator crafted animals to hide from their prey. But now we have a different alternative, which is that animals that were better hidden survive better, reproduce more, and over the course of thousands, perhaps millions of years, they've developed elaborate camouflage. There's been a lot of work on Paley's favorite example – the eye. So Darwin himself noted that the human eye did not seem to emerge all at once but rather you could look at other animals and find parallels in other animals that seem to suggest that more rudimentary forms are possible. And more recently computer simulations have developed--have been developed that have crafted eyes under plausible assumptions of selective pressure and what the starting point is.

So, this is the theory of natural selection. The good question to ask is, "why am I talking about evolution in Introduction to Psychology class?" And the answer is that there are two ideas which come together. And in fact, they're both of the dangerous ideas. One idea is that Darwin's idea--that biological forms evolve through this purely physical process. The second idea, the rejection of Descartes, is that our minds are the product of physical things and physical events. You bring these together and it forces you to the perspective that what we are--our mental life is no less than the eye, no less than camouflage, the product of this purely physical process of natural selection. More to the point, our cognitive mechanisms were evolved not to please God, not as random accidents, but rather for the purpose of survival and reproduction. More contentiously, you could argue they've been shaped by natural selection to solve certain problems. And so, from an evolutionary point of view, when you look at what the brain is and what the brain does, you look at it in terms of these problems. And this is what psychology is for. This is what our thinking is for. We have evolved mental capacities to solve different problems: perception of the world, communication, getting nutrition and rest, and so on.

Now, we're going to talk about how to apply evolutionary theory to psychology. But as we're doing so we have to keep in mind two misconceptions. There are two ways you can go seriously wrong here. The first is to think that, well, if we're taking an evolutionary approach then natural selection will cause animals to want to spread their genes. So, if we're being biological about it, that means everybody must run around thinking "I want to spread my genes." I want to--and this is just really --Oops. I shouldn't do that. This is really wrong. It's [the text on the slides] even in red. And what this fails to do is make a distinction between ultimate causation and proximate causation. And those are technical terms referring to--Ultimate causation is the reason why something is there in the first place, over millions of years of history. Proximate causation is why you're doing it now. And these are different. Obviously, for instance, animals do all sorts of things to help survive and reproduce but a cockroach doesn't think "oh, I'm doing this to help survive and reproduce and spread my genes." A

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cockroach doesn't know anything about genes. Rather, the mechanisms that make it do what it does are different from its own mental states, if it has any--why it does them.

This is a point nicely made by William James. So, William James is asked, "Why do we eat?" And he writes, Not one man in a billion when taking his dinner ever thinks of utility. He eats because the food tastes good and makes him want more. If you asked him why you should want to eat more of what tastes like that, instead of revering you as a philosopher, he will probably laugh at you for a fool.

And it's really the common sense answer. "Why are you eating?" Nobody's going to answer, "Because I must sustain my body so as to spread my genes in the future." Rather, you eat because you're hungry.

Those two theories, you eat because you're hungry and you eat to sustain your body so you could spread your genes in the future, are not alternative. Rather, they're different levels of explanation. And you can't confuse them. The ultimate level which does appeal to survival and reproduction does not--is independent from the psychological level. To give another example, people protect their children so you ask, "Why do people protect their children? Why would somebody devote so much effort to protecting and helping and feeding their children?" Well, the evolutionary explanation is animals that don't protect their offspring don't last over evolutionary time. We protect our offspring because they contain fifty percent of our genes, but that's not the psychological explanation. Nobody but a deranged psychologist would ever answer, "Oh, I love my children because they contain fifty percent of my genes." Rather, the psychological explanation is a deeper--is different and has a different texture. And this will be a lot clearer when we talk about the emotions, where you could really see a distinction between the question of why we feel something from an evolutionary point of view and why we feel it from a day-to-day point of view.

The second misconception is that natural selection entails that everything is adaptive, that everything we do, everything we think is adaptive. This is wrong. Natural selection and evolution, more generally, distinguish between adaptations and byproducts and accidents. Many of you are currently, or will as you get older, suffer back pain. If I was to ask you, "So, why do you suffer back pain? How does back pain help you survive and reproduce?" Well, the answer is it's not an adaptation. Back pain is an accidental byproduct of how our backs are shaped. Don't go looking for an adaptive reason for hiccups or self-pity or bloating after you eat. There's all sorts of things a body will do that have no adaptive value, rather just accidents. We have a body that does all sorts of things. Some things it will do by accident and this is certainly true for psychology.

So, a lot of the things, for instance, that occupy our interest or our fascination in day-to-day life are almost certainly evolutionary accidents. The number--The three--Three of the main preoccupations of humans are pornography, television, and chocolate but if I asked you, "Why do you like porn?" and you'd say, "Because my ancestors who liked porn reproduced more than those who didn't," [laughter] it's not true. Rather, you like porn, assuming you do, [laughter] as an accident. You have evolved--For instance, should you be a heterosexual male, you have evolved to be attracted to women. That is most likely to be an evolutionary adaptation because being attracted to women and wanting to have sex with women is one step to the road to having kids, which is very good from an evolutionary perspective.

It so happens, though, in our modern environment that people have created images that substitute. So, instead of actually going out and seeking out women you could just surf the web for hours and hours and watch dirty movies and read dirty books – evolutionary adaptive dead ends. They're accidents. Why do you like chocolate bars, assuming that you do? It is not because your ancestors in the African savanna who enjoyed chocolate bars reproduced more than those who didn't. Rather, it is because we've evolved a taste for sweet things. And we've evolved a taste for sweet things, in part, because the sweet things in our natural environment like fruit were good for us. In the modern world we have created things like chocolate, which are not so good for us but we eat anyway.

A lot of the debates--There's a lot of controversy in psychology over the scope of evolutionary explanations. And a lot of the debate tends to be over what's an adaptation and what isn't. There are some clear cases. We have color vision. Why do we have color vision? Well, I think everybody would agree we have color vision as an adaptation because of the advantages it gives us for seeing and making visual distinctions. We are afraid of snakes. We're going to talk about that in more detail but there's a straightforward adaptive story about that. We are afraid of snakes because, really, our ancestors who weren't afraid of snakes didn't reproduce as much as those that were. We like chocolate bars and we enjoy NASCAR. Those cannot be adaptations because chocolate bars and NASCAR are recent developments that could not have been anticipated by evolution.

Those are easy questions. Here are some hard questions. Music. Everywhere in the world people like music. Is this an adaptation for some selective advantage or is it an accident? Steven Pinker, who wrote The Language Instinct that you read before, caused a huge amount of controversy when he argued that music is just an evolutionary accident. He described it as auditory cheesecake, something we like to gorge ourselves on that have no--has no adaptive advantage. Other people argue music does have an adaptive advantage. Sometimes males use violence to coerce sex. Is male sexual violence a biological adaptation or is it an accident? There's more than one language. Is that just an accidental byproduct of the way language works or is there some sort of group or selectionist advantage sketched out in some way of having multiple languages? What about visual art? What about fiction? What about our love for stories? Those are all matters of heated debate.

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And so, we have to keep in mind some things plainly are accidents. Some things almost certainly aren't accidents. Where the action is in the study of psychology and the study of evolution of cognition is trying to figure out which is which. So, those are the misconceptions we have to avoid. But still, who cares? Again this is an Introduction to Psych course. Why are we talking about evolution? Why should it matter to a psychologist how the mind has evolved? I'm going to talk about evolution now but for the rest of the course I'm just interested in how our minds are, period. S,o why would evolution matter?

Well, many people think it doesn't. For instance – and they think it doesn't for different reasons – one claim is a metaphysical one. You might be a dualist. You might reject the idea your mental life is the product of your brain and hence evolution is irrelevant to psychology because the brain and the mind--because the brain, which may have evolved, has nothing interesting to do with the mind. Lisa Simpson got it wrong when she said the Pope--She got it half right when she said the Pope favored evolution. It is true. John Paul II, many years ago, made a statement saying that Darwinian theory is not incompatible. Darwinian theory is a view about the evolution of species that is not motivated by any animus, is a genuine scientific theory, and should it turn out to be true, it is not incompatible to truth about man as taught by the Church. And scientists were thrilled by this and they were--they said he's endorsing evolution. But what a fewer people talk about is the fact that after he said this he drew the line. He allowed for evolution of the body but he would not allow for evolution of the mind. So it was--he wrote:

If the human body takes its origin from preexisting living matter, the spiritual soul is immediately created by God. Consequently, theories of evolution which consider the mind as emerging from the forces of living matter or as a mere epiphenomenon of this matter are incompatible to the truth about man.

So, you might not want evolution to be true about the mind because you might believe that the mind is not subject to the same physical laws as the rest of the physical world. That's one way you could reject evolutionary psychology. Another way to reject evolutionary psychology is to accept that the mind is a physical thing but then argue that all of these instincts and these hard-wired facets of human nature might exist for other animals but they don't exist for people. So, the anthropologist Ashley Montagu in '73, close to when The Six Million Dollar Man was shown, by the way, said:

With the exception of the reactions of infants to sudden withdrawals of support and to sudden loud noises, the human being is entirely instinctless. Man is man because he has no instincts, because everything he is and has become he has learned from his culture, from the man-made part of the environment, from other human beings.

You might say, "Look. He could believe that in '74 but, of course, all of the infant studies that have come out since

then suggested that's not true and nobody would believe that nowadays." But in fact, the view is often hold--held--Louis Menand in a New Yorker article a few years ago wrote, "Every aspect of life has a biological foundation in exactly the same sense, which is that unless it was biologically possible it wouldn't exist. After that it's up for grabs." And this is in the context of an argument that evolution can't tell us anything about what's most interesting about people. Menand is not--is an educated, intelligent scholar. He is presumably well aware of the findings of Spelke and Baillargeon about how people are hard-wired to understand the objects in social life and so on. But his point is just that when it comes to the more interesting aspects of human nature, the stuff we're naturally, intuitively interested in, that's more cultural. And the evolutionary theory and Darwinian theory just doesn't have anything much to say about it, not because the mind is separate from the brain but just because humans are much more cultural organisms, and so biology has little to say about it.

There's a third objection, which is you might think, "Okay, the human mind actually does contain instincts. There is a human nature but we should just study it by studying people. How could evolution, the study of evolution, the consideration of evolution tell us anything interesting?" I actually, in my own work, think evolution can tell us some interesting things. And I want to try to make a case for ways in which evolution can inform and enlighten us about the mind as it is.

First, I want to make a point, which is although this course is Intro Psych and it is about the mind as it is, still I think by any account the evolution of consciousness, morality and so on, just is intuitively interesting. It's the sort of thing that people are just fascinated by and I think it's a question of interest in and of its own right. But here's how it could tell us about psychology. For one thing, it can tell us what can be innate and what cannot. So, some problems, some evolutionary problems, have been around for a long time and could lead to special biological adaptations. If I told you there is a biological adaptation for talking, mate selection, childcare; maybe it's true, maybe it isn't, but it's not crazy. From an evolutionary point of view, it's a reasonable possibility that it is.

Other problems are recent and our brains could not be specialized to deal with them: written communication, interacting with strangers, driving a car, playing chess. If you were to argue that there's a part of the brain devoted to playing chess, I would say you're utterly wrong. You cannot be right because, from an evolutionary point of view, there could be no such part of the brain evolved because playing chess is a recent innovation. As a result, a focus on evolution could help discipline us to make coherent claims about what is built-in and what isn't built-in.

Third, we're going to talk about human differences in this course. We're going to devote a class to human differences of the sort of what makes you different from her, different from her. Why do we have different intelligences in this class? Why are some of us arrogant and some of us humble? Some of us like--attracted to men, others attracted to women, and so on. But there's also questions of group differences. And evolutionary theory can help us say intelligent things about

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what sort of group differences you should expect because evolutionary theory predicts that some populations should evolve in different ways than others.

The most obvious example is that children should be different from adults. The evolutionary problems faced by a child are very different from the evolutionary problems faced by an adult. And you can make specific and rather interesting predictions about how children's brains should different--differ from adults' brains. Evolutionary theory predicts--does not make any predictions about racial differences or ethnic differences. Some might exist, but there's no adaptive reason why humans who have evolved in different parts of the world should have profound differences in their mental capacities.

What does evolutionary theory say about sex differences? Well, it says some interesting things, and we're going to devote a class to discussing them, but what I think is going to be true--proved to be important is that we'll be able to use evolutionary biology to talk sensibly about what sort of distinctions between the sexes, between males and females, one would expect to find and what sort one wouldn't expect to find. We can make educated predictions. I'm going to have--I want to put here a clip of a man. This is a scene from a movie, the movie "Roger Dodger," that begins with a man making quasi-evolutionary claims about the differences between men and women. And I want to put this as an example of what you could call "barroom evolutionary psychology." And I want us to hold this in our minds because we're going to return to these claims and discuss their validity. [clip playing]

I like this for a few reasons. First, I like the backward reference to William James and utility. Second, it is a gorgeous combination of some things that are actually reasonably rational and total bull crap. And--but what evolutionary biology will give us is the tools to distinguish between the two. On the face of it immediately, the ability to read maps, the claim that that has a biological--that differences in that ability have a biological root is crazy. On the other hand, the claim that one--that males may develop a trait not because it's advantageous but to attract females is less crazy. The telepathic stuff is really crazy but--;So, I'm not at this point--We're going to devote a lecture to sex. I do not, at this point, want to make any claims one way or another. But what I want to suggest is that from a biological point of view we could say sensible and intelligent things about what differences should exist and what shouldn't.

Finally, and most of all, looking at something from the perspective of design, the perspective of what's it for, can often give you interesting insights as to its current nature. And I'll give you two quick examples, one that's not from psychology, one that is. Women suffer--Often women who are pregnant early in their pregnancy suffer from morning sickness, nausea, throwing up and so on. This has traditionally been viewed as just a breakdown in the system--too much hormones, everything's askew; women get nauseous. Margie Profet suggested an alternative and this won her theMacArthur Genius Award. And this was the claim that maybe pregnancy sickness is not an accident; rather, it's designed, it has a biological purpose. In particular, as the baby develops in the uterus, it is vulnerable to various sorts of poisons or teratogens. Profet suggested that pregnancy sickness is a hypersensitive period where women are extremely sensitive, get extremely nauseous towards the sorts of foods that could damage their baby.

Now, if she just ended there it's a story. How do we know it's true? But then she went on to examine it the same way that any scientist examines any claim – by making predictions and testing them. And this makes some interesting predictions. It suggests the timing of onset and offset of pregnancy sickness, of morning sickness, should correspond to the period of maximal vulnerability on the part of the developing embryo or fetus. Suggested the types of foods avoided should correspond to those sorts of foods that were most deadly for the fetus and that were deadly for the fetus during the periods where humans evolved. This last qualification is an important one. Women do not develop an aversion to alcohol during pregnancy even though alcohol is extremely dangerous to the developing child. The answer is an easy one. Alcohol wasn't around during our evolutionary history and we could not have evolved a system to protect ourselves from it.

And finally, there should be a relationship between miscarriage and birth defects in a surprising direction. For Profet, and she has evidence to back this up, pregnancy sickness is not a glitch in the system. Rather, it's the sign of a healthy act of protective mechanism going on. And in fact, the more morning sickness the more the baby should be protected. Something which, by and large, appears to be true. That's an example of how the question--when dealing with this they say, "Hey. Women throw up when they get pregnant" and then say, "Look. Maybe that's not just a glitch. What's it for?" You could then learn some interesting things.

Here's a different example based on the last lecture, this wonderful lecture by Peter Salovey on sex and love where he talked about the "big three." These are the "big three" to remind you of what attracts us to somebody else. You are very attracted to the person next to you or a person that--because of proximity, similarity, familiarity. And there is abundant evidence supporting the truth of this. It's almost always true but the evolutionary psychologist looks at this and says there's something seriously wrong here. There are some cases where that has to be totally, absolutely mistaken. To realize what this is, think for a moment. What humans are you most close to, most similar to and most familiar with? What humans did you spend over ten years of your life with who are genetically and environmentally as close to you as if they were related, who you are intimately familiar with? Are those the humans that you find the hottest? [laughter] No. They're your siblings and they are not hot. [laughter]

I was on Google Images this morning. I put up some hot siblings and--but--although we may find them hot, they do not typically, with some rare and bizarre exceptions, find [laughter] one another hot. Why not? Well, this is not a huge puzzle from the standpoint of evolutionary biology. Evolutionary biology posits that humans, as well as other animals, should have

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incest avoidance. We should love--we should be attracted to those familiar to us, similar to us, close to us, but not kin. Kin are off limits. There is a good reason why. Because if you inter-mate with your kin you have bad offspring [laughter] and so animals should be wired up not to mate with their kin. And in fact, this is what happens.

There are--Parents of teenagers have all sorts of concerns. And a lot of the concerns are, in fact, sexual. How do you keep your son and/or your daughter from going out and having sex with too many people, or the wrong people, or unprotected sex? But there are no parenting guides in the world that say "How do you keep your children from having sex with one another?" [laughter] You typically do not need to because they do not want to have sex with one another.

Now, this is--actually also illustrates the difference between proximate and ultimate causation. So, you think for yourself, "Eew. Do I want to have sex with my sister?" You don't think to yourself, "I would prefer not to, for the offspring that we will create will be nonviable and it'll be a waste of my reproductive efforts." Rather, you think, "Eew," because at a gut level you respond. And this sort of instinctive response is what you get from an evolutionary analysis of sex.

But this story is deeply incomplete because the question that gets raised is "how do you tell?" You don't want to have sex with your kin but how do you tell your kin? People don't carry their DNA markers on strips that you could see. How do you tell who your kin are? And this actually turns out to be a really interesting question. It used--And some research suggests that the answer is simple. You avoid sex with people you grew up with. And these studies actually come from kibbutz studies, studies where people are raised communally on an Israeli kibbutz. They know they're not related, but still, the fact that they were raised together as kids suggests that there's a cue at a gut level not to be attracted to one another.

It turns out there's some reason now to believe this story is incomplete. A paper that came out in Nature five days ago reported a series of extremely interesting studies. And they found that the cue of being raised together as a child with somebody--yes, that does diminish sexual desire, but an even bigger cue was "did you observe your parents, and in particular, your mother, taking care of that person?" If you did, that seriously diminishes sexual desire and brings it down to the level of disgust. And again, these are the sort of questions and issues you begin to ask when you approach things from an evolutionary perspective.

Okay. For this lecture--the rest of this lecture and then the next couple of lectures, I'll be discussing some basic aspects of human nature that are, to some extent or another, informed by evolutionary theory. And what I want to start for the remainder of this lecture is a discussion of rationality. Now, some of you maybe not want to go into--not want to go into psychology because there's no Nobel Prize for psychology. You might all think, "Hey, if I'm going to go into the sciences I want a Nobel Prize. Think how proud Bubby and Zadie would be if I won a Nobel Prize. Wouldn't that be the best?" You can get one. Psychologists have won the Nobel Prize. Most recently, Danny Kahneman won a Nobel Prize. You win it in economics, sometimes medicine; not a big deal. He won it for his work done over the course of many decades on human rationality. And this work was done in collaboration with Amos Tversky, who passed away several years ago. And this work entirely transformed the way we think about human decision-making and rationality.

Kahneman and Tversky caused a revolution in economics, psychology, and the social sciences more generally, by causing us to shift from the idea that we're logical thinkers, who think in accord with the axioms of logic and mathematics and rationality, more towards the idea that we actually have sort of rough and ready heuristics. These heuristics served us well during the time--during our evolutionary history, but sometimes they can lead us astray. And I want to give some examples of these heuristics. And I'll give four examples of heuristics that are argued to permeate our reasoning.

The first is "framing effects." This was a classic study by Kahneman and Tversky involving this sort of question. The U.S. is preparing for the outbreak of a disease that's going to kill six hundred people. There are two programs. Program A: If you follow it two hundred people will be saved. Program B: There's a one-third chance everybody will be saved and a two-third chance nobody will be saved. Who would choose program B? Who would choose program A? Okay. And that fits the responses. Most people choose program A. That's--It could go either way. What's interesting is if you frame the question differently, like this, you get very different responses. And instead of focusing on the people who will be saved, you focus on the people who will die and, instead of focusing on the chance that nobody will die and the chance that everybody will die, you'd flip it around, you get a corresponding flip. And this is known as a "framing effect."

The idea of a framing effect is that you could respond differently to a situation depending on how the options are framed. And, in particular, this combines with "loss aversion." People hate a certain loss. "Four thousand of these people will die" is extremely aversive and so the framing can influence your decisions. And clever advertisers and clever decision makers will frame things in different ways to give you--give rise to different intuitions. Sometimes this could be fairly simple. So, you have this ad of a hamburger that's eighty percent fat free versus twenty percent fat--You don't have to be a brilliant ad executive to figure out which one to go for.

It turns out that this sort of fundamental act – the fundamental role of framing effects – is not limited to humans. So, I want to take a second and tell you some work done by my colleague, Laurie Santos, with capuchin monkeys. And what she does is she takes these capuchin monkeys and she teaches them to use money. She teaches them to use little discs to buy themselves either pieces of banana or pieces of apple. And they like to eat this. And they very quickly learn you can hand over a disc to get some banana or some apple. [laughter] Now, Dr. Santos and her colleagues have done many studies using this method, but the study I'm interested in illustrating here shows framing effects in these nonhuman primates.

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So, what she does is--There's two options. In one option, the experimenter shows one object to the capuchin and low--and then either gives one or two--half the time gives one, half the time gives two, for an average of one and a half. The other experimenter does exactly the same thing; gives one or two for an average of one and a half, but starts off displaying two. Now, if you weren't a human, how would you feel about these two experimenters? They both give you the same amount. And capuchins are extremely sensitive to how much they get, but it turns out as predicted they don't like the pink experimenter because the pink experimenter is--he gives you two--shows you two and half the time he gives you one. This guy shows you one, and half the time gives you two. And over time they develop a preference for the experimenter that shows them one initially, suggesting that they are being subject to framing effects or choices relative to a reference point.

A different sort of demonstration is the "endowment effect." This is a robust and very interesting effect. Here's the idea. I show you something like a cup or a chocolate bar and I say, "How much will you give me for this chocolate bar? It looks like you're pretty hungry. How much will you give me for this chocolate bar?" And you say, "I'll give you two dollars for this chocolate bar." Most people on average give two--the chocolate bar--gives two dollars for a chocolate bar. The other condition's exactly the same except I hand you a chocolate bar and say, "How much money will you sell me that chocolate bar for?" There, people say, "Two fifty," and in fact, what happens is once you own something its value shoots up. And this has mystified economists and psychologists. It makes no sense. The chocolate bar doesn't even have to move. I just leave it on the table and say either "How much will you spend," "How much will you give me for this?" or "Okay. It's yours. How much do you want for me to take it back?" The answer is, it's framing. If you're asking how much you want for it, it's a game. It's just how much will you pay to get something. But if you're being asked how much do you want for me to take it from you, you treat it as a loss. And as a loss it becomes more valuable. Those are framing effects.

The second example is base rates. There are seventy lawyers--sorry, seventy engineers and thirty lawyers and John is chosen at random. Let me tell you about John: forty-years old, married, three children, conservative, cautious, no interest in politics, awkward around people. His hobbies include carpentry, sailing, and solving mathematical puzzles, like online dating. [laughter] What do you think John is? A lawyer or an engineer? Who thinks he's a lawyer? Good. Who thinks he's an engineer? Okay. Most people think he's an engineer, but here's the thing. You switch it. Right? Thirty engineers, seventy lawyers? It doesn't change. People--No matter what this number is--these numbers--it doesn't seem to change who you think he is or how confident you are.

People look at John as an individual and they ignore the background status of where he came from. They ignore base rates. Base rates are very difficult to think about and I want to give you an example of this. And the example will be on the slides for when you print them out--print it out because you might want to work through it yourself. But I'll give this to you quickly. There's a disease that hits one in a thousand people, a pretty common disease. There's a test for the disease and if you have it, it's going to tell you you have it. It tests for a certain thing in your blood and "boom," if the thing is in your blood the test will go "boom." If you have it, it will tell you you have it. It doesn't miss. On the other hand, it's not perfect. It has a false positive rate of five percent. So, if you don't have the disease, five percent of the time the test will say you have it. So, if the test says you don't have it, you're fine. But if the test says you have it, maybe you have it but maybe it's a false positive. You take the test. It says you have the disease. Without pen and paper, how likely do you think the odds are you have the disease? Who says over fifty percent? Okay. Before people sinisterly shouted the right answer, people will tend--medical students were given this, medical students less savvy than you, and the average is between fifty percent and ninety-five percent.

The answer is, as some people quickly noted, two percent. And here's how it works. One percent of a thousand will have the disease. That person will test positive. The test never misses. That leaves nine hundred ninety-nine people who don't have the disease, and we'll say about fifty percent of these people have it. So, for every fifty-one people who test positive, only one will have the disease, giving an average of about two percent. This sort of thing is very difficult. Our minds are not evolved to do base rate computation. And so, any problems involving base rate computation, including real world problems, like what to do when you come back with a positive test, we screw up. And often we screw up in the direction of panic.

The third bias is the "availability bias." And this is simply that if you want to know how frequent something is, how available it is to come to mind is an excellent cue. But this could lead to mistakes. A classic example by Kahneman and Tversky is you ask people--one group of people how many English words end with "ng" or what proportion of English words, another group of people what proportion end with "ing." It turns out you get much bigger numbers for "ing" than "ng" though, of course "ng" has to--"ing"--sorry, "ng" would include everything with "ing." It's just a lot easier to think about these things.

This can show up in the real world. What are your risk of getting killed--What's your risk of getting killed by a shark? Well, if you ask people what their risk of getting killed by a shark is, they characteristically overestimate it. I will give you the news of what the risk is for getting killed by a shark. Injured in any given year: one in six million. Killed: one in five hundred million. If you live in Florida, which apparently is Shark Central, your chance of getting injured is about one in a half million. People will overestimate the risks because shark attacks are very salient. They are always reported in the news and they're very interesting. What is the chance of getting killed by potato salad? [laughter] Well, food poisoning, death by food poisoning, injury by food poisoning runs to about one in fifty-five, one in 800 for some sort of injury and one in 55,000 killed.

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Potato salad is 1,000 more times more dangerous than shark attacks. But you get it wrong because you don't think, "Oh, my God, big news story. Somebody dies by potato salad." [laughter] And so, we tend to overestimate the chance of being killed by dramatic effects.

How many Jews in the United States, what proportion? Who thinks it's over three quarters of the United States is Jewish? [laughter] I'm kind of anchoring here. Okay. Okay. Who thinks over half? Who thinks over forty percent? Who thinks over twenty percent? Okay. Who thinks over fifteen percent? Who thinks over ten percent? Who thinks over seven and one-half percent? Who thinks over five percent? Okay. Who thinks overall there's more than five percent of the United States that's Jewish? Who thinks over three percent? The answer is somewhere between 1.9 and 2.1%. Most people think--The average American thinks it's twenty percent. There is-- [laughter] If you're curious about demographics, and this map isn't to be entirely trusted because I got it from Wikipedia, [laughter] this is the distribution of the Jewish population, self-identified as Jewish in different parts of the United States. [laughter] New York City is, of course, the most dense population with nine percent. New Haven has 3.5%.

Now, why do people get it wrong? Well, there's all sorts of reasons and this is going to come out in the context of social psychology when we talk about how people think about human groups. But one quick answer is people who are plainly Jewish are prominent in positions where people notice them, like entertainment or, in the case of you guys, academia. And this could lead to--this availability-- "Can I think of a Jew? Yeah." [laughter] This availability causes us to overestimate the proportion to which Jews are represented in the population.

Final example. Confirmation bias. This is a very nice study and it's very simple. It's--You're in a jury of a custody case. You have to give a child custody – either a mother or father sole custody. One parent has average income, average health, average working hours, reasonable rapport with the child, and a relatively stable social life. The second parent has an above-average income, minor health problems, lots of work-related travel, a very close relationship with the travel--with the child, and an extremely active social life. Think for a moment. Who would you award custody with? There's no--Obviously, there's no right answer here.

Just think for a moment. Who would award custody to parent A? Who would award custody to parent B? Okay. As I think there is in this room, when this study is done there's a slight advantage to parent B. Here's what's interesting. You give another group of people this question. "Which parent would you deny custody to?" You get a slight advantage for parent B. Now, this is to some extent an illustration of framing problem but it's also a more general illustration of the confirmation bias. So, when you're asked to award custody to, you then ask, "Well, what is a good--what is a sign that somebody's a good parent?" And the good parent aspects of B jump out. When asking about denying custody you ask, "Where is a cue that somebody's a bad parent?" And the bad parent aspects of B jump out. In general, when we have a hypothesis we look for confirmations.

This makes some things, which are logically easy extremely difficult problems when we face them in the real world. And I'll end with my final example, that of the Wason selection task. Here's the game. And people--I don't want people to shout it out just yet. There is four cards [pointing to a slide depicting four cards: D, G, 3, 8]. Each card has a letter on one side and a number on the other side. You have to judge whether this claim is true or false. "If a card has a 'D' on one side, it has a '3' on the other side." How many cards do you have to turn over to test whether that rule is right? Okay. Somebody shout out what one card is you have to turn over. "D." Everybody gets that right. What else? Do you need to do any other cards? How many people think it's "D" and "3"? I'm raising my hand to fool you. [laughter] People answer either "D" or "D" and "3" but think about it. What would make this rule wrong? It's wrong if it has "D" on one side and not "3" on the other. Right? That's what it would be to be wrong. You then would have to check "D" to see if there is a "3" on the other side. You were all right about that. That means you'd check "8" to see if there's a "D" on the other side. "Three's" not going to tell you anything. That's hard. People find this very hard.

Okay. Big deal. But what's interesting is you can modify it in certain ways to make it a lot easier. And this is the work of Leda Cosmides and her colleague, an evolutionary psychologist at Santa Barbara who has argued that if you frame these questions in ways that make ecological sense, people are much better at them. And basically, she does studies where she has people who are evaluating a social rule. Imagine these cards. On one side of the card is an alcohol--is a drink. On the other side is a person's age. You are a bartender and you want to make sure nobody under twenty-one drinks beer. Which cards do you turn over? Well, now it's easier but the logic is the same. It's a violation that there's "under twenty-one" on one side, "beer" on the other side, so you need to check the "under twenty-one" here and you need to check the "beer" here. And when you make these logical problems more ecologically valid they turn out to be much easier.

Okay. There's a little bit more but I'll hold it off until next class. And I'll end with the reading response, which is to do your own bit of reverse engineering and evolutionary psychology. And I'll see you all on Wednesday.

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Lecture 11 Professor Paul Bloom: On Monday we--I presented an introduction to evolutionary psychology, the looking at psychology from an evolutionary perspective, and trying to make a case and give some examples of how it can help illuminate and illustrate certain aspects of how the mind works. One of the advantages of an evolutionary perspective on the mind is that it forces us to look scientifically at what we would otherwise take for granted. There are a lot of aspects of how we are and what we are and what we do that seem so natural to us. They come so instinctively and easily it's difficult, and sort of unnatural, to step back and explore them scientifically but if we're going to be scientists and look at the mind from a scientific perspective we have to get a sort of distance from ourselves and ask questions that other people would not normally think to ask. And the clearest case of this arises with the emotions. And as a starting point there's a lovely quote from the psychologist and philosopher William James that I want to begin with. So, he writes:

To the psychologist alone can such questions occur as: Why do we smile when pleased and not scowl? Why are we unable to talk to a crowd as we talk to a single friend? Why does a particular maiden turn our wits upside down? The common man--[None of you are the common man.] The common man can only say, "Of course we smile. Of course our heart palpitates at the sight of the crowd. Of course we love the maiden. And so probably does each animal feel about the particular things it tends to do in the presence of certain objects. To the lion it is the lioness which is made to be loved; to the bear the she-bear. To the broody hen, the notion would probably seem monstrous that there should be a creature in the world to whom a nestful of eggs was not utterly fascinating and precious and never to be too-much-sat-upon object which it is to her.

Now, there's a few things to note about this passage. First, it's incredibly sexist. It assumes not just merely in reflexive use of phrases. It assumes that--William James assumes he's talking to males, male humans who sometimes take the perspective of male bears. And so, it assumes a male audience. You wouldn't normally--You wouldn't actually ever write this way. A second point is it's beautifully written and you're not--;also, not allowed to write that way anymore either. It's poetic and lyrical and if--William James characteristically writes that way. I think he writes so much better than his brother, Henry James, an obscure novelist. [laughter] Finally though, the point that he makes is a terrific one, which is yes, all of these things seem natural to us but the reason why they seem natural is not because they are in some sense necessary or logical truths. Rather, they emerge from contingent aspects of our biological nature.

And so we need to step back. We actually--We need to step back and ask questions like--and these are questions we're going to ask--Why does poop smell bad? Avoid the temptation to say, "Well, poop smells bad because it's so stinky." The stinkiness of poop is not an irreducible fact about the universe. Rather, the stinkiness of poop is a fact about human psychology. To a dung beetle poop smells just fine. Why does chocolate taste good? Well, chocolate--The good tastiness of chocolate isn't some necessary fact about the world. It's a fact about our minds that doesn't hold true for many other creatures. And so, we have to step back and ask why to us do we find chocolate appealing?

Why do we love our children? Don't say they're lovable. Many of them are not [laughter] and, as William James points out, every animal, most animals, many animals love their children. They think their children are precious and wonderful. Why? Why do we get angry when people hit us? Suppose somebody walked up to you and slapped you in the face? You'd be afraid. You'd be angry. Would you get sleepy, feel nostalgic, suddenly desire some cold soup? [laughter] No. Those are stupid alternatives. Of course if somebody slapped us you would--we would get angry or afraid. Why? Why do we feel good when someone does us a favor? Why don't we feel angry? Why don't we feel fearful? What we're going to do throughout this course is step back and ask these questions. We're going to ask questions nobody would have otherwise thought to ask, where the common man wouldn't address, and this is, of course, standard in all sciences.

The first step to insight is to ask questions like why do things fall down and not up? And I imagine the first person who articulated the question aloud probably met with the response saying, "What a stupid question. Of course things fall down." Well, yes, of course things fall down, but why? Why is our flesh warm? Why does water turn solid when it gets cold? These are natural facts about the universe, but the naturalness needs to be explained and not merely assumed. In this class we're going to explore, throughout the course, what seems natural to us and try to make sense of it. And to that end we have to ask questions that you wouldn't normally ask. We've already done this to some extent with domains such as visual perception, memory, language and rationality, but now we're going to move to the case where it's maybe even somewhat more difficult to do this. Now, we're going to start dealing with the emotions. We're going to talk about the emotions, why they exist, what they're there for, and how they work.

I want to start off with the wrong theory of the emotions. And the wrong theory of the emotions is beautifully illustrated in the television and movie series Star Trek. In this alternative fantasy world, there are characters, Mr. Spock in the originalStar Trek, Data in one of the spin-offs, who are described as competent, capable, in fact in many ways, super competent and super capable people. But they're described as not having emotions. Spock is described as not having emotions because he's half Vulcan, from a planet where they lack emotions. Data is an android who is said to lack an emotion chip.

This lack of emotions on this--on a TV series does not hurt them much. They're able to fully function. And in fact, in a TV series emotions are often seen as a detriment. You do better off without them. And there are many people in sort of

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common sense who might think "Gee, if only I could just use my rationality, think reasonably and rationally and not let my emotions guide my behavior I'd be much better off." It turns out that this is a notion of how to think about the emotions that is deeply wrong. And in fact, makes no sense at all.

Using the example of Star Trek, Steven Pinker, in his book How the Mind Works, nicely illustrates the problem here. He writes, "Spock must have been driven by some motives or goals. Something must have led him to explore strange new worlds, to seek out new civilizations and to boldly go where no man had gone before." Presumably, it was intellectual curiosity that set him to drive and solve problems. It was solidarity with his allies that led him to be such a competent and brave officer. What would he have done if attacked by a predator or an invading Klingon? Did he do a handstand, solve the four-color map theorem? Presumably, a part of his brain quickly mobilized his faculties to scope out how to flee and how to take steps to avoid a vulnerable predicament in the future. That is, he had fear. Spock did not walk around naked around the ship. Presumably, he felt modesty. He got out of bed. Presumably, he had some ambitions and drive. He engaged in conversations. Presumably, he had some sociable interests.

Without emotions to drive us we would do nothing at all. And you could illustrate this scientifically. Creatures like Spock and Data don't exist in the real world but there are unusual and unfortunate cases where people lose, to some extent or another, their emotions. And you could look at these people and see what happens to them. The classic case, the most famous case, is that of a man called Phineas Gage. Phineas Gage is the classic Intro Psych example – an extremely poor guy, poor schmuck.

In 1848--He was a construction foreman. In 1848 he was working at a site with explosives and iron rods. And due to an explosion, an iron rod passed through his head like so. Imagine that rod shooting upwards. It went under his eye and popped out the top of his head. It landed about one hundred feet away covered with blood and brains. The rod itself weighed thirteen pounds. Amazingly, Gage was not killed. In fact, he was knocked unconscious only for a short period and then he got up and his friends surrounded him and asked, "Are you okay?" And they--And then they took him to the hospital. On the way to the hospital, they stopped by a tavern and he had a little pint of cider to drink, sat down and talked to people. And then he had an infection, had to have surgery. But when it was all said and done he wasn't blind, he wasn't deaf, didn't lose language, didn't become aphasic, no paralysis, no retardation. In some sense, what happened was much worse. He lost his character.

Here's a description at the time of what Gage was like. And this is from Damasio's excellent book Descartes' Error: He used to be a really responsible guy, a family man, very reliable, very trustworthy. But after the accident he was fitful, irreverent, indulging at times in the grossest profanity, manifesting but little deference for his fellows, impatient of restraint or advice, a child in his intellectual capacities and manifestations. He had the animal pleasures of a strong man. His foul language is so debased that women are advised not to stay long in his presence.

And he couldn't hold a job. He lost his family, couldn't hold a job. He ended up in the circus. He was in the circus going around the country with his big iron rod telling everybody the story as they surrounded him and clapped. There are other cases like Phineas Gage, cases where people have had damage to that same part of the brain, parts of the frontal cortex. And what they've lost is they basically lost a good part of their emotions. And what this means is they don't really care that much about things. They can't prioritize.

Damasio tells a case of one of his patients who was under the pseudonym here of Elliot. And Elliot had a tumor in his frontal lobe. And the tumor had to be removed and with it came a lot of Elliot's frontal lobe. And again, as a result of this, Elliot was not struck blind or deaf or retarded, and he didn't become the sort of profane character that Phineas Gage became, but he lost the ability to prioritize. He lost the ability to set goals. Damasio describes him here:

At his job at an activity he would read and fully understand the significance of the material [He works in an office.] but the problem was he was likely, all of a sudden, to turn from the task he had initiated to doing something else and spending an entire day doing that. He might spend an entire afternoon deliberating on which principle of categorization he should apply to files. Should it be the date or the size of the document, pertinence to the case or another?

He couldn't set his goals. He couldn't--He ended up not being able to keep a job, not being able to deal with people. And these are not men who have lost their emotions. There is no case around where you could have your emotions entirely blotted out. But they lost a large part of their emotional capacity and as a result, their rationality failed.

Emotions set goals and establish priorities. And without them you wouldn't do anything, you couldn't do anything. Your desire to come to class to study, to go out with friends, to read a book, to raise a family, to be--to do anything are priorities set by your emotions. Life would be impossible without those emotions. And so, there's certain themes we're going to explore here. The first is this, that emotions are basically mechanisms that set goals and priorities and we're going to talk a lot about--in this class and the next class about universals. We're also going to talk about culture. It turns out that cultures, different cultures, including differences between America and Japan and the American South and the American North, have somewhat different emotional triggers and emotional baselines to respond to. But at the same time, as Darwin well knew, emotions have universal roots that are shared across all humans and across many animals.

So, the agenda for this class and the next class is going to go like this. First, I want to talk a little bit about facial expressions, which are ways in which we communicate our emotions – not the only way, but an important way – and look, in particular, at the case of smiling because it's kind of interesting. Then I want to look at one case study of a nonsocial

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emotion, that of fear. I want to then deal with feelings towards our kin, people we're genetically related to, and then--and this will take us to the next class, feelings towards non kin. So first, faces. And as an introduction to faces I have a brief film clip from Paul Ekman, who is one of the world's great scholars in the study of facial expressions. [clip playing]

In Ekman's work, he presents us with instructions on how to make different faces and identify faces. Ekman actually has a sort of more practical career along with his scientific career. He trains police and secret service members to try to figure out cues to honesty and dishonesty. There's a very interesting New Yorker profile on him by Malcolm Gladwell a few years ago, something you might be interested in. But let's do one of his faces.

Please lower your brows and draw them together. That means even those who aren't making eye contact with me now. Tense your lower and upper eyelids. Don't pop out contact lenses but just tense them. Stare. Your eyes can bulge somewhat. [laughter] Okay. Now, the last part is important. Press your lips together with the corners straight or down. That's good. You got it. [laughter] Okay. Just because you are not making eye contact with me doesn't mean I can't see you. Okay. [laughter] Well, what you're looking like presumably is this [referring to a slide]. And what face is that? What emotion does that correspond to? Anger.

There's all sorts of databases of different faces from around. This guy--I don't know who he is but he seems to be on a lot of these things [laughter] but the thing is you don't need to rely on him. You don't need to rely on Western faces. Even if you go on line there's, by now, a lot of databases from faces from all sorts of genders and national origins. This is from a Japanese women facial expressions. And there are some subtle and very interesting differences across countries and across people, but there's also deep universals. You don't have to work very hard to figure out what these different facial expressions mean.

I want to give one more face example because I want to focus on this a little bit. This one's a little bit easier. Raise the corners of your lips back and up, please. [laughter] Raise your cheeks. Raise your lower eyelids if you can. [laughter] They're smiling. You're smiling. You can stop [laughter] smiling. Yale is actually really big on smiling. We have two of the world's experts on smiling. This is Angus Trumble, the curator at the British Art Gallery who wrote this wonderful book, A Brief History of the Smile looking at the smile in art. And this is my colleague, Marianne LaFrance, who is actually not smiling in that picture but she studies smiling and smiling in adults, smiling in children, smiling across cultures, and the different social uses of smiling. And there are some interesting discoveries people have made about smiles and about smiles and the emotions.

One--Oh. Well, one is that smiles are universal. We know, for instance, that young children smile. This is my son, Zachary, when he was younger, not that weird-looking kid [laughs] next to him. [laughter] Thank God. [laughter] And even blind children, children blind from birth, will smile. They'll smile appropriately, making an important point that smiling is not learned by looking at other people's faces.

Smiling is also not uniquely human. Nonhuman primates smile as well. Smiles are social signals. You might imagine that people smile when they're happy. This is actually not the case. It's not as simple as that. Rather, people smile when they wish to communicate happiness and we know that from several studies. There are some studies of bowlers and the studies are very nice. What they do is they film bowlers. So, the bowlers do their bowling and sometimes they knock down all the pins, which is called a what? A strike. So a strike--and that's good in the bowling world. So, they knock down all the pins but what they don't do, is they don't smile after they knock down the pins. They are being filmed. They don't smile. Then they turn around to their friends and give a big grin.

Other studies have looked at films of people who have just won Olympic gold medals. Now, not surprisingly, people who have won Olympic gold medals are very happy. This is good news to win an Olympic gold medal. But they don't actually stand on the podium grinning. Rather, they stand there with their faces in a normal expression. Then when they stand up and face the crowds, there's a big smile. You can ask yourself whether during sex, an activity where many people enjoy, whether or not people smile during sex. And you can discover this yourself with [laughter] a partner or a mirror. [laughter]

So, there are other things we know about smiles. There are different types of smiles. There are actually quite a few different types of smiles that are different in interesting ways. This is Paul Ekman again. Which one's a better smile? Who votes for the one on the right? Who votes for the one on the left? There are two different sorts of smiles. The one on the right is a smile of greeting. It's sometimes known as a "Pan Am" smile. Pan Am is a now defunct airline which had at that time--They were--They don't call them stewardesses anymore but they're--the stewardesses would come in and they would smile. That was part of their job. But it was a big, fake smile, the Pan Am smile, a smile to communicate "hello" and--but it's as opposed to a smile where the communication is that of genuine happiness. The difference is around the eyes. It's not the mouth. It's the eyes.

A real happiness smile, what's known as a Duchenne smile, after a neurophysiologist who studied it, involves moving the eyes. What's interesting is about only one out of every ten people can fake a Duchenne smile. So, if you smile at somebody, and you just hate their guts but you want to smile at them, it's--unless you're quite gifted it's difficult to fake a really good, really happy smile.

You could--It's not difficult to study smiles in the real world. You could look at politicians, for instance. Politicians are often in contexts where they have to smile a lot. And what they do is they simply give the Pan Am smile. The mouth moves

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up, particularly if somebody is attacking their record or ridiculing them, and they'll smile and--but it's not a sincere smile. The eyes don't move.

My favorite example of this was a few years ago when there was a huge battle for the House majority leader. And a guy named--a Republican named John Boehner won this position in quite a heated battle. And they took a picture of the guy--This is not very nice. They took a picture of the guy, Roy Blunt, as he stepped out. And he had lost and this was his expression. [laughter] And he's not really very happy [laughter] as opposed to a smile like this, which is a real smile.

So, you have two sorts of smiles: A real happiness smile [or] a Duchenne smile--called--also known as the Duchenne smile, and then a Pan Am smile, or greeting smile. And you'll use each of those smiles at different points in your day and in your life. It turns out that these different smiles have real psychological validity. They seem to sort of reflect deep differences in your mood and emotions and thoughts. Ten-month-olds, for instance, give different sorts of smiles. When their mother approaches there they give a real happiness smile. Then when a stranger approaches or someone else approaches there they'll tend to give more of a greeting smile.

John Gottman studied married couples. And John Gottman does a lot of work--Well, what he does is he looks at film clips of couples. And by analyzing the film clips he tries to predict will their marriages survive. And one of his cues--There's different cues. Incidentally, sort of side topic: The death knell for a marriage for Gottman--This is his big finding. It's not if they fight a lot. It's not they scream at each other. It's not even if they hate each other. The death knell of a marriage is contempt. And so, if he shows these clips: I walk in, "Honey, I'm home," and my spouse has the look of contempt, it's a bad sign. [laughter] But another clue is the sort of smiles they give when they see each other when they walk into the lab. If it's a true happiness smile, that's actually bodes better for the relationship than a Pan Am, or greeting smile.

Finally, studies have been done of college yearbook photos looking at people thirty years later. And it turns out that there's a correlation, a reliable relationship between how happy somebody is now and back thirty years ago in their yearbook photo--what sort of smile they're giving.

There is some evidence for a third sort of smile. This is known as a coy smile or an appeasement smile. This is sort of a very specialized sort of smile. This is a smile of embarrassment or stress. You give it when you want people to like you, you want to join in; you want to make people feel positive about you. But you're in, sort of, a high-stress situation often with some sort of risk. And what you do is you sort of you turn away. There's no eye contact. You turn away and kind of give this-- [demonstrating by tilting his head to the side]

And this actually shows up in other primates. Here's a nice picture. [laughter] So, the rhesus monkey bites her own infant, and the infant gives a scream and then the submissive, coy smile. And it also shows up in human infants. Here's a nice clip of a coy baby smile. I'll walk you through it. The baby is being approached, [laughter] goes like this [with locked-gaze the brows raise and a smile starts], smiles like this [smile widens and head turns up a left], and then the aversion [smile widens and head is further averted]. Yeah. Babies are cute. [laughter] Any questions at this point about smiling? What are your smiling questions? [laughter] Yeah. Student: Do nonhuman primates' smiles [inaudible] Professor Paul Bloom: That's a good question. I don't know. There's evidence that the coy smile shows up in non--The question was, "Do nonhuman primates give the same smiles that humans do?" such as a distinction between the Pan Am smile, a greeting smile, versus a genuine smile of happiness? I don't know. I'll find out for you for next class though. That's a good question. Yeah. Student: How come some people's smiles are better than other people's smiles? Professor Paul Bloom: How come some people's smiles are better than other people's smiles? The non-interesting psychological answer, some people are better looking and there's more thing-- [laughter] but the deeper answer is some people are better able to smile. Some people are better able to use the cues to express true happiness.

There's something else about smiles which is going to come up, which your question raises, I think, which is going to come up in--when we talk about emotional contagion and actually, some issues of morality. Smiles are extremely contagious. So, what I'd like people to do--If you're sitting next to somebody, please turn around and find someone next to you and look at them. Don't do anything. Just look at them. Whoever is being looked at, look back. [laughter] This is not-- [laughter] Please arbitrarily decide. Okay. Please arbitrarily decide on the smiler. That will be--No, not at me, at each other, [laughter] and that will be the person--If you are unable to resolve this dispute--yes, you two, please--if you are unable to resolve this dispute, the person to the right of me will be the smiler. So, look at each other expressionless. [laughter] Now, the person who is the mandated smiler, [laughter] on three, please smile. One, two, three. [laughter] Okay. [laughter]

Worst class demo ever [laughter] but if one could imagine more restrained circumstances, it is actually extremely difficult to be facing somebody who's really smiling at you and not smile. This is true, by the way, for virtually every other emotion. The phenomena is known as "emotional contagion," where if you're facing somebody, for instance, and they're--they look at you in a face of absolute rage, it is very difficult to just sit there without your own face molding in accord to their own. And the reasons why this happens and how that works is something we'll talk about later on. So that's--One more question. Yes. Student: [inaudible]

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Professor Paul Bloom: I don't know if that's--The question is, "Is there a difference between smiling with your teeth versus just your lips closed?" There probably is. That's not a main smile difference but my bet is that there probably is a difference. And my bet also is that that sort of distinction, how much teeth you show when you smile, is the sort of thing that would show regional and country by country differences. For instance, there's been research finding that people in England smile different from people in the United States. And I think that those are the sort of contrasts that you would expect to find in cross-cultural differences. Every culture is going to have Pan Am smiles, happiness smiles, coy smiles, but the variation of that sort is something which will vary as a result of how you're raised and the people around you.

I want to deal with a few emotions in this class and next and the first case study of an emotion I want to deal with is the emotion of fear. And I want to deal with fear for different reasons. One reason is it's a basic emotion, it's universal. All humans have it. Many nonhumans, probably most nonhuman, species have it too. And it also brings us back to the lecture on behaviorism where we talked about classical conditioning and different theories of what people are afraid of. It's a nonsocial emotion. What I mean by this is it's possible, of course, to be afraid of a person, but unlike an emotion like gratitude, it's not intrinsically social. You could be afraid of falling off a cliff or something. It has a distinctive facial expression again.

This is a famous picture of Lee Harvey Oswald who was being assassinated by Jack Ruby. And this is the detective's face standing there, a mixture of fear and anger – the face being drawn back in a universal expression that every human everywhere would be able to recognize.

So, the basic question to ask is "What are we afraid of?" And the answer's a little bit interesting. We're afraid of spiders, snakes, heights, storms, large animals, darkness, blood, strangers, humiliation, deep water, and leaving home alone. We are afraid of other things too but those are big things to be afraid of. I'm not even going to ask. If there's somebody who--in this room, who's not afraid of any of those things? You're a tougher person than I am. These are universal fear elicitors. Why? What do they have in common? Why would you be afraid of those things? And the answer is--And why would--why are there so few people afraid of guns, cars, and electrical outlets?

The answer is not particularly surprising. These are things that--something's ticking over there. [referring offstage] These are things that are scary in our ancestral environment. More particularly, these are things that through the course of human evolution have been dangerous to us. And so, we are afraid of these things [pointing to a slide containing spider, snakes, heights etc.] and not so afraid of these things [pointing to guns, cars, electrical outlets, etc.]; similarly for nonhuman primates. So, chimpanzees are afraid of certain things and they can often develop phobias for certain things, but the phobias they develop, the fears they develop, are things like spiders and snakes.

There was a nice study done in urban Chicago, in the inner city of Chicago. And they asked children raised in the inner city, "What are you most afraid of?" And you might think they would say, "I'm afraid of being shot. I'm afraid of guns. I'm afraid of being killed by somebody or being harmed by somebody. I'm afraid of being run over by a car." The two biggest fears of children in urban Chicago are that [pointing to the slide], snakes and spiders, even though many of these children have probably never seen a snake outside of a zoo in their lives. These are natural fears.

There is some research done by the psychologist Judy DeLoache at University of Virginia where she's studying babies' fears of spiders and snakes, babies obviously who, since their parents are normal, have not yet seen spiders and snakes. There are various ethical reasons why you can't show babies--you can't try to construct phobias in babies of spiders and snakes but the research she's finding using more indirect methods finds, as one would expect, these are what psychologists would call "pre-potent stimuli"; that is, these are things that naturally elicit fear and concern. And that's all I have to say about fear.

I want to turn for the rest of this lecture and for next lecture next week to the social emotions. And the social emotions can be broken down into two categories. [a student sneezes] Bless you, bless you. Those emotions you feel towards your kin, towards your genetic relatives, and those emotions that you feel towards the people you're not related to but interact with. And I want to focus particularly on emotions that generate kind or altruistic behavior.

"Altruism" is the biologists' term meaning kindness, generosity, and evolutionary biologists have worked really hard to explain why animals might evolve to be kind. A very old, very wrong view of evolution is that evolution has shaped animals such that they're merely survival machines. If so, then from an evolutionary standpoint any kindness towards an animal--that an animal shows towards another animal--is a mystery. If evolution wired us up simply to survive, then it's a puzzle why animals would relate positively to other animals. But of course, that's not true.

Here's a simple example showing it's not true. Imagine two genes, two sorts of animals each containing their own gene. Gene "A" makes an animal care for its offspring. Gene "B" makes an animal care only for itself. Imagine what will happen in the next generation. Plainly, Gene "A" will win out. It's a very simple case. An animal who has evolved a brain that says, "Take care of your offspring" will do much better from a natural selection point of view from an animal who has evolved a brain that says, "Eat your offspring." The animal that eats its offspring, those genes are a biological dead end. What matters then is not survival, per se. What matters is reproduction. And so, that simple fact is why we would expect animals to care for their children, because children are the means through which genes replicate.

But it gets a little bit richer than that. And this is one of the major revolutions in evolutionary biology over the last half century. Forget about the animal a bit and take another perspective. Take a perspective of the cold virus. People have been

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sneezing in the front row. Now, you're coughing. Thank you. Why do you sneeze when you get a cold? Here's not a-- [more coughing, laughter] Point made. Here is--Here's not a bad answer. You sneeze because you've got all these germs inside you and your body wants to get the germs out, so you sneeze. It's not that it's totally wrong, but it's not bad.

The real answer is a little bit more interesting. Don't look at it from the person's perspective. If you have a cold, try to get away from your own selfish perspective, "I have a cold." Look at it from the perspective of the cold virus. The cold virus has evolved just as much as you evolved. And it's evolved due to survival and reproduction. What the cold virus does is evolve different strategies to cause it to reproduce. And what it does is--one way to reproduce is to occupy other animals and manipulate their bodies so as to expel it. From this point of view then, the reason why you sneeze when you have a cold is that your cold--the cold virus is using your body as a tool to replicate itself. From this person--this perspective, a person is just a germ's way of making other germs. And there's tons of other examples of this.

There's a parasite known as toxoplasmosis that lives in the bodies of rats. But it gets passed on when the rats get eaten by cats. And then it ends up in the cats' feces and then it ends up back in rats. If you are a rat and you have toxoplasmosis, you are perfectly healthy except for one thing. The toxoplasmosis rewires your brain and it makes you less afraid of cats. Now, again, this is not some sort of bizarre quirk of a humorous god. Rather, it's because this is a perfectly--this is the adaptive strategy of the toxoplasmosis virus.

In fact, a real powerful virus would skip the respiratory system altogether, even better than a cold virus. What it would do is it would take over the brain and it will make people want to run around and have sex with other people and kiss them on the mouth. And in fact, there is some evidence that this happens. There's some evidence, for instance, that one of the effects of sexually transmitted diseases like syphilis is it arouses the libido, makes people more sexually engaged, because this is part of the strategy through which these viruses replicate themselves. Imagine a virus, for instance, that captured an animal's brain and then modified the animal's brain such that the animal would run out and bite other animals so as to pass on the virus. And then, of course, you would call that virus "rabies." Along these lines, the evolutionary biologist Richard Dawkins took the general step of suggesting that animals are the vehicles through which genes exploit to reproduce. From this perspective, an animal is just the person's--is just the gene's way of creating another animal.

Well, as psychologists, what benefit does that--does this way of analysis give us? It actually can help us explain altruism. So, which genes are going to survive? Well, the genes that survive are going to be the ones that make the most copies of themselves. Animals are vehicles through which genes reproduce. An animal's merely the gene's way of making another gene. Hence, selfish genes will lead to altruistic animals because, to the extent that evolution operates at the level of the genes, there's no hard and fast distinction between your own body and someone else's body.

And here's an illustration by the biologist Haldane. So, Haldane was once asked, "Would you lay down your life for your brother?" And he responded, "No, but I would gladly give my life for three brothers or five nephews or nine first cousins." Now, he's joking. You don't actually do the math if you're normal. But what he's capturing is the logic, the ultimate causation of our feelings towards our kin. Our genes have wired us up--our brains up to love our children and love our kin because, in this way, our genes manage to replicate themselves. And in fact, you get his calculations by looking at genetic relatedness.

The genetic relatedness, from an evolutionary standpoint, affects how much you care for other people. From the standpoint of your genes, you dying for the life of three brothers is an excellent compromise because the genes replicate by fifty percent more. If you imagined--;So, here is his calculations. If you imagined a choice between this one gene that makes the animal choose to die and the other gene that makes an animal choose for its brothers to die, the gene that sacrifices the body it belongs to will make more copies in the future. And there's an interesting irony to this. The selfish gene theory is often seen as sort of a cold-blooded evolutionary analysis, but it provides a scientific basis for real, genuine altruism, for really arguing that, from the standpoint of the genes, there really is no hard and fast difference between yourself and another person.

From this perspective, we can start to answer some interesting questions at least about nonhumans. When a new male lion takes over a pride what he does is kill all the remaining cubs and any lionesses undergo spontaneous abortions. This all might seem very cruel but from a genetic standpoint it makes sense. The other cubs are genetic competition for him. They do not have his genes. Moreover, only once they're out of the way can he reproduce and copulate with the females. The females do their spontaneous abortions because that's a reliable adaptive trick. These cubs are not going to survive once they are born so the female's best strategy is to get rid of them and start anew.

From a psychological point then, animals have evolved to be nice to their kin, particularly their children, and particularly in birds and mammals. Birds and mammals invest in quality and not quantity, as opposed to fish and reptiles. For birds and mammals, we don't have many kids but--so we devote a huge amount of psychological energy to protecting the ones that we have. Moreover, the kids we have are vulnerable for long periods of time and require our resources. So, there's various psychological mechanisms that this gives rise to. One is how parents or how adults in general respond to children. Another one is how children respond to parents. And I'll briefly talk about a few of these phenomena.

[plays a sound of a baby crying] Small animals make distress calls. They chirp, they mew, they bleat or they cry. The governing of a distress call is actually an extremely delicate high-wire act for any young organism from an evolutionary point of view. It has to on the one hand be annoying enough to actually generate help, to get people to help you, to feed you, to pick you up, to take you and put them next to you. On the other hand, it can't be so annoying that the people around you

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kill you [laughter] and so it's complicated. But, from your point of view, you're wired up to respond to them. That sound is, at very minimum, extremely annoying. And it's more--it's not annoying because of its volume or pitch. It's annoying because your brains are wired up so that that baby cry is going to drive you up the wall.

On the more positive side, babies are cute. I got this [picture] from Google Images, typing in "cute baby," [laughter] getting rid of the porn and [laughter] coming on to that. No, no, Playboy, but anyway it was over that. [laughter] And do not be tempted to say, "Isn't it wonderful that the way nature works is that babies are cute? Otherwise we would have killed them." [laughter] That's not the right story. If--Babies are not--Human babies are not, sort of, metaphysically cute. If Martians came down they wouldn't say, "Oh, cute baby." Rather, they're cute because of how our brains are wired up. They're cute because there are certain cues that correspond to the way our brains work.

And in fact, this is how it works for all mammals. So, babies have these big, protruding foreheads, an upturned little nose, chubby cheeks and big eyes. Those are the ingredients for cute. Stephen Jay Gould has a wonderful essay where he discussed this, looking at the evolution of Mickey Mouse from the Walt Disney character. Mickey Mouse starts off as an ugly, little rodent. [laughter] Over time he gets cuter and cuter and cuter as the artist converged on more and more baby-like features.

Studies of adults show what's known as a baby-face bias. This is not unique to the United States. The same studies have been done in Asia. You find a baby face in an adult, Leonardo DiCaprio, to be particularly naïve, helpless, kind and warm. And in mock trials, people with baby faces are more likely to be found innocent than people like Ben Affleck, [laughter] who do not have baby faces. [laughter] Now, one question which is going to come up for an entire lecture later on is "who is sexier, the baby faced man or Testosterone Man?" here [pointing to Ben Affleck]. [laughter] And I am going to ask actually for a vote because I'm going to return to this. I do not--I only want the men to vote, please. Who would go for--And forget the fact that he looks sort of unhappy. Who would go for Ben Affleck here? Okay. [laughter] Who would go for Leonardo? Okay. [laughter] Well, the women votes would actually be more complicated. We will discuss when we get the lecture on sex. Your choice will depend on where you are in the menstrual cycle. [laughter]

Now, so far, we're talking about how babies respond to--We're talking about our responses to babies. What about babies' responses to us? Well, there's a very old theory known as the "Cupboard Theory" proposed by the behaviorist B.F. Skinner which argues that babies' attachment to their parents is because the parent provides food, characteristically breast milk, but it could be food from a bottle or whatever. And because of operant conditioning, the baby is driven towards the adult. An alternative theory is that of Bowlby, which is that they're drawn to their mother for comfort and social interaction as well as fear of strangers.

To test this, the psychologist Harlow performed a series of ingenious experiments with nonhuman primates distinguishing between what he called "wire mothers" and "cloth mothers." And you'll see illustrations of this to follow. Wire mothers are mothers that are built that they give food. They have a little nipple attached and you can drink from it and give food to the baby. And that's the baby's source of food. Cloth mothers don't give any food but they give warmth and comfort.

There was a while in the psychology department where one professor was known to be extremely supportive to his students but didn't really provide much warmth. And he was known as the cloth mother. And another one was very productive and everything but provided no love. And she was known as the wire mother. But anyway, I'll show you the movies. [movie playing] I have to warn you this third and final movie is an example of why this research is not currently done, but it illustrates an important scientific point. Oh. Now him-- [movie playing]

I think I'm-- [showing pictures of cute baby animals] They're just more Google Images. [laughter] I think I'll--I want to begin next class by wrapping up and explaining the Harlow studies in more detail and what they tell us. And then we'll move towards altruism, towards non kin. I'll see you next week.

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Lecture 12 Professor Paul Bloom: So what we're doing today is continuing on the theme of emotions. "Emotions" is a two-part lecture and we're continuing along certain themes.

I want to begin by responding to a question which was raised in the last class concerning smiling and nonhuman primates. It was a very good question. The issue was: we know that humans have different sorts of smiles to convey different sorts of information. The question was, "do nonhuman primates, like chimpanzees or gorillas or gibbons, have the same many sorts of smiles?" So, I contacted the world's expert on smiling, who did not return my e-mails. So, I contacted the second world's expert on smiling who told me that the answer is "no," that primate--nonhuman primate smiles actually correspond almost entirely to appeasement smiles. They're "don't hurt me" smiles. They're equivalent to the "coy smile" that we saw on humans. But that nonhuman primates do not use smiles for greetings; there's no equivalent to the "greeting smile" or "Pan Am smile"; nor do they use them as genuine expressions of happiness. There's no equivalent to the "Duchenne smile." That's as far as I know. If the world's expert gets back to me and says something different, I'll keep you posted.

Another thing. Going back to the beginning theme of the class, what we started--just to review, we talked about the different functions of emotions. And then we talked about smiling and facial expressions. And then we turned to some--to a nonsocial emotion, the case of fear. And then we shifted to social emotions. And we talked about social emotions towards kin and the special evolutionary reasons that would lead them to evolve. And as we were ending, we were talking about the relationship between an animal and its children, particularly in cases like humans and birds and mammals where there tends to be a close relationship with our children.

We invest in quality, not quantity. I might produce very few children in my life. And my evolutionary trick then is to focus very intently on them and make sure they survive. If I were to produce 100 children, I could stand to lose a few, but if I just produce five in my lifetime or two or one, they become very precious to me. And so, the story of the evolution of a species like us involves a long period of dependence and deep, deep bonds between the parent and the child. And that's part of what I talked about, how parents respond to children.

And I want to begin this class by giving an illustration from a documentary about parental response to children, but I want to give it in a species that's not us. And here is why. I'll explain why with an analogy. I have a friend of mine who studies the psychology of religion. He studies why people hold religious beliefs. And he tells me that when he's talking to a non specialist, somebody not in the field, he doesn't ever tell them, "Yeah, I'm really interested in why people believe in the Bible or why people light the candles on Sabbath or why people go to church" because these are religions that people around here hold, and if you tell people you study them they'll sort of be puzzled, "why would you want to study something like that" or offended. If you want to talk about the psychology of religion to an audience like this, what you do is you start with the exotic. So, you start by talking about people who put butter on their heads.

Dan Sperber talks about a culture where the men put butter on their heads in the summer. And it kind of melts and that's part of--one of the things that they do or--you talk about a culture that believes in spirits or that trees can talk. You say you're studying it and they say, "Oh, that's interesting. I wonder why they believe that?" And you use that as a way to look at more general facts that exist even in our culture. You use the fact that we don't take the exotic for granted as a way to motivate the scientific study of things we do take for granted.

And this is, of course, true more generally. This was the point in the William James quote when he talked about things that are natural to us and noticed that some very odd things are equally natural to other species. And it's true, I think, in particular when we talk about things like the love we have for our children. So, one way to look at the love we have for our children scientifically, isn't to look at it head-on, because the love we feel towards our own children feels sacred, it feels special, but look at it in other species. And so, one of the nicest illustrations of this is the Emperor penguin, which was--which--whose childcare and mating practices were dramatized in a wonderful movie called "March of the Penguins." And this is interesting because they had this incredibly elaborate and quite precarious system of generating and taking care of offspring.

So, I want to show you a brief clip of the movie to illustrate some parts of this. What they do at the beginning, which is not--which leads up to this, is they take a very long trek from the water to their breeding grounds. Their breeding grounds is--are protected from the wind and they're on a firm piece of ice so they could hold the whole pack. They do the breeding there and it's there that the eggs are created. So, this is where the movie begins at this point. [clip playing]

"March of the Penguins" was the second best--second most popular documentary of all time, beaten only by "Fahrenheit 9/11." And people responded to it in different ways, which are informative when we think about the generalizations you could make from animal behavior to human behavior. Some conservative commentators saw this as a celebration of family values, such as love and trust and monogamy. Some liberals, who hate everything that's good and true, [laughter] responded by saying, "Well, yeah, they're monogamous for one breeding season. It's a year. Then they go and find another mate. If you add it up, it's pretty slutty." [laughter]

I think more to the point, people were impressed and stunned by the rich and articulate and systematic behavior that these animals were showing. Plainly, they didn't pick it up from television, movies, culture, learning, schooling, and so

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on. To some extent, this sort of complicated behavior came natural to them. And it's understandable that some proponents of intelligent design, or creationism, pointed to this as an example of how God creates things that are deeply, richly intricate so as to perpetrate the survival of different animals. From a Darwinian standpoint, the Darwinian would agree with the creationist that this couldn't have happened by accident, this is just far too complicated, but would appeal to the--to this as an exquisite example of a biological adaptation, in particular a biological adaptation regarding parental care to children shaped by the fact that children share the parents' genes and so parents will evolve in ways that perpetrate the survival of their children.

Then there's the other direction, which is how children respond to parents, how the young ones are wired up to resonate and respond in different ways to the adults around them. And we quickly talked about some different theories of this. And I'll just review what we talked about last class. Babies will develop an attachment to whoever is closest. They'll usually prefer their mothers because their mothers are typically those who are closest to them. They'll prefer her voice, her face, her smell. It used to be thought that there is some sort of magical moment of imprinting that when the baby is born, the baby must see his or her mother and "boom," a connection is made. If the baby doesn't, terrible things will happen with attachment later on. This is silly. There is no reason to believe there's some special moment or special five minutes or special hour. It's just in the fullness of time babies will develop an attachment to the animal that's closest to it. They will recognize it as, at an implicit level, at an unconscious level, as their kin.

Well, how does this work? How does the baby's brain develop--come to develop an emotional attachment to that creature? Well, you remember from Skinner that operant conditioning could provide a good answer to this. And this is known as the "Cupboard Theory," which is babies love their moms because their moms provide food. It's the law of effect. It's operant conditioning. They will approach their mothers to get the food from them. And they will develop an attachment because their mother provides food. And this is contrasted with a more nativist, hard-wired theory developed by Bowlby which claims that there's two things going on. There is a draw to mom for comfort and social interaction and fear of strangers.

Now, in the real world, it's difficult to pull apart these two means of attraction because the very same woman who's giving you comfort and social interaction is also the one giving you milk. But in the laboratory you can pull them apart. And that's what Henry Harlow did in the movies you saw last week. So, Harlow exposed primates to two different mothers. One is a wire mother. That's a Skinnerian mother. That's a mother who gave food. The other is a cloth mother set-up so that she'd be comfortable and give warmth and cuddling. And the question is, "Which one do babies go for?" And as you can remember from the movies, the results are fairly decisive. Babies go to the wire mother to eat--as one of the characters said, "You've got to eat to live." But they viewed the--they loved the cloth mother. They developed an attachment to the warm, cuddly mother. That's the one they used as a base when they were threatened. That's the one they used as a base from which to explore.

Okay. And that actually--Oh, that's just--I have a picture. And that actually takes me to the--Oh, except for one thing, it almost takes me to the end of the question of our emotions towards kin. One question you could ask is, "What if there's no contact at all?" Now, you could imagine the effects of how--A lot of people are interested in the question of the effects of the child's early relationship to adults around him or her in how the child turns out later. This becomes hugely relevant for social debates like daycare. So for instance, a lot of psychologists are interested in the question, "Is it better for a child to be raised by a parent, usually a mother, or does it make a difference if the child goes to daycare? What if the child goes to daycare at six months? What if the child goes to daycare at two years? How does this affect the child?" The short answer is, nobody really knows. There's a lot of debate over whether or not there are subtle differences and it's deeply controversial. But we do know that it doesn't make a big difference. We do know that if you got raised by mom, or perhaps mom and dad, or maybe just dad all through your life until going off for school and I--my parents threw me in a daycare at age three months--it's not going to make a big difference for us, maybe a subtle difference though it's not clear which way it would go. But it won't make a big difference.

But what if there's no contact at all? What if--What about terrible circumstances where people get no cloth mother, they get nobody for attachment? This is a really--In the real world, of course, you can't do experiments on this. And in the real world with humans, this only happens in tragic cases. But this has been studied. So Harlow, again, raised monkeys in solitary confinement so they were raised in steel cages with only a wire mother. In other words, they got all the nutrition they needed but they got no mothering. It turned out that you kind of get monkey psychotics. They're withdrawn. They don't play. They bite themselves. They're incompetent sexually. They're incompetent socially. They're incompetent maternally. In one case, one of these monkeys raised in solitary confinement was artificially inseminated. When she had a child she banged its head on the floor and then bit it to death. So, you need to be--you need--This shows--This is kind of a stark demonstration that some early connection, some early attachment is critical for the developing of a primate.

Obviously, you don't do these experiments with people but there are natural experiments, humans raised in harsh orphanages with little social contact, and these children--If the--In other words, they get fed, barely, but nobody picks them up and cuddles them. These children, if this happens for long enough, they end up with severe problems with social and emotional development. From an emotional point of view, they're often insatiable. They really need cuddling and support or they're apathetic, they don't care at all. Now, there's some sort of good news, which is if you get these people or these

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monkeys early enough you can reverse the effects of this bad development. So, there's some research done with monkey therapists. So then, what they do is they take the monkey, they raise it in a steel cage, the monkey comes out, the monkey is kind of psycho, and then they send in a younger monkey who is just goofing around, jumping all around the place and everything. And experience with this younger monkey who just follows them around and clings to them leads to gradual improvement. It makes the solitary monkey become better.

There might be a similar effect with humans. So one story more about--of an anecdote than an experiment was a situation where at the age of one and a half, children were taken away from a really harsh orphanage where they had no contact and brought into a home for mentally retarded women where these women gave them plenty of contact and cuddling and apparently, from what we know, brought them back to normal. And this is all I want to talk about, about the emotions we feel towards our kin, towards our children, and towards our parents. Any questions or thoughts? Yes. Student: Do children in orphanages comfort each other? Professor Paul Bloom: It's a good question. Do children in orphanages comfort each other? I don't know. The situation probably wouldn't be there--The problem is children in orphanages who are in these terrible situations tend to be babies and very young and they wouldn't be thrown together in situations where they could comfort each other. It's a really interesting question. What if it was a situation where children were raised without a supportive cloth mother at all, would not be able to pick them up and hold them, but they could play amongst themselves and support each other? I don't know the answer to that. Teaching Assistant: Yes. Professor Paul Bloom: Yes? Is there evidence on that? Teaching Assistant: Yes, there is. [inaudible] Professor Paul Bloom: Yes. [laughter] The answer is there is evidence, [laughs] as everybody knows, [laughter] that this sort of--amongst the young, support can actually help the monkey and the children. Somebody else had a question here? Yes. Student: What does that tell us about the middle ground, if the parent is comforting just a little bit and then not that much [inaudible] Professor Paul Bloom: Right. So this is--The question is, "What does that tell us about the middle ground?" So this is an extreme case but what do we know about the middle case? Say your parent--You're not raised in a cage, you're not in a Romanian orphanage, but your parents just don't pick you up very much. They don't love you very much. There's no good evidence that that has any effect on a person. The problem is, and we're going to talk about this in much more detail in a couple of weeks, is it's true that parents who aren't affectionate have kids that aren't affectionate but it's not clear this is because of a genetic connection or an environmental connection. The one thing we do know is that in the middle ground, effects tend not to be dramatic. So when you get away from extreme cases, effects are hard to see and require careful experimental research to tease out. I think what it's safe to say for a lot--for everything but the severe conditions is we don't know what kind of effects there are. But if there are effects they are not big and dramatic ones.

Okay. Animals' good feelings, animals' emotional attraction to their kin, is not a huge puzzle from an evolutionary point of view. Evolution is driven by forces that operate on the fact of how many genes get reproduced and replicated among your descendants. So, it makes sense that animals would be wired-up to care for their kids. It would make sense that kids who are wired-up to survive would develop attachments to their parents. What's more of a puzzle though is that animals, including humans, seem to have exquisitely complicated relationships with non-kin. In particular, animals are nice to non-kin. You are nice to people that you're not related to. There are a lot of examples of this. Animals groom one another. You go, you pick off the lice and the bugs off your friend; they pick it off you. They give warning cries.

So, warning cries--All sorts of animals give warning cries. You are--I don't know. You're a little animal and a big animal comes charging and you say, "Hey!" Oh. You may sort of cry and everybody runs away. And that's very risky for you but you do it anyway, often to protect people you aren't related to. Often animals share childcare. And from a cold-blooded, natural selection, survival-of-the-gene point of view, you would imagine that if you lend me your kid for the day I would eat him for the protein and "it's not my genes and actually it gives more for my kids." That's not quite how it works though.

Animals share food. In fact, that animal, hugely ugly, the vampire bat, shares food. What happens is the vampire bat--vampire bats live in caves and they fly out. And what they do is often a bat will strike it big. She'll find a horse, for instance, bite the horse, pump in tons of blood and then fly back. And what it does is it doesn't keep it to itself. Rather, it goes around the whole cave and vomits blood into the mouth of all the other vampire bats so everybody benefits. Isn't that nice? [laughter] Now, what you're tempted to say is, "Well, that's really nice. Everybody benefits," but this raises a puzzle from the evolutionary point of view.

Remember, animals benefit more, and to this situation, animals benefit more by working together than by working alone. The benefits outweigh the costs. This is known as "reciprocal altruism" meaning my behavior to you, my good behavior to you, my altruism for you, is predicated on the idea of reciprocation, "I'll benefit from you." And you imagine how vampire bats, for instance, why this makes sense. This is--If you're a vampire bat, it's a better system when anybody strikes it big to feed you rather than for anybody who strike it big, use the blood and then spit out all the rest of it. But here's the problem. Here's why it's such a puzzle. The problem is the existence of cheaters. And in economics and sociology these are

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also known as "free-riders." And what a cheater or free-rider does is it takes the benefits without paying the cost. Imagine two genes. Imagine one builds a vampire bat that accepts blood from others and shares blood. The other gene accepts blood from others and doesn't share blood. In the long run, "B" will actually out-produce gene "A" because in fact, "B" will be healthy while other vampire bats get sick. And then so the offspring will do better.

An even sharper example is an example of warning cries. So, gophers give warning cries when there's a predator. It is extremely adaptive to give a warning cry. Sorry. It's extremely adaptive to respond to a warning cry. You hear a warning cry, you-- "Oh, crap," you run away. It is not very adaptive to give a warning cry. A really good solution then is to listen to warning cries but not to give them. Suppose we had a system--It is very adaptive when people are going to the bar, when people buy drinks to accept the drinks. It is not so adaptive, from the standpoint of one's wallet, to buy people drinks. Here is a solution. Accept drinks but don't pay for drinks. And if everybody fell to that solution, the idea of buying a round would fade. So, there is the puzzle. Since cheating--Since a cheater, in the short run, can always out-win--does better than a non-cheater, how could this cooperation evolve? How could it be an evolutionarily stable strategy?

And the answer is "cheater detection." Reciprocal altruism can only evolve if animals are wired up to punish cheaters. Now, that requires a lot of mental apparatus. You have to recognize cheaters, you have to remember cheaters, and you have to be motivated to punish cheaters. And not every animal has this degree of complicated apparatus but actually we know that vampire bats do. So, in one clever study--So the theory says--the evolutionary theory says "yeah, I see what these vampire bats are doing," but you see--and this is a case where evolution makes a nice prediction that couldn't evolve unless bats are keeping track. If bats aren't keeping track, then the system could never exist because the cheaters would just take it over. They must be watching for cheaters.

So, the experiment which was done is you--a vampire bat strikes it big, it flies back, and then you keep it--as a scientist you keep it from giving blood to anybody else. Then what happens? Well, what happens is when the other bats strike it big they starve the selfish bat, just as if we go to bars and everybody buys a round except for me. And this happens over and over and over again. Pretty soon you're going to buy a round but you're not going to give me one. And so, just as humans are keeping their eyes out for people who are taking the benefits without paying the costs, so are other animals. And it is argued that this sensitivity to cheating, this focus on reciprocation, plays a powerful role in the evolution of social behavior and the evolution of social emotions.

And a classic illustration of this is The Prisoner's Dilemma. Now, many of you, I think, have seen The Prisoner's Dilemma in one course or another? It shows up--It is one of the main constructs in the social sciences. It shows up in cognitive science, psychology, economics, that you could--The teaching fellows are passing around something which you're not going to use right away. But for some of you this is the first time you're going to be exposed to The Prisoner's Dilemma so let me spell it out.

Here's the idea. You and a friend commit a crime. You rob a bank, for instance. For the sake of this example, you are prisoner two. You get caught. The police put you in a little room and they say, "We want to know everything that happened. In particular, we want you to rat out your friend." Now, here are the options, and one thing about this is nothing is hidden. The police officer could actually print out a copy of The Prisoner's Dilemma and put it right in front of you. And what he could say is, "Look." You're prisoner two. "You could cooperate--Well, you have two options. You could either cooperate with your friend, you could stay silent, or you could defect or you could squeal." But the police officer says, "Look. If you--Let me tell you something. If you cooperate with your friend and he squeals on you, you'll go to prison for life and he'll walk out. However, if you squeal on him and he cooperates, he keeps quiet, he'll go to prison for life and you'll walk out." So, what do you do? Now, on the nice side, what you can do is you could say, "No. I'm going to be quiet. I'm going to cooperate." Now, if you could trust your friend to cooperate, you're fine, you each get a little stint in prison, but of course your friend might defect. Your friend might squeal.

Here is the important structure of The Prisoner's Dilemma. No matter what you--what your friend chooses to do, you're better off squealing. So, suppose you're prisoner two. You believe your friend's going to cooperate with you. He's not going to be--he's not going to give the information out. Well, then your best thing to do is squeal on him. What if you believe he's going to squeal on you? Well, your best thing to do is squeal on him but if you could get your act together and you could coordinate this, you would both be quiet and get a fairly minor penalty. And you could see this--This is the standard origin of the prisoner's dilemma, why it's called "The Prisoner's Dilemma," but you could see this all over the place. So, here is the logic. The best case for you is to defect while the other person cooperates. The worst case is to cooperate while the other person defects.

Back to the police thing. The best case for you is to give up all the information; the other guy stays silent; you cut a deal; you walk home that day. The worst case is you're quiet, he cuts a deal, you go to prison for life, but overall the best is that each cooperate and overall the worst for both is if each defect. And the reason that makes this tragic is this. Regardless of what your opponent does, it pays to defect, but if both people defect both are worse off. I'll give a couple of other examples. No. [referring to a slide] That's just to show that there's a cartoon corresponding to The Prisoner's Dilemma. It is that common.

Here's the idea. I am--I break up with my wife. We've been married for a while. We've decided we're not going to go through it together anymore and we break up. We're living in separate houses and we're starting to talk divorce. It occurs to

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me--Here's me. I put that out there. "Should I get a divorce lawyer?" I ask. Now, I know divorce lawyers are really expensive. And it's kind of difficult to get a divorce lawyer. But if I get a divorce lawyer--And so neither one of us get a divorce lawyer we'll just do okay. We'll get a mediator. We'll split the money down the middle. That'll be okay but I'm kind of tempted. If I get a divorce lawyer and she doesn't, my divorce lawyer will take everything she's got. I get everything, she loses everything. Maybe I should be nice. Hold it. What if she gets a divorce lawyer and I don't? Well, then I'll lose everything, she'll get everything. Well, we should both get a divorce lawyer then but we'd both do pretty badly.

Imagine we're two countries, country "A" and country "B." Should I do nuclear disarmament? That's pretty good. We'd do okay if both countries disarmed. We would live our lives; we'll raise taxes; we'll do whatever countries do. But wouldn't it be cool if I build up my weaponry and they don't? I'll invade, take everything they got. That's kind of tempting. Uh oh. Also, if I don't do anything and they do it, they'll invade my country, take everything. So, we both build up our weaponry and we both do pretty badly. Once you start thinking about things this way, there's no end to the sort of notions that could fall under The Prisoner's Dilemma.

A good example is a drug deal. Suppose I want to buy marijuana from you, or "reefer" as they call it on the street. [laughter] So, I have $1,000 and from you I'd like to buy a ton of reefer so--I'm rounding off. [laughter] So, you say, "Wonderful. Wonderful. Let's meet behind the gym, two in the morning on Friday, and we'll do the exchange. You bring $1,000, I bring the reefer." "Oh, cool. Okay. Good." And I think, "that's pretty good, a thousand bucks, I get the reefer, you get a thousand bucks. That's okay, that's the normal thing." But now something occurs to me. "Nobody's going to go to the cops if things go badly. So instead of doing--bringing the money, why don't I just bring a gun? You come with your reefer, I stick a gun in your face, take the reefer, go home."

Maybe I won't do that, but now I worry because you're thinking the same thing. So, you could show up with a gun, stick the gun in my face, take the thousand bucks, go home. I'll have no reefer. What will I smoke? [laughter] So, we both think this way. So, we both show up behind the gym, two in the morning, with guns. [laughter] Well, that's not as bad for either one of us if I had--I--you had a gun and I didn't have a gun. But still, we're both worse off than if we could cooperate and just do the damn trade. And so that's the structure of The Prisoner's Dilemma.

You can only appreciate The Prisoner's Dilemma by actually doing it. So, here's--here is a numerical equivalent to The Prisoner's Dilemma. Everybody should have a card in front of you, a file card. If you don't--If you didn't get a card, a piece of paper will do just as well. Please write on one side "cooperate" and on the other side "defect" and then please find a partner with whom to play one game. This is a one-shot game. One of you is player one. The player on the right-most side from my right could be player one. The other one is player two. Do you each have a partner? If you have three people, you could cluster together and do two and then two and just think. It is actually best if you've never met or spoken to the person you're about to deal with. And the game is, when I say "go," simply show the person your choice.

To be clear, if you are player one and you cooperate and player two cooperates as well, you each get three dollars. If you are player one and you cooperate while player two defects, player two gets five dollars and you get bupkis and so on. On three, just show the card to your opponent, to your person you're playing with. One, two, three. [laughter] Okay. How many people in this room cooperated? How many cooperated? How many defected? [laughter] Okay. How many people are now five dollars richer? Okay. How many of you got nothing? [laughter] Okay. So, you're learning. You're learning that the person next to you is really an SOB. [laughter] Now, find the person next to you and you get to play again. And you get to play five games in a row. Play five games in a row and keep score. You just show it to each other, record the numbers, show it, show it, show it, show it. Go now. [laughter] Anybody here win twenty-five dollars? Yes, twenty-five? So you-- Student 1: He cooperated four times and I defected-- Professor Paul Bloom: That's twenty, twenty-one. [laughter] Okay. That's good. That's good. So, it really is a measure of honesty. [laughs] Anybody win twenty or more? Fifteen or more. Fourteen or less. Anybody do five or less? You're a good person. It's good. It's good. You played it with him? Student 2: Yes. Professor Paul Bloom: Bad person. [laughter] It's not really about good or bad. There was a great game once. It's a simple game, but it was a great game, a great, famous competition a long time ago, about 20 years ago, set up by the great computer scientist Robert Axelrod. And he put together a competition where people brought in computer programs to play this game, to play The Prisoner's Dilemma. And there were sixty-three competitors. And these computer programs were incredibly--Some of them were very simple, always be nice, always be--always cooperate, always defect. Some were elegant, prime number solutions and prototype responses, genetic algorithms crafted to figure out what the other person was doing and suss them out.

But the winner was developed by Anatol Rappaport. And Anatol Rappaport actually died about a month ago at quite an old age, a great scientist. What was interesting about this was he was the winner with his program but his program was also one of the simplest. It may well have been the simplest. It was called "Tit-for-Tat" and it worked very simple. It took four lines of basic code. The first time you meet a new program, cooperate. The first time you meet somebody, be nice. After that, do on each trial what the other program did on the previous trial. This beat sixty-two others.

And here is why. It had certain beautiful features. It starts friendly. Remember the best long-term solution is everybody's be--everybody's nice. It starts off nice but you can't--it's not a sucker. If you screw with it, it will defect back on

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the next turn. It is, however, forgiving. Do you want to get nice with it? Be nice. If you're nice, it'll be nice back at you later on. It's also transparent, nothing complicated about it, and that's actually important. It's not merely that it's not a sucker and forgiving. More to the point, it is--you could tell it's not a sucker. And you could tell it's forgiving. And this very powerful algorithm learned to cooperate even in the situation--and helped--learned to make it out the best even in a situation where there's a risk of cheating and betrayal.

Some psychologists have argued that our emotions correspond to the different permutations on The Prisoner's Dilemma. We like people who cooperate with us. This motivates us to be nice to them in the future much as the Tit-for-Tat algorithm says, "If you are nice to me now, I'll be nice to you back." We don't like being screwed with. We feel anger and distrust towards those who betray us. That motivates us to betray or avoid them in the future. And we feel bad when we betray somebody who cooperates with us. This motivates us to behave better in the future. You can break down the cells of The Prisoner's Dilemma in terms of emotions that they give rise to.

I did an experiment last night with my seven-year-old and my ten-year-old. I explained to them The Prisoner's Dilemma. I didn't give the divorce lawyer example but-- [laughter] and we gave them a big thing of chocolate chips and--the good chocolate chips. We had the good chips and we had the matrix and we had them play. Now, what they did isn't so interesting, but what's interesting is they were furious at each other. One of them, the younger boy, was--kept being betrayed by the older boy including tricks like he'd say, "Okay. Let's both cooperate." "Yeah. Okay." Then he'd cooperate-- "defect!" And [laughter] the response was anger, though not actually guilt on the part of the other boy [laughter] but rage. And we see these sort of things all the time in real life.

You're familiar with The Prisoner's Dilemma but there's another game, which you might not be familiar with. It's called The Ultimatum Game. How many of you have encountered The Ultimatum Game? Okay, some of you. Very simple. Choose a partner. It's a very simple game. When economists study this they actually do this with real money. I do not have real money to let you do this too. One of you is "A," one of you is "B." The one on the right most from this side is "A." The other one is "B." Here is a very simple rule. I'd like "A" to turn to "B" and make an offer. "A" has ten dollars. You can give "B" any amount you choose from that ten dollars, from one dollar to ten dollars. "B" can do only one thing. "B" can accept it; if you accept it, you agree to take home the money and "A" keeps what ever's left--or reject it. If you reject it, you get nothing. Nobody gets anything.

Is everybody clear? So "A" is going to say, "I'll give you so and so dollars." "B" would say, "Okay," in which case "B" walks away with so and so dollars or--and "A" walks away with whatever rest or "B" could say, "Reject," in which case nobody gets anything. So, this game comes in two steps. The first thing: I would like "A" to turn to "B" and make your offer. Don't--"B" doesn't do anything yet. Make your offer. Your offer should be one word. People are explaining their offer. Make your offer. Okay. Stage two. Do not negotiate. [laughter] You're not--I see people waving their hands and it's complicated. It should be a number from one to ten, a positive integer. Now, "B" --I would like "B" to say one word and you can say it really loud on three. Accept or reject. One, two, three. [laughter]

Wow. How many people accepted? Anybody reject it? Good. Okay. How many people offered ten dollars? [laughter] How many people offered more than five dollars? Okay. How many people offered one dollar? Okay. When you offered one dollar did you accept? Anybody else offer one dollar? When you offered one dollar did your partner accept? Okay. How many people offered either four or five dollars? Okay. This is an interesting game because the person who offered--who accepted one dollar was being rational. One dollar is better than no dollars. So, the psychology of human rationality is such that, from a logical point of view, you should reason one dollar is better than nothing. A rational person should accept one dollar. And because we're smart, a--you should offer one dollar but not many of you offered one dollar. Why? Because you knew people are not purely rational. People, even in a one-shot game, won't accept unfair distributions. They'll reject them just out of spite. And so, you need to offer more. And this has been studied from a neuro-economic point of view, which basically provides neuroanatomical evidence that people--if you offered them one dollar they get really pissed. [laughter] Nobody likes to be offered a dollar.

Now, there's a more general moral here, which is actually an interesting surprise of some relevance to everyday life. A rational person is easily exploited. A rational person's responses to provocations, to assaults will always be measured inappropriate. If you know I'm rational and you're in a sharing situation with me, you could say to me, "Hey. Here's a dollar. Hey, Mr. Rational, a dollar's better than nothing." "Well, okay," because I'm rational. Similarly, you could mess with me because you could harass me in all sorts of ways, take things that I own, as long as you reason that a rational person wouldn't start a fuss about this.

There is some advantage to being irrational, to having a temper. Because if you have a temper and you're known to be irrational, people are forced, by dint of your irrationality, to treat you better. Who am I going to take from? The person who's extremely reasonable or the person who has a hair-trigger temper? Well, I'm going to pick on a reasonable person because the unreasonable person might do unreasonable things. And this is faintly paradoxical, but often to be irrational, or at least to have a reputation for mild irrationality, gives you an edge.

Now, this isn't focus of provocation but this has also been presented in the theory of why people fall in love. Suppose you're choosing who to devote your life to, and it's a matter of huge trust. We're going to raise kids together. It's very important for you that I don't leave. And I am very rational so I say to you, "We should mate and have children because I

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find you the most attractive of everybody who was available that I've met so far. I'm very rational and so long as this continues to be the case we'll be together." Well, that's reasonable and rational but wouldn't you rather be with somebody who's head over heels in love? Head over heels in love is irrational but it's also, within certain parameters, endearing because the irrationality of the person means you could trust them more in the long run, just like the irrationality of somebody who has a temper means you don't mess with them as much.

The studies have been done more with regard to violence than with love. And in fact, the irrationality--the benefits of irrational violence have been translated in terms of the study of homicide and other crimes. Daly and Wilson describe the cause of murder. Most murder is not caused by reasonable provocation. Most murder is not rational in its response. Most murder is generated by insult, curse, petty infraction, but this is not crazy irrationality. It's adaptive irrationality. Daly and Wilson point out, "in chronically feuding and warring societies an essential manual--manly virtue is the capacity for violence. To turn the other cheek is not saintly, but stupid or contemptibly weak." If I show myself a rational person when picked on or harassed, I'll be known as somebody you could pick on and harass.

And in fact, it turns out even in the modern world--This is from a New York Times I just picked up a year ago today. And the point is that the violence is due to people disrespecting each other or giving a dirty look. And you might think "isn't that irrational?" But it's not irrational in circumstances where people live together in an environment where they have to deal with each other over and over again, and often where there's not much support by the police as indications they talked about here. What's particularly interesting is this sort of importance of a reputation for violence differs from culture to culture. And I've been talking so far in this class--and in fact, so far in this course--about universals, about things that are built in, things that show up across humans and other animals. I want to turn now and end this lecture by talking a little bit about a cultural difference. And it's a psychologically interesting cultural difference with regard to the emotions. And it's built around the difference turning around what sociologists call "cultures of honor."

A culture of honor has certain properties. You can't rely on the law. And it has resources that are easily taken. And sociologists have argued that when those conditions are met it becomes important to develop a reputation for violent retaliation. That becomes important. Examples of culture of honors include Scottish highlanders, Masai warriors, Bedouin tradesmen, and Western cowboys – all cases where there's resources such as cattle that are vulnerable and easily taken, but you can't count on calling 911 and having people come help you. But the culture of honor that's been studied the most by modern psychologists is the American South.

This was settled by herdsmen and traditionally has less centralized legal control. So, the sociologists say the American South has more of a culture of honor than the American North. But how do you know? What does that do? We're interested in this class in claims about psychology. So, it took Richard Nisbett and Dov Cohen to study cultures of honors and look at differences. And they found some interesting differences. Gun laws tend to be more permissive in the southern--in the American South than the American North. Corporal punishment and capital punishment tend to be more approved of. Attitudes towards the military are more positive. In questionnaire studies, people are more forgiving towards cultures of honor. Somebody insults my woman and I punch him in the face. This is considered less bad in the American South than the American North. There's a higher rate of violence but only in certain circumstances. The streets of the American South as a rule are not more dangerous than the American North. The difference is there's a higher rate of crimes that are crimes of honor such as, for instance, if somebody breaks in to my house, me shooting him. Or if somebody insults me, me killing him.

Now, this is sort of survey studies. So, Nisbett and Cohen did one of the more interesting psychological studies I have ever heard of. And they did this at--This--Sorry. This is Nisbett and Wilson. They did this with University of Michigan undergraduates. They did a subject pool thing like you're doing now, and on it your demographic information was listed. And what they did was they took white males who are not Hispanic and not Jewish. That was their sample. Culture of honor is a phenomena limited to males and they wanted to make it sort of a clean study so they wanted to focus--get a homogenous sample. So, not Hispanic, not Jewish. And they provoked them. And the provocation was genius.

What they did was they said--they brought people in to the psychology building, as you'd be brought in to Kirtland or SSS or Dunham [psychology buildings at Yale] and they said--they had somebody go in to the desk and they said, "Yeah. Go down the hall for the experiment." There was a hallway and then you walked through the hallway. And walking in the other direction at that moment a graduate student--a male graduate student would start to walk. And he's holding some files. And what he does is he bumps the person, looks at him and says, "Asshole" [laughter] and keep walking. Now, to be fair, the graduate student survived bumping into hundreds of males, calling them assholes and then walking to--Fights did not break out, nobody was shot. But then they brought the men--now went in to a room and they were tested. And it turned out that there were differences in the stress response.

On average, males from the American South showed higher hormone response and stress response than males in the American North--increases in testosterone and cortisol. There's always differences in later behavior, the people--suggesting that they were made angry. They gave differences in fill-in-the-blank questions, for instance. I don't remember the examples but it's examples like "John went to the store and bought a 'blank'" and then the northerners would say "and buy an apple." And the southerners would say "an AK-47 [laughter] to kill that freaking graduate student." [laughter] Now, again, the American South--people in the American South were not overall more violent than the American North, but they were more sensitive to provocations of honor.

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Now, when I gave this lecture a few years ago, a southern student contacted me afterwards and said that she felt that picking out the southern minority at Yale was in some regard offensive and that people say things at Yale about southerners--American southerners that they would never say about any other minority group. So, there's two points I want to make regarding this. One is, of course, these are average differences. Not every northerner and southerner would differ along these lines. But another one is I think the effect is real, but it's not entirely clear that it reflects poorly on the cultures of honor as opposed to the other cultures. So, Nisbett, for instance, is himself a southerner and he points out that he went to the North he was most astonished by how rude people are. And this is because the North--the American North is not particularly a culture of honor, and so there's less proper behavior towards other people because there's no fear of retaliation or response. Moreover, the culture of honor virtues like honor, loyalty, courage and self-reliance, are on the face of it not necessarily bad things.

In any case, this is an interesting example of how there's an evolutionary background but culture modifies and shifts it in different ways. More generally, I've suggested over the last couple of lectures that emotions like fear, the love you have towards your children, anger, gratitude are not aberrations or noise in the system. Rather, they're exquisitely complicated motivational systems that are crafted to deal with the natural and social environment. And we know this only from an analysis that starts from an evolutionary approach. So, to bring us back to D'Arcy Thompson, "everything is the way it is because it got that way." And your reading response for this week is that. [referring to a slide] And I'll wish you good luck on the exam on Wednesday. And I'll see you there.

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Lecture 13 Professor Paul Bloom: What we've been talking about so far in the course are human universals, what everybody shares. So, we've been talking about language, about rationality, about perception, about the emotions, about universals of development, and we've been talking about what people share. But honestly, what a lot of us are very interested in is why we're different and the nature of these differences and the explanation for them. And that's what we'll turn to today.

So first, we'll discuss how are people different, different theories about what makes you different in a psychological way from the person sitting next to you, and then we'll review different theories about why people are different. And this is the class which is going to bother the most people. It's not dualism. It's not evolution. It's this because the scientific findings on human psychological differences are, to many of us, shocking and unbelievable. And I will just try to persuade you to take them seriously.

Okay. So, how are people different? Well, there's all sorts of ways. Your sexual identity--It is at the core of your being for almost all of us whether you're male or female. How we refer to you in language, what pronoun we use, is indexed on how we--on your--on how--whether you're male or female and related to that though imperfectly is your sexual orientation, who you're attracted to. The question of why some of us think of ourselves as males and others as females, and the question of why some of us would ideally want to have sex with males, others with females, others with both, and then a few others who have harder to define desires, is such a good question that we're going to talk about it after spring break while all the sexual desire has been spent and you could focus on [laughter] on a scientific discussion of this--not that I recommend you do that on spring break.

How happy are you? This is also such a good topic it's going to get its own class. The very last class of the semester is devoted to happiness and the question of what makes people happy, what makes people unhappy, and what makes people differ in their happiness. If I asked you to rank how happy you are from a scale of 1 to 10, the numbers would differ across this room. And there's different theories as to why. Your success and failure in life--This is somewhat interesting because you could study this in more or less objective ways. We don't have to ask people. We could look at your relationships, how they begin, how they end, your job satisfaction. We could look at your criminal records. Some of you are going to see time. Most will not. Some of you will get into little troubles all through your life. Some of you already have seen the inside of a police station, possibly a lineup. Others couldn't go near such a thing. What determines that?

And at the root of all human differences are two main factors. And so, I want to talk about the two main interesting factors. One is personality. The other is intelligence. And this is what--These are the differences I'll talk about today first from the standpoint of how do we characterize them, how do we explain them, and then from the standpoint of why these differences exist in the first place.

One way to characterize personality is in terms of people's style with dealing with--in dealing with the world and particularly their style with dealing--in dealing with other people. So, you take a simple character you know of and you could talk about that person's personality. You could talk about it in terms of being impulsive, irresponsible, sometimes lazy, good-hearted. You could compare that person's personality with other people's personalities such as my colleague who gave a talk last class. He's wonderful. He's responsible and reliable and very kind [laughter] and different from Homer. And so, this difference is a difference in personality.

Now, when we talk about personality we're talking about something else as well. We're talking about a stable trait across situations and time. So, if all of a sudden the person next to you kind of smacks you in the head, you might be angry but we wouldn't call that "personality" because that's something that's a result of a situation. We'd all feel that way in that situation. It's "personality" if you walk around all the time angry. That'd be a stable trait. That'd be something you carry around with you and that's what we mean by personality.

Now, how do we scientifically characterize differences in personality? And it's a deep question. There's been a lot of attempts to do so. Any assessment has--Any good assessment has to satisfy two conditions. And these are terms which are going to show up all over psychological research but it's particularly relevant for this sort of measure. One is "reliability." Reliability means there is not measurement error. And one crude way to think about reliability is, a test is reliable if you test the same person at different times and you get the same result. My bathroom scale is reliable if whenever I stand on it, it gives me more or less the same number. It's not reliable if it's off by ten pounds in the course of a day. Similarly, if I give you a personality test now and it says that you're anxious and defensive, well--and then give it to you tomorrow and it says you're calm and open minded, it's not a reliable test. So, reliable is something you could trust over time.

"Validity" is something different. Validity is that your test measures what it's supposed to measure. So, validity means it's sort of a good test. Forget about how reliable it is. Does it tap what you're interested in? So, for example, suppose I determine your intelligence by the date of your birth. I figure out what day you were born and I have a theory that, from that, predicts how smart you are. That's my intelligence test, the date of your birth. Maybe people born in January are the dumbest, people born in December are the smartest. Is that--I was born on Christmas Eve. [laughter] Is that a reliable test? Yes, it's a wonderfully reliable test. I'll test you today; I'll test you tomorrow; I'll test you next year; I'll test you the day you die; I'll get the same IQ score. Is it a valid test? It's a joke. It's absolutely not a valid test. It has nothing to do with intelligence. But

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you noticed these are two different things. Something can be reliable but not valid and something can be valid and not reliable.

Now, there are no shortage of personality tests. You could get them all over the place including on the web. So, I took one recently. I took "which super hero are you?" [laughter] And it's a series of questions determining what super hero you are. You could take this yourself if you want to. The same web page, by the way, offers you a test in whether you're "hot" or not. We'll discuss that later. And when I did this [laughter] it told me I was Batman [laughter] and "you are dark, love gadgets, and have vowed to help the innocent not suffer the pain you have endured." Now, the honest-- [laughter] Now, to be honest though, it's neither reliable nor valid. When I first did the test I came up as "The Incredible Hulk." I then changed my answers a bit and was "Wonder Woman." [laughter] And finally, out of frustration, I carefully tailored my answers so I would be Batman. But the fact that I can do that, well, raises questions about both the reliability of this measure and its validity.

Here is an example – a real world example. This is, in black and white form, a version of the Rorschach test, the Rorschach inkblot test. How many people have heard of the Rorschach test? Okay. Is there anybody here who has actually, in any sort of situation, taken a Rorschach test? Some people scattered in the room have taken them. It was originally used only for psychiatric cases but then became extremely common. About eighty percent of clinical psychologists claim to use it and most graduate programs in the American Psychological Association who are accredited teach it. Catholic seminaries use it for people who want to join the seminary.

It was invented by a guy named Herman Rorschach. He devoted his entire life to the inkblot test. His nickname when he was a teenager – I am not kidding you – was "Inkblot." [laughter] And the idea is by looking at these inkblots and then seeing what somebody says you get great insights into the nature of their personality, into what they are. Anybody want to try it? Come on. Yes. What do you see? Student: I see two people holding hands pressed together. Professor Paul Bloom: Two people holding hands pressed together. Very good. Anybody have a different reading? Yes, in back. Yes. Yes. Student: Dancing bears. Professor Paul Bloom: Dancing bears. Okay. Good.[laughter] Good. Okay. I got to write your name down-- [laughs][laughter] report you to health-- No. Dancing bears, very good. Anybody else? One other. Yes. Student: A man in a ski mask. Professor Paul Bloom: A man in a ski mask. Well, it turns out that there are right answers and wrong answers to the Rorschach test. According to the test, and this is from a real Rorschach test, "it is important to see the blot as two human figures, usually females or clowns." Good work over there. "If you don't, it's seen as a sign you have problems relating to people." [laughter] If you want to go for "a cave entrance" or "butterfly" or "vagina," that's also okay. [laughter]

Now, the Rorschach test is transcendently useless. It has been studied and explored and it is as useless as throwing dice. It is as useless as tea leaves. Nonetheless, people love it and it's used all over the place. It is used for example in child custody cases. If you have broken up with your partner and you guys are quarreling over who gets to keep the kids, you might find yourself in a shrink's office looking at this. And in fact, this is why they end up on the web. There are services. There are people who have been kind enough to put on the web these inkblots, including the right answers to them. But they are worthless as psychological measures.

Can we do better? Well, we probably can. Gordon Allport did a study where he went through the dictionary and took all of the traits that he believed to be related to personality and he got eighteen thousand of them. But what was interesting was they weren't necessarily independent traits. So, the traits like "friendly, sociable, welcoming, warm-hearted" seemed to all tap the same thing. So, Cattell and many others tried to narrow it down, tried to ask the question, "In how many ways are people's personalities different from one another?" How many parameters of difference do you need? How many numbers can I give you that would narrow you in and say what personality you are?

One approach was from Eysenck, who claimed there were just two. You could be somewhere on the scale of introverted-extroverted, and somewhere on the scale of neurotic and stable. And since there's basically two types of traits with two settings for each, there are basically four types of people. Later on he added another trait which he described as "psychoticism versus non-psychoticism" that crudely meant whether you're aggressive or empathetic. And then you have three traits with two settings each giving you eight types of people. Later on Cattell dropped it down into sixteen factors. So, these sixteen personality factors are sixteen ways people would differ. And so, if I asked you to describe your roommate along these sixteen dimensions, you should be able to do so.

More recently, people have come to the conclusion that two or three is too few, but sixteen might be too many. And there's a psychological consensus on what's been known as "The Big Five." And "The Big Five" personality factors are these, and what this means is when we talk about each other and use adjectives, the claim is we could do so in thousands of different ways, but deep down we're talking about one of these five dimensions. This means that when a psychological test measures something about somebody, about their personality, if it's a good test it's measuring one of these five things. And it means that, as people interacting with one another in the world, these are the five things that we're interested in. So, one of them is "neurotic versus stable." Is somebody sort of nutty and worrying or are they calm? "Extrovert versus introvert." "Open to experience versus closed to experience." "Agreeable," which is courteous, friendly versus non agreeable, rude, selfish.

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And "conscientious versus not conscientious," careful versus careless, reliable versus undependable. A good way to think about these things is in terms of the word "ocean," o-c-e-a-n. The first letter captures openness, conscientiousness, extroversion, agreeableness, and neuroticism. And the claim is those are the four--the five fundamental ways in which people differ from one another.

Well, why should we believe this? Why should we take this theory seriously? Well, there's actually some evidence for it. It seems to have some reliability in that it's stable over time. So, if you test people over years--If I test your personality now on the five traits and test you five years from now, it will not have changed much. And once you pass the age of thirty, it's very stable indeed. If you think about your parents and then give Mom and Dad a mental test on where they stand on each of the five traits, ten years from now Mom and Dad will still be there. It also seems to get agreement across multiple observers. So, if I ask for each of their five traits--If I ask your roommate what he or she thinks of you, then I ask your professor what he or she thinks of you and your mom what he or--what she thinks of you, [laughter] how would--back to gender--How would they match up? They tend to overlap a lot. You walk around and you leave--and your personality leaves a trail in the minds of people around you. And this trail is characterized in terms of these five dimensions.

Finally, it seems to be--predict real-world behavior. If this didn't have anything to do with the real world, you wouldn't be very happy calling it valid, you wouldn't take it seriously as a test, but it does. So, conscientiousness--how you score on a conscientious scale, relates to how faithful you are to your spouse. How openness--open you are on a psychological personality test relates to how likely you are to change your job. "Extroverts" look people in the eye more and have more sexual partners because they're extroverts. So, these are real scales. The "Batman, Hulk, Wonder Woman" doesn't correspond to anything in the real world, but where you stand on each of these five dimensions does seem to capture it.

As an example of the agreement, by the way, somebody did a study of several of the characters on the television show "The Simpsons" because they wanted to find characters which everybody knew. And they had thirteen subjects judge these Simpson characters on each of the five dimensions. These is "openness, neuroticism, conscientiousness, and extroversion" and they found considerable agreement. And this isn't actually--What I've covered up [on the slide] is the "agreeableness." So, for those of you who have never seen the television show, this is all going to be confusing, but those of you who have, can you guess which characters would be particularly agreeable? Anybody guess. Yeah. Student: Flanders Professor Paul Bloom: Flanders. You are right. The most agreeable people are Flanders and Marge. Who would not so agreeable? Student: Krusty Professor Paul Bloom: Krusty is actually--Krusty is a complicated case [laughter] but Mr. Burns--but also--Where is he? Oh, he's not--Nelson, where's Nelson? Anyway, there's Nelson. You get strong consensus that Ned Flanders and Marge Simpson are highly agreeable people, 6.27 and 5.46, while Mr. Burns and Nelson are very low. Nelson's the little kid that when trouble happens he goes, "Ha ha." And that's a psychological sign for low agreeability. [laughter]

Okay. That's all I want to say at this point about personality and how we measure it and, again, we're going to get back to it later when we talk about differences in personality. Now, I want to deal with the second big difference. The second big difference is intelligence. Now, how do you define intelligence? There's no easy definition. Like personality, it's kind of difficult to get your fingers on what we're talking about here. In one survey they asked 1,000 experts to define intelligence. And some answers showed up over and over again. So, just about everybody said intelligence involves abstract reasoning, problem solving, and the capacity to acquire knowledge. That's at the core of being smart. Other people mentioned things like memory, mental speed, language, math, mental speed again, knowledge, and creativity also as hallmarks for intelligence. And again, it might be difficult to define it but you have a gut feeling about what it is.

So, you know Homer is actually--and this is part of the show--is actually of limited intelligence. My colleague is of very high intelligence, a wonderful fellow, [laughter] but he's probably not as smart as that guy [pointing to a picture of Einstein] who is really, really smart. And this guy, Ralph Wiggum, is particularly stupid. [laughter] And so you have a range. And it's important to figure out how to characterize it; this is what research does, but there's a gut feeling that there are some people who are smart and other people who are very smart and some people who are dumb and others who are very dumb. What you want to do, from a scientific standpoint, is characterize this in a more robust and interesting fashion. And the textbook has a nice review of the history of attempts to define and measure intelligence, but there is a couple of ideas I want to focus on.

One is an idea developed by Spearman, which is there's two types of intelligence. There is "G" and there is "S." "S" is your ability on specific tests. So, if there is ten tests that you're given as part of an IQ test, ten subtests, you'll get a different score on each of the subtests. There'll be a math test and a reading test and a spatial test and you'll get different scores. "G" refers to a general intelligence. And the general intelligence is something you bring to each of the tests in common. So, this is diagrammed here. You have these six tests. For each of them there is an "S" and then above that there is a "G."

Now, "G" is a very important notion. The term "G" is used by psychologists a lot even in casual conversation. People say, "So, what do you think of him?" "I think he is high 'G.'" And what you mean is he's a smart guy. Why do you need "G?" Well, you wouldn't need "G" if your performance on each of these tests had nothing to do with each other. If the

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tests were genuinely separate, there'd be no general intelligence. But what people find over and over again is that when it comes to explaining people's performance on multiple intellectual tasks, there's two things going on. There's how good there is--they are on the specific task, but then there's also a sort of general correlation that people bring to the tasks.

And I could express this with an athletic analogy. Imagine I'm running a gym and we have all of these different athletic tests. So, we have a running test, we have a basketball shooting test, a swimming test, fencing, a list of ten of them. Now, each of you go through each of the tests and then you'll each get ten scores. But what we'll discover is that the scores are not independent of one another. People who are good at one athletic thing tend to be good at another. If there's somebody who's really good at running and swimming, odds are they're probably pretty good at climbing. And the same thing holds for IQ, which is above and beyond how good people are at specific things there seems to be a factor as to how well they are in general. And this factor is known as "G."

Now, there's, again, an extensive history of modern intelligence tests and what's really interesting is the tests now. What you need to know about the modern tests, the Wechsler test for both adults and children, is how they're scored. The way they are scored is that 100 is average. So, it's just automatic. Whatever the average is is 100. It's as if I did the Midterm--graded the Midterm, computed the average, gave everybody who got the average 100, said your score is 100. It's just the average. It works on the normal curve and what this means is that it works so that the majority, 68%, get between 85 and 115 on their IQ test. The vast majority, 95%, get between 70 and 130. If you are, say, above 145 IQ, which I imagine some people in the room are, you belong to 0.13% of the population. That's the way IQ tests work. Now, this is about IQ tests. We could now ask about their reliability and their validity. What do they mean? Well, this has turned out to be a matter of extreme debate. This [slide] just reiterates what I just said. A lot of the debate was spawned by the book by Herrnstein and Murray about--called The Bell Curve. And in The Bell Curve these authors made the argument that IQ matters immensely for everyday life and that people's status in society – how rich they are and how successful they are – follows from their IQ as measured in standard IQ tests. Now, this book made a lot of claims and it's probably before many of you--many of your time, but spawned huge controversy. And as a result of this controversy some interesting papers came out.

One response to the Herrnstein and Murray book was by the American Psychological Association, which put together a group of fifty leading researchers in intelligence to write a report on what they thought about intelligence--what they thought about, "Does IQ matter? How does IQ relate to intelligence? How does--what's the different--why are people different in intelligence? Why do different human groups differ in intelligence?" and so on. At the same time, there was also another group of IQ researchers, not quite the same as the first group, got together and wrote another report. And if you're interested in this, the links to the reports are on the Power Point slide.

Well, what did they conclude? The conclusions were slightly different but here's the broad consensus by the experts regarding the importance of IQ tests. And the claim is IQ is strongly related more so--probably more so than any other single measurable human trait to many important educational, occupational, economic, and social outcomes. In some cases, the correlation is very strong such as success in school and success in military training. In other cases, it's moderate but robust such as "social competence." And in other cases it's smaller but consistent, "law abidingness," and they conclude whatever IQ test measure it is of great practical and social importance. So, IQ matters. More particularly, IQ matters for "social achievement," for "prestigious positions," and for "on the job performance" and other work-related variables. If I know your IQ score, I know something about you that matters. It's not irrelevant just as if I know your score on a personality test of The Big Five I would know something about you that actually would tell me something interesting about you in the real world.

On the other hand, there's a lot of controversy about why this connection exists. So, to some extent, people have worried that the effectiveness of IQ is a self-fulfilling prophecy. And here is why. If society takes IQ tests important--seriously, they become important. So, it's true that your IQ is very related to your success in getting into a good school like Yale. But the reason for this, in large extent, is because to get to Yale they give you an IQ test, the SAT. So, the same for graduate school. There is the GRE, which is yet another IQ test. So, to some extent, it's a self-fulfilling prophecy. I could make--Society could choose to make how tall you are extremely important for educational success. They could say nobody under six feet tall gets into Yale. And then some psych professor would stand up and say, "Of course, height is profoundly related to educational accomplishment," and it would be because people made it so.

So, to some extent, the society that draws highly on IQ tests regarding promotion and educational achievement and military status and so on--it's just going to follow that IQ then becomes important. At the same time, however, the role of IQ is pretty clearly not entirely a social construction. There is some evidence that your IQ score relates to intelligence in an interesting sense including domains like mental speed and memory span. So, your score on an IQ test, for instance, is to some extent related to how fast you could think and your memory abilities.

Now, I want to shift to the second half of the class and talk about why. So, we talked about two differences, one in "personality", one "intelligence." I want to talk about why people differ but before I do, do people have any questions? Yes. Student: About personality--This morning I took a test--The way the test was, they asked you 100 questions and [inaudible] Professor Paul Bloom: It's a good question. The question is this young man took--just took a personality test. He was accepted into Slytherin, which is a Hogwarts reference. I'm hip to that [laughter] and--but the question is a good one. You're

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a clever man, high "G," and you wanted to be in Slytherin. How do we know you didn't work the test? You're going to get these personality tests all the time and the personality tests--You're applying for a business and one of the tests says "I like to steal from my bosses." Well, I don't think so. No. That's a little IQ test right there. So, the question is how do you avoid that problem? The test constructors have done so in certain clever ways. For instance, there are often catch questions designed to catch a liar. Some of these questions pose very unrealistic phenomena so you might have a question in there saying "I have never done anything I am ashamed of." Now, some people will say, "Yes, that's true of me," but they tend to be liars. And so, unrealistic questions tend to catch liars.

Also, you get the same question asked in different ways across the one hundred items and they could use the correlations to figure these things out. Again, the proof is sort of in the pudding. The reliability and validity of a test is determined, in part, by just how well it does at predicting your future performance on the test and your real world performance. And a test that is easily fooled--easily tricked by smart people wouldn't survive long as a personality test. So, we know the test you got is a pretty good test because it seems to work for most people. Yes. Student: [inaudible] Professor Paul Bloom: It's a good question. The question was about "Emotional IQ," which is something I'm actually going to touch upon a little bit later in the course, but people have talked about different forms of intelligence. And emotional intelligence, social intelligence, is arguably a candidate for success across different domains. The evidence for its predictive power is not as strong as for regular IQ tests so you might be right. It might turn out to be a much better predictor but one, it's not clear that we know that yet. Peter Salovey has actually done some very interesting research on this and is continuing work along those lines. The second thing is emotional intelligence is actually related to good, old-fashioned intelligence. They kind of pull together a lot. So, it's not entirely separate but that's a good point and I'd like to return to it a little bit later on in the course. Yes. Student: [inaudible] Professor Paul Bloom: Good question. How do you determine when--what a good test is? And again, it's a real art going through the details of how to do that but the broad answers involve reliability and validity. It's a good test if I test you today and I test you tomorrow and I get the same score. It's a really good test if your score on that test predicts your grades or, if it's a personality test, predicts how many girlfriends you have or predicts whether people think you're a nice guy. So, you have to see both the replicability of the test over time but also its relationship to real world phenomena. And that's important, again. Why do we know the Batman, Wonder Woman, Hulk test is a bad one? Well, one answer is because what I--how I score on that test isn't going to tell you anything about me. It's not going to relate to my grades. It's not going to relate to how well I'm liked. How do we know the SAT is useful? Well, it actually corresponds with other things like grades. Yes, in back. Student: [inaudible] Professor Paul Bloom: Absolutely. The question is--When I'm talking about personality I'm defining it in terms of something which is stable over time. And your question, which is a good one, is, "How do we know it's stable over time?" Can't it change? And the answer is "yeah." A lot of personality does change over time. A personality test you give to a ten-year-old will relate but not so strongly with that individual when he's fifty. On the other hand, we know that the psychological claim that there exists such a thing as personality and it is stable over time. It's supported by the fact that if you're an extrovert now you'll likely be an extrovert twenty years from now. Not perfectly, so you're right. You could change. You could become an introvert, you could become more of an extrovert, but wherever you stand now is significantly related to where you'll be in the future. And that justifies talking about it as a stable trait. Same with IQ. Your IQ might change. It might go up, it might go down, but it won't go up and go down that much and this is why it makes sense to talk about intelligence as a more or less stable trait.

Okay. Why are we different? Well, you're different because of two things: Your genes and your environment, your nature and your nurture, your heredity and your experience. And this doesn't say anything. This is just defining the question. But the question of the role of genes and the role of environment in explaining human differences is an interesting one and it could be explored in different ways.

But before talking about it I have to clear up a common misconception. I'm going to talk about the effects of genes and I'm going to talk about heredity but I want to be clear. I am talking about the role of genes and also the role of environment in explaining human differences, not in explaining human characteristics. So, the distinction is we're interested in the amount of variation due to genetic differences, not the proportion of an individual's trait that's due to genes.

So for instance, you could pull these apart. The question of--When we ask what's the role of genes, what's the role of heredity in how tall people are, the question is not asking for you--what is the role of your genes in determining how tall you are? It's not clear that's even a sensible question. The question is there's a height difference between you and me and him and her. How do we explain that difference? And I could illustrate why heredity doesn't mean the same thing as the contribution of the genes. Height is reasonably heritable, meaning the differences between people in the population and how tall they are is due in large part, not entirely, but in large part to their genes.

What about the number of legs people have? Well, the number of legs people have from zero, one or two, is actually not very heritable at all because almost everybody has two legs and people who have fewer than two legs typically have lost one or both legs in an accident. It's not due to their genes. So, of course, whether or not you have legs is a very

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genetic matter but the differences in number of legs is not usually genetic. And so, heredity is a claim about differences, not a claim about the origin of any specific trait.

Well, now we--That's what heredity, which is genetic--Now, we could talk about environment. And we could break up environment into two sorts of environment. One is shared environment. And shared environment is the extent to which the differences are caused by things--by phenomena that people raised in the same household share. So if one--Suppose some of you are neurotic. And suppose we want to say part of that's due to your environment. Well, suppose you're neurotic because you have lousy parents. That would be part of your shared environment because presumably siblings raised in the same household would have the same lousy parents.

This is contrasted with non-shared environment, which is everything else. Suppose I think you're neurotic because when you were five years old somebody threw a snowball at you and it bounced off your head. That's non-shared environment. Suppose you're neurotic because you won the lottery when you were twenty-one and all the money messed you up. That'd be non-shared environment.

So, what you have here is heredity, shared environment and non-shared environment, and this equals one. That's everything. Non-shared environment is a sort of garbage can category that includes everything that's not heredity and not shared environment. Suppose you think you're neurotic because aliens from the planet Pluto are zapping your brain. Suppose you're right. Well, that would be non-shared environment because they're, presumably, not necessarily zapping your siblings' brains. Everything else is non-shared environment.

It becomes interesting to ask, for all of these differences, the physical differences like height, but psychological differences like personality and intelligence, how do we parcel it out into what's genetic and what's environmental? This proves to be really difficult in the real world because in the real world it's hard to pull apart genes and environments. So, you and me will have different personalities. Why? Well, we were raised by different parents and we have different genes. We can't tell--My brother and me might share all sorts of things in common but we have the same parents and the same genes, fifty percent of the same genes. So how do we tell what's causing us to be alike?

So to do--to pull these things apart you need to be clever. You need to use the tools of behavioral genetics. And to use these tools you have to exploit certain regularities about genes and about environment. One thing is this. Some people are clones. Monozygotic twins are genetic duplicates. They share one hundred percent of the same genes. That's kind of interesting. Dizygotic twins are not clones. They share fifty/fifty. They are just like regular siblings. And adopted siblings have no special genetic overlap. That's zero percent above and beyond randomness. Those three groups then become rather interesting particularly when we keep in mind that by definition two people raised in the same house by the same parents have one hundred percent the same shared environment.

So now, we can start to answer these questions. Suppose you find that monozygotic twins are much more similar than dizygotic twins. Well, that would suggest that there's a large role of genes in those traits that you're interested in. It would not cinch the matter because there are other factors at work. For instance, monozygotic twins look more alike than dizygotic twins and maybe they have different and--they have more similar environments because of this similarity in appearance.

Are monozygotic twins just as similar as dizygotic twins? If so, then it would show that that extra overlap in genes doesn't really matter. And so, it would suggest a low role of heredity. Are adopted children highly similar to their brothers and sisters? If so, then there's a high role of shared environment. Suppose the Bloom children, and there are seven of them, all have an IQ of 104 and we adopt three kids and then at the end of the day those three kids each have an IQ of 104. That would suggest that--And we do this over and over again across different families. That would suggest that there's something about the Bloom family being raised by me that gives you an IQ of 104. On the other hand, if the IQ of the adopted kids had no relationship to those of the biological Bloom children, it would suggest that being raised by me has no effects really on your IQ. It's sort of separate.

A separate--A second--A final contrast, which is the thing that psychologists love, is identical twins reared apart. That's the gold standard because you have these people who are clones but they're raised in different families. And to the extent that they are similar this suggests it's a similarity of their genes. And in fact, one of the most surprising findings in behavioral genetics--The caption here [a cartoon on a slide] is "Separated at Birth, the Mallifert Twins Meet Accidentally." [The cartoon twins] ended up at a patent office with the same device. One of the hugely surprising findings from behavioral genetics is how alike identical twins reared apart are. They seem to have similar attitudes to the death penalty, to religion and to modern music. They have similar rates of behavior in crime, gambling and divorce. They often have been found to have bizarre similarities. They meet after being separated at birth and they meet at age thirty and then it turns out that they both get in to a lot of trouble because they pretend to sneeze in elevators. There was one pair of twins studied by behavioral genetics who were known as the "Giggle Twins" because they were--both would always giggle, they'd burst into giggles at every moment even though it couldn't be environment because they weren't raised together.

More objectively, the brain scans of identical twins reared apart show that their brains are so similar in many cases you can't tell whose brain is who. I could tell your brain from my brain from a brain scan and my brother's brain from my brain from a brain scan. But if I were to have an identical twin it would be very difficult to tell whose brain is whose even if we had no environment in common.

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So, this leads to two surprising findings of behavioral genetics. This is the first one. There is high heritability for almost everything. For intelligence, for personality, for how happy you are, for how religious you are, for your political orientation, there--for your sexual orientation, there is high heritability. There's a high effect of genes for just about everything.

Now, that's actually not the controversial thing I'm going to tell you. But before getting to the more controversial thing I want to raise another issue which often gets discussed and has a good treatment in the textbook. This suggests that individual differences within this--within a group have genetic causes. Does that mean that group differences are largely the result of genetic causes? So, we know that there are clear differences in IQ scores among American racial groups, between whites and Asians, African Americans, Ashkenazi Jews. There's clear and reliable IQ differences as well as some other differences.

Now, to some extent, these groups are partially socially constructed. And what this means is that whether or not you fall into a group it's not entirely determined by your genetic makeup. It's often determined by social decisions. So, whether or not you count as a Jew, for instance, depends not entirely on genetic factors but also on factors such as whether you're reform or orthodox and whether you--so whether you would accept that a child of a Jewish man and a non-Jewish woman is Jewish. Similarly, categories like African American and white and Asian often overlap broad genetic categories and they don't make fully coherent genetic sense.

At the same time though, there is plainly some genetic differences across human groups and say with regard to vulnerability to disease. Ashkenazi Jews for instance are vulnerable to Tay-Sachs. And the fact that you could have this sort of genetic vulnerability suggests that there is some sort of reality to these groups. So, you have to ask the question now, to what extent does the high heritability in individuals mean that there has to be a heritable explanation across groups? And the answer is "not at all." I'm not saying that this means that there's no genetic explanation for human group differences. All I'm saying is the question of the phenomena of--within-group genetic differences does not mean that there is across-group genetic--sorry, between-group genetic differences.

There is a nice example by Richard Lewontin, the geneticist, where he imagines two plots of--what are you--some sort of wheat, yeah, two plots of land and each one has a set of seeds and--Oh, no. They're over there. [pointing to slide] No. Anyway, one of them you fertilize a lot. The other one you fertilize a little. Now, within each plot how much the seed grows is actually largely determined by the genetics of the seed. And so, you'd find high heritability for growth in the seeds. But the difference between groups has no genetic cause at all. It's caused by which groups you fertilize more than others.

Here's another way to do the logic. Suppose from the middle [aisle of the classroom] down here, you guys, [pointing to the people on the right] I hate you, I really hate all of you, and [pointing to the people on the left] I like you, so I make up two Midterms. You probably didn't notice but there were two Midterms. This Midterm was fiercely hard, savagely hard [pointing to the people on the right]. It took many of you until the end of class to do it. This Midterm [to the people on the left] was, "Which is bigger, a dog or an elephant?" [laughter] because I like you and I want you all to succeed.

So, you have two different groups, you guys and you guys. Within each group some people are going to do better than others. The explanation for that might actually have to do with your genes. It might have to do with your environment, how much you study, but all sorts of reasons for that. Within each group some of you will do better on the hard test than others on the hard test, some better on the easy test than others on the easy test. But how do we explain the group difference? Well, it has nothing to do with genes. The group difference, the fact that you will do much worse than you, has to do with the exams I give. My point, again, is that there is a logical difference between a within-group difference, within this half of the class, and a difference between groups, within--between this group and this group.

What do we know about--;So, that just shows they're not the same thing but what's the fact of the matter? What do we know about human differences between different human groups? Again, the textbook has a good discussion of this but I'm going to give two reasons from the textbook that at least group differences are at least to a large extent due to environmental and not genetic causes. One is that the differences we find in IQ seem to correspond better to socially defined groups than genetically defined groups. They seem to correspond to groups defined in terms of how people treat you and how people think about you as opposed to your DNA. And to the extent that turns out to be true that would mean that a genetic explanation is not reasonable for those differences.

A second factor is that we know IQ can differ radically without any genetic differences at all. And the most dramatic evidence of that is the Flynn effect. The Flynn effect is one of the freakier findings. The Flynn effect is the finding that people have been getting smarter. You are much smarter on average than your parents if--and the IQ tests hide that. Here is why they hide that. They hide that because they always make 100 the average. So, you come home and you say, "Dad, Dad, I just did an IQ test. I got 120." And your father says, "Good work, Son. I got 122 when I was your age," but what neither of you acknowledge is your test was much harder. As people got better, they had to make the test harder and harder. And this is plotted by the Flynn effect.

[referring to a graph] One of these lines is American and one is Dutch. I don't know which is which but the gist of it is that somebody who would have--that if you in 1980 would take the 1950 test, your average person in 1980 would score 120 on the 1950 test. What this means is if you take your person who's average now and push him back through time twenty years, thirty years, he would do much better than average. Nobody knows why people are getting smarter and there's

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different theories of this. And in fact, well, wait until you see your reading response. But what this illustrates is that IQ can change dramatically over the span of a few decades without any corresponding genetic change. And that leaves open the possibility, in fact, maybe the likelihood, that the differences we find in human groups, existing human groups, are caused by the same environmental effects that have led to the Flynn effect.

Okay. This is not the surprising claim though, the high heritability for almost everything. This is the surprising claim. Almost everything that's not genetic is due to non-shared environments. The behavioral genetic analyses suggest that shared environment counts for little or nothing. When it comes to personality or intelligence then, an adopted child is no more similar to his siblings than he or she is to a stranger. To put it a different way, the IQ correlation in genetically unrelated adults who are raised in the same family is about zero. Suppose the Bloom family all has an IQ of 104 and we adopt a kid. What will this kid's--We adopt him as a baby. We raise him to be a twenty-year-old. What's his IQ? Answer? We have no idea because the IQ of the Bloom family who are unrelated to him has no effect at all.

Now, if you think about the implications of it, it becomes controversial and Newsweek, I think, caught the big issue when they put in their title the question "do parents matter?" And the question--And the issue is parents are shared environment. To say shared environment does not affect your intelligence or your personality suggests that how your parents raised you does not affect your gene--your intelligence or your personality. This isn't to say your parents didn't have a big effect on your intelligence and personality. Your parents had a huge effect on your intelligence and your personality, around 0.5 actually. They had this effect at the moment of conception. From then on in, they played very little role in shaping you--what you are.

The case for this which generated the Newsweek cover came up in a controversial book by Judith Harris called The Nurture Assumption which has a very long subtitle, "Why Parents Turn--Why Children Turn Out the Way They Do, Parents Matter Less than You Think and Peers Matter More." Judith Harris has had an interesting history. She was kicked out of graduate school at Harvard and told that she wouldn't amount to much. The person who wrote the letter saying that she was not going to amount to much was the department chair, George Miller. In 1997, she won the George Miller award for her astounding accomplishments. And when she wrote the book she took as a starting point, her point of disagreement, a famous poem by the poet Philip Larkin and many of you have probably heard this. The poem goes like this: They fuck you up, your mum and dad. They may not mean to but they do. They fill you with the faults they had And add some extra just for you.

The last line of the poem, the last bit of the poem, ends: "Man hands on misery to man. It deepens like a coastal shelf. Get out as early as you can and don't have any kids yourself." It's beautiful. [laughter] Harris wrote a rebuttal: "How sharper than a serpent's tooth to hear your child make such a fuss. It isn't fair. It's not the truth. He's fucked up, yes, but not by us." [laughter]

Just to show that academic debates never end, a British psychoanalyst named Oliver James, outraged by Judith Harris' book The Nurture Assumption, wrote another book in response called They Fuck You Up. [laughter] Now, how do you tell your grandparents, "I wrote a book." "What's it called?" "Can't tell you." [laughter]

Anyway, look. If you're paying attention, this has to sound wrong. You must be thinking of course there must be an effect of shared environment. Of course parents have an effect. After all, good kids have good parents. There is no doubt at all that this is true. There is a high correlation between parent and child for everything. If your parents read a lot and there's a lot of books in your house, you will become a reader. If your parents are religious, you will be religious. If you're raised by Bonnie and Clyde, you will be a young thug. [laughter] If your parents are poor, you're likely to be poor. If your parents are brilliant, you're likely to be brilliant. No doubt at all. It is an extremely robust correlation. But the problem is this correlation could be explained in different ways. Everybody thinks it's because parents do something that affects their kids. Your parents are bookish, they read to their kids, so their kids become bookish, but another possibility, which we know is true, that almost always parents share their genes with their kids.

Another possibility is it's the parents who are affecting--sorry, it's the child who is affecting the parents, not vice versa, and to illustrate this, these different possibilities, I want to tell you a little bit about a study. And I really find this a fascinating study. It was reported last year and it was a study shown that--suggesting that family meals help teens avoid smoking, alcohol, drugs. It involved a phone questionnaire where they phoned up teenagers and their parents and said, "Hey, teenager. Do you do a lot of drugs?" "Yes." "Do you have dinner with your parents?" "No." And they take it off--and then they ask other people and they find that the kids who are the good kids have meals with their parents, suggesting this headline.

I like this study because I have read--I must have read in my career a thousand studies and this is the worst study ever done [laughter] in the history of science. And it's almost--We could devote a week to discussing what's wrong with this study. Let's just--But here's the idea. It is possible that they are right. It is actually possible--there's no--I have no evidence against it – that having meals with your kids makes them into good, drug-free, non-promiscuous, non-drinking kids. Of course, it's equally possible it's the other way around. If little Johnny is kind of--is out there smoking pot and cavorting with prostitutes and stuff like that, he's not going to come home for the family meal. It's the other way around. While if he's a good

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kid, he might be more likely to have a family meal. So, the direction--It might actually be not family meals make good kids but rather good kids stick around to have--if they have nothing better to do and have meals with Mom and Dad. [laughter]

Another possibility is there's good families and bad families. A good family is likely to have drug-free kids and a family meal. A bad family is likely to have stoned kids and no family meal. [laughter] So, there--maybe there's an effect of that. The parents had nothing to do with the family meal.

Here's the even weirder part. They didn't factor out age so think about this. Their sample included children ranging from twelve to seventeen but let me tell you something about twelve-year-olds. Twelve-year-olds don't use a lot of drugs and are likely to eat with their family. Seventeen-year-olds are stoned all the time and they don't eat with their family. [laughter] I've just begun on this study but the point is when you hear something like--So now, take something which you may be more likely to believe. Maybe you believe that having parents who read to their kids, that's good for their kids. Well, maybe it is but most of these criticisms apply to that study too. A bookish kid is more likely to get his parents to read to him. A good family--Parents who are good parents in general are more likely to do all sorts of good things to their kids and have good kids besides.

Take another case, the so-called cycle of violence. Yes, it's true. Parents who smack their kids tend to have statistically more violent kids. But maybe the causality goes the other way around. Maybe if you have a kid who is a troublemaker you're more likely to smack him. Maybe, which seems to be entirely likely, the propensity for violence is to some extent heritable. And so, even if the kid was not raised by the smacking parent, whatever properties of that parent caused him--led to that violence got inherited by the kid.

Now, again, this isn't going to sit right for you and I've had--I put this down because last year when I gave this talk people ran up to me and told me this. They said, "Look. I know my mom and dad had a huge role in my life. That's why I'm so happy and successful," then other people said, "That's why I'm so miserable and screwed up," but either way blame it on Mom and Dad or thank Mom and Dad. And you might think you know. When you become famous and you stand up and you get your awards maybe you'll thank your mom and dad. When you go to your therapist and explain why you're so screwed up maybe you'll blame Dad. "He never took me to a baseball game." Well, maybe, [laughter] but you don't know. Were you adopted? If you weren't adopted, you can't even begin to have the conversation about how your parents messed you up because if you're a lot like your parents you might be a lot like your parents because you share their genes. Of course, you resemble your parents. Moreover, how do you figure out which is the cause and which is the effect? "Mom smacked me a lot and that's why I turned out to be such a rotten person." Well, maybe she smacked you because you were rotten. [laughter] I don't want to get personal but it's very difficult to pull these things apart.

A final point on this. One response to Harris' book is this. "Look. Even if this is true, you shouldn't let this get out because if parents don't mold their children's personalities maybe why should they treat their kids nicely?" And you might be wondering this. You might be thinking, well, gee, if you don't have any effect on how your kids turn out, why be nice to them, but there are answers. You might want to be nice to them because you love them. You might want to be nice to them because you want them to be happy. You might want to be nice to them because you want to have good relationships with them. And I have a little bit more but I'm going to skip it and I'm going to move right to your reading response, which is very, very simple, easy to answer, easy to grade: Explain the Flynn effect. It's a toughie so just explain that. Okay. Have a wonderful spring break and I'll see you when you get back.

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Lecture 14 Professor Paul Bloom: Sex is really strange. You ask people, "What's your favorite activity?" and if you ask people, particularly college students, particularly just fresh from spring break – I've seen teen movies – they'll often answer, "Sex." or some word that is synonymous with sex. But there's a kind of a puzzle about how much time we spend on sex. And it turns out there is data on this. So, people say sex is their favorite activity, but it turns out we actually know how much time the average American spends on sex. And the data I'm going to follow from was summarized in this wonderful book by James Gleick:

Americans tell pollsters their single favorite activity is sex. In terms of enjoyability, they rank sex ahead of sports, fishing, bar-hopping, hugging and kissing, talking with the family, eating, watching television, going on trips, planning trips, gardening, bathing, shopping, dressing, housework, dishwashing, laundry, visiting the dentist, and getting the car repaired. On the other hand, these same studies suggested the average time per day devoted to sex is four minutes and three seconds. [As Gleick says,] This is not much, even if the four minutes excludes time spent flirting, dancing, ogling, cruising the boulevard, toning up in gyms, toning up in beauty parlors, rehearsing pick up lines, showering, thinking about sex, reading about sex, doodling pornographically, looking at erotic magazines, renting videos, dreaming of sex, looking at fashion magazines, cleaning up after sex, coping with the consequences of sex, building towers or otherwise repressing, transferring, and sublimating.

And I like this passage because it illustrates two points, two important points. One is we don't actually spend that much time on sex. In fact, the four minutes and three seconds is an interesting number because when you do times studies on how much Americans spend filling out tax-related forms for the IRS, it's four minutes and a few seconds. But the passage also points out that regardless of the brute time we spend on it, it is extraordinarily important. Everything in life follows from it – marriage, family, children, much of aggression, much of competition, much of art and music and creative pursuits. Much of everything follows from it. If we were a creature without sex, everything would be different.

And what's interesting is, there are creatures without sex. There are creatures that reproduce by cloning. And in fact, this basic fact about people – that we fall, roughly, into males and females – is an evolutionary mystery. It's not clear why animals that are somewhat large have two sexes. From a biological Darwinian perspective, having two sexes is bizarre because each time you have an offspring you toss away half your genes. My children only have--each of them have half my DNA. If I were to clone, they would have all of it. And so, it's a puzzle how sex ever evolved.

This is not a course in evolutionary biology, and that's not the puzzle we're going to be looking at today. We're going to look at a few questions. First, we're going to talk from first a theoretical point of view and then an empirical point of view about how males and females are different. Then we're going to talk about sexual attractiveness, some research about what people find to be sexually attractive, and then we'll talk a very little bit at the end about the origins of sexual preference: why some people are straight, others gay, others bisexual, and others harder to classify.

Now, of all the topics I'm presenting, sex is one of the sort of dicey ones from an emotional point of view. These are difficult issues because sex is, by definition, an intimate part of our lives, and it matters a lot. Moreover, sex is fraught with moral implications. And since I'm talking about this from, at least at the beginning, from a Darwinian evolutionary perspective, I'm obliged to start off by dealing with some of the moral consequences and moral implications.

So, for instance, many biologists – all biologists I would say – will have argued that sexual behavior, sexual action, sexual desire is, to some extent, a biological adaptation existing to spread our genes. From that perspective then, non-procreative sex – including gay sex, sex with birth control, sex by post-menopausal women – does not serve this reproductive goal and, in some sense perhaps, is unnatural. And one might argue then, "Does this mean it's wrong?" We'll also be talking about sex differences, differences between men and women, for instance, in how much you want anonymous sexual encounters, differences between men and women in social intelligence, in aggression and empathy. And regardless of what you think about these differences, whether you think they're right or wrong or it doesn't matter, you'll ask the question, "To what extent are they mutable?" That is, if they exist through Darwinian natural selection, to what extent can we ever get rid of them? And I want to address those two issues, the issues of morality and inevitability, from the very start. And I want to start off with--for each of them have a quote by a prominent evolutionary scholar. So, the first one is by Steve Pinker in How the Mind Works. And he writes,

Nature does not dictate what we should accept or how we should live our lives. Well into my procreating years, I am so far voluntarily childless, having squandered my biological resources reading and writing, doing research, helping friends and students, and jogging in circles--ignoring the solemn imperative to spread my genes. By Darwinian standards, I am a horrible mistake, a pathetic loser, but I am happy to be that way, and if my genes don't like it they can go jump in the lake.

Pinker's point, I think, is a reasonable one. It is true that certain things we do exist to serve the dictates of natural selection, but that doesn't make them right? If you think that something is only right if it leads to the generation of more genes, if it leads to reproduction, then you're not going to think very much about birth control. You're not going to think very much about any sort of non-procreative sex. On the other hand, if you're--Moreover, if you think something's wrong if it's unnatural, you're going to think much about flying in a plane or refrigerating food or surviving a severe infection. More generally, our bodies and brains have evolved for reproductive success, but we can use these brains to choose our own

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destinies. Nothing moral necessarily follows from the facts of biology. That's all I'm going to say about morality. But I want you to keep it in mind when we discuss different claims about what's evolved and what hasn't.

What about inevitability? Here I want to turn to Richard Dawkins. Richard Dawkins writes, If a child has had bad teaching in mathematics, it is accepted that a resulting deficiency can be remedied by extra-

good teaching in the following year. But any suggestion that the child's deficiency might have a genetic origin is likely to be greeted with something approaching despair. If it's in the genes, it is determined and nothing can be done about it. This is pernicious nonsense on an almost astrological scale. Genetic causes and environmental causes are in principle no different from each other. Some may be harder to reverse, others may be easy. What did genes do to deserve their sinister, juggernaut-like reputation? Why are genes thought to be so much more fixed and inescapable in their effects than television, nuns or books.

I like the nuns. And the point here is what causes something is logically separate from what can reverse it. And you can think of clear cases where something is plainly genetic but is fairly easily reversed and where something is cultural and is very difficult to reverse. Here's an example. My eyesight is quite poor. The reason why my eyesight is quite poor is not due to the patriarchy, television, culture or "the man." Rather, my eyesight is quite poor due to the crappy genes Mom and Dad gave me. It is genetically determined if anything is. It is also fairly easy to fix. There are these machines where they put panes of glass in front of your eyes and help you to see better. More advanced machines known as contact lenses actually stick the thing into your eyes, and at the cost of occasional infections you come to see better. It's biologically caused but fairly easy to fix.

On the other hand, take an example of society's treatment of the obese. It turns out when we – and we'll get to this a little bit when we talk about sexual attractiveness – how thin somebody is or how fat they are; what you think of that is actually not particularly hard-wired. It varies a lot from culture to culture. But once it's in a culture, it is almost impossible to shake. So, the point, there is just that genetic does not mean inevitable, and cultural does not mean easy to fix.

Okay. That's general background. Let's start with basic Sex Ed. What's the difference between males and females? Well, don't even think penis and vagina. There are a lot of animals that have neither one. And the difference actually runs deeper. By definition, when biologists talk about this, animals that are males have a little sex cell, which carries genes and nothing else – sperm cells. Animals that are females have a big sex cell, which has genes but also food and a protective cover and all sorts of other stuff. Typically, the little sex cell is much littler than the big sex cell. This is the only erotic picture I'm going to show you today. It's a bunch of these little sperm circling around the egg. It's romantic.

But this raises a puzzle. I just described male and female roughly in terms of a size difference. Males are the smaller of the sex cells; females are the bigger. Why is it then that for so many animals males are the bigger ones, physically, and the more aggressive ones. This has been a puzzle that has occupied scientists for a long, long time. And we're pretty--there is now a pretty clear answer to it. And the answer goes like this. It is based on an idea by Robert Trivers called "parental investment." And what parental investment is, it's defined here as, any investment that's going to increase the offspring's chance of survival at the cost of the parent's ability to invest in other offspring.

So, for example, suppose an animal could create an offspring by blinking an eye and then the offspring would run off? That would be extremely little investment. Suppose another animal had to work for ten years, and during those ten years could not create another offspring. That would be a huge investment. Trivers points out that within a species, females typically have a much higher parental investment than males. Because females have these big sex cells, they typically incubate them internally. They carry them. If they're eggs, they might have to sit on them. And hence, each potential child is a huge cost.

For males, which have the small sex cell, you don't have the same thing. For males, it might just be a few moments of copulation and that's it. If you could ask yourself, for humans, each one of you in the room, "What is the minimum effort you can do to create a child that has half your genes?" And it's apparent that the male investment, on average, is lower than the female investment. Males can choose, or might do better off in some circumstances by putting a lot of investment into their offspring, but females don't have a choice. Females, barring technological advance, have a huge investment into any offspring; not investment in the sense or hard work and effort, though there's that too. Investment in the sense that when you're--when you're pregnant with one offspring, you can't have another.

What this does is it has ramifications that percolate upwards. So, it leads to different psychologies. Males--and a single male could fertilize several females, forcing some males to go mate-less and giving rise to competition to see who can mate with the most females. For females, however, females can always find mates. So, sheer numbers don't count. But there's competition to mate with the right males, those whose offspring have the best chance of surviving. The competition now explains the puzzle we started with. It explains why males are typically larger, and often why males have evolved special weapons. These special weapons evolved for fighting other males for reproductive access. It also explains something else. Females, biologically, are choosy. And so males have to compete not merely with other males to get reproductive access but also to woo females. And so often, males have evolved special displays like this [showing a picture of a peacock's plumage], which exist only to be beautiful, only to be attractive and to attract mates.

This cold evolutionary logic was captured in this cartoon, which really does sum up a hundred of mate-selection research. The logic goes like this then: difference in the size of sex cells leads to differences in typical parental investment,

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leading to differences in the sorts of psychological and physiological mechanisms that evolved. Okay, that's a good story. What sort of evidence is there for it? Well, it turns out this could explain some otherwise surprising things. For instance, there should be--there are some cases where the parental investment is switched, some cases where it turns out--where the males end up with more investment than the females. And it--and the theory predicts that in these cases you should get an asymmetry.

So, in cases like pipefish, for instance, the male takes the eggs into a pouch and plugs them into his bloodstream. The females shoot off. They have less of an investment than the males. In this case, you would predict, as is true, the females should be larger, the females fight other females more than males fight males, and the females try to compete for the attention of the males. Recall the movie "March of the Penguins." We saw a clip from it, and this was in the context of discussing the emotions that have evolved toward our offspring. But remember the story and how both the male and the female have to go to tremendous lengths to protect the egg. And if one of them fails, the egg dies and neither one has it. You should then not even have to remember whether male penguins are much bigger than female penguins. You should realize they should not be, and in fact they aren't. They're about the same size because the parental is equal.

You should be able to predict the size differences and aggression differences based on differing parental investment. So for instance, elephant seals are four times--the males are enormous. They're four times bigger than the females. And this is in large part because elephant seals compete for harems of females. It's a "winner take all." Gibbons are about the same size. And this is because gibbons are pretty monogamous; they raise children together.

This illustrates something, which is, it's not always the case that male parental investment is low. There are some species, including gibbons, where it's in the male's reproductive advantage to care for the offspring. Imagine a situation, for instance, where an offspring would die if both parents didn't watch it for many years and where the effort devoted to that offspring had to be exclusive. If you focused on another family or went away, the offspring would die. In that case, you'd have equal investment. It would matter equally to the male and the female to invest in their offspring, and the cost would be the same. There's no species--it's hard to see species that have that much of an equal system, but some primates are close to it. And this raises the question then, "What about humans?" What about us? What do we know about the differences between males and females?

Well, humans are a relatively polygamous species. Most cultures--most human cultures are polygamous. American culture is what they call "serial monogamy." So, we're not like some species of birds. We don't mate for life. We do a series of peer-bondings for some period of time. It could be for life, but indeed may not be and usually isn't. Males are bigger than females. Human males--the size estimates vary so much, but the average human male is about fifteen percent larger than the average human female. This suggests that there's some--there's been, in our evolutionary history, some male-male competition for access to females, which suggests, in turn, that the parental investment is not quite equal. Males have smaller testicles for their body size than chimpanzees, but larger testicles than gorillas and gibbons. And this suggests that there was some intermediate amount of competition for the capacity to create sperm. And this is relevant for a different sort of competition, which regards the impregnation of females that have multiple mates. And this suggests that over evolutionary history women were not wantonly promiscuous, but were not entirely monogamous either; so much so that it paid from an evolutionary point of view to evolve--males to evolve the capacity to produce more sperm than other males.

Aggression. Males are meaner. I mean I'm summarizing here. Meaner is not a technical term. Yes, females can be meaner, but males are at least more physically violent. They're more violent in the womb, in utero; they're more violent as children, and they're more violent as adults. Again, this is not to say that you can't find violent women or non-violent men. It's just on average there is this difference. They kick more; males kick more in the uterus. As children they're more involved in play fighting and violent combat-like sports. And as adults, wherever you go you will find a prison. And wherever you go you will find that prison is mostly full of men. They are far more likely to kill one another and to harm one another. Male sex hormones, like testosterone, are not the sort of thing one would want to inject in somebody unless you want them to turn kind of mean. They increase aggressiveness, both in humans and in other primates.

What about sexual choosiness? Do male humans and female humans differ in the extent to which they will favor anonymous sex? And this is relevant from an evolutionary perspective, because the parental investment theory predicts males should be more receptive to anonymous sex. Because for males, to impregnate somebody else might fortuitously lead to another offspring; it might be good for you and doesn't carry the sort of harm that females, on the other hand, have to be very picky. Because they have to choose carefully. Remember, these systems evolved before birth control and vasectomies and so on. So, what do we know cross-culturally and psychologically?

Well, prostitution is a universally, or near universally, male interest. There are male prostitutes, of course, but contrary to some various fantasies and sitcoms, they cater to male customers. Pornography is a human universal. In every society, males have done some sort of depictions of naked females for the purposes of arousal. Often they carve them into trees or do sort of sculptures. One of the weirdest findings in the last decade or so is that this extends as well to monkey porn. And so, some scientists at Duke set up a situation where monkeys could pay in fruit juice, by giving up fruit juice, to look a picture either of the female's hindquarters or of a celebrity monkey, a socially dominant monkey, some sort of combination of People Magazine and Penthouse. And so, there's some interest in this even by non-human primates.

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What about actually preference for sexual variety? Well, you can get at this in different ways. There is what biologists describe as the "Coolidge Effect." I have this here [on a slide]. And the Coolidge Effect is based on President Calvin Coolidge. And it's a story about Calvin Coolidge and his wife, who were being shown around a farm separately. And the person showing around his wife pointed out that there were a lot of hens; she noticed that there were a lot of hens but only one rooster. And she asked the guy showing her around, "Is one rooster enough?" And the guys said, "Well, you know, the rooster works very hard. The rooster has sex dozens of times a day." And she said, "Well, be sure to tell that to the president." The story goes, the president went around, the guy tells the story to the president. The president asks the man, "Huh. Has sex dozens of times each day. Same hen every time?" The guy says, "No, different hen every time." And he says, "Tell that to Mrs. Coolidge."

Now, there are two responses to this sort of story, and they're both kind of negative. One thing is, "Well, everybody knows males prefer anonymous sex with strange women. Duh." The other response is, "That's sexist claptrap." You might think--you might be a male and say, "That's not me." You might know males and say, "The males I know are not like that." So, how do you find out? Well, there are indirect measures, such who goes to prostitutes. But there are also fairly direct measures. One fairly direct measure is you could ask people in anonymous surveys. So, in fact, I'll give you some anonymous surveys. I'm not going to ask people. And you just ask them. So, for instance, I want everybody to consider this question. How many sexual partners do you want to have in the next month? What is it--we're coming up to April. How many sexual partners do you want in April? Next two years? Take many of you through graduation. When you leave Yale, what do you want--like, "I had X sexual partners, and that's what I wanted." Or your lifetime? We get people to answer these questions.

Professor Chun last year in this course had clickers, and he got people to do it. We are not so high tech, so we'll just do it in our heads. But here is the way the answers come out. Women say less than one in the next month. That doesn't mean they want less than one; that means many of them--many of them say zero, some say one and so on. One--four to five. Men--two, eight, eighteen. You can ask other questions from this population. So, you could ask, "Would you have sex with a desirable partner you have known--so somebody really desirable--for a year; women say yes, six months--unsure, week or less--no. Men [slide reads "yes, yes, yes"] [laughter]--and with men you could get a majority going to five minutes.

This is all Q & A, pen and pencil sort of things. Some brave scientists have actually done experiments. And in one experiment somebody--I don't, you know, this is the sort of thing which you probably wouldn't do nowadays. This work has been done ten years ago, where they have an incredibly attractive man and an incredibly attractive woman and they approach people on campus. They're not from campus; they're actors brought in. And they go to people, to strangers, and they say, "I've been noticing you around campus. I find you very attractive. Would you go out with me tonight? Would you come over to my apartment tonight? Would you go to bed with me tonight?" The experiment you wouldn't think anybody would've done has been done, and women about--a very attractive man, over half of the women approached say, "Yeah, I will. [go out with you tonight]" Very few agree to this ["Would you come to my apartment tonight?"], and nobody agrees to this ["Would you go to bed with me tonight?"]. For men, the data are like this, they go up to there and then up to there [they say yes 50%, 69% and 75% of the time respectively]. In this study, the twenty five percent of males who said "no" apologized profusely, and they said, "Oh, you know, my fiancé's in town, and [unintelligible]."

What about behavior? Well, you--if we're interested in sex differences, you can't actually figure out what people want, male female differences, by looking at simply at the average number of times people have sex because if males and females have different priorities, then heterosexual sex is a compromise between two groups of people with competing interests. What's a more clear reflection then is gay sex between two women or between two men, because then you get a pure reflection of sexual desire. Now, the data here tend to be very messy. Again, they're survey studies but by and large every study done tends to find a difference in the expected direction, which is that females tend to be--lesbians tend to be much more monogamous than gay men. Some studies prior to AIDS – this was many years ago – found gay men to be extremely promiscuous, often having over a hundred or over a thousand partners. You wouldn't find this sort of promiscuity in females. And a way to think about this is, what these gay men are doing is exactly what your average heterosexual man would do if he had that degree of willing females who were as willing as he was. And this all suggests that there's some sort of difference along lines expected in sexual choosiness in humans.

What about sexual attractiveness? What about mate preference? What do we find attractive? Well, unlike the choosiness studies, here we actually have some pretty good cross-cultural data. So one study, for instance, was done in 10,000 people from thirty-seven countries, asking people, "Who do you want to be with?" And there are different studies, some of them asking, "Who do you want to marry?" Other studies, "Who do you want as a mate? Who do you want as a sexual partner?" And one main finding is kind of reassuring, everybody likes kindness and intelligence, or at least everybody says they like kindness and intelligence. These are valued pretty highly.

But at the same time, there are sex differences. Females focus more on power and status and more on interest in investing in children. And think about that from an evolutionary point of view and it makes sense. It doesn't matter hugely, from the standpoint of reproduction, how old the man is. The difference between fifteen and twenty-five and thirty-five and forty-five may matter a lot for his status in the community, his physical strength, his lifespan but from the standpoint of his sperm it doesn't matter hugely. Later on there's a drop off and it does begin to matter, but it doesn't matter hugely. What

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does matter is his interest in being a good father, in protecting you from predation, from murder, from assault by other people, and in taking care of the kid. Women's brains are wired up to find males with those properties.

Similarly, males focus a little bit differently. They're more interested in all of these things, but also on the ability to have children. So, from an evolutionary point of view, there's actually a very big difference between a twenty-year old and a fifty-year old, from a male standpoint looking at a female, because the one can have offspring and the other cannot. So, this is a difference.

But what I want to focus more on right now is back to another similarity. Everybody likes beauty. And I want to devote a little bit of this lecture to talking about physical beauty. Physical beauty, as these beautiful people say, is a curse. So she--she's like a big model, a supermodel, maybe even a super-supermodel--points out the arbitrariness of finding her devastatingly beautiful. Famous actor points out how frustrating it is that people only ignore his accomplishments and focus merely on his physical beauty. This is very frustrating. So what is beauty? What does this mean we say we find--you know, yeah, they really are very attractive people. What is it about that that makes you look and say, "Yeah, that makes sense?" Well, we kind of know the answer. We know some universals.

Beauty seems to signal two things. Beauty seems to signal youth--I mean, not pre-school youth, but youth like sexually mature but young. And so the cues we find beautiful are cues to that – large eyes, full lips, smooth, tight skin. Beauty signals something else. Beauty is a marker for health. And so what we find beautiful, things like the absence of deformities, clear eyes, unblemished skin, intact teeth – that's very big – and an average face. And that last part might seem a little bit strange. What would be so good about an average face? And there are different answers to that, but one answer is, an average face, on average, should be considered attractive because any sort of deformities are variations from the average. And if you average every face together, you get a face that--where nothing bad has happened to it. There's no distortion, there's no deviation. As one gets older, the face gets less symmetrical and so on. Average-ness seems to factor out all the bad things that could happen.

Good theory. How do we know it's true? Well, there's a photo roster that comes--that I have access to for this class. So, I can look at each of your pictures, and I will make you a bet about who has the most beautiful face in this course. The bet is it would be all of you. Aw. Wouldn't it be funny if I shouted out somebody's name? And you know, A) I don't have the energy to do this, and B) it would probably violate four hundred different privacy laws or whatever. But if I took all those faces and morphed them together, I would get a very pretty face. And how do we know this? Well, people have done this. They've done it with--so look at the faces from here to here. And if you are like most people, you see as you're going to the right they're looking better and better and better. It's subtle, but it's actually not so subtle that babies don't notice it. The same researchers who constructed this--these face--these average Caucasian faces, male and female, have shown these faces to babies and find that babies that prefer to look at average faces--suggesting that our preference for averaging is not the product of culture but rather is to some extent hard-wired.

These two people don't exist. They're computer composites. They're a heavily averaged male face and a heavily averaged female face, both from a Caucasian data sample. They don't look bad right? They're good faces. They don't cheat. So the hair, for instance, is identical--so they don't--you can't use hair cues. But they're pretty attractive. But the story of attractiveness does not end there. How do you get a better than average face? What can you do to these faces, these average faces, and make them look even better? Well, I'll have a vote. Who's prettier? Who says the one on the right? Who says the one on the left? Left is average face, and there might be variation in this class. There are definitely variations in what people favor. This is a feminized version of the average face where certain prototype features were made more feminine than average to cue this as more of a sexual object.

This is more complicated. Who thinks face A is more attractive? [face A has exaggerated chiseled jaw and square chin] Who thinks face B is more attractive? Okay. Most people like face B. The exception is, and this has been statistically replicated, I think, now in three labs. Face A is preferred by women who are ovulating, and the story about why is complicated and will take us beyond the scope of this class. But currently the idea is that this [face B] is a really handsome guy; he's young, he's healthy, he looks strong, good provider; this guy [face A] is really hot, and he may not be a good provider and everything, but I'm sure he has wonderful genes. So, the idea is that one should have sex with him [face A] and then have him [face B] raise the kids.

We've talked so far about things, about sex and sexual attractiveness largely from a biological perspective, looking at universals. And in fact, there are some universals in what men and women have in common and what distinguishes men and women. And in some of the sex differences, particularly related to aggression and mate preference, seem to be universal. They seem to show up to some extent across every culture you look at and, hence, are likely candidates for biological adaptations. But there are other sex differences that people are aware of where the origins are far less clear. And I think that intelligent, reasonable people could disagree about this, but I am personally quite skeptical about the extent to which these reflect biology. I'll mention them to capture the debate, but the thing to keep in mind here is that biology, natural selection, is one reason why the men in this class might differ from the women in this class. But of course, there are other, social, factors.

Babies are treated differently. There have been many studies where you take a baby and swaddle it in blue and describe it as a boy versus swaddle it in pink and describe it as a girl, and people treat it differently when they think it's a boy

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than when they think it's a girl. You're treated differently too. It matters a lot--and there's study after study suggesting, for instance, that when you send an email or a job application or a paper to a scientific journal, it matters whether it has the name John Smith on it versus the name Joan Smith. It matters because people have different expectations and different reactions to males versus females. Some if you may have firsthand experience with this if you're a man with a name that could be taken as a woman's name – friend of mine is named Lynn, and often people think he's female – or if you're a woman who has a name that could be taken as a man's name, or if you have a name sufficiently foreign to Western ears that people can't easily tell. You'll often find people saying, "Oh," people are high-fiving each other there [referring to students in the class]--you'll often find some degree of surprise and some degree of people saying, "Oh my, I didn't know you were a man. Now I will treat you differently." And so, these social factors could play a role in explaining some male and female differences.

Also, there are the facts of gender self-segregation. So here something very interesting happens developmentally. Males segregate with other males; females segregate with other females--for a period lasting, it depends on the culture, but say from age four to age eleven. This self-segregation might exaggerate and enhance sex differences. It might be, for instance, as Eleanor Maccoby has proposed, that boys are slightly more aggressive than girls. But then boys go into groups of boys, and that enhances and exaggerates their aggression while the girls' non-aggressive behavior is enhanced and exaggerated in different ways by them falling into girls' groups.

So, what sort of differences are we talking about when we say we're not sure of their cause? Well, one difference is one in empathy. So Simon Baron-Cohen wrote a wonderful book called The Essential Difference where he argues that men are by nature less empathetic, women are by nature more empathetic, and that this is a core sex difference. So, what do you know? Well, what's the source for this? One thing is men are more violent. Simon Baron-Cohen describes violence as the ultimate act--murder as the ultimate act of a lack of empathy. There's some relationship between how much testosterone you have in your system and how social you are – more testosterone, less social. Boys tend to be less empathetic than girls, and there's some evidence, though it's not conclusive, that boys do worse than girls on social cognition theory of mind tasks. That's what I have here, though that is quite debated.

And the biggest effect, which isn't debated at all, is problems with empathy, problems of social cognition, are much more frequent in men than in women. So, these disorders like autism, Asperger's Syndrome, conduct disorder and psychopathy are predominately male. And Simon Baron-Cohen suggests that--basically, he has this slogan where he says, "To be a man is to suffer from a particularly mild form of autism." That males are just socially clueless relative to women. Final bit of trivia--This is Simon Baron Cohen, who is a very famous developmental psychologist, but his cousin Sasha Baron Cohen is far more famous. Another debate is a debate concerning sex differences in the capacity for math and science.

A few years ago there used to be a president of Harvard known as Larry Summers. There are so many reasons to hiss at this point. And Larry Summers is no longer president of Harvard for various reasons, but one reason was this quote, which included in his speculations about sex differences, "...in the special case of science and engineering, there are issues of intrinsic aptitude, and particularly of the variability of aptitude..." He argued, or suggested, that the under-representation of women in the sciences in academia is because of an intrinsic aptitude difference; women are, on average, less biologically predisposed to do this sort of reasoning. The variability point is that he wasn't suggesting that there's just a difference on average. In fact, he agreed that the average skills of men and women are identical. The claim is that males show more variation. This means that there are more male retarded people and more males who are just horribly bad at this, but it also means there are more male geniuses. And he suggested that this plays a role.

This, as you can imagine, proved to be an extremely controversial claim, and rather than go through it – because it would take me a class to treat the pros and cons of this argument responsibly – I'm going to refer you to a wonderful debate between Steve Pinker, who was quoted earlier, and Liz Spelke who's one of the big infant cognition people. And we spoke a lot about her work earlier on in the course. And they have a wonderful debate between two of the smartest people I know on The Edge, which was done at Harvard about a year ago and is on video here [http://www.edge.org/3rd_culture/debate05/debate05_index.html]

So, if you're interested in sex differences and different theories about the mechanism of sex differences, this is where you should go.

Finally, and a final topic, some of us, about 98%--and the numbers are very difficult to pin down. Maybe it isn't 98%; maybe it's ninety-seven, maybe it's ninety-nine. Let's say 98% of women are sexually attracted to men. About 96% of men are sexually attracted to women. And the numbers vary and it's very difficult to estimate it properly. As you could imagine, there are all sorts of problems with this sort of research. But there's some proportion of the population that's exclusively homosexual--some proportion of the population of men who are only attracted to other men, some proportion of the population of women who are only attracted to other women. When people talk about sexual orientation here, it's important to realize we are not talking here about behavior. There are all sorts of reasons why somebody might have sex with somebody of the same sex. You know, they might be bored. You may, you know, be experimenting, be whatever. The question is, "What do you want to do?" All things being equal, what sort of person--if you could be sexually or romantically involved with

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any person, who would it be? And most people are heterosexual. There's a considerable amount that varies cross-culturally of people who are bisexual. But the real puzzle is exclusive homosexuality. So, why?

Well, nobody knows. We know some reasons, some answers are probably not right. It is not the case, almost certainly – maybe there are some exceptions – but it is not the case that people choose their sexual orientation. I'm not going to do this in this room, but if you asked people to raise their hands as to how many people decided who to become sexually attracted to, very few people would. Part of the issue rises in the fact that people who are gay are often extremely discriminated against, and they have no wish to be gay. They might even think it's morally wrong for them to be that way. That makes it implausible that their sexual orientation is a conscious choice.

What about experience after puberty? So, there is a view that keeps coming up over and over again in the literature that people who are gay have in some sense been seduced by people, by other people--or something happened to them afterwards. This seems unlikely. There are in particular the seeds of sexual orientation later on in life seem to show up quite early in life. Again, the studies are sort of suspect, but there's some reason to believe that people who are gay and people who are straight are different long before they hit puberty with regard to their sexual and romantic fantasies.

You would now expect me to say, "Well, being gay and being straight is built in. It's hard-wired. None of these stories seem right. It seems to be built in." And the answer to that is, sort of. So, if you do the standard behavioral genetic tests, and you by now know how to do them--you'd look for differences between monozygotic and dizygotic twins, you'd do the adoption comparison--you know adopted siblings and biological siblings. The answer is yes, you find that there is some sort of genetic predisposition towards homosexuality. But it can't be entirely genetic. One reason why it can't be entirely genetic is, if I'm gay and I have an identical twin, the odds that my identical twin will be gay--it's about fifty percent. Those are very high odds compared to the average in the population. But if it was truly genetic, entirely genetic, what should the number be? A hundred percent – he's my clone. He should be exactly as I am. And it's not. So, we know then that some sort of experience, possibly prenatal experience, is what explains it.

Why is it so – I said before this is a huge puzzle – why is it such a huge puzzle? Well, exclusive homosexuality is an evolutionary mystery. Again, do not think that this carries any moral weight to it. What it does mean though is that it doesn't seem to follow as a biological adaptation. The puzzle is not why is it that some men have sex with men. That's not a big puzzle. Maybe they have sex with men as some sort of recreational things or pair bonding or whatever. That's not the puzzle.

The puzzle is why are there some men who don't want to have sex with women? Similarly, why are there some women who don't want to have sex with men? From an evolutionary adaptive standpoint, you would think that the genes that give rise to such a behavior would be weeded out because creatures with that behavior typically, putting aside modern technology, don't have offspring. And that's what makes it such a puzzle. So, your reading response for this week is "solve that puzzle." I know I said early on in the course that reading responses would be really easy and just require you reciting back things, but that proved to be too boring. So, just solve this deepest of all puzzle. The thing in brackets at the end is very important. Your account, whatever it is, should bear some relationship to the facts as discussed in lectures and readings. We have about five more minutes. Any questions or thoughts? Yes? Student: I like your leather jacket. Professor Paul Bloom: Thank you very much. She likes my leather jacket. Any questions or thoughts, just like that one? No. Yes? Student: My question's not exactly like that one, but in other animals do they--is there similar data on other species? Professor Paul Bloom: On sexual preferences? That's a very good question because certainly your answer to the origin – give me two more minutes – certainly your answer about the origin of sexual preference in humans will be informed by the question of cross-species data. What we do know is that there are many animals that engage in homosexual behavior; they engage in sex with members of their own sex. What I don't know is whether you get exclusive homosexual behavior. So, I don't know what the rate is in nonhuman primates, for instance, of primates who do not want to have sex with members of the opposite sex. Okay, I'll see you all Wednesday.

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Lecture 15 Professor Paul Bloom: Let me begin by just reminding us where we are in this course, reminding us of what we've done and what we have yet to do. We started by talking about the brain, the physical basis of thought. And then we moved to some general introductions to some foundational ideas in the study of psychology, Freud and Skinner. We spent a bit of time on more cognitive stuff: development, language, vision, memory. Then we took a little break and the dean told us about love. Then we dealt with the emotions, rationality, and evolution, and a lot of that. What we learned particularly regarding the evolution of the mind provided supporting material for what follows. We learned about cognitive neuroscience using the study of face recognition as an important case study--human differences, behavioral genetics, nature and nurture, sex and food. My lecture was on sex. Dr. Brownell came and spoke to us about food. Today, morality. Next week, social thought and social behavior, mysteries; basically, a series of topics that don't fit anywhere in the course and really make psychologists scratch their heads. These topics are sleep, laughter, and religion, mental illness, two lectures on madness, what can go wrong in your minds, and a last lecture on happiness. And then you're just done. You know a lot of psychology and a lot of stuff and you're well prepared for your ultimate major in psychology, ultimately graduate training at a good school.

How many people here are either psych majors or expect to become psych majors or cognitive science as though you could raise your hand to? Okay. Good. It's nowhere near enough [laughter] and so I'll ask the question again. Once you deal with happiness and then mysteries, you're really not going to want to--What is there? Chemistry? Anthropology? [laughter] Pre-med? Give me a break. [laughter]

Okay. We're going to deal with three facets of morality. I'm going to talk about moral feelings, moral judgments, and then moral action with particular focus on why good people do bad things, which will lead us to review and discuss the Milgram study, which was presented in the movie on Monday. Now, moral feeling is what we'll start off with and we've already discussed this in a different context. The question is, 'How could moral feelings evolve?" So, moral feelings we could view as feelings of condemnation, shame, emotions like that--shame, condemnation, pride, righteous anger, but also simple affection, caring for other people, wanting to do well by them, being upset if an injustice is to be done by them. And you might think that the existence of these feelings is a mystery from an evolutionary point of view. If evolution is survival of the fittest, nature red in tooth and claw, how could animals evolve moral feelings? But in fact, we know the answer to this. And there are two answers to this.

One answer is kin selection. So, evolution works at a level of the genes and because of that it could give rise to animals that are themselves altruistic. And they're altruistic because they act to preserve other animals that share the same genes. And so, I'm not going to spend any time on this because we've discussed it in detail, but we know from previous lectures that people will be generous to others. And there's an evolutionary explanation for your generosity towards kin. It could be mathematically worked out. Your caring, your moral feelings towards other creatures to the extent of the proportion of genes that you share with them. The most altruistic behavior of all, giving your life to help another, can be explained in cold-blooded evolutionary terms. Animals that are altruistic even to the point of dying to help another, those genes will, under some circumstances, be preserved over the genes of people who are less caring. And that is one force towards kindness.

A second force towards kindness is cooperation. Even if animals are unrelated, they are nice to one another. Animals will give warning cries, they will groom one another, they will exchange food, and the reason for this is that animals have evolved, our minds have evolved, to enter into sort of cooperative situations with other people and to surmount prisoner's dilemmas, to surmount deception and cheating. This gives rise to some emotion including emotions that could be viewed as moral emotions, like guilt and anger, and again, grounds altruistic behavior in an evolutionary perspective.

This is all by means of review but the question you can now ask is, "Fine. That's why moral feelings might evolve, but what do we know as psychologists about the emergence in nature of moral feelings in individuals? What's the psychology of moral feeling?" And this is an issue I'm going to talk about now but I'm going to return to next week when we deal with issues such as liking and disliking, racial prejudice and other things. But I want to deal now with a couple of interesting case studies about moral feelings from a psychological point of view.

The first one I want to deal with is empathy. And empathy has different definitions but we can simply view it as the feeling that your pain matters to me. If you are hurt, that is, in some sense, painful for me. If you are sad, that affects my own mood. I am not a selfish creature. I am built, I am hard wired, to be attuned to your pain. This is an old observation. Adam Smith, who is often falsely viewed as a proponent of selfishness and hardheadedness, was quite explicit about the pull this has. He notes:

When we see a stroke aimed and just ready to fall upon the leg or arm of another person, we naturally shrink and draw back our own leg or arm and when it does fall we feel it in some measure and are hurt by it as well as the sufferer. If you see somebody being kicked in the groin in a movie, you might yourself tense up. If you see somebody bang their thumb with a hammer, you might cringe. Here is a good illustration of somebody in anticipatory pain. [laughter] Now--It's a very British face actually.

[laughter] Now, we know certain things about this empathy, some which might be surprising. The pain of others is aversive even for babies. We know this because if babies hear other babies crying they will get upset. The crying of babies is aversive to babies.

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Now, some of you may be sufficiently cynical to say, "That could be explained in other ways. For one thing, one theory is that babies hear other babies cry, because babies are so stupid they think they themselves are crying; if they're crying they must be in some sort of pain so they cry some more." But clever psychologists have ruled this out. What they did was a study where they exposed babies to tape-recorded sounds of other babies crying and tape recorded sounds of themselves crying. Babies cry more to this pain of other babies than they do to their own pain, suggesting that their response is to some extent a response to the "otherness" of the characters.

We know pain is--of others is aversive for chimpanzees and we know this in certain ways. But we know this, in particular, from a series of studies that would be unethical if they were to be done today. In these studies, they put a chimpanzee in a room and there's a lever. And when the chimpanzee slaps the lever, it gets some food. Trivial, smart animal, piece of cake. But the room has a window leading to another room. And in the other room another chimpanzee is placed. This second chimpanzee is not a relative of the first chimpanzee and they've never seen each other before. Now, when the first chimpanzee hits the lever the second chimpanzee gets a painful electric shock, putting the first chimpanzee in a horrible dilemma. In order to feed himself, he has to torture another animal. Chimpanzees do not starve themselves to death. It's very unlikely any of you would either but they go a long time without food, suggesting they do not want to cause this other chimpanzee pain. It only works within species. So, in another experiment they put a rabbit in the other room and the chimpanzee would slap the lever repeatedly to make the rabbit scream in pain [laughter] and jump.

Now, we've known for a long time that empathetic feeling is not logically linked to morality. This is a point made by Aristotle. I could see you writhing in pain. That could cause me pain but it doesn't mean I'm going to be nice to you. I could run away from you. I could turn my head or I could blame you for causing me this misery. But it does happen that emotional--that this sort of empathy does lead to moral concern and action. If we do an experiment and we induce you to feel empathetic to somebody, we get you to feel what they're feeling, you're more likely to be nice to them. And people differ in the extent to which they feel empathy. People differ to the extent it will hurt them to watch me slam my thumb with a hammer. If you are high empathy, you're more likely to be a nice person than if you're low empathy, suggesting there is some connection between empathetic feeling and liking.

Now, empathetic feeling, like any other human capacity, differs across people. Some of us have a lot of it. Some of us don't have much of it. There is some reason to believe that in the population known as "psychopaths," a population we'll return to later on when we discuss mental illness, this sort of instinctive empathy is broken and the pain of others just doesn't bother them very much. I have some illustrative quotes here. In Damon's book, a wonderful book on psychopathy, he talks about a thirteen-year-old mugger who specialized in mugging blind people. And when asked about the pain he caused his victims he responded, "What do I care? I'm not her," which is logically correct but, in a sense, inhuman. The fact that it's another person should make you care.

The serial killer Gary Gilmore basically said the pain of others gratified him and caused him no unhappiness at all. "I was always capable of murder. I can become totally devoid of feelings of others, unemotional. I know I'm doing something grossly--" and here is a very bad word "--wrong. I can still go ahead and do it." And Ted Bundy, when interviewed at one point, said he was astonished that people made such a fuss about all of his murders because he said, "I mean, there are so many people." And if any of you here are nodding in agreement at these sentiments, [laughter] that's not such a good sign. These are particularly callous and cold-blooded statements suggesting that this instinctive empathy, this aspect of moral thought, is not--is present in most of us but not in all of us.

The second case study of moral feeling is "in-group" and "out-group." In our affections, in our caring, who we like, who we feel close to, whose pain bothers us, we are not indiscriminate. I care a lot more about my children than I do about my friends and I care more about my friends than I care about strangers. We're all like that. We also favor our group over others in every possible way. You are a member of many groups. You are men. You are women. You're Yale students. You're young. You're white, you're black, you're Asian. You're a member of these groups and, as we will discuss repeatedly when we talk about social cognition and social behavior, this membership matters a lot to you. What's particularly interesting is even groups that are formed, that you were not born with, that are formed on the fly, exert a huge amount of control over your moral feelings and moral attitudes. And the best example of this is discussed in detail in the textbook. And this is the Robber's Cave study. And this Robber's Cave study serves as a nice illustration of morality in everyday life.

The study was, eleven- and 12-year-old boys at a camping program. These were well-adjusted, pretty rich kids, racially homogeneous, and they were put into separate cabins. And the cabins were given leaders and they gave themselves names. Being unimaginative boys, they called themselves "The Eagles" and "The Rattlers" but as--what happened was, being separated they developed distinctive cultures. And when these groups were set in competition against each other, the Eagles versus the Rattlers, the within-group intensity grew. The Eaglers began--Eagles began to care a lot more about other Eagles than about anybody else.

So, there's within-group solidarity. And then there were negative stereotypes. So, these groups developed different cultures. It was a randomly cut apart--kind of like Yale College is actually, where you get a random assortment of people. But despite the fact that the assortment is random, the division is random, cultures begin to emerge. The Eagles prided themselves on being clean living, not using cuss words and treating each other with respect. They viewed the Rattlers as dirty and tough and kind of slovenly slobs. The Rattlers viewed the Eagles as goody-goody kids. It's cruel.

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Finally, [laughter] it all evolved into hostilities, raids and violence. The Eagles burnt a Rattlers banner, cuss words were occasionally used, and so Sherif, the psychologist designing all of this, went, "Excellent," [laughter] and then the problem--He then says, "Now we've created two different warring cultures. That was fun. [laughter] What do we do to make them friends again? And then we figure out how to--now we've done that and this'll solve all sorts of problems." So they started off. They wanted to have--They set up peace talks where a representative of the Eagle and a representative of the Rattler were set to meet and plan ways so that they could disarm and stop using cuss words and everything like that. This failed. The kids who engaged in the peace talks were ostracized by their own groups as treasonists. That failed. They decided to set up individual competitions like the Olympics where they--where people wouldn't compete as Eagles or Rattlers but rather they would compete as individuals. That failed too. Like the Olympics, people--the teams took their--they took their individual accomplishments as reflecting on the group and it evolved into Eagles versus The Rattlers.

They shared meals, they turned--which turned into food fights and more cuss words. They shared movies, more fights, more cuss words. They shared fun with firecrackers, [laughter] which was a disastrous thing which nearly brought the experiment to an end. [laughter] They brought in a religious figure to give them sermons on brotherly love. [laughter] The sermons were entirely unsuccessful. What's interesting is they--the Eagle--they took them to heart. These were good kids. They were respectful of religious authority but the lessons they took from them is "I should learn to love my neighbor." If I'm a Rattler, I should learn to love my fellow Rattler and appreciate him as a fellow, as a person. "I love him. It's love, not like those scummy Eagles." [laughter] They all failed.

Here's what worked. Sherif told the kids--all of the kids--that the water line to the camp was cut and they all had to defend the camp. What this did was it established a super ordinate goal, that is a goal that everybody shared, and perhaps more important a common enemy. This is where the solution, by the way, to bringing together--and you could write this down--to bringing together all the warring countries and religions of this planet is an alien attack. [laughter] By the logic of the Sherif it will bring us all together as a group.

A different question is, there in that experiment the "groupiness" was established in a very powerful way. They lived separately, they interacted with each other, they had their own names. The psychologist Tajfel after World War II was interested in the question of what could make a group. In other words, what do I have to do to you to put you in a different group from him? What do I have to do to this class--this side of the class to put you in a different group from this side and different from that side? And what would I have to do for those groups to matter such that, for instance, if I separate you in one group and you're in another group and I give you a hundred dollars will you give the money more to him or to him, will you give it more to your own group or to another group? And what he found was you don't need much.

In one experiment he showed people pictures of modern art and based on their responses he described them as Klee lovers or Kandinsky lovers. Now, this is all made up. They were just random assignments but the Klee lovers viewed themselves as more similar to other Klee lovers. They thought the Klee lovers tended to be smarter than the Kandinsky lovers and the Klee lovers would devote more resources to themselves than to others. This is why it's called "minimal groups." You don't need much to make you into a group.

And in fact, later experiments just flipped a coin. So the lot--the experiment goes like this. I ask everybody in this class to take out a coin. You all flip it. Everyone who has heads, you're one group. Everyone who has tails, you're the other group. Then I ask people in the heads group, "Which group do you--Putting yourself aside, which group on average do you think is smarter?" You'd say, "Well, you know, it kind of works out that the heads group is kind of really--heads, smart." Which group--"Here is some money. You have to distribute it." You're more likely--It's a subtle effect when you make the groups so minimal but you're more likely to give it to your own group than to others and this suggests that moral feelings are exquisitely attuned not necessarily only to individuals but also to the psychology of groups. Any questions at this point about moral feelings? Yes. Student: How you formed the groups--How is that morality? Professor Paul Bloom: It's morality--It bears on morality because it bears on--So, the question is, "How does group membership, how does that relate to the topic of morality?" And the answer is the moral feelings we're talking about are feelings like empathy and caring. For me to have a moral feeling towards you means you matter to me. If you were to be harmed, I would view it as wrong. And the group experiment suggests that the extent to which these moral feelings operate are partially determined by the groups to which we belong to. If I'm American and you're from another country, I will view myself--this is a very--kind of obvious finding--my obligations to you will be seen as less than if you were another American. If I'm a Klee lover and you're a Kandinsky lover, I don't think you quite deserve as much as me.

Moral judgment is an area that is tremendously exciting and there's a lot of recent research on this. By moral judgment I mean not empathetic feelings, not feelings of caring and love or approval and disapproval, so they're not feelings of caring and love and empathy, but notions like something is good or bad, something--like something is fair or unfair. So, there are three hallmarks for moral judgments. So, suppose I say I don't like strawberry ice cream. That's an evaluation. That's a judgment but it's not a moral judgment. Why not? Because I don't think it carries a sense of obligation. I don't think anybody's obliged to eat or not to eat strawberry ice cream. And it doesn't carry a notion of sanctions, meaning I don't think anybody should be punished for eating strawberry ice cream. On the other hand, if I say I don't like baby killers, that actually is a moral judgment in my case. So [inaudible] I say, "Well, I don't like baby killers. You like to kill babies. I actually think we

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are obliged not to kill babies." If you disagree with me, you're wrong and you should stop killing those babies. [laughter] Should you fail to stop killing those babies, I think you should be punished for killing babies." And that's what my judgment about "no killing babies" makes it a moral judgment.

Now, some people attempted to look at this the wrong way and say, "Look. What a weird topic, morality. I don't believe in morality. I believe in Nietzsche. I don't believe in ethics," but I don't believe you if you were to say that because morality isn't--morality as we talk about it in this context isn't just regarding your position on big questions like political issues or big moral questions like abortion or capital punishment. Rather, some sort of moral judgment happens all the time, often unconsciously. So, as you live your life you have to answer questions like what should you eat? Any moral vegetarians here? I'm just raising my hand to encourage people. [laughter] Okay. Anybody give to charity? Anybody not give to charity? Good. [laughter] Different from the moral vegetarians I noticed. Who do you socialize with? There's homeless people around Yale and New Haven. What do you give to them? Do you avoid their eyes? Do you--What do you want to do with your life? Who do you have sex with? Under what context or conditions? These are moral questions.

My favorite moral dilemma is as I'm walking down the street and I see somebody I sort of know, do I avoid eye so we don't have a conversation [laughter] or do I say, "Hey. How are you doing?" or do I kind of do the nod hoping that there won't be more than this nod? [laughter] And then after I leave and I say, "Oh, I should have made eye contact with that person. I'm such a jerk. [laughter] There is a homeless person [simulating making great eye-contact with them]" [laughter] and--but these are day-to-day moral questions we struggle with all the time and so there's a centrality in the study of how we do moral reasoning.

So, what do we know about moral reasoning? Well, we know that there are some universals. There are some aspects of moral reasoning that show up everywhere on earth. And there is some evidence, though it's not particularly strong at this point, that these same intuitions show up in young children and in nonhuman primates like chimpanzees, capuchins, macaques and so on. And these are things like anger at cheaters, gratitude toward sharers, the sort of things you'd expect to come out in a prisoner's dilemma, feelings that some things are right and some things are wrong. These are foundational. But at the same time the study of moral reasoning is a fascinated--fascinating issue for those of us interested in cross-cultural psychology because there are plain differences across cultures. So, the anthropologist Richard Shweder gives a list here of human differences:

People have found it quite natural to be spontaneously appalled, outraged, indignant, proud, disgusted, guilty and ashamed by all sorts of things. Then there's a long list: "masturbation, homosexuality, sexual abstinence, polygamy, abortion, circumcision, corporal punishment, capital punishment, Islam, Christianity, Judaism, capitalism, democracy, flag burning, miniskirts, long hair, no hair, blah blah, parents and children sleeping in the same bed, parents and children not sleeping in the same bed, women being allowed to work, women not being allowed to work.

If I put it down in a list and got people to tick it off, what you all thought, there would be some differences. Some of you think meat eating is okay. Some of you do not. Some of you--You might have different views about divorce. Most of you believe women should be allowed to work. Most of you will be in favor or not morally scolding of homosexuality. You'll be lukewarm about polygamy. Nobody would like abstinence and so on. [laughter] But if we gave that same list to people in a different culture, they'd tick off entirely different things. These are ways in which people vary. I don't think people vary in their feelings about baby killing. I don't think people vary about the feelings of I do something for you and then you don't do something for me. I think that's gut-level, hard-wired, evolved to solve prisoner's dilemmas. But these are important issues and these vary a lot from culture to culture and a good theory of psychology has to explain how these differences arise.

And Shweder has a theory which is quite interesting. Shweder argues that there are three styles of thought, three different frameworks of moral thought, three different ethics. There's an ethics of autonomy. This is what moral philosophers within our culture view as morality, notions of rights, of equality, of freedom. But many cultures focus on an ethics of community, bringing together duty, status, hierarchy, and interdependence. Other cultures focused more on an ethics of divinity where notions such as purity, sanctity, pollution and sin are relevant.

So for example, when we're talking about the rights of men and women and what they should be allowed to do, many people in our society following an ethics of autonomy will argue that they should have equal rights in all domains of behavior. Since they are sentient, free creatures, they should have a right to do whatever they want unless there is a compelling argument against it and a compelling argument would have to involve some infringement of the freedom of other people. On the other hand, if you're in an ethics of community you might argue that men and women have different rights and different responsibilities. They may be born to perform certain things and as such they're duty bound to follow them. If you're from an ethics of divinity, you may appeal to religious injunctions against certain actions and behaviors and these may differentially restrict the behavior of men and women. You might believe for instance, that women should not prepare food when menstruating because it would contaminate the food. You may believe that there's--there are severe restrictions about who could have sex with one another that don't have to do with human rights and human freedom. It has to do with the way things should be because of issues of pollution and sin.

Now, Western cultures, as I've said, are highly invested in an ethics of autonomy and so debates we have in our culture tend to be framed in terms of an ethics of autonomy. If we have a debate about abortion in this class, people--some people might say, "Look. The fetus is a sentient being and as such it has a right to survive and shouldn't be killed by its

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mother." Other people would argue, "No. A woman has full freedom over her own body and as long as a fetus is within the body they--she has a right to control it." If we're arguing about hate speech, we could talk about the balance between the rights of the freedom of speech versus the right to a certain quality of education free of harassment and humiliation. Those are the ways we frame things but one of the more interesting discoveries in this field is that although people think that they're governed by the ethics of autonomy, even people within our culture, even highly educated people within our culture, even people like you show moral judgments that are not quite as simple.

So, this is the work of Jonathan Haidt at University of Virginia. And Haidt finds if you ask people, they believe in our culture that they hold to an ethics of autonomy. If it doesn't harm anyone, it's okay. So, if I was to ask you your attitudes about sex, most of you--not all of you, you come from different cultures, you have different attitudes--but most of you would say sex between consenting adults is okay as long as nobody gets hurt, as long as nobody gets hurt people's rights are respected. So, gay marriage, for instance, or gay sex would be okay with you because it is--nobody is harmed and these are consenting adults. Haidt points out that there are certain problems with this argument and he illustrates this problem--these problems with stories like this:

Julie and Mark are brother and sister. They are traveling together in France on summer vacation from college. One night they are staying alone in a cabin near the beach. They decide it would be interesting and fun if they tried making love. At the very least, it would be a new experience for each of them. Julie was already taking birth control pills but Mark uses a condom too just to be safe. They both enjoy making love but they decide not to do it again. They keep that night a special secret which makes them feel even closer to each other. What do you think about that? Was it okay for them to make love?

Who says yes? Good. I know that some people would say yes, shoot up their hands, and they look around in astonishment that no one else is with them. [laughter] Who says no? Okay. Who is not sure? You're not sure. That's the weirdest of all. [laughter] Haidt finds that the distribution even among this--If you--Look. If you go home and you ask your parents, they say, "Ew. What is--What are you learning at Yale?" [laughter] This is a very unusual culture and where some people will say it's okay.

What Haidt finds is most people say it doesn't and then he simply asks them, being a good psychologist, "Okay. What's wrong with it?" And this is the brother/sister case. And the responses are interesting. Because people view themselves as committed to an ethics of autonomy, they can't just say it's disgusting. So, they exhibit what Haidt describes as "moral dumbfounding," meaning that they struggle to find an explanation. They say it's terrible because they'll have a kid and the kid'll grow up freaky [laughter] and then the experimenter--it's an interview situation--says, "Well, no. Remember they're both using a lot of birth control." "Maybe she's under age." "No, not under age." And finally, "Well, it's just wrong."

Similarly, another one of the scenarios--[laughter] This isn't as bad as you might expect. [laughter] The family dog is playing outside and gets hit by a car. [laughter] They bring it in and they say, "Oh, Fido's dead, Fido's dead, but what's for dinner?" So, they cook it and eat it. Who says it's okay? Good. [laughter] Who says it's not okay? Okay. Then they notice that their toilet is kind of dirty. "But whoa, there is an American flag." [laughter] They then use the toilet to clean the flag. Who says that's okay? [laughter] Anybody think it's not okay? And just keep in mind we're getting sort of even responses here. On all of these, the majority of people who are not college students in elite universities say, "Oh, that's so wrong."

Finally, there is this one. And this one really is as bad as one might expect. [laughter] A guy is lonely so he purchases a frozen chicken from the supermarket, brings it home and has relations with it. [laughter] Then he cooks it and eats it. [laughter] Look. This is a scientific paper in the Psych Review. [laughter] Okay. Who says that's okay? [laughter] Good. And I notice there is consistency among people. The people who think it's okay have every right to say that they believe, if they really, sincerely believe it's okay, they are committed to an ethics of autonomy. Those of you who think it's not okay, none of these, should ask yourself why and should then scrutinize your reasons. People are very smart and they could present--easily present reasons why. They could say, "Oh, disease," but these reasons tend not to be sincere. If you take away the considerations that the reaction stays. And these are then interesting case studies of how our moral judgment is governed by factors that we might not be conscious of. Our moral intuitions can surprise us.

The motivation for Milgram's work, and this is the final thing we'll talk about in the context of morality--The motivation for Milgram's work was the Holocaust and he was interested in exploring why such a thing could happen. I should note by the way--you know from the movie that Milgram was a Yale professor. He left Yale when he didn't get tenure, moved to Harvard, didn't get tenure there too. He was--He had a reputation by then as a mad doctor. He ended up at City University of New York, became a full professor at age thirty three, died in his early '50s, did not lead a good life but had extraordinary discoveries. Another discovery which we'll talk about next week is--Has anybody heard the phrase "six degrees of separation?" Milgram, and we'll talk about that later. Milgram had a powerful imagination.

Okay. So we know--This is all review. There is the guy. How many of you laughed when you saw the movie [A movie on Milgram's conformity studies called "Obedience"]? Interesting question why and we'll talk about that in a little while. Shocks, "slight shock" to "XXX." There is--This is just repeating what you've seen. The learner protests as he's being shocked more and more but the experimenter continues to request obedience. For those of you who haven't seen the movie, again, the setup is someone is a subject. They don't know--They think that they're teaching somebody in a memory game but actually the person who is being shocked is a confederate who is trained to react in certain ways as he's being increasingly

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shocked. And the finding is that the majority of people will deliver fatal shocks to this person who they had never met based on the instructions of another person.

Now, there are some immediate bad explanations for this. One explanation is these are really strange people. "These are an abnormal group of psychopaths." But we know that's not true. It's been replicated with many subjects. There's no reason to believe that the subjects in Milgram's original study were in any way unusual. It's also a misreading to say that people are, in general, sadistic. You remember from the movie nobody got pleasure from giving the shocks. They felt acutely uncomfortable, embarrassed, conflicted, under a huge amount of stress. They weren't liking doing this.

There were follow-up studies. This is the original study. If you take it away from Yale, some of the authority goes away, and similarly, the extent to which there are fatal shocks goes down. As the teacher is with the learner next to him, it goes down. If you have to put the guy's hand on it, you're less likely to kill him. If the experimenter gives you instructions by phone, you're less likely to do it. If an ordinary man, not the guy in a white lab coat but an ordinary guy, says, "Hey, keep shocking him, that's okay," you're less likely to do it, and if there is a rebellion, if somebody else rebels and says, "I won't do it," you are much more likely not to do it yourself. There are some--Oh, sorry. Yeah, and if you could get to choose your own shock level, you could keep--then very, very few people go all the way. So, these are an important list of factors as to the factors that can make somebody less likely to bring it up to the killing level. And as a result we can look at those factors and think about what is the perfect situation for making somebody do something like this and the perfect situation not to.

Some more serious critiques of Milgram: Milgram's experiment is why we have human-subjects committees. This is a terribly stressful experiment to do to people and, as I say now about a lot of studies that I describe in this class, it would not today be done. People did say they were happy to have participated and only 2% said that they were sorry, but still serious damage could have been done and perhaps was done. These people left the lab having learnt about themselves that they'll kill another person if someone tells them to, and as psychologists I don't think we have any right to do that to people. I think people can learn this--these things about themselves. We have no right to put you in a circumstance where you believe you killed somebody and then tell you it was just pretend--we just made you kill somebody. And that's a serious ethical criticism.

Historians and sociologists have brought in things back to the questions that Milgram was interested in and argue--and this is controversial--the extent to which obedience really is a good model for acts of genocide. So, just to take one example among many, Goldhagen argued that the participants in Nazi Germany and in the Holocaust were actually not people who were obediently following orders but rather were enthusiastic, people who volunteered to do it. Still Milgram's work is interesting in many--for many reasons, in large part because he provides an illustration of the perfect situation for getting somebody to do a terrible thing and the perfect situation has certain ingredients. It includes authority, in this case the authority of Yale and the authority of science. "This is an experiment that must go on." The notion of a self-assured experimenter--The results would be very different if the experimenter himself seemed nervous, unwilling to proceed, confused, but he was confident and he kept saying that he will take responsibility. There was distance between the learner and the experimenter. Recall you get less of an effect if you have to touch the guy but distance makes it easier for you to kill him. And finally, there's a new situation and no model of how to behave. One of the reasons why the Milgram experiment is so nice to know is that if this ever happens to you, not as an experiment but in real life, it will no longer be new to you. You'll know what sort of thing this is and you'll be able to examine it in that light.

I want to end this lecture summing up, drawing a lot upon Milgram and some other work, and talk first about two forces for evil and then to end by talking about two forces for good. The first force for evil is deindividuation of self. And what this means is--one reason why people are so bad in groups is because you could diffuse your responsibility. If I'm running through the street alone with a baseball bat smashing through windows, it's me and I know it's me. If I'm with twenty other people, it's not me anymore. It's part of the group and I don't feel as bad. Responsibility becomes diffuse. One of the powers of a group then is it diminishes responsibility.

You could diminish responsibility in other ways. Another way of diminishing responsibility is you could accept orders. It's not me. I'm just an instrument of somebody else telling me what to do. And yet another way of diminishing responsibility is anonymity. Here's a question. In so many violent acts and so many people go to war, what they do is they paint their faces or they put on masks. Why? Well, there's anonymity from others. If I'm wearing a mask as I do my terrible stuff, nobody will know it's me, but there's also a psychologically liberating effect. If I'm anonymous, it's not me and I could do terrible things without feeling the same moral responsibility.

This analysis has explained why people don't always help others in need. If there's a group, responsibility to help decreases and this is captured in different ways but the main idea is we all think someone else will help so we don't. There's a diffusion. This [slide] just summarizes some studies--some famous studies supporting this. And the classic example, which is discussed in detail in the textbook, is the Kitty Genovese case where somebody was murdered in the common lot that apartment buildings surrounded while dozens of people watched, dozens of good, normal people watched and did nothing. If there's some advice I've heard on this, which is pretty good advice: If you're ever in a predicament on a city street, you have a heart attack, you broke your leg, you're being mugged and everything, and there's--this is based on the research, screaming "Help" is often not very successful because if I'm with ten people and there's somebody screaming "Help," I look at the other nine people. They're not doing anything. They're looking at me. I'm not doing anything. We keep walking. What is useful is point to somebody and say, "You in the green sweater, call the police," and the psychological evidence is if you--if

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somebody's--if I am wearing the green sweater and somebody asks me to call the police I will call the police. I'm a good guy. I wouldn't sit aside when somebody's being harmed. On the other hand, if somebody says, "Somebody call the police," well, I got things to do and so diffusion of responsibility explains both when we're willing to do terrible things and also when we're willing to help people who are in trouble.

Denigration of others. There's a lot of ways to make other people matter less. So, this is the flip side. The way to do terrible things--One way to do terrible things is to lose yourself so you're not an individual anymore but another way to do terrible things is so that the person you're doing it to isn't an individual. How do you do that? Well, you have psychological distance or physical distance. I'm more likely to kill you if you're very far away than if you're close. I don't--I could describe you and start to think about you not as a person and language can be used for this. Instead of people you could use terms like "cargo," instead of murder, extermination. Humor is very powerful in denigrating and demoting people. When you start laughing at somebody you think of them as less of a person and we'll get to that a little bit more when we talk about laughter.

You could take away their names. One of the more interesting things in the United Nations Declaration of Human Rights is a very interesting right. It says, "Every person has a right to a name." And you might think what a strange right but there's a cleverness to it. When you take away somebody's name they matter less. People have names. People have distinct, individual names that mark them as people and once you know somebody's name you are less likely to do bad things to them. And another option which I'm interested in from the standpoint of my own research is you could see them as disgusting.

Disgust is what Paul Rozin has called "the body and soul emotion." And we know certain things about disgust. It is a human universal. It is a basic emotion with a characteristic facial expression. Remember Paul Ekman's work on the basic emotions, the universals of emotional expression? Disgust is one of them and it is universally elicited by certain things like this list. Wherever you go, feces, urine, blood, vomit, rotten flesh and most meat will be disgusting. Now, if that was all we had to say about disgust, it wouldn't affect morality very much but we know that people can be seen as disgusting. And Charles Darwin actually, who was an astute observer of human behavior, tells a nice story to illustrate this: how "a native touched with his finger some cold preserved meat and plainly showed disgust at its softness whilst I felt utter disgust at my food being touched by a naked savage though his hands did not appear dirty."

People can be disgusting and if people are seen as disgusting they matter less. The philosopher and legal scholar Martha Nussbaum nicely summarizes this: "Thus, throughout history certain disgust properties have repeatedly and monotonously been associated with Jews, women, homosexuals, untouchables, lower class people. All of those are imagined as tainted by the dirt of the body." Any--I won't read this but this is a typical bit of Nazi propaganda. Any genocidal movement that has left behind a written record has been shown to use the mechanism of disgust to dehumanize people and make them easier to kill. I'll skip that.

I want to end though on a positive note. And the positive note are forces for good. So, forces for bad are to lose yourself as an individual, lose yourself in a crowd, lose yourself because there is some authority using you as an instrument, lose yourself because you're anonymous, plus treat others not as people, as numbers, as objects, as disgusting things, but there are some forces for good. These include "contact" and "interdependence." What this often--What this can be viewed as, as an extended version of selfish gene theory, which is that to the extent you're interconnected with other people you care about them more for purely selfish reasons. Robert Wright presented this in a very blunt way, but I think his quote is quite moving: "One of the many reasons I don't want to bomb the Japanese is that they built my minivan." And the idea is he has economic codependence with these people. They're a different group. He might want to kill them under normal circumstances but the interdependence gives rise to a moral connection.

Thomas Friedman proposed the "Golden Arches Theory of Human Conflict," which said that no two countries which each have a McDonald's will ever go to war because McDonald's forces global interdependence. This was falsified in the NATO bombing of, I think, Sarajevo but still his heart's in the right place, the idea that interconnection makes you more likely to get along with other people.

More generally, there's what's been called "The Contact Hypothesis." So, interdependence is one thing but what's maybe more interesting is that simple contact with other people. Particularly if you're of equal status, you have a common goal, and you have social support makes you like people more. There are now dozens, probably hundreds, of studies that show that people who would otherwise show animosity towards one another, like blacks and whites in the United States, like each other more if they're brought together. And there's a lot of social psychology research as to the conditions in which you have to bring them together. The Robber's Cave study talked about before is a nice example. It was not easy to bring them together but when they had a common goal that brought them--that caused the interconnection and then the contact led to moral feeling.

The military is a superb example. The military in the United States was a situation which brought together people who wouldn't otherwise have any contact and they liked each other. There has been study after study showing that people in the military who were otherwise, for instance, racists after working with people of different races liked them more because you had all of the right ingredients. You had--They had--They worked together for a common goal, the military supported bringing these people together, and they were brought together on an equal and fair footing.

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There is, of course, a lot of debate about universities like Yale to the extent in which they promote interdependence--sorry, they promote positive contact between groups. And you could think of yourself as an exercise. If these are the conditions for contact, to what extent are they met in the university setting between, say blacks and whites, people from the American South versus people from the American North, people from other countries versus people from the United States? And I know there's debate on campus about the extent to which there is segregation within the Yale community. And you could ask yourself the--about the extent of that segregation and how that reflects--what role that should play with regard to the Contact Hypothesis.

Finally, and this is the last thing I'll say: If you take another person's perspective, you'll care more about them. This is the final force for good from a moral perspective. JFK, when making the plea for equal rights, didn't produce an abstract philosophical argument but rather tried to invite his listeners who were white to engage in perspective taking. If an American, because his skin is dark, cannot eat lunch in a restaurant open to the public--[and so on and so on and so on], then who among us would be content to have the color of his skin changed and stand in his place? Who among us would be content with the counsels of patience and delay?

Again, Nussbaum goes on and talks about how in Greek dramas--Greek dramas invited people to take the perspectives of those who they would never imaginably be or even be in contact with and argue that this gave--led to an empathetic expansion. I think one of the greatest circles for moral good is storytelling where you're invited to take the perspective of another and see the world as they do.

Finally, there are direct ways. You can ask people--and this is a way which we talk to our children when we try to get our children to expand their moral concern of compassion. We say, "Try to see it from their point of view. How would you feel if--"Then there's indirect ways. You can, for instance, use the power of metaphor. There could be familiar things that you are close to and you could bring in together new things as falling under the rubric of these familiar things. So, if I wanted to cause you to feel moral concern for a fetus, I would do well to describe it as a pre-born child. If I wanted you to care about an animal, I would do well to describe it as if it were human. If I wanted to think about all of you and get--and establish more of a connection with you, I would not describe you as unrelated strangers. Rather, you are my brothers and my sisters. And of course, any political movement that tries to bring us together--people together says--uses a family metaphor.

Finally, when Steven Spielberg tried to get us to entertain the notion that computers and robots are sentient moral beings he did not show us one that looked like this [a faceless mechanical-looking robot]. He showed us one that looked like that [a cute child actor].

Okay. The reading response for next week is a simple one. I know I've been giving difficult reading responses. This is simple. You could write it up very short and that will be a passing grade if you just write it up very short. You could also write it up a bit longer. Suppose the Milgram experiment had never been done and it was being done for the first time here. What would you do? What do you think everyone else would do? Okay. I'll see you next week.

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Lecture 16 Professor Paul Bloom: This is going to begin a two-lecture sequence on social psychology on how we think about ourselves, how we think about other people, how we think about other groups of people. We've talked a lot about the capacities of the human mind and some of these capacities involve adapting and dealing with the material world. So, we have to choose foods, we have to navigate around the world, we have to recognize objects, we have to be able to understand physical interactions. But probably the most interesting aspect of our evolved minds is our capacity to understand and deal with other people.

We are intensely interested in how other people work. The story that was a dominant news story in 2005 was this. And some of you--this--for those of you who aren't seeing the screen, is the separation of Jennifer Aniston and Brad Pitt. I remember where I was when I first heard about this. [laughter] And it's an interesting sight. Just remember--stepping back. As psychologists we have to question the natural. We have to take things that are commonsense and explore them. And one thing which just happens is, we're fascinated by this stuff. We're fascinated by the lives of celebrities. We're fascinated by the social lives of other people. And it's an interesting question to ask why. And this is one of the questions which I'm going to deal with in the next couple of lectures but before I get to the theory of social psychology I want to talk about an individual difference.

So, we devoted a lecture early on--of a couple of weeks ago, to individual differences across people in intelligence and personality. I want to talk a little bit about an individual difference in our social natures and then I want people to do a test that will explore where you stand on a continuum. That test is the piece of paper you have in front of you. Anybody who doesn't have it please raise your hand and one of the teaching fellows will bring it to you. You don't know what to do yet with it so don't worry. The test was developed actually by Malcolm Gladwell who is a science writer--in his wonderful book The Tipping Point. And as he introduces the test, Gladwell recounts another experiment done by Stanley Milgram, of course famous for his obedience work but he did a lot of interesting things.

And one classic study he did was he gave a package to 160 people randomly chosen in Omaha, Nebraska and he asked these people to get the package somehow – and this was many years ago before the internet, before e-mail – to get the package to a stockbroker who worked in Boston but lived in Sharon, Massachusetts. What he found was that most people were able to do it. Nobody, of course, knew this man but they knew people who might know people who would know this man. So, most people succeeded. Most people were able to get the packages to this man and it took at maximum six degrees of separation, which is where the famous phrase comes about that we're all separated from another person by six degrees of separation. This is not true in general. This was a very--a single experiment done within the United States, but the idea is appealing, that people are connected to one another via chains of people.

But what Milgram found that was particularly interesting was that in about half of the cases these packages went through two people. That is, if you plot the relationships between people--We can take each person in this room, find everybody you know and who knows you and draw a line, but if we were to do this you wouldn't find an even mesh of wires. Rather, you'd find that some people are clusters. Some people are what Gladwell calls "connectors." It's like air traffic. Air traffic used to be everything flew to places local to it but now there's a system of hubs, Chicago O'Hare for instance or Newark where planes fly through. Some people are hubs. Some people are the sort of people who know a lot of people. Some people in this room might be hubs, and it is not impossible to find out.

The piece of paper you have here is 250 names chosen randomly from a Manhattan phone book. They capture a range of ethnicities, different parts of the world, different national origins. Here's what I'd like you to do. And I'll give about five minutes for this. Go through these names and circle how many people you know. Now, the rules of this are, to know somebody you have to--they have to know you back. So, if it's a celebrity--Well, here--one of the names here is Johnson. Now, I've heard of Magic Johnson but Magic Johnson has never heard of me, so I cannot circle it. On the other hand, our department chair is Marcia Johnson. She has heard of me, so I could circle it. Go through and circle it. Circle all the people you know who know you. Those are the people you're connected to. If you know more than one person with the same last name, circle it twice. If you don't have this piece of paper and you want to participate, please raise your hand and one of the teaching fellows will bring it to you. I'm going to talk a little bit more about this while people go through this.

The issue of connections between people is intellectually interesting for many reasons and might allow us to develop some generalizations about how people interact. The game of Six Degrees of Separation has, of course, turned into a famous movie trivia thing revolving around the actor Kevin Bacon, I think chosen just because it rhymes with "separation." And the game of "Six Degrees of Kevin Bacon" is played by taking any actor and computing how many steps it would take to get to Kevin Bacon. And some computer scientists have developed this. They've gone through each of the quarter million actors and actresses on the international movie database and computed their "Bacon number." And the Bacon number is the number of steps it takes for them to get to Kevin Bacon. So for instance, Ed Asner was in the movie Change of--;"JFK" with Kevin Bacon. So, Ed Asner has a Bacon number of one. Elvis Presley was in the movie "Change of Habit" with Ed Asner and that's his closest connection to Kevin Bacon. So, Elvis Presley has a Bacon number of two.

It turns out that if you look at the 2.5--sorry, the quarter million people on the movie database and compute their Bacon number, the average Bacon number is 2.8. That's how many steps your average person is away from Kevin Bacon. You could then, for any actor or actress, compute the most connected one. So, the most connected one would be the one for

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whom the quarter million are, on average, the most connected to. And the answer of the most connected actor or actress is reasonably surprising. Does anybody want to guess? I'll start you off with the wrong answer and this, by the way, can be found on this web site. It's not John Wayne. John Wayne has been in many movies, 180 movies, in fact, over sixty years, but he isn't well connected at all because mostly he was in westerns so we saw the same people over and over again. Meryl Streep also isn't it because Meryl Streep has the misfortune of playing only in good movies. [laughter] So, she has no connection with people like Adam Sandler and John-Claude Van Damme. [laughter] Guess. Any guesses? Student: Christopher Walken Student: Nicholas Cage Professor Paul Bloom: Christopher Walken is a good one. We could look it up. I only know a few names here. Christopher Walken is not a finalist. Nicolas Cage is an interesting case. Has Nicolas Cage been in good movies? I don't want to get--I'm going to get more controversial than I want to. Student: A guy who is one step above an extra. He's like a B-list actor at best. Professor Paul Bloom: Pardon me? The most connected guy? The most connected guy, and I think this shows that you're right, is Rod Steiger. He's the most connected actor in the history of acting because it isn't that he's been in more movies than everybody else. Michael Caine has probably been in the most movies of any person on earth, but he's [Rod Steiger] been in all sorts of movies. He was in "On the Waterfront," "In the Heat of the Night," and really bad movies like "Carpool." He's been in dramas and crime serials, thrillers, westerns, horror movies, science fiction, musicals. Now, some people are like Rod Steiger. So, some people in their day-to-day lives have many interactions and I think one of the things we know from interacting with people is we can distinguish them from other people.

How many people have finished their things right now? Okay. I know one person in the department who is one of the most connected people I know on earth. If I wanted--If I really had to talk to Rumsfeld, I'd go to this person and say, "Can you get me in touch with Rumsfeld?" If I wanted to get somebody whacked, I'd ask this guy. [laughter] Then I know someone else in the department and, as best I know, I'm the only person she knows. [laughter]

So, how many people scores below ten on this? How many between ten and twenty? Between twenty and thirty? Thirty and forty? Between forty and fifty? Fifty and sixty? How many people scored above sixty? Anybody above sixty? Gladwell has done this in a lot of places. The average is twenty-one among a college crowd. Some people score as high as over 100. The older you are, the more--the higher you tend to score, maybe obviously, not--the longer you've been in the country the higher you tend to score. Journalists tend to score reasonably high, academics not so high, and--but what Gladwell points out is some people have the gift. Some people are more social than others and this connects in all sorts of interesting ways.

The issue of connection has social factors and it's one answer that sociologists give for why it's good to go to Yale. So, one answer is, well, because of the great intellectual benefits. Put that aside. Let's be more cynical here. Another answer is that you develop powerful friends. And that's closer, but the interesting answer sociologists come to is it's not so much you develop powerful friends; rather, you develop powerful acquaintances. Through Yale you know a lot of people and they don't have to be close friends but they are acquaintances. And sociologists point out that for a lot of aspects of your life, like getting a job, acquaintances matter, connections matter, and the connections you establish by going to a place like Yale hold you in good stead for the rest of your life, above and beyond any intellectual qualities that this place may offer.

Here's what we're going to do for the next lecture and a half, two lectures. We're first going to talk about the self. Then we're going to talk about the self and other; basically, differences between how we think of ourselves and how we think about other people. Then we're going to talk exclusively about how we think about other people and then we'll talk about how we think about groups like Harvard students or gay people or black people. I'll start with my favorite finding of all time and this is about the self. And this is about the spotlight effect.

So, my mornings are often rushed because I have two kids. So, I get up and sometimes I don't set the alarm and I get up late; I stagger out of bed; I wake the kids; I greet the servants; I get ready; [laughter] I make breakfast. I run out of the house and then usually around 3 o'clock somebody points out, in one case a homeless man, that I have a big glob of shaving cream in my ear or--because I neglected to actually look in the mirror while I shaved. Or I have once been to a party and I found my shirt was misaligned, seriously misaligned, not one button but--Anyway, [laughter] so--and so I feel when this happens I'm very immature. And I basically feel this is the end of the world, this is humiliating and everybody notices. And so the question is, how many people notice when something happens? And the spotlight effect--Well, before talking about my favorite experiment ever, there is an episode of "The Simpsons" that provides a beautiful illustration of the spotlight effect. And then it has a beautiful illustration of psychological testing, so I'll give you them quickly one after the other. [clip playing]

So, Tom Gilovich, a social psychologist, was interested in the question of the spotlight effect, which is when we wear a pink shirt to work, shaving cream in our ear or whatever, do we systematically overestimate how much other people notice? He did a series of experiments. And in one experiment what he did was he got in the subjects – standard Intro Psych drill – and said, "I want you to wear a T-shirt for the next day and I want it to have a picture on it," and he got them to wear T-shirts that had pictures on it that were the most embarrassing pictures that they could have on it. It turns out that if you ask people what's the worst picture to have on the T-shirt that you are wearing, the number one answer is Hitler tied with Barry Manilow. [laughter] The best pictures to have on your T-shirt are Martin Luther King Jr. and Jerry Seinfeld.

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It turns out that people--And then he had them go about their day and asked them, "How many people noticed your T-shirt?" And then the psychologists went around and they asked the people, "How many of you noticed this person's T-shirt?" And it turned out they got it wrong by a factor of about two. They thought, say, 100 noticed, but fifty people noticed. And across study after study after study Gilovich and his colleagues have found support for the spotlight effect, which is that you believe that people are noticing you all the time but they aren't. They're busy noticing themselves. And this is actually a useful thing to know.

Gilovich got interested in this because he's interested in the psychology of regret. And it turns out that if you actually ask dying people, or really old people basically, "What do you regret from your life?" they regret the things as a rule that they didn't try. But when you asked them why they didn't try it the answers tended to be "I would look silly." And it turns out, interesting to know, that people just don't care as much as other people think you are. You could take that as good news or bad news but the spotlight is not on us as much as we think it is.

There's a second effect Gilovich discovers called "the transparency effect." And the transparency effect is quite interesting. The transparency effect is that we believe that we're more transparent than we are. I need somebody up here who thinks that he or she is a bad liar. Just--I just need you to say three sentences. I'll even tell you what it is ahead of time. I'm going to ask you three questions: "Have you been in London? Do you have a younger sibling?" and "Do you like sushi?" I want you to answer with one of those answers there. I want you to lie about one of them. The task will be for everybody else to recognize and guess which one you're lying about. Do you want to go up? Yeah. And I will even write down which one you should lie on. So, I want you to lie as to that number. Okay? Have you ever been in London? Student: No, I have not been in London. Professor Paul Bloom: Do you have a younger sibling? Student: Yes, I have a younger sibling. Professor Paul Bloom: Do you like sushi? Student: No, I do not like sushi. Professor Paul Bloom: Okay. Let's have a vote. She was lying about one of them. Who votes for one? Who votes for two? Who votes for three? Pretty much of a tie between two and three. You could say which one you were lying. Student: Three. Professor Paul Bloom: The effect--there are two aspects of the effect. One aspect is people are actually quite good at lying. It is a rare person who couldn't stand up there and everybody would figure out what they're lying about, but the transparency effect is we don't feel that way. We often feel like things bleed out of us and so people will systematically overestimate the extent to which other people notice their secrets. And this is actually, in general, why it's sometimes difficult to teach or to tell stories because we constantly overestimate how much other people know. We think of ourselves as more transparent than we are.

A second social psychological phenomena is you think you're terrific. If I asked people, "How well are you doing in Intro Psych this semester?" and I asked you to give yourself a percentage rating relative to the rest of the class, then if everybody was accurate, or at least not systematically biased, the number should add up to 50%. Roughly half of you are doing better than average and roughly half of you are doing worse than average. It turns out though that people will systematically and dramatically view themselves as better than average. They will view themselves as better than average when asked how good they are as a student, as a teacher, as a lover, and particularly, as a driver. [laughter] Everybody who drives thinks that he or she is a wonderful driver.

This has been called the "Lake Wobegon effect" based on Garrison Keillor's story about a place where all the children are above average. And the Lake Wobegon effect in psychology involves a systematic bias to see ourselves as better than average. What psychologists don't really know is why the Lake Wobegon effect exists, and there are a couple of proposals. One is the nature of the feedback we get. So, for a lot of aspects of your life you only get feedback when you're good, when you do something good. In a normal, productive, healthy, happy environment, people don't scream at you about how bad you're doing but they compliment how good you are and that could lead to an inflated self-esteem on the part of people in certain domains.

Another possibility is there's different criteria for goodness. For a driver, for instance, when I ask you to rank how good you are as a driver, what people often do is they think--they say, "I'm better than average," but what they do is they focus on one aspect of their driving. So, some of you might say, "Hey, I'm just a great parallel parker so I'm a great driver." Others might say, "I'm very careful, great driver." Others might say, "I take chances no one else will--great driver," [laughter] but above and beyond that there does seem to be a psychological effect manifested here and manifested elsewhere, which is a motivation to feel good about yourself. You think you're important, which is why the spotlight effect exists. You think your thoughts bleed out, which is why the transparency effect exists. But above and beyond that, in a normal, healthy mind you think you're terrific.

And so, this shows up in all sorts of ways. It shows up as well in what's been called "the self-serving bias." Half of you did above average on the Midterm; half of you did below average on the Midterm, but if I went up and asked each of you why the answers would not be symmetrical. People who did well in the Midterm would describe it in terms of their capacities or abilities. They'd say, "It's because I'm smart, hardworking, brilliant." People who did poorly would say, "The Midterm was

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unfair. I was busy. I have better things to do with my time." Professors as well--When people get papers accepted it is because the papers are brilliant. When they got them rejected it's because there's a conspiracy against them by jealous editors and reviewers. There is this asymmetry all the time. The asymmetry has been found in athletes, in CEOs and in accident reports. And again, this is sort of a positive enhancement technique. You think that you're terrific and because you're terrific the good things that happen to you are due to your terrific-ness; the bad things are due to accident and misfortune.

The final aspect of self that I want to talk about is the idea that what you do makes sense. And this is one of the more interesting sub domains of social psychology. The idea was developed by the social psychologist Leon Festinger and it's called "Cognitive Dissonance Theory." And what Festinger was interested in was the idea that what happens when people experience an inconsistency in their heads. And he claimed it causes an unpleasant emotional state, what he described as "dissonance." And he argued that we act so as to reduce dissonance. When there's a contradiction in our heads we're not happy and will take steps to make the contradiction go away.

This all sounds very general but there are some striking demonstrations of this and how it could work in everyday life. So, this very simple example is that--is the confirmation bias. Some of you are politically right wing. Some of you are politically left wing. If I asked you what magazines you read, it turns out people who are right wing read right wing magazines, people who are left wing read left wing magazines, because people don't as a rule enjoy getting information that disconfirms what they believe in. They want to have information that confirms what they believe in and that supports it. If you support Bush you're going to be looking for good news about Bush, if you don't support him you'll be looking for bad news.

And this manifests itself in all sorts of interesting ways. I'll tell you about a very simple experiment. I'll--It was done by Louisa Egan here at Yale and it illustrates a point which is going to--which--and then I'll talk about real world implications of this. Very simple. You have three M&Ms. You pretest to make sure that the person doesn't like any M&M more than the other. And there are three M&Ms. Who cares? But then you ask them to choose between two of them. So, suppose they choose the red one. You've got to choose one. So, they get to eat the red one. Now, they're offered--You take the red one away and now they're offered a choice between the two remaining ones. It turns out, to a tremendous degree, and you could imagine yourself in that situation, they choose this one, the one that wasn't the one they turned down. And the claim is that when you choose this, in order to justify your decision, you denigrate the one you didn't choose. And so this one you didn't choose is then tainted and you turn and then when compared to a third one you favor that third one. What's particularly interesting is you get this effect easily with undergraduates but you also get it with four-year-olds and with monkeys. So, the same denigration tends to be more general.

Well, that's a laboratory effect but there are some more interesting manifestations of cognitive dissonance. One is the insufficient justification effect, which is so famous it had a cartoon based on it. The guys says, "Why should I hire you as my consultant?" The dog--Some dog says, "I use my special--the special process of cognitive dissonance to improve employee morale." "How does it work?" "Well, when people are in an absurd situation their minds rationalize it by inventing a comfortable illusion." Not quite right. When people are--have an internal conflict, when there's something uncomfortable--Well, that's right. So says to this person, "Isn't it strange you have this dead-end job when you're twice as smart as your boss? The hours are long, the pay is mediocre, nobody respects your contribution, yet you freely choose to work here. It's absurd. No. Wait. There must be a reason. I must work here because I love this work, I love this job." [laughter]

This actually works. Here is the classic experiment by Festinger. Gave two groups of people a really boring task, paid one of them twenty dollars, which back when this study was done was real money, gave another group of subjects one dollar, which was insultingly small, then asked them later, "What do you think of the task?" It turns out that the group that had--were paid a dollar rated the task as much more fun than the group given twenty dollars. So, think about that for a moment. You might have predicted it the other way around, the twenty dollars, "wow, well, twenty dollars, I must have enjoyed it because I got twenty dollars," but in fact, the logic here is the people with twenty dollars when asked, "What do you think of the task?" could say, "It was boring. I did it for twenty dollars." The people paid one dollar were like the character in the Dilbert cartoon. When paid a dollar they said, "Well, I don't want to be a donkey. I don't want to be some guy who does this boring thing for a dollar. It wasn't that bad really, it was kind of interesting, I learnt a lot," to justify what they did.

This has a lot of real world implications. Festinger did a wonderful study with people--a group of people, and he wrote this up in a book called When Prophesy Fails, who were convinced that the world was going to end so they went on a mountain and they waited for the world to end. They had a certain time and date when the world was going to end. He hung out with them and then the time passed and the world didn't end. What people then said, and this is what he was interested in--;So, people's predictions were totally proven wrong and they left their families, they gave away their houses, they gave away all their possessions, they lost all their money, but what Festinger found was they didn't say, "God, I'm such a moron." Rather, they said, "This is fantastic. This is exactly--This shows that us going to the mountain has delayed the ending of the world and this shows that we're doing exactly the right things. I couldn't have been smarter." And in general, when people devote a lot of energy or money or expense to something, they are extraordinarily resistant to having it proven wrong.

Now, people have manipulated cognitive dissonance in all sorts of ways and, for instance, hazing. Hazing is cognitive dissonance at work. Fraternities and med schools and other organizations haze people. What they do is when people enter the group they humiliate them, they cause them pain, they cause them various forms of torture and

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unpleasantness. Why? Well, because it's very successful at getting somebody to like the group. If I join a fraternity--it is also by the way illegal so – but if I were to join a fraternity and they say, "Welcome to the fraternity, Dr. Bloom. Here. Have a mint," and then we have a good time and everything. I'm thinking "okay, sounds like a fun idea." But if I join a fraternity and they pour cow poop on my head and make me stand in the rain for a month wearing pantyhose while they throw rocks at me [laughter] I then think--after it I think "God, I went through a lot of stuff to get into this fraternity. It must be really good." And in fact, hazing through cognitive dissonance draws the inference that this is really, really valuable and this is why it exists.

If you are a political--If you are running for office, you will tend to have volunteers and not necessarily pay people. One reason for this is obvious; it's cheaper not to pay people, but the other reason is more interesting. If you don't pay people, they are more committed to the cause. Again, it's cognitive dissonance. If you pay me ten thousand dollars a month to work for you, I'll work for you and I'll think "I'm doing it for ten thousand dollars a month, that makes a lot of sense," but if I do it for nothing then I have to ask myself, "Why am I doing it?" And I will conclude I must think very highly of you.

Therapy for free tends to be useless therapy. This is one-- [laughs] Therapists ask for money for all sorts of reasons, including they like money. But one reason why they ask for money is if you don't pay for therapy you don't think it has any value. You have to give up something. So, cognitive dissonance will lead you then to think that what you are giving it up for has some value and then you establish a liking for it.

Finally, cognitive dissonance shows up with children. One of the most robust and replicated findings in education or developmental psychology is very simple. You take two groups of kids and you ask them to do something like draw pictures. Half of the kids you reward. Maybe you give them a sticker or a toy. The other half you don't reward. Now, according to sort of a simple-minded view of operant conditioning in behaviorist psychology, the children you reward should do it more. That's how operative conditioning works. In fact though, the children who you reward later on think that this activity has less value and they are less likely to do it when there's no reward present. And the idea, again, is the kids who don't get rewarded say to themselves, "Well, I just spent time doing it, it must have an intrinsic value," while the children who get rewarded say, "I did it for the sticker. I did it for the toy. I don't care much for this." And so, rewarding children has a danger, which is if you give them too much reward and too much a value for what they're doing they will denigrate the activity.

Now, we need to be careful here about what's going on. It's not simple inconsistency. So, go back to this insufficient justification effect. So, the dollar group rated a task as more fun than the twenty dollar group. And it's true; each group needed a justification for lying about the task. Each group needed a justification for saying how interesting the task was, but they each had a justification. They were each doing it for money after all. So, cognitive dissonance is a little bit more subtle. It's not just that there's a clash. Rather, we adjust our beliefs to make ourselves look more moral and rational than we are. Go back to hazing. There's a perfectly good reason why I let them do all those things to me. I'm the sort of person who will let people do those things to me. The problem is that's not an answer I could live with. So, cognitive dissonance motivates me to create an answer that's more comfortable for me, an answer such as "This must be a really wonderful group with a wonderful bunch of people." And in other words, we are biased to believe that we are terrific.

So, to sum up, there are three main findings about you that come out in social psychology. One is you believe everybody notices you even when they don't. You're the hero of your story. The second one is, you're terrific, you are better than average in every possible way, each one of you. And finally, what you do makes sense. If it doesn't make sense, you'll--If it doesn't make sense or, more to the point, if it's something that you do that's foolish or makes you look manipulative or cheap, you'll distort it in your head so that it does make sense.

I want to move now to how we think about self and other, how we think about ourselves relative to how we think about other people. And this brings us to the notion of attribution. So, an attribution is a claim about the cause of somebody's behavior and Heider--;Now, there's all sorts of reasons for somebody's behavior. Suppose you insult me or suppose you're very kind to me. I could say you're a kind person or you're a rude person. I could say "this must be a great day for you" or "you must be a lot of--under a lot of stress or you must want something." There's different sorts of attributions we could make to people but Heider's insight is we tend to attribute other people's actions to their personality characteristics, to long-standing aspects of what they are. And this is known as a person bias. And more generally, people tend to give too much weight to the person and not enough weight to the situation. This is also sometimes known as the fundamental attribution error. The fundamental attribution error, which is one of the core ideas in psychology, is that we tend to over-attribute things to a person's personality or desires or nature and not enough to the situation or the context.

There's a lot of demonstrations of this. A lot of the demonstrations have to do with intelligence so, for example, there's actually been studies showing that people tend to overestimate the intelligence of professors. Why? Because I stand up here and I talk about the one or more than one thing I know about and so it's easy to infer that I must know a lot but in fact by the time this semester ends I will have tell you--told you everything I know. [laughter] And if you stood up and started talking about everything you knew you'd look really smart too.

The best study to show this is a quiz show study, which is you take two people and you flip a coin. And one of them is the quiz master and the quiz master gets to ask questions, any question he or she wants. And the other person has to answer the questions. And if they play seriously, the quiz master's going to destroy the other person. "What was my dog's name?" [laughter] "Well, I don't know." "What's the capital of the city in which I was born?" "Well, I don't know." And then you'd expect a third person watching this to say, "Who cares? It's just--They're just doing this because of the coin they

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flipped." But in fact, when the person watching this has to assess their intelligence they give the quiz asker a higher intelligence rating than the other person. After all, "He seemed to know a lot of answers. The other person didn't get much right."

We tend to fail to discount the situation. If you were giving a job talk--and this is for people in graduate school particularly--If you were giving a job talk and the slide projector breaks, you're screwed. Nobody is going to say to themselves, "Oh, well, it's not such a good talk because the slide projector broke." They'll say, "It's not such a good talk because of the person." Somebody could give a talk and we could throw smarties at them the whole time and then you could--then the other people would say, "The person looked kind of upset during the whole talk. [laughter] I wonder--They seemed like a nervous type." [laughter]

This can be taken to extremes and the biggest extreme is the case of actors, which is if there's ever a case--Anybody know who this is, the actor? [laughter] Have none of you been alive in 1950? [laughter] This is Robert Young. Does anybody know the part he plays? He played an--He played a doctor called Marcus Welby in this famous show "Marcus Welby, M.D.," and Marcus Welby was a wonderful doctor. He was compassionate and kind, he made house calls, he saved lives, he counseled people, and it turned out that Robert Young was then deluged with mail, thousands of pieces of mail, by people asking for his advice on health matters. [laughter] And he then, in a twist, exploited the fundamental attribution error--people confusing the actor for the role--exploited this by going on TV and espousing the benefits of Sanka decaffeinated coffee where he produced the famous line "I am not a doctor but I play one on TV," [laughter] whereupon people heard this and said, "Well, he must have some authority then about medical matters." [laughter]

It turns out that the confusion between actors and their roles is extremely common. Many people, for instance, view Sylvester Stallone as either an actual hero during the Vietnam War or sort of a hero during the Vietnam War given all his Rambo stuff but in fact, of course, he played--he was in a Swiss boarding school teaching girls age twelve through fifteen during the Vietnam War. But it doesn't seem that way because the role infects how we think about the person. When this movie came out twenty years ago they needed a character to play a gay man. According to IMDb, [The International Movie Database] where I get all my information, they hit up all the big stars, Harrison Ford, Michael Douglas, and Richard Gere, and they all turned it down because they didn't want to play a gay man because people would think that they were gay. Finally, they got Harry Hamlin to do it, who was kind of a B-list sort of guy.

The biggest extreme of the fundamental attribution error, confusing the actor for his role, is Leonard Nimoy who, because he played the emotionless Vulcan, Spock, on Star Trek, was then repeatedly viewed by people who saw him on the street as if he was an actual Vulcan. [laughter] He got sufficiently upset about this to write a book called I Am Not Spock where he described all the ways in which he was not a Vulcan. [laughter] His career, where he attempted many times to play roles that were different from his Vulcan nature, stalled until finally many years later he gave up and wrote another book called I Am Spock [laughter] where he finally conceded to the fundamental attribution error. [laughter]

If I gave this lecture ten years ago, I would say that the fundamental attribution error is a human universal, something that we're born with, a fundamental aspect of human nature. This is not entirely true though and we know that through some very interesting cross-cultural research that compares these biases across different countries, in this study between the United States and India. And it turns out that for whatever reason, and it would take another course to talk about the different explanations, but people start off at, say, age eight not committing the fundamental attribution error but in Western cultures, where there's an ideology perhaps that people are in charge of their own destiny, the error occurs and people over-attribute the role to the person.

In some Eastern cultures there's more of a view about faith and more attributions to situation. And this has been shown in many ways. For instance, if you look at newspaper reports about murders, in cultures like the United States the report tends to emphasize the personal characteristics of the person accused of the murder. In countries like India, the reports tend to emphasize, to a greater degree, the situation that the person found himself in that might have driven him to commit a murder. So, this is an important reminder that just because we find something in our culture and just because it might well be pervasive doesn't mean necessarily that it's universal.

So, to summarize so far, and we're going to look at this a little bit more for the rest of this lecture, we've talked about two morals in social psychology. One is enhancement of the self but the other is what you can call "oversimplification of the other." So, we know ourselves that our behavior is due to a complicated cluster of the situation and our personal natures. When things go badly, in fact, we'll blame the situation. When things go well, the self-serving attribution bias, we'll credit ourselves. We don't do this for other people. For other people we're a lot less forgiving. You do something stupid, that's--you're a stupid person. I do something stupid, it's an off day. And so, you have this difference between how we think about ourselves and how we think about other people.

Let's talk a little bit about what we think about other people and start by talking about why we like other people. And here I'm going to some extent to go over material that was raised earlier in the course in Peter Salovey's wonderful lecture. So, some of this, our liking of other people, is obvious and we talked about it in Dean Salovey's lecture, we talked about it when we talked about sexual attractiveness. We like people who are honest, who are kind, who are smart, who are funny, but study after study finds more fundamental processes are also at work and here is a list of three of them.

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One is proximity. We tend to like people who we're close to physically, who we are physically and spatially close to, who we spend a lot of time with. In one study they looked at a housing project in Manhattan and they asked people where their best friend was and 90% of them said, "My best friend is in the same building as me," and 50% of them says the same floor. Ask yourself who is your best friend at Yale. For how many of you is it somebody in your same college? Okay. How many in a different college? So, call it a tie but then there's a lot more colleges that aren't yours than the one--How many of you would you--say your best friend is somebody your--currently on your same floor? Yeah. If you were going to marry somebody from this class, it is the person you are sitting next to? [laughter]

Now, in some sense this is an--a rather trivial finding. Of course you're going to get more involved in people you encounter frequently. How else is it going to work? But it's actually more than that. The more you see something the more you like it and this is sometimes known as "the mere exposure effect." The mere exposure effect is simply seeing something makes it likable perhaps because it becomes comfortable and safe. In one study by James Cutting, Cutting taught an Introduction to Psychology course and before each lecture he'd flash pictures on the screen. He'd have a screen saver showing pictures on the screen, paintings, and didn't say anything about them. People would sit down, look at them while they prepared their notes. At the end of the semester he then asked people to rate different pictures as to how much they liked them, and even though people had no memory of seeing one or--versus the other they tend to like the pictures more that they had seen before. They were somehow familiar and somehow more likable.

If I showed you a picture of yourself versus a mirror image of yourself and asked which one you'd like more, the answer is very strong. You'd like your mirror image more because the mirror image is what you tend to see from day to day. If I showed your best friend a picture of you versus a mirror image picture of you, your best friend would say he or she likes the picture more because that corresponds to what he or she sees each day. Familiarity is itself a desire for liking, a force for liking.

Similarity--we like people who are similar to us. Friends tend to be highly similar to one another. So do husbands and wives. Now, to some extent, similarity is hard to pull apart from proximity. So, the fact that you are similar to your friends at Yale might just be because you are close to your friends at Yale and people who are at Yale tend to be fairly similar to one another. But there's a lot of evidence that similarity, above and beyond proximity, has an effect on attractiveness and on liking. Similarity predicts the success of a marriage and through a phenomena people aren't exactly sure about, couples become more and more similar over the course of a relationship.

Finally, people like good-looking people. People like attractive people. Physically attractive people are thought to be smarter, more competent, more social and nicer. Now, some of you who are very cynical and/or very good looking might wonder "yes, but good-looking people like me actually are smarter, more competent, more social and morally better." This is not a crazy response. It is--it could be, for instance, that the advantages of being good looking make your life run a lot easier. Teachers are more responsive to you, people treat you better, you have more opportunities to make your way through the world, you make more money, you have more access to things, and that could, in turn, cause you to improve your life. This would be what's known in the Bible as a "Matthew effect." A Matthew effect is a developmental psychology phrase for the sort of thing where, well, as Jesus said, "For unto everyone that hath shall be given and he shall have abundance." That means if you're good looking you'll also be smart but from him that hath not shall be taken away even that which he hath. It's a long version of the rich get richer and the poor even lose what they hath. So, there's a variety of studies suggesting that teachers rate attractive children as smarter and higher achieving. Adults think that when an ugly kid misbehaves it's because they have an ugly soul [laughter] while the attractive kid, "oh, that little scamp, somebody must have been bothering him."

When I was in the University of Arizona and we lived next--and all I remember of my neighborhood is we lived next to this little boy and his name was Adonis. [laughter] Cute kid, but come on. [laughter] Also in mock trials judges give longer prison sentences to ugly people. [laughter] That's the Matthew effect, those who hath little get even that taken away and thrown into prison.

There is a recent study, which I'll tell you about but I am not comfortable with it as an experiment. The study observed people in a shopping--in a parking lot of a supermarket and found that parents were a lot rougher to the kids if their kids are ugly than if their kids are good looking. And they attribute it to the fact that, for all sorts of reasons, the ugly kid just matters less to the parent. I was watching a poker game once on TV and somebody who lost said, and I quote, "They beat me like an ugly stepchild" [laughter] and the fate of the ugly stepchild is, in fact, not a very good fate but this is not a good study. For one thing, and I don't know how to phrase this in a politically correct way, but the parents of ugly kids are likely to themselves be ugly people [laughter] and maybe what they're finding is just ugly people are more violent than good-looking people. [laughter] This is an excellent time to stop the lecture [laughter] so I'm going to stop the lecture and we're going to continue social psychology on Wednesday.

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Lecture 17 Professor Paul Bloom: Just to review, here's where we left off. The discussion from last lecture and for about half of this lecture is going to be social psychology. And so, we started off by talking about certain fundamental biases in how we see ourselves. We then turned to talk about a bias and how we see other people, the fundamental attribution error. And now we're talking a little bit about some aspects of how we see other people. So, we quickly talked about certain aspects of why we like other people including proximity, similarity, and attractiveness, and where we left off was a discussion of the Matthew effect, which is basically that good things tend to compound. If you're rich you'll get a better education, if you're smart people will like you more, if you're attractive and so on. Nobody bring up their papers at this point. They'll collect them at the end of class. What I want to talk to-- [laughter] Okay, except for you. Just hand me it now. [laughter] I'm going to ask the teaching fellows to stop anybody from approaching that area.

I want to begin by talking about [laughter] impression formation, how we form impressions of others, and tell you a couple of interesting things about impression formation. The first one is, first impressions matter a lot. They matter a lot for different reasons. They might matter a lot because humans have, in general, a confirmation bias such that once you believe something other information is then encoded along the likes to support what you believe. So, the classic study here was done by Kelley where a guest speaker comes in and some of the students received a bio describing the speaker as very warm, the other as--do not bring your paper up if you're coming in late. Just--at the end of class, yeah. [laughter] Others got a bio saying--thanks, Erik--the speaker was rather cold and then it turned out later on [laughter] when they're asked for their impressions of the speaker people are very much biased by what they first assumed. If I'm described to you as a vivacious and creative person and you see me and I'm all kind of bouncing around and everything, you could then confirm this as, "Look how vivacious and creative he is." If I'm described as somebody who drinks too much, you might think he's an alcoholic. If he's described as somebody who's insecure and nervous, you could interpret my activity as nervous twitches. Your first impression sets a framework from which you interpret everything else.

This was the theme of an excellent movie called Being There starring Peter Sellers. And the running joke of the movie "Being There" was that the main character, the character Chauncey Gardner, somehow through accident had the reputation for being a genius but while, in reality, he was actually mildly retarded. But he would go around and people would ask him his opinions on politics and he would say things like "Well, I like being in the garden." And because of his reputation as a genius people said, "Wow. That's very profound. I wonder what he means." And--or people would talk to him and he'd just stare at them and say--and people would say--would be intimidated by his bold and impetuous stare when actually he just totally didn't know anything. So, first impressions can shape subsequent impressions not just when dealing with people. A little while ago there was a sniper, actually a pair of snipers killing people in Washington and the one thing everybody knew about it was there was a white van involved. It turned out there was no white van at all but in the first incident somebody saw a white van, this was reported in all the newspapers, then every other incident people started seeing the white van. So, they started looking for them and they started to attending--attend to them. So, first impressions matter hugely when dealing with people because it sets the stage for how we interpret everything else.

A second finding building on the first is that we form impressions very fast, very quickly, and this is a literature known as "thin slices." The idea is you don't have to see much of a person to get an impression of what they are. The first studies done on this were actually done on teachers, on university professors. So, university professors have teaching evaluations and you could use this as a rough and ready approximation of what students think of them. So, what you do then is--the question that these people were interested in, Rosenthal and Ambady, two social psychologists, were how long do you have to look at a professor to guess how popular a teacher he is? So, they showed these clips for a full class. Do you have to see them for a full class? Do you have to see them for two classes? Do you have to see them for a half hour? How long do you have to be around a person to see him, to estimate how good a lecturer that person is? And the answer is five seconds. So, after clips of five seconds people are pretty good at predicting what sort of evaluations that person will have.

Remember "The Big Five," how we evaluate people on "The Big Five?" Well, you have a roommate and your roommate you could evaluate on "The Big Five." You've had a lot of experience with him or her. How much time do you need to evaluate somebody on the five dimensions of personality? The answer is, again, not much time at all. After very brief exposures to people, people are very accurate at identifying them on "The Big Five." One of the more surprising findings is--concerns sexual orientation or "gaydar." That's not a scientific term [laughter] but the same psychologists were interested in studying how quickly you can--if at all how long does it take to figure out somebody's sexual orientation?

Now, what they did was--they were clever psychologists so they set it up in a study where the people did not know sexual orientation was at issue. So, for instance, they may be people like you who filled in a form, one question along a very long form was your sexual orientation, and then you're sitting down being interviewed by somebody and your interview is being filmed, and then other people are shown--who don't know you are shown the film. And the finding is that people based on thin slices are quite good at detecting sexual orientation. Everybody's good at it, gay people are better at it than straight people, and, again, you don't need much time. You just need about a second. You see somebody for about a second, you could make a guess. You're far from always right. In fact, you're just a bit better than chance but you are better than chance at telling sexual orientation. So, these two facts taken together, thin slices and the power of first impressions, means that just by a brief exposure to somebody it shapes so much of how you're going to think about them in the future.

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Now, we can look at this from the other direction. We're talking about the perceptions of other people, how we perceive other people, but social psychologists are also interested in the question of what happens to other people as a result of being perceived in a certain way. So, one question is, "What would cause me to perceive somebody as intelligent or stupid, gay or straight, anxious or level-headed?" A second question is, "What are the effects of being judged that way?" And psychologists have coined a term, talk about self-fulfilling prophesies, and the claim here more specifically is what's known as "the Pygmalion effect." And the Pygmalion effect is if I believe you have a certain characteristic this might cause you to behave as if you have that characteristic.

The name comes from the play by George Bernard Shaw Pygmalion, and the quote here is "The difference between a lady and a flower girl is not how she behaves but how she's treated. I shall always be a flower girl to Professor Higgins because he always treats me as a flower girl and always will," made into a better known movie, My Fair Lady. But I think that the same theme is better exemplified in a far better movie, La Femme Nikita, where a cold-blooded killer is treated with respect and affection and then she becomes a much more warm and accessible person, and then she kills a lot of people but that--[laughter] but still it illustrates the point.

And this point has tons of empirical validity. The classic experiment was by Rosenthal and Jackson where they told teachers that some of their kids were really smart and other kids were less--were not really smart, they weren't expected to show a huge jump or spurt in their IQ, and this was of course trickery. The children were chosen at random but the children who were described as showing--as expected to show a jump in IQ, in fact, did show a jump in their IQ scores and this isn't magic. It's basically--if I am told that you're a genius and your genius is about to be in full-flower throughout this class and it's a small class as these classes were, I'll focus more on you, I'll give you more of my attention. If I'm told "not so much for you," you'll suffer relative to him. And so the Pygmalion effect shows how our expectations can really matter.

This brings us to the final--the issue of expectations and how we judge people is a story that could be told about individuals but it's also a story that could be told about groups. And this is where I want to end this section on social psychology by talking about groups. A lot of social psychology is concerned with the question of how we think about human groups and we've already discussed this in the lecture on morality when we talked about the human dynamic pushing us to think in terms of "us" versus "them" as shown in the Robber's Cave study and also shown in the minimal group research by Tajfel showing that from a motivational, emotional standpoint it's not difficult for us to think in terms of "my group" versus "your group." And this way of thinking has real consequences for our emotional life, our affective life, and how we choose to distribute resources. What I want to talk about here though is a different aspect of how we think about human groups. I want to talk a little bit about stereotypes.

Now, "stereotypes" in English often just is a bad word. To have a stereotype is to be--is to have something wrong with you. You might say it's not good to have stereotypes. Psychologists tend to use the term in a broader sense. We tend to use the term to refer to information we have about categories and intuitions we have about the typicality, our frequency of certain features of categories. And it turns out that collecting information about categories is essential to our survival. We see novel things all the time and if we were not capable of learning and making guesses, educated guesses, about these novel things we would not be able to survive. So, when you see this object over here you categorize it as a chair and you recognize that you could probably sit on it. This apple is probably edible, this dog probably barks and has a tail and eat me--eats me and doesn't speak English. These are all stereotypes about chairs and about apples and about dogs. It doesn't mean they're logically true. This could be a vegetarian dog, a poison apple, an explosive chair, but [laughter] they're typically true. And if you were suddenly stripped of your ability to make generalizations, you'd be at a loss. You wouldn't know what to eat, how to interact. So, some sort of ability to record information and make generalizations is absolutely essential to making it through life.

What's interesting though is we also categorize types of people. So, we have stereotypes in our heads about men and women, about children, adolescents or adults, whites, blacks, Asians and so on. Now, this is not essentially a bad thing for a couple of reasons. First, some of these stereotypes are positive. You might have positive stereotypes about certain groups. You might believe some groups are unusually creative or intelligent. You might have a particularly positive stereotype about your own group even if your own group is Yale students or your own group is people from France or your own group is people from such and so college. You might have positive stereotypes. More importantly, we collect stereotypes about groups of people through much the same way we collect stereotypes about categories like chairs and apples and dogs. And so they're pretty often accurate.

When there are studies which ask people who is more likely to be a lawyer, someone who's Jewish or someone who is Hispanic, who is likely to be taller, somebody from Japan or somebody from Sweden, people can answer these things. They have their stereotypes that guide their answers, and the answers are not arbitrary or random. Their answers are often correct and often possessing stereotypes lets us make reasonable and correct generalizations about the world.

That's the sort of good news about stereotypes but there's also bad news. One problem is that they're not always accurate and there's a couple of factors that could lead them away from accuracy. One is what we talked about before regarding first impressions, which is a confirmation bias. If you believe that homosexuals are effeminate, that gay men are effeminate, then this is going to shape how you see future gay men. If you see an effeminate gay man, you'll probably say, "Ah, more evidence for my theory." If you see a man who is not effeminate, you might ignore it or say maybe he's not really

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gay after all. If you believe black men are criminals, then when you see a black man who is a criminal you'll chalk it down as support but you'll pay less attention to evidence that white men are criminals and some black men are not criminals. You won't look at this as a scientist objectively scanning data. Rather, you'll be biased in certain ways. You'll be biased to put extra weight on the cases that support your theory and diminish cases that refute it.

Furthermore, our data is not always reliable. So--oh, and this is actually an example of this at work. It turns out in the world of classical music there's a stereotype of women being simply less proficient than men: they play smaller than men, they don't have the same force and they have smaller techniques, they're more temperamental and so on. If you asked somebody who was a judge, the judge would say, "Look. This is just the way things are. I'm not being biased at all." The test of this then is to have blind auditions where people do their auditions behind a screen so you can't tell whether they're man or a woman, or for that matter, white or black or Asian or whatever. It turns out when you do that women get hired far more suggesting that the stereotype is A, incorrect and B, has a real negative and unfair effect on people getting hired.

A second problem is – what I was talking about immediately before this – is some of our data are misleading so we get a lot of the information about the world from the media. The media would include television and movies but would also include plays and books and stories. And to the extent these portray an unrealistic or unfair or biased perception of the world we could construct stereotypes that are faithful to the data we're getting but the data is not representative. And so people, for instance, object to the fact that when there's Italian Americans on TV they're often members of the Sopranos, a mobster family. Throughout history Jews have been upset at the portrayal of Shylock in "Merchant of Venice," not a very nice guy. And often in response people who want to foster more positive views will often try to--will often put in representatives from other groups in unusual ways to make that point. Anybody here ever see the television showBattlestar Galactica? Okay. Who's that? He's the star of "Battlestar Galactica." You don't know because you're too young. In the original "Battlestar"--[laughter] and I hate you. [laughter] In the original "Battlestar Galactica," this was the star. This was the main character known as "Starbuck," who got transformed into a woman in the more recent one, a sort of example of how portrayals are shifting in interesting ways.

There's also, of course, moral problems over stereotypes. So, it's fine to judge chairs and apples and dogs based on the stereotypes. It's even fine to judge breeds of dogs. If I told you that I decided to buy a greyhound instead of a pit bull because I wanted a dog of a gentle temperament, nobody would scream that I'm a dog racist [laughter] involving--and--but honestly, it's a stereotype. Greyhounds are supposed to be more passive and gentle than pit bulls. I think it's a true stereotype but it's a stereotype nonetheless. But we have no problems when it comes to things like breeds of dogs with stereotypes. We have serious problems judging people this way. So, for instance, it's a moral principle that some of us would hold to that even if stereotypes are correct it is still immoral to apply them in day to day life. The term for this would be "profiling."

Now, it gets complicated because there are some cases where we do allow stereotypes to play a role. When you all go and get driver's licenses or when you did get driver's licenses you have to pay higher auto insurance premiums than I do. I think this is perfectly fair because young people like you get into a lot more accidents with your reefer and your alcohol [laughter] and so it is--now, some of you are saying "that's a stereotype." And it is a stereotype but it's a statistically robust one and nobody lines up to protest this. It's an acceptable stereotype to make a generalization from. On the other hand, what if insurance companies determined that people from Asia got into more accidents than people from Europe? Would people be equally comfortable charging people from Asia higher rates of insurance? Almost certainly not. So, the issues are complicated as to what sort of generalizations we're--are reasonable to make and what aren't.

There's also a second problem. Stereotypes have all sorts of effects. Now, some of them are obvious effects. If people--for instance, if people pull you over while you're driving because you're black, this could have a huge effect on how you feel welcome in this society on race relations and so on. But some of the effects are more subtle and more interesting and you might not expect this. And this is some work done by the psychologist Claude Steele and his colleagues at Stanford. And the issue is called "stereotype threat." Imagine you have a math test and this is the front of the math test. Claude Steele made an interesting discovery. Here is how to make black people do worse on this math test. It's very simple. The finding is that if your race or your group has a negative stereotype associated with it in any particular domain, being reminded of it serves as a stereotype threat and hence damages your performance in all sorts of domains. If the stereotype is "your group doesn't do good in this," if I remind you that you're a member of that group immediately before doing it, your performance will drop. Now, you know how to make women do worse on math tests too, like that, and this has a demonstrative effect.

So, stereotypes are complicated and morally fraught things. When people study stereotypes they often make certain distinctions between three levels of stereotypes and this is nicely summarized here. There's "public." If I asked you: One of the people running for the Democratic nominee for president is black, another one is female--if I asked people to raise their hands for who thinks that because being black or because being female they should be automatically disqualified for being president, few of you would raise your hands. Those are your public presentations of stereotypes. Even if I was to ask you on a sheet of paper, you might deny it because you might be afraid that it's not anonymous. Then there is private. Private is what you really think but you don't tell people. Some of you--some of the population of the United States are not going to vote for somebody because he or she is black but they won't tell you but they know it to be true. That's common

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sense. What's more interesting is below even that there may be unconscious associations that work that people don't actually know about but affects their thoughts about race, gender and other social groups.

So, here are some data about what people publicly say. This is the proportion of people who say they will vote--they would vote for an African American president. What's interesting is when--around when I was born the answer in the United States was about half. Now, it is as close to one hundred percent as you can get it. Here is another one. This is also public stereotypes of blacks, proportion of white respondents endorsing each trait. Now, it's infinitesimal. These numbers are so low they could be dismissed as people filling in the wrong things or making jokes or just being confused compared to [laughter] stunningly superstitious high rankings. And so, there's been a profound change in public presentations, public views, on race but what about implicit views? This gets more complicated.

Here is a simple study. This is the sort of study that you might do here at Yale. What you might do, for instance, is be sitting at a computer screen and you'll be given incomplete words to fill out like "hos-" and you have to fill out this word. What you don't know is that pictures of black faces or pictures of white faces are being flashed on the screen but they're being flashed on the screen subliminally so fast you don't even know you're seeing them. Still this has an effect. When you see black faces subjects are more likely to fill this with words like "hostile" while whites more likely to fill it with words like "hospital."

I will now welcome you to participate in an experiment on implicit attitudes. This was developed by Mahzarin Banaji who used to be at Yale and now is in an inferior university in Boston [laughter] and it's called implicit attitudes test and it's the biggest psychology experiment ever done in terms of people. I don't know. A million people have participated in this and you could just go online, implicit.harvard.edu and then you could do it yourself. But we'll do it now as a group. If you did it in the lab or on your computer screen, you would do it by pushing buttons. We'll do it by speaking. And it's very simple. You're going to see things over here and they're either going to be words or they're going to be pictures. If it's an African American or a bad word, a negative word, I want you to shout out "right," this side, "right." If it's a white American or a good word, I want you to shout out "left." People ready. Try to do it as fast as possible without making any mistakes. [audience response] [laughter] Because of the very loud wrong person we're going to try that again. [laughter] Are you ready? [audience response]

Good. That is "congruent," congruent according to a theory that says that people, both African Americans and white Americans, have biases to favor white Americans over African Americans. How do we know by this? Well, we compare it. That's "congruent." Now, it's different. If it's a white American or a bad word, say "right." If it's an African American or a good word, say "left." [audience response] Okay. For all I could tell, people did equally well but this experiment has been done tens of thousands of times and you could do it yourself on a computer screen. And this is one way of doing it but they'll alternate and they'll give you different ones to shift around and everything. And it turns out that this version people are slower at than the other version suggesting that their associations run one way and not the other. And this work has been extended for all sorts of ways looking at for example at gender, looking at the connection between women and English and men and math, looking at age, attitudes towards people who are obese versus people who are thin, attitudes towards people who are straight versus people who are gay, and you could go online and do these studies and it'll give you some feeling for the sort of implicit attitudes that we have within us.

Well, a legitimate question is "Who cares?" I mean, if you do the--If you look at the results for the study, it turns out that there is an association as bias to view white Americans as positive and African Americans as negative but it shows up in half a second difference. Who cares? Well, there's two answers to this. One answer is there are times in your life where half a second can matter a lot. So, studies with police officers using reaction time in split-second choices on who to shoot find that your stereotypical attitudes play a huge role in who you're likely to shoot when they're holding an object in their hand that's unclear. Also, more generally, it could be that these implicit attitudes play a role in judgment calls. In cases where you have a hard decision to make, you know you're not racist. You have no explicit racist attitudes, honestly you really don't, but the argument is that these stereotypes can affect your behavior in all sorts of subtle ways.

Here is one example. What they do is they do an experiment where somebody is in trouble. You hear a scream from outside either from a black person or a white person. In one condition you're the only person around. In another condition there's other people around you. Now, we know from the work in the Bystander effect that in general which one are we more likely to help in, when we're the only person or multiple? [audience response] "Only," exactly. And in fact, when it's the only person just about everybody helps regardless of the color of the person in trouble but when you're with other people there's a big difference. Now, again this isn't--these things are not done with members of the KKK. They're done with the standard university undergraduates like you and these--and if you were in this group you wouldn't say, "Oh. I didn't want to help because the person's black." Rather, what you would say is, "Well, I didn't think it was worth helping. There were other people around. Someone else would help," but we know by looking at it that this difference makes a real difference.

A final study, and this was done by my colleague who just got hired here, Jack Dovidio, who's done some wonderful work, looked at how people judge to hire somebody based on their recommendations. This is a little bit of a confusing thing. The green bars are the African Americans. The blue bars are the white Americans. And in some cases these people have strong recommendations. When they have strong recommendations in 1989 you're willing to hire everybody, and this [the level of hiring for African versus white Americans, depicted on a slide] is not a difference at all. But when their

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recommendations are so-so, when it's a judgment call, the subjects are significantly more likely to hire the white American than the African American. Nineteen eighty-nine was a long time ago but the same results showed up in 1999. The same results also showed up about a year and a half ago. And again, this doesn't show that people are explicit terrible racists. It does show that people possess these stereotypes that make a difference in their real-world behavior.

A way to put this all together is in Trish Devine's automaticity theory, which goes something like this. The idea is that everybody holds stereotypes. These are automatically activated when we come into contact with individuals. In order to not act in a stereotyped fashion, we have to consciously push them down, we have to consciously override them, and that's possible, but it takes work. It takes work both at the individual level and it takes work at the group level. Any questions or thoughts about this? Yes. Student: [inaudible] Professor Paul Bloom: It's a good question. These results are surprising and disturbing and I said there is work to be done at an individual and group level and this young man challenged me to be more explicit about that. Here is one case. We have job searches and sometimes job--senior job searches involve the faculty sitting in--around in a room and tossing out names and we use these names as a basis for further discussion. "Hey, I wonder--What about that person? That person does great work." What we do now in the psychology department is we make a special point of trying to get names from disadvantaged groups, not with an eye towards an affirmative action policy but rather because there's a lot of evidence suggesting that people who are just as qualified don't come to mind unless you make some sort of procedure to do it.

Here's another example. A lot of journals do blind reviewing now because of the evidence I talked about before regarding sexual stereotypes, that whether it has a male name or a female name makes a difference. So those are not--those are group level in that they're not saying, "You get rid of your prejudices by trying harder." It's rather, "Let's set up a system so that your prejudices can't work," the blind auditions, for instance, being a beautiful example of that. At an individual level, your question's a harder one and I'm not exactly sure what we could do but I think what we should do is be conscious of these things and know that it's not enough to say, "Well, I'm explicitly not racist so I'll give everybody a fair shake," but to recognize we might have biases and to work hard to overcome them, not by overcorrecting in some random way but trying to--if you're interested for instance in qualifications setting up some system that these qualifications can be observed absent knowledge of race or sex. Yeah, in back. Student: [inaudible] Professor Paul Bloom: Yes. The question's a good one. How much of this is due to stereotypes and how much of this is due to an own-group bias? So, the fact that--so, the experiments as I have described them are to some extent ambiguous. The fact that white Americans favor white Americans over black Americans might be because of stereotypes but they also might be of in-group favoritism. I think the answer is that both play a role but some of the effects are due to stereotypes above and beyond in-group favoritism. And one reason why we know that is in studies like the IAT, the Implicit Attitudes Test. African Americans show much the same effect as white Americans. So, African Americans also are biased against African Americans and in favor of white Americans, showing it doesn't reduce to group favoritism though that probably plays a big role.

Okay. I'm going to shift and spend the rest of this class on a couple of mysteries. Here's a summary. The first one is a minor mystery. I think we have some progress in explaining it. The second one is a total mystery. The first one's sleep. Sleep is a motivation. It is a motivation like food or drink. It is a form of torture. I won't get into definitions of what torture is but it would cause somebody tremendous pain and anguish to keep them from sleeping. When you're really tired sleep is what you want to do like when you're really hungry you want to eat. How many people here on average--from the beginning of the semester until now get on average more than eight hours of sleep a night? That's good. Good.

There is a sort of school of sleep macho. A sleep macho used to be "I only get forty-two minutes of sleep a night." Now sleep macho is "I sleep eleven hours." [laughter] Who gets on average more than seven? On average more than six? Who here has been making it since the beginning of the semester on under six hours a night? Okay. Anybody of you that has been getting under five hours a night? Okay. There is big individual differences in how much sleep people need and sleep itself is what we spend a lot of our life on but it's very hard to study and we didn't used to know much of it because you can't ask people what's happening during it because they're sleeping so you need sort of clever methods. One such clever method is an EEG. You bring somebody in the sleep lab, you put electrodes on their scalp and you see what these--what sort of electrical activities you get in the brain. Right now many of you are showing irregular beta waves suggesting intense comprehension and great intellectual focus. [laughter] Some of you are awake but non attentive and your brain's giving you these large, regular alpha waves. Some of you are sound asleep, deep in delta. [laughter]

When you sleep you get the following stages. You start off with a transition period when you're falling asleep. We call that stage I. Then you get successively deeper, II through IV, slow, irregular, high amplitude delta waves, and then once you reach stage IV you start going up again, up through stage III and II. Then REM sleep emerges, rapid eye movement sleep. REM sleep is neat because your brain looks like it's wide awake but – and I'm going to talk a little bit more in detail about this later – you're relaxed, your rapid eye movements occur; that's where your--the name comes from and dreams occur and then on a good night's sleep you've got four to five sleep cycles and it looks like this. You start off and you go

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down, down, down, and then you come up, then you get your first REM cycle, again, again, again, again, again, and then you wake up.

So, the general takeaway message here is that there's two types of sleep. There is slow-wave sleep or "quiet sleep." Your eyes drift separately and slowly you're hard to wake up. Then there is REM sleep. Your brain is active as if you were awake, your EEGs are similar to waking, paralyzed except for the eyes, oh, men get erections and you have dreams. One sleep researcher joked that these two are connected because what happens is dreams fly around through the ether and then their erections serve as antennas so you pick them up. [laughter] Don't write that down. [laughter]

Why do we sleep and why don't we--why aren't we always awake? There's a couple of answers to this. Probably the best answer is our body is worn out during the day and sleep is necessary to put it back into shape. So, when you sleep growth producing hormone goes through the body, your brain and other organs get restored, there are--you need less food, your immune system seems to be hard at work, and in fact, one answer--people always wonder what happens if you'd stop sleeping and the answer is not one discovered in the laboratory but it's been recorded in different cases. If you stop sleeping you die. You don't die in some dramatic way. You get sick and then you die, suggesting that sleeping is good to keep you healthy. And an analogy I like to think about is that your--when you bring your car in to repair it--for repairs, when you're repairing your car, the first thing you do is you stomp it and shut off the engine. You make it stable and at rest so you can then work on repair. A related view is that sleep emerged to preserve energy and keep you out of trouble at night. And these views are of course not incompatible. This explains why we sleep at all and this probably explains why we sleep at night. There are sleep disorders. I won't go through them. I just list a few of them here. They're sort of bad things that could happen to you when you're asleep. One particularly trendy sleep disorder that's been discovered recently are side effects of sleeping pills such as Ambien. So, one of the bizarre side effects is some people with Ambien while sleeping go downstairs, open up their refrigerator and eat huge amounts of food. [laughter] A more recent side effect of Ambien that's quite serious is some people become--have the compulsion while they're sleeping to go driving, which is not good. [laughter]

What we're really interested in though when it comes to sleep is dreams. So, remember Hamlet. People--you've all studied Hamlet, "to be or not to be." That's all I know but basically [laughter] he was deciding--he--I wrote this down though. He was deciding whether or not to kill himself and so he made up two lists. The lists of reasons to kill himself were "the slings and arrows of outrageous fortune," "a sea of troubles," and "the heartache in the thousand natural shocks that flesh is heir to." He only had one argument not to kill himself: Nightmares. "To sleep, perchance to dream, for in that sleep of death what dreams may come when we have shuffled off this mortal coil might give us pause." He was worried about nightmares. Now, dreams have always fascinated people and philosophers. If you take a philosophy course, there'll be a couple of questions about dreams that you will wonder about. One is "Are you dreaming right now?" So, Rene Descartes famously wondered whether the real world doesn't exist. Maybe right now it's just a dream. See also "The Matrix." And can you be immoral in a dream? We do all sorts of things in dreams that are bad. Are these sins? And the great theologians and philosophers like Augustine wondered about this, can you sin in a dream? I will answer both questions. You are not dreaming right now, unless you're asleep but if you're--and you can't usually be immoral in a dream. The exceptions are lucid dreams where you choose what to dream about, and then possibly you could be immoral if you encourage bad habits of thought.

What do we know about dreams? Well, first there's a distinction, a distinction between real dreams versus sleep thought. So, real dreams are you're in a submarine wrestling a chicken while your grandmother looks disapprovingly on. Those are real dreams. "Sleep thought" is the sort of thing you get typically before you fall asleep and it's like "did I take the garbage out, where is the garbage, did I take the garbage out?" And so it's really just this kind of rumination and you could do this while you're sleeping. So, if you're woken up during slow-wave sleep you're going to be thinking "Did I take the--yes, while I was dreaming I was thinking about the garbage," but if you're woken up during REM, "But a monkey was eating my grandmother," and that sort of thing. [laughter] So, there is a distinction.

What do people dream about? Well, we know some facts about dreams. Everybody dreams. Not everybody remembers their dreams. If you want to remember your dream by the way keep your dreams--keep a dream diary, very useful, but everybody dreams three to four times a night. That depends on how much sleep you get but dreams leave fragile memories. They fade quickly. This is why a dream diary or writing up--writing your dreams as soon as you wake up turns out to be useful.

What do people dream about? Well, basically, the way to find that out is you ask people and people have--psychologists and sociologists have collected dream reports. If you go to dreambank.net, a guy named Hill collected 50,000 dream reports; you could make some generalizations. Most dreams are bad. They're not bad, bad, they're not nightmares, but most dreams are from a scale of one to ten with five and a half in the middle they're on the negative side. They report misfortunes. People in tribal societies have dreams with more physical aggression than people in industrialized societies. Men have more aggressive dreams than women. Americans have more aggressive dreams than Europeans. Yeah. [laughter]

What do people want to dream about? Well, psychologist--the findings were totally not going to surprise you. Women want to dream about romance and adventure. Men want to dream about sex with strangers. [laughter] Turns out that once you get past the hormonal blast of adolescence about 10% of dreams have explicit sexual content.

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What's the most common dream? Guesses. Falling. That's a good guess. Falling is among the top dreams but falling is not the winner. Somebody else. Flying? Also close. Public speaking? Good phobic dream but not it. Naked in public, not it. [laughter] Excellent. Being chased. Evolutionary psychologists and cognitive neuroscientists have puzzled over this one. It seems to be sort of a primal dream but the dream about being chased is a biggie. Has anybody here ever dreamt of being chased that you could remember? Yeah. Being chased is the big one. Naked in public? [laughter] Grandmother killed by a monkey? [laughter] No.

So, what are dreams for? There are Freudian theories that dreams are disguised with fulfillment and other things. There is not much support for these. One theory which is popular is that dreams are a side effect of memory consolidation so your body, sort of below the neck, rebuilds itself while you're sleeping but also what happens while you're sleeping is your memories get played over and over again to consolidate them into different parts of the brain. Almost--the best analogy here is backing up a computer. Your brain backs itself up. In the course of backing itself up, there are sort of random events flash to consciousness and get put together in a coherent story. From this perspective, dreams serve no adaptive function at all but rather they're epiphenomena. They are the byproducts of another system.

Final topic is laughter and this is a true mystery. I got interested in this--well, I got interested in this as a developmental psychologist watching my own children laugh and trying to figure out what it is that made them laugh. This is my son, Zachary, pretty young [clip playing] but [laughter] this is not the youngest record of laughing. I found this on the web. [clip playing of an infant laughing] [laughter] It's a huge puzzle. From an evolutionary point of view, people's pursuit of sex and food and drink and sleep are not these huge mysteries, our abilities to understand language and make sense of the visual world and cohere in groups, but the fact that we make this weird noise at bizarre circumstances is a huge puzzle and typical--typically psychologists have failed to explain this puzzle.

So, here's something; here's a first guess I read in a neuroscience textbook. "We laugh when there is incongruity between what we expect and what we actually--what actually happens unless the outcome is frightening." [laughter] Now, this is a fair effort. It is about as wrong as anything can be wrong in any possible way. [laughter] The first thing is it doesn't really explain "why?" So, why should a non-frightening incongruity cause people to make a distinctive loud noise consisted of staccato segments of one fifteenth of a second each separated by a fifth of a second? It doesn't explain why we make that loud noise when dealing with incongruity. It's not the case that incongruity causes laughter. If there was a bowl of fruit up there as you walked in, it'd be incongruous but people wouldn't shriek with laughter and point to the fruit. [laughter] It's also--a lot of laughter isn't caused by incongruity so a lot of times when we laugh there's nothing incongruous in any deep sense about it. So, laughter is kind of a puzzle. We don't know why we laugh. We don't know what makes us laugh.

Over the last five, ten years there's been some work done on this. A lot of the work is done by Robert Provine who summarizes this in his excellent book Laughter. And Provine decided to do something that nobody in the history of the world has done. He decided to send himself and his students to different places including shopping malls and observe when people laughed and write down what made them laugh. And this is the first descriptive step to developing a theory of laughter. And his big finding is that you could separate people--you could separate the question of laughter from the question of a joke or the question of humor. Most of what people--what made people laugh wasn't in any sense a joke or humorous. So, he had over a thousand laughter-initiated situations and here are some typical comments that initiated laughter, sometimes uproarious laughter, on the parts of people. "I'll see you guys later." "Look. It's Andre." [laughter] "Are you sure?" "I know." "How are you?" "I try to lead a normal life." It's sort of funny. [laughter] It was anyway in a context where it wasn't particularly amusing. "It wasn't you." "We can handle this." Only ten percent of the comments were--could be re-coded later on as people--as actually humorous in any sense. And these included "Poor boy looks just like his father," [laughter] "You smell like you've had a good workout," [laughter] "Did you find that in your nose?", [laughter] a reference to dormitory food, [laughter], "He has a job pulling back skin in the operating room." [laughter]

So, Provine suggests we separate the question of laughter and jokes and then ask what do we know about laughter? Well, here are some basic facts that--remember we're trying to think like evolutionary biologists here. Humans have this universal trait. There's no society without laughter. It's early emerging as we saw in those clips. So, what's it for? What does it do? If it's an accident, what's it an accident from? What properties does it have? And there are some properties that are important to know. It's social and communicative. Why do we know that? Because it's loud. Laughter is not like hunger. Hunger can be silent. Hunger is not essentially a message to other people but when humans – when it involves a loud noise – the reason why we've evolved loud noises is to communicate with other people.

Laughter could be viewed as a form of involuntary noisemaking and it's contagious. That's another interesting thing about it. One of the great discoveries in television and movies was the invention of the laugh track. The laugh track makes things a lot funnier because people laugh a lot more when they're in groups. The rim shot after a comic remark is an attempt to simulate--sort of a pre-technological attempt to simulate the sound of laughter. Children are particularly influenced by the contagiousness of laughter, but just in general, if you hear somebody laughing, like the kids you saw before, it's the sort of thing that could easily make you laugh.

Other primates do it to some extent and then it's interesting when they do it. Monkeys laugh when they attack. When monkeys get together to kill and eat somebody they make a kind of a laughing noise and chimpanzees laugh when they tickle each other.

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And then you'll see--And what's tickling? Well, a fair definition of tickling is touching parts of the body in a mock attack. You sort of attack somebody and they're laughing but if it's--but if somebody's trying to mug you you're not "Ah, this is so funny." [laughter] You have to realize that this is a mock attack; you're simulating attack. So one theory is--is a signal of mock aggression and collective aggression. It's basically--it's like a sound of some sort of mob attack. It's mock aggression in the sense that when people laugh they're often teasing, kidding around. They're throwing out insults, maybe they're tickling each other, maybe they're making fun of each other, maybe they're making fun of themselves, and there's some aggression to it. Most laughter is inspired by some degree of aggression, but it's attenuated and it's not real. And the laughter is a signal this isn't real. And collective aggression--a lot of mob assaults, executions, lynchings, rapes are accompanied with the sound of laughter. When you're in a group doing something terribly aggressive and you are not--you don't feel like you're at risk you might laugh and laughter is a signal to other members of your group as a signal of solidarity and what you're doing together. A different way of putting it--and none of this is going to come in with a sharp, decisive theory. These are sort of flailing away at different ideas but another way of doing--an older way is proposed by Plato, who viewed laughter as a form of bonding against a common enemy. It's a sound of group cohesion against the common enemy. Comedians have not missed the aggressive nature of laughter. Dave Barry writes:

The most important humor truth of all is that to really see the humor in a situation you have to have perspective. Perspective is derived from two ancient Greek words, 'pers' meaning something bad that happens to someone else and 'ective' meaning ideally somebody like Donald Trump.

[laughter] And the idea is that it's something bad happening but not to you or to somebody you love. Mel Brooks puts it in somewhat sharper terms, distinguishing between comedy and tragedy: "Tragedy is when I cut my finger. Comedy is when you fall in an open sewer and die." [laughter]

To sum up, ingredients of humor is there has to be a target who experiences some harm. It could be an enemy. It could be a friend. It could be yourself. The harm shouldn't be so serious that it elicits strong negative emotions like fear, grief or pity. So, if a stranger slips on a banana peel and lands on his butt, I might laugh because I'm not overcome by compassion. If he splits his head open and there's blood everywhere, I'm less likely to laugh unless I don't like him or something. [laughter] And this is why the humor--why the damage is often a certain sort of damage involving things like embarrassment, sex, scatology, a banana peel, pie in the face, your pants fall down or something, where there's no real harm. So, empathy, caring, sympathy don't kick in, but instead there's the aggression unleashed at somebody and there has to be some level of surprise.

This is what--this is where the humor for that baby comes in, which is you couldn't predict when the sound was coming and some aspect of that was what made it so funny then, what elicited the laughter. This is--what elicited the laughter for Zachary was watching the classic film Winnie the Pooh and the Blustery Day where Rabbit climbed on a high bunch of shelves and it all came crashing down on him. But he didn't--he wasn't dead. He was just kind of stunned. [laughter]

Final question for anybody interested in laughter is, "Why can't we tickle ourselves?" Now, I've talked about laughter on two separate occasions and on each of the occasions when I talked in front of a large group like this somebody came up to me afterwards and said, "But I can." [laughter] And [laughter] I don't--and they seemed sincere but if people say, "I can tickle myself," how many people here will own up to being able to tickle themselves? One? [laughter] It's a fascinating question why some people can. The general story of why we can't in general is because there's no surprise, there's no mock aggression, and also there may be a general deadening of self-stimulation.

I'm going to end with the final reading response. Think of an interesting testable idea about either dreams or laughter. You could go into as much detail as you want. If you want your thing could be one sentence long but it could be longer. I will ask the teaching fellows to each send me their one or two most interesting remarks. I will then judge and then the winner will win some small prize, either of a literary or a food nature. Okay. I'll see you all on Wednesday.

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Lecture 18 Professor Paul Bloom: I am extremely pleased to introduce the fourth and final guest lecture of the semester. Professor Susan Nolen-Hoeksema. Susan is a professor in the Department of Psychology and the Director of Graduate Studies. She is well known for her work in clinical psychology and especially her research in depression, the nature and causes of people with depression, with special focus on sex differences in depression. She basically does everything someone can do. She is a noted scientist, winning many awards and publishing massive amounts of work in scientific journals. She is an award-winning teacher and has authored what, in my mind, is the very best textbook in her area. And she's a noted popular writer who has written popular and accessible books bringing the message and ideas and theories of clinical psychology to the broader public. The only other thing I'll mention before we welcome her is that she's going to teach next year her course in clinical psychology, which has a superb reputation as an extremely interesting course. If you are interested in what you hear today and you want to learn more about it, that's the course you should take. So, let's please welcome Dr. Susan Nolen-Hoeksema. [applause] Professor Susan Nolen-Hoeksema: Thank you Paul. Can everybody hear me okay? Okay. So, what I want to do today is to give you a very brief overview of how modern clinical psychology looks at mental disorders, some of the ways we think about what constitutes a mental disorder, some of the characteristics that kind of cut across mental disorders, and then I'm going to use the case of mood disorders, that is depression and what is now called bipolar disorder, what you may know more popularly as manic-depression, as sort of examples of how we think about a particular set of disorders and some of the ways we go about researching the theories -- different theories for the disorders and some of the prominent treatments for disorders these days. Okay? So, I'm going to do both a fair amount of lecturing, and then I've got lots of video clips to show you as well. So, I'm going to be roaming around and changing venues here fairly often.

So, the first and most fundamental question in clinical psychology is, "What is abnormality?" Where do we draw the line between normal, healthy, typical behavior and what we might want to call abnormal, atypical, deviant, unhealthy, maladaptive mental problems? We tend to have an intuitive sense of what we mean by abnormality, and we'd like to believe--a lot of people who come into my course say, "Well, of course, you know, you guys have figured it out. You know where to draw the line. You have criteria. You have blood tests, right? --that tell me whether I have depression or schizophrenia or one of the things I've read about." Well, the reality is that we don't.

First of all, there is no biological test for any of the known mental disorders right now. And instead what we have is a set of behavioral criteria for how to diagnose different mental disorders. And what I mean by behavioral criteria is a set of symptoms that the person reports to you about how they feel, how they think, and a set of observations about their behavior and how typical or atypical it is. And you take the sort of set of symptoms the person shows or reports, and you match them up against the existing criteria for different mental disorders. And then it comes down to a fairly subjective judgment call about whether the person meets the criteria or not. Unfortunately, these judgment calls, because they are so subjective, can be influenced by a lot of factors. And we won't have a chance to go into these too much today, but just to highlight a few of them.

The first is social norms. Whether you get labeled as having a mental disorder or a problem depends very heavily on what your social or cultural norms are. So, a woman wearing a veil in a Muslim community or culture would be seen as typical, even prescribed, behavior. Whereas a woman wearing a veil in a non-Muslim culture, especially until fairly recently, was often looked upon as very atypical or abnormal behavior.

The second kind of thing that gets--that influences whether something is called normal or abnormal is certain characteristics of the target person. In particular, I've highlighted here, gender. Whether you're a man or you're a woman really influences how unusual a certain behavior is. So, crying is a good example. A man crying in our culture is seen as fairly unusual, whereas a woman crying is seen as much less unusual. On the other hand, a woman beating up someone is taken as quite unusual behavior where it's less unusual for a man. So, we have gender stereotypes, gender roles for what is acceptable behavior, and our judgments as to whether something is normal or abnormal get influenced by those gender roles.

And the third thing that can influence whether something is labeled abnormal or not is the context. And here I'm giving you the example of "paranoia." If you're paranoid and hyper-vigilant, looking for threat in downtown Baghdad, that's considered very adaptive behavior these days because it could prevent you from getting hurt or killed. Whereas, if you're in a quiet little farm in Central Connecticut, being extremely paranoid and believing there's someone who's going to shoot you around the corner is not considered as normal or as acceptable or adaptive behavior. So, the context in which you exhibit a particular behavior also can heavily influence whether it gets labeled by others as normal or abnormal.

In the field of clinical psychology we have a number of different ways, kind of heuristics that we use to label things as abnormal or unhealthy or troubling. And three of these characteristics are what we often call the three Ds: distress, dysfunction, and deviance. So, behaviors that cause the individual or others significant distress often get labeled as abnormal or unhealthy. Depression is a prime example, as we'll see when we talk about the characteristics of it. It's a miserable state of being; you're unhappy, you're sad, you may even feel so badly you want to kill yourself. And that very, very high level of distress is part of the reason why it's labeled as a mental disorder. Other mental disorders don't cause the individual distress, but they may cause other people distress.

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So, one example of this is something called "antisocial personality disorder," where the individual has no regard for the rights of other people, has no hesitation to steal or--steal from or hurt other people, has no empathy or sympathy for other people's feelings and so can inflict a lot of harm on other people and has absolutely no distress over this whatsoever. But this behavior causes other people distress, and that's one of the reasons why that's labeled an abnormal behavior or a mental health problem.

The second general criterion is "dysfunction." If a set of behaviors prevents the person from functioning in daily life, then it might be labeled as abnormal or might end up being labeled as a mental health problem. Again, depression is a good example. People who are depressed often become completely non-functional. They can't get up and go to class; they can't go to work; they can't interact with their friends; they withdraw and become totally isolated socially. So, they might lose their job; they might flunk out of school. And this complete decline in functioning is one of the major reasons that we consider depression one of the most debilitating disorders.

And then finally, "deviance," the behaviors or feelings are highly unusual. This is probably the most controversial of the three because it weighs, it is so heavily influenced by the social norms. What's deviant in one culture is not deviant in another culture. But if a set of behaviors is completely unacceptable to a culture, highly unusual, they're more likely to end up getting labeled as abnormal.

Okay. So, how do we pull this all together? Well, these days the manual for making diagnoses in clinical psychology and psychiatry in the United States is called the Diagnostic and Statistical Manual or the DSM, and it's in its fourth revision. It's been around since the, I believe the '50s, and the early editions in the '50s and '60s were highly subjective and based on Freudian theory. But since 1980 there's been real effort to make the criteria much more objective, to make the set of behaviors or observations that are required to diagnose someone be things that are observable, that you can see in other people that they can report on reliably, and that one clinician and another clinician will agree upon. So, the DSMgives lists of symptoms with the required symptoms for a diagnosis, the number of symptoms that have to be present, and the notions of deviation, dysfunction and distress are built into these criteria. And I'm going to give you a couple of examples of these criteria when we talk about the specific types of mood disorder.

So as I said, I'm going to use mood disorders as kind of a case example here of how we go about diagnosing and understanding psychopathology, but I also just want to impart some information because mood disorders are one of the most common problems that people face. As many as one in four women will have an episode of serious depression at some time in her life, and about 13% of men will have an episode of serious depression in their lives. So, these are extremely common kinds of problems that people experience, particularly at your age. The college years are one of the peak times of onset, first onset, of depression in particular. And also, for bipolar disorder, or manic-depression, the late adolescent, early 20s are the peak onset times for these disorders as well.

So, the mood disorders divide into what's called unipolar depression disorders, which is depression only and then bipolar disorders where the person cycles between depression and mania. And here are the DSM criteria for major depression, one of the most severe forms of depression. And as I said, the DSM sets up these relatively observable criteria and how many you have to have and what absolutely has to be present in order to get the diagnosis. So, the first criterion in the DSM for major depression is that the individual has to either show sadness or a diminished interest or pleasure in their usual activities, which is referred to as anhedonia. So, you have to have one or the other of these to sort of pass the first criterion. So, you might say that you feel sad and blue and just--or actually say you feel depressed. Some people feel those feelings very strongly. Other people don't really feel so sad or blue, but what they'll say is that nothing interests them anymore. It's like the emotion has been sucked out of their life altogether. They don't have any fun doing the activities they used to do before. They don't want to hang with their friends. They just--they don't care about eating. Just nothing feels right, feels good, anymore.

And then the individual has to have four of the--at least four of the following symptoms in addition to sadness or anhedonia. First, they can show significant weight or appetite change. So, you may completely lose your interest in eating and lose a lot of weight, or some people go on eating binges. I had a very good friend who was depressed for about a year, and she gained fifty pounds because she would just eat. She would binge eat, especially at night. There are sleep disturbances--insomnia, which is having trouble sleeping, or hypersomnia, which is sleeping all the time. There's a particular form of insomnia that's especially likely in depression where you can go to sleep at night, but then you wake up at about three or four in the morning every night and you can't go back to sleep at all. You're just up for the rest of the night. But other people want to sleep all day long, and in the clip I'm going to show you in just a minute the woman talks about sleeping twenty, twenty-two hours a day, getting up, eating a little bit, and then going back to bed because she was exhausted still.

The third criterion is psychomotor retardation or agitation. The retardation is much more common, and what this means is that sort of everything about the person's movement is slowed down. They'll walk more slowly. Their reaction times will be slowed down. And because they're so much more slow moving, depressed people are often more prone to accidents. They just can't react as quickly as they need to when they're driving or when they're crossing the road and a car is coming at them suddenly. So, they get into more accidents. And their speech may be slowed down. They may talk very, very slowly and it's as though it just takes a tremendous amount of energy to get even a common sentence out. A much more, much

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smaller number of people get agitated instead of slow down. They may be hyper and just feel like they can't sit still and such, but the agitation is much more rare than the retardation. People feel really tired, fatigued and like they have absolutely no energy. They can't get up and can't get moving. As I said, they may want to just sleep all of the time.

Number five is feelings of worthlessness or excessive guilt. They may feel as though everything is their fault, and the guilt feelings or sense of worthlessness can even get psychotic. They can lose touch with reality. When a person loses touch with reality when they're depressed, it typically has really depressing themes. They may believe that they are Satan and that they have to commit suicide because they're inflicting evil on the world. They may believe as though random events are their fault, you know, that a flood that just happened somehow they caused. So, the feelings of worthlessness and guilt can get completely out of touch with reality, psychotic. More commonly, they're just unrealistic. They're negative self-esteem, just being down on yourself, feeling stupid and worthless and ugly and bad.

Number six is diminished ability to concentrate or indecisiveness. When you are depressed it's really hard to pay attention. You'll read a passage over and over again and you just can't process it at all. You can't concentrate on a lecture so going to class is just useless. You have to make a decision about what a paper topic is, and it just seems like the most monumental thing on earth. You just can't decide anything, you can't think anything; your thoughts are completely clouded and overwhelmed.

And then suicidal ideation or behavior; it means you think about committing suicide, you think about dying. And a subset of people actually take action to try to hurt themselves or kill themselves. Now, it should be said that suicidal thoughts and behavior don't only happen in depression. They actually happen in all types of psychopathology, but they're particularly common in depression.

So, you have to have at least one--four of those symptoms plus sadness or anhedonia, and these symptoms--it can't just be a bad day that you're having. These symptoms have to be present persistently for at least two weeks to get the diagnosis. Now, truth be told, most episodes of major depression actually last a lot longer than two weeks. In fact, the average length of an episode, if it's not treated, is at least six months. So, people stay this miserable for a very long period of time, but the minimum criterion in the DSM is at least two weeks.

So, what I want to do is to just show you a short clip of a woman who has had a lot of episodes of depression. Fortunately, at the moment she's not in an episode. But she can speak very articulately about what it's like to be in the midst of an episode and some of the significant symptoms that she had. [video clip plays]

Okay. There are couple of things she talks about that I just want to comment on. One is this differentiation between everyday sad mood and the kind of depressions we all experience and the kind of debilitating, overwhelming depression that she experiences. And it is true that there is this continuum from getting bummed out because you didn't do well on a test or because you broke up with a boyfriend or girlfriend or something like this and being completely not functional, vegetative, the way that this woman becomes whenever she gets depressed. And it would be nice if we were really sure where the cutoff was between those normal everyday depressions and what's really a disorder. But the reality is we don't really have real clear demarcation lines. There are a lot of people who have more moderate forms of depression than Tara here talks about but who still would qualify for a diagnosis and are still suffering and impaired by their symptoms. So, I don't want you to get the sense that if you don't have the kind of horrible version on the extreme end of the continuum of depression that Tara has, then there's nothing wrong with you, because that's not the case. People who are really slowed, whom their functioning is interfered with--they're just really unhappy with life--have problems that can be helped and do need attention. And it is the case that much more moderate forms of depression can morph into more serious forms if they're left untreated. So, there is this continuum.

The other things I wanted to comment on that she talks about early on in this piece is the fact that she hauls herself up and goes through her day, even when she's feeling really, really depressed. And there is this characteristic of a lot of depressed people that I call the "walking wounded." They just haul themselves through the day trying to act normal, trying not to let anybody know that there's anything wrong with them, trying to keep up with their schoolwork or their employment. But they're miserable and they're not functioning at the level that they're capable of and such. And that's something that's very, very common, and it's in part because people don't feel as though they should have to get treatment or they're ashamed of getting treatment or seeking help for depression. And so, they just keep going on and going on, sometimes for years, in a very sorry state before--sometimes they just--they end up actually falling apart to the point where they have to get help.

Okay. The other category of mood disorders that I mentioned is bipolar disorders. And as I said, bipolar disorder involves symptoms or periods of depression but then also distinct periods of the opposite of depression, which we call "mania." So, the person cycles back and forth between debilitating depressions and manic episodes. So, let me describe manic episodes to you now.

So, the first criterion is that instead of feeling down, blue or depressed the person has an abnormally and persistently elevated expansive or irritable mood that isn't just, again, a good day because you won a prize or got an "A," but rather, it's this unusually positive, expansive mood for at least one week persistently. And then the person has to have three or more of the following symptoms.

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First, inflated self-esteem or grandiosity. The individual may feel as though they are the smartest, the most creative, insightful, powerful person on earth, and they are perfectly happy to tell you this. So, there is no problem with self-esteem, thank you very much. "If you can't keep up with me it's your fault." There's a decreased need for sleep; they may only sleep a couple of hours a night and get up raring to go. They tend to be more talkative than usual, and there's a really pressure to their talk. They'll talk really pressured, and they'll talk really, really fast. And one of the reasons they're talking really, really fast is they have this flight of ideas. The thoughts are just racing through their mind, and they can't talk fast enough to get them out. And if you can't follow them, that--well, that's because you're not smart enough to follow them. But they've just got too many good ideas and they've got to get them out.

They're highly distractible. And then there is this increase in this--what the DSM calls this "goal-directed activity." Out of their grandiosity will come these grand schemes for--often for making a lot of money and they'll pursue these with great vigor no matter how totally irrational they are. So, it's not at all uncommon for them to cash out all the family bank accounts, to sell the house, to sell the car, to sell the kids so that they can finance this great scheme for making a zillion dollars on the Internet tomorrow. Right? Okay. And they'll pursue this with tremendous vigor.

They'll also get involved in all kinds of, what the DSM discreetly calls "pleasurable but dangerous activities." There's a lot of sexual promiscuity, a lot of drug abuse, a lot of, as I said, getting--going and gambling, believing that you're on a hot streak, there's nothing can stop you. You know, you're just so brilliant and you've got this scheme, you've got the plan. You're going to make it. Okay? So, the individual has three of more of these kinds of symptoms plus this elevated, expansive and often quite irritable mood. It's not just that they're happy, you know, and sort of upbeat. It's just that they're just impatient and irritable and trigger-fire. And sometimes they can become violent because they're just--they're so incredibly agitated and irritable.

So, let me show you a couple of clips. I have one really short one. It's not a real high quality clip, but it's a very, very nice example of an older woman who is in the midst of a manic episode. And it shows what this kind of agitation and flight of ideas and racing thoughts can look like. And then the other one is--I'll introduce whenever you--we do it. [video clip plays] Okay. So while she was at the hairdresser's it's a nice example of how she was just pressured to speak. Nobody was telling her that she had to say all of these things. They were just standing there with a camera and she was going on and on and on about these things. And as you could see she was getting more and more agitated and more and more irritated as she was retelling her story. And then what? In the last little bit there you saw her flip from her mania into a more depressed state. And this poor lady, unfortunately, is having a hard time finding a stable point. He talked about lithium there, and I'll talk about it in a little bit--about the use of lithium as a drug to try to stabilize these mood swings. But at this point in this video, it's not working for this lady. And so, she's flipping back and forth, but they're having a hard time finding that middle ground.

So, I want to show you another clip--it's a little bit longer--of a man who has bipolar disorder. He is not currently in an episode of either depression or mania, but again, he can talk about some of the things he got himself into and how it manifested in his behavior. [video clip plays] Hypomania is a more mild version of mania, but it's the same symptoms. [video clip resumes]

Okay. Just a couple of things that Bernie talks about that I want to comment on. One is that just as in depression, mania has--runs along a continuum. So, it can be relatively mild all the way to extremely severe and even psychotic. So, when a person with mania loses touch with reality, instead of having beliefs that they are Satan or they've done some horrible thing, they'll believe that they are some supernatural being. They may believe that they are the Messiah or that they are Albert Einstein, you know, come back to life, or that they have supernatural powers or something of this sort, so that their false beliefs, their delusions and their hallucinations, the things that they see and hear that aren't really there tend to be very grandiose in their themes. Bernie's mania is not on the far end of the continuum by any stretch, but you can see it still gets him into trouble.

Now, there are people who have--who cycle between fairly low levels of mania and fairly low levels of depression, back and forth. And there's been some argument that people who are kind of chronically, mildly manic--especially if they're really smart or they have a special talent – can make it work for them. And there is a wonderful book by Kay Jamison, who is a professor at Johns Hopkins where she chronicles--She does sort of historical biographies on a number of well-known authors and poets and musicians, Robert Schumann and a number of politicians, Winston Churchill and such, arguing that they actually had mild forms of bipolar disorder and that they were able to sort of channel the manic episodes through extraordinary talent or intelligence in ways that made it work for them. There are also a number of arguments that very, very successful CEOs sometimes are people who are chronically slightly manic. They can go on a couple of hours a night of sleep; they're obviously really quite grandiose and self-confident, and that they can maintain this kind of moderate level of mania, keep it under control and channel it in ways that work for them. So, if you're interested in that book, send me an email and I'm happy to send you the citation for it.

But for the most part, mania can get people into tremendous trouble. They can, as I said, get involved in sexual promiscuity that puts them at risk for sexually transmitted diseases. They can get involved in drug activity. They can get themselves arrested. They can certainly send themselves and their family into bankruptcy. And these kinds of negative consequences of the mania often are what motivates the person to get help because the mania itself can be rather

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pleasurable to have. Also, what motivates them to get help is the plunge into depression, the knowledge that they will, at some point, come out of the mania and go into a debilitating depression.

Bipolar disorder is much less common than depression. I said that about 22% of women and about 13% of men will have an episode of serious depression at some time in their lives. Bipolar disorder occurs in only about 1% of the population, and it's equally prevalent in women and men. So, it's a really quite different disorder in many ways from depression alone.

I want to give you some other statistics about depression per se, and this only applies to depression. There are quite large age differences in the prevalence of depression. These are data from a nationwide study of people between the ages of fifteen and fifty-five, and these are the percentages of people in this study. And there were several thousand people in the study. These are not people who have sought treatment for depression but just a random community sample. And this is the percentage who've had an episode of major depression in the past month. And as you can see, the fifteen to twenty-four age range has the highest rates, and then they go down somewhat, although the thirty-five to forty-four is fairly high as well with age. You might be surprised to learn that the rates of major depression in the elderly are actually quite low by most national statistics. And that's true up to about age eighty or eighty-five. And the arguments for why this is the case are very interesting.

There are some people who argue that as you get older you get wiser, and so that's why we see lower rates of depression in older age. There are other people who argue that current generation--younger generations now; your generation and the one above you--are more prone to depression and will be for the rest of your life compared to your grandparents, because of historical changes in the kinds of social support and family networks available and a number of other historical cultural changes. The other sort of side of the argument is that because depression is known to impact negatively your physical health – depression is associated with higher rates of cardio-vascular disease, stroke, immune system diseases, a whole host of diseases that people die from--that people who have a lifelong history of depression are actually more likely to die at an earlier age, and that's why we see relatively low rates in older age people. We don't know yet which of these explanations is true. It may be that they're all true to some extent.

There are also gender differences in depression. These are data from a compilation of hundreds of studies of children and adolescents, looking at not full-blown depression but levels of depression on self-report questionnaires. Probably most of you have filled out these questionnaires, like the Beck Depression Inventory that ask you how you've been feeling in the last month. And there's a kiddy version of this, and these are data from that, from several thousand children. And as you can see here, prior to the age of about thirteen, boys and girls have relatively similar levels of depression. But beginning around the pubertal years, girls' rates of depression go up quite dramatically and boys' rates stay the same or go down. And by the time they're eighteen or twenty you get almost a two-to-one ratio of depressed girls to depressed boys. And then this is true for the rest of the adult age span.

There are lots of hypotheses about this, why it's true. There are biological hypotheses that have to do with hormones. There are sociological hypotheses that have to do with the kinds of stress, and particularly abuse, in girls' lives relative to boys'. We don't know exactly why. It's probably a lot of these things coming together that make this huge two-to-one ratio true.

So, let's talk a little bit about the major theories and treatments for the mood disorders. There are biological theories and treatments, what are known as cognitive behavioral theories and treatments and then interpersonal theories and treatments. And I'll walk you through examples of each of these.

So, first, genetics. It's pretty clear that genetics are involved in the mood disorders, especially bipolar disorder. There is very strong evidence in bipolar disorder, and there are a number of ways--Have you talked about how you do genetic studies? Okay. So, you guys know about twin studies for example and family history studies. So, this is actually a compilation of a group of studies. And here you've got some of them – twin studies--compared. So, in monozygotic twins, if your identical twin has bipolar disorder, you have over a 60% chance of having the disorder yourself. In contrast, if it's your--if you're just a fraternal twin of a person with bipolar disorder, you only have about a 12% chance of having the disorder. So, that massive difference there is very strong evidence that there's a genetic component to the transmission of the disorder. Similarly, the more distant you get in terms of your biological relation to a person with bipolar disorder, the lower your rate or your risk of the disorder is. So, the second degree relatives of a person with bipolar disorder only have about 2% chance of getting the disorder. And that's barely above what's in the general population, which is about a 1% chance of getting the disorder. So, it's very clear that bipolar disorder has a genetic component to it.

With depression alone, major depression, there are probably versions of the disorder that have a stronger genetic component to them than others. And in particular, folks who have what's called "early onset depression," where their first episodes come on in childhood or very early adolescence, seem to have a form of depression that has a stronger genetic component to it. Whereas, people who have depression that is clearly triggered by a major life event like a trauma or a loss--those types of depression are less clearly linked strongly to genetic factors.

There are also a number of neurotransmitters that have been implicated in the mood disorders. And the class of neurotransmitters that's been researched most often is what's called the monoamines. I'm sure you've heard about the link between serotonin and depression, but there are two other monoamines, norepinephrine and dopamine, that have also been linked to both of the mood disorders, both bipolar disorder and depression. And it used to be thought that it was just that in

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people with depression they didn't have enough of these neurotransmitters, enough serotonin, in particular, in the system, in the brain, in order to function normally. But now the theories on what the role of neurotransmitters is have a lot more to do with the receptors for these neurotransmitters and their functioning. And the notion is that the receptors for neurotransmitters like serotonin don't function efficiently. So, even if there's enough of the chemicals in the synapses in the brain, the neurons can't make use of them because the receptors aren't functioning appropriately. And so what the drugs that help relieve depression do is to improve the functioning of these neurotransmitters.

There's a very interesting line of work that's going on right now looking at the intersection of genetic predisposition neurotransmitter functioning and stress. And we have one of the world's experts on this kind of work now here at Yale, Julia Kim-Cohen, who just joined us in the last year. But there are several recent studies. There's another person in psychiatry, Joan Kaufman, who's done some of this work. But there are several recent studies that find that certain variations or polymorphisms on the serotonin transporter gene predict who will become depressed in the face of stress.

So, a classic study was done by Avshalom Caspi and colleagues, and they found that people who have one or two of what's called the short allele on the serotonin transporter gene--so this is a particular variation on the serotonin transporter gene--if they had one or two of these short alleles and they were confronted with stress, they were more likely to develop depression. But it's important to sort of dissect this. So people who had--it didn't really matter which of these genes you had. If you were never confronted with major kinds of stress, like maltreatment, if you weren't confronted with stress, you were no more likely to have depression regardless of what kind of serotonin gene you had. But if you had either one short allele or two short alleles and you were confronted with maltreatment as a child, you had a much greater probability of becoming depressed at some time in your life. And this has been replicated with other samples, with other forms of major trauma. And basically the story is, it takes the intersection of a genetic predisposition and major stress to create full-blown depression in some people. Now, that may not be true for all genetic predispositions or all forms of depression, but this serotonin finding has actually been replicated now in at least four different studies. So, it seems to be a pretty reliable effect. So again, genes do not determine the disorder, but the intersection of genes and stress seems to be a major risk factor for the disorder.

There are a number of brain areas that seem to be involved in the mood disorders where there is just dysregulation or dysfunction. The prefrontal cortex, as you probably have studied, is an area of the brain that's very involved in higher order complex thinking and problem solving and in goal-directed behavior. In people with depression, there's lowered activity in the prefrontal cortex, suggesting that--which may play a role in the difficulties in concentration, in goal-directed behavior, in planning and problem solving and in regulating emotion.

The amygdala is an area of the brain that is involved in the processing of emotional information. And people with mood disorders show overactive amygdala responses to emotional information. This is true in both bipolar and in depression. The hippocampus is an area of the brain that's very involved in memory and in concentration. And in people with chronic depression, you often see shrinkage in the hippocampus, and this may be related to their problems in concentration and attention. And then finally, the anterior cingulate is an area of the brain that's involved in a lot of different activities, but pertinent to the mood disorders, particularly in responses to distress--to stress and in sort of the choice of behaviors. And it may be that dysregulation of the anterior cingulate may be involved in the person's difficulty in responding appropriately to stress, in choosing good coping behaviors and changing their behaviors whenever their behaviors aren't working well.

So, from the biological theories come a number of different drugs to treat the mood disorders. Two of the older classes are called the monoamine oxidase inhibitors and the tricyclic antidepressants. The tricyclics are still used these days to some extent. They're relatively effective. About 60% of people respond well to the tricyclics, but they have a lot of side effects, and they can be fatal in overdose. And so there was a--has been always a search for other alternatives to them. The drugs that have really taken over the market are the selective serotonin re-uptake inhibitors or SSRIs. This is Paxil, Prozac and the like. They were introduced in 1987--Prozac was--in the U.S. market and truly took over the market in the treatment of depression and anxiety and a number of other disorders. Now, they're not that much more effective than the sort of old style antidepressants, but they have fewer side effects and they tend to be easier for people to tolerate.

More recently, there are selective serotonin/norepinephrine re-uptake inhibitors. These drugs, by the way, what these drugs supposedly do is to prevent the re-uptake of serotonin or serotonin and norepinephrine back into the sending neuron. So, it creates more of the neurotransmitter there in the synapse. And these are reasonably effective drugs, although, again, there's a substantial number of people who don't respond to them, especially immediately. And they'll often have to cycle through a number of drugs before they find one that works.

Lithium is the drug of choice for the treatment of bipolar disorder. It seems to stabilize the mood swings by stabilizing the number of different neurotransmitter systems. But the lithium is problematic because there are tremendous side effects. It's also dangerous for women to take while they're pregnant in terms of fetal development. So, it's a very tough drug to stay on. There are lots of gastrointestinal side effects and such, and people are often on lithium and the antidepressants because lithium often only affects the manic episodes but it doesn't really relieve the depression. And then finally anti-psychotic medications, that is those help people who've lost touch with reality, are sometimes used to treat the mood disorders whenever the person has lost touch with reality.

I'm going to go through and talk about some of the psychosocial treatments because I want to get to them as well. The cognitive behavioral therapies are based on Aaron Beck's Negative Cognitive Theory of Depression. Aaron Beck is a

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psychiatrist at the University of Pennsylvania who really founded this whole line of work. And according to Beck, this--now, this applies to depression alone. It doesn't really apply to bipolar disorder. People who are depressed have a negative view of the self, of the future and of the world, and he calls this the "negative cognitive triad." And this negative cognitive triad is fed by specific cognitive deficits or biases. So, depressed people show a lot of distortions in thinking. "All-or-nothing thinking" is thinking that things are either all good or all bad. They can't sort of see the gray areas in between. There's "emotional reasoning," and an example of that is just if I feel like a loser I must be a loser. Of if I feel stupid, I must be stupid. And then "personalization," that is the self-blame that you often see in depressed people. And these kinds of distortions in thinking, these distorted ways of interpreting situations, feed a kind of general negative view of the self and hopelessness about the future.

People who are depressed also make attributions for negative events that are internal, that is, they blame themselves--that are stable. They see bad things as lasting forever and that are global. They see bad events as affecting many areas of their life, which, again, feeds their depression and their general assumption that life is terrible. And evidence that these--for these cognitive theories, that these negative cognitive styles predict depression--one of the best studies predicting this was a study that was jointly done at Temple University and the University of Wisconsin where they identified first year college students with a negative cognitive or attributional style. But these were people who had never experienced an episode of depression yet. They then tracked them for the next two years, and the bars here--the red bars are the percent of those with a negative cognitive style who developed an episode of major depression in that two and a half years versus the percent of those without a negative cognitive style. And as you can see, there's quite a substantial difference between the two. So prospectively, these characteristics seem to predict your risk for depression.

In turn, there is a cognitive behavioral therapy that's based on Beck's theory. And the major steps in this involve identifying the themes in a person's negative thoughts and triggers for them and in helping the person challenge those thoughts by asking them what the evidence is for their interpretations, whether there are other ways of looking at the situation, how they could cope with the situation if a bad thing really did happen. So, the therapist helps the client recognize negative beliefs or assumptions and then challenges the truth value of these, and then change aspects of the environment that are related to depressive symptoms. So, they challenge your rational thinking, but they also recognize that there are really bad things that sometimes are going on the life of a person who is depressed, and they help them engage in more active problem solving to change those environments. They also teach the person ways to manage their mood so that they don't tumble down into depression. And these cognitive behavioral therapies have been shown to be extremely effective and as effective in some ways as the drug treatments.

So, this is a recent study in which they had 240 patients with major depressive disorder. They gave them four months of acute treatment with either cognitive behavioral therapy or Paxil, which is an SSRI. And in eight weeks here--they also had a placebo control group where they just got a pill, but it was a sugar pill. At eight weeks, the Paxil group, which is in red, and the CBT group, which is in yellow, were relatively even, although the Paxil group had a little bit of an edge over the CBT group. But by sixteen weeks the Paxil and CBT group were absolutely even in terms of the percent of people who were no longer depressed. So, both of them resulted in about 60% of people not being depressed.

And then one of the things that's been found over and over again with cognitive behavioral therapy is that it not only helps people get out of a current episode of depression, it helps to prevent future episodes of depression because it teaches the person new coping skills for dealing with new stressors that arise. So, in this same study they followed the patients for an additional twelve months. And of the Paxil group, half were left on full-dose medications to see if you could prevent depression by just keeping people on the meds, and half of the Paxil group were withdrawn to a placebo. And let's look at the placebo group first here.

This is the sad news about depression. If you just take drugs to get out of a current episode and you go off of the drugs without having any kind of psychotherapy, your rate of relapse tends to be very high. So, in this group of 240, almost 80% relapsed in the first year after going off of the active medication. Again, these were people who did not get any cognitive behavioral therapy. Of those people who stayed on Paxil alone, about 50% relapsed. But of those people who got cognitive behavioral therapy, only about 35% relapsed. And this kind of finding has been replicated over and over again, namely that CBT can reduce the rate of relapse in depression quite dramatically.

I want to give you a flavor for what CBT looks like, and I've got a short clip of a therapist who is actually, interestingly, the daughter of Aaron Beck and his heir in terms of the practice and development of cognitive behavioral therapy. And she's demonstrating CBT. This is actually a role play, but it's a pretty realistic role play, of how she goes after and helps to challenge a gentleman's negative cognitions about himself. This is a guy in the role who's recently lost his job and is really depressed over his job loss. [video clip playing]

Okay. I'm going to stop there because we're running out of time. But I just want to comment on a couple of things that she's doing. So, you see that she's having him generate his own challenges to his negative thoughts and write them down. And the whole--one of the major premises in CBT is it's not just what goes on in the therapy session that is effective. In fact, that's a minor part of it, but what the person practices in the time between therapy sessions. And so, what she's doing is helping him come up with a series of phrases he can say to himself when he feels discouraged and plunging down. She's

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also helping him do what's called "anticipatory coping," anticipating those situations that are going to trigger negative feelings and negative thoughts and coming up with ways of combating them in the moment that he can enact at the time.

Cognitive behavioral therapy is very structured, it's very focused and it's designed to be relatively short-term. The one other major kind of psychotherapy for depression is interpersonal therapy. It's based on the theory that negative views of the self and expectations about the self and relationships are based on upbringings that really fostered these kinds of negative self-views. And so, what you need to do is to help clients understand their negative self-views and how they're rooted in their past relationships. Interpersonal therapy is less structured than cognitive behavioral therapy, and it's more focused on the past. CBT is very focused on the present and dealing with the current situation that you're facing and combating that and developing coping styles for that.

There are a few studies comparing interpersonal therapy with CBT, but much less research has been done on IPT than CBT. But it is a positive alternative for some people, particularly those who find that their depression is very tied-up in recurrent themes in their relationships that seem to happen over and over and over again.

But to end, the good news about depression is that there are these alternative therapies. There is a number of drug therapies and there are at least two psychotherapies that good controlled research has shown can be very helpful. So, people have a choice, and there is absolutely no need for people to stay in depression but rather to seek out the kind of therapy that applies to and appeals to them the most. Good. Thanks very much.

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Lecture 19 Professor Paul Bloom: The final topic of the course is clinical psychology, also known as abnormal psychology or psychopathology, and this, for many of us, is what psychology is really about. It's about mental illness. It's about clinical psychologists. And we started talking about this when Dr. Nolen-Hoeksema gave her guest lecture last week and I want to continue through this today. It is a topic of tremendous scientific importance but also a topic of great personal importance for many of us. Many of the people in this room have been mentally ill, strictly speaking, at some point in their lives. Some of you are under some sort of therapy or treatment or medical intervention right now. Some of you are on Prozac or Zoloft or Ambien or Wellbutrin or any of those other medications to deal with psychological problems you are facing. Others are also talking to psychiatrists, psychologists, social workers, and other people.

Many of you who are not at this point mentally ill will become mentally ill during your stay at Yale. [laughter] And this is a difficult period in many people's lives and it's a period of people's lives where mental illness emerges in many of us. By one estimate, one half of all college graduates in the United States – and the number is very high with college graduates, highly educated people – one half of you will have some sort of mental illness in your life serious enough to require some sort of treatment. Those of you not directly affected with mental illness yourselves will no doubt experience your loved ones, your family, your friends getting some sort of illness, be it Alzheimer's or schizophrenia or depression or some sort of anxiety disorder. So the personal importance of clinical psychology, the personal importance of understanding what can go wrong and how best to treat it, simply can't be underestimated.

Now, when we talk about mental disorders, the scope of this is very broad. It includes the prototypical schizophrenic which you could see on the streets of New Haven, somebody walking and gesturing and talking to themselves and sometimes screaming. It includes alcohol addiction and cocaine addiction and other addictions. It includes somebody with Down syndrome or autism, an old person losing his memory, a teenager falling into a deep depression, somebody with a severe social phobia to the extent that he or she can't leave the house. Then there are also very hard cases where it's difficult to say one way or another--that guy's photographing me as I'm talking and it's freaking me out [laughs] [laughter] in kind of a social phobia way. There's difficult cases where it's just hard to tell mental illness from just [laughter as Professor Bloom waves goodbye to the photographer] bad behavior in general. So, consider a killer without a conscience or a mobster like John Gotti. Is he mentally ill? And this is a question which is a deep one and we'll wrestle with it a little bit actually towards the end of this lecture.

What about somebody who acts in a kind of unusual or zany way? This is originally supposed to be a picture of the character Kramer on "Seinfeld" but, given his unusual antics in the last few months, it could be a picture of the actor who plays him who got into all sorts of trouble. What about someone who is just kind of wacky? At what point does wackiness move into the domain of mental illness? What about unusual lifestyles such as extreme altruism? Batman devotes most of his life to helping others. He sleeps one hour a night and this hour is fraught with nightmares and then he fights crime. What about somebody, and this was a case reported in The New Yorker a few months ago, who has lots of money and a loving family and has his kidney removed to help a stranger? And he says, "I have two kidneys. It's minor pain, a minor operation. I could save someone's life." And his wife says, "You're mentally ill. That's just crazy to do that." Where do we draw the line? And so, there are these great philosophical and moral questions over the boundaries and how to think about mental illness.

So, how should we think about mental illness? Well, there are some answers we could quickly dispense with. It used to be thought that severe mental illness was a result of demonic possession. If you read the Gospels, Jesus Christ wandered around a lot, met crazy people and exorcised the demons from their bodies. It was a common way of thinking about craziness. We now believe that this is not true. What about--yeah, it's not true. What about social deviants? Some people including the psychiatrist Thomas Szasz claim that when we label somebody as mentally ill this is not a medical decision. It's rather a social decision designed to ostracize people who deviate from society's norms, to ostracize them and rid them of moral agency. It's not that we disagree with them. It's not even that we see them as evil. Rather, we see them as sick and as such we don't even have to accord to them the respect that we accord to criminals.

Now, this is not entirely an unreasonable view. In many countries around the world, dissidents, people who argue against the state, are often determined to be mentally ill and thrown in asylums. Blacks in the United States who tried to escape from slavery were described as having a mental illness. Why would they want to do so unless they were mentally ill? Up until 1973, to be a homosexual, to be gay, would count in the official records of how we classify illness as being mentally ill. And many people saw this, and we see this now, not so much as reflecting a sort of unbiased medical analysis but rather as reflecting biases that people have against gay people. And these are political and social and moral biases. They are not objective medical judgments. Even now I've been recording every president that has been the president of the United States in my memory including Bush and particularly Clinton has been described by his opponents not merely as awful, evil, terrible, "hate his policies," but as mentally ill. Every president at some point or another, some bright, intelligent person figures to call him a psychopath and put that in Time magazine. Now, put aside whether--the extent to which these things are accurate, point being that we often use medical labels, particularly labels like "psychopath," "schizophrenic," "delusional," to ostracize and pick out people we disagree with.

At the same time though, this is not entirely right. People go too far when they say there's no such thing as mental illness. Some people are mentally ill in a very real sense of "illness," in the same sense we would describe somebody as

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physically ill if they were to have cancer. This illness damages their functioning. They cannot function well. They do not tend to be more creative or more productive or more vivacious. Rather, for – with very few exceptions; possibly some exceptions revolving around mania as Dr. Nolen-Hoeksema discussed – with very few exceptions being mentally ill is just very bad for you in every possible way. Moreover, when people are treated, when people get better, they become more competent, happier, better able to participate in the world, and they do not choose to go back to their mental illness, suggesting that it really is illness in the serious sense. And so the modern treatment of psychological disorders treats them as disorders like medical disorders. Schizophrenia is as much a disease as is cancer and should be thought of in the same way.

There's a whole field of abnormal psychology of tremendous scope. We've already discussed many mental illnesses in the context of other things. So, for instance, we talked about amnesia in the context of memory and how it works. We talked about autism in the context of social reasoning. There are many more and I'm not going to read through them. These are the major categories just for people's interest from The Diagnostic and Standard Manual. You don't have to--you're not responsible for all of these. And this is an illustration, which people might find interesting, of sex differences in these--in the major disorders. And the patterns, as you could see, are kind of neat. Women are more prone to have anxiety disorders and mood disorders. Men are much more likely to suffer from substance disorders, particularly alcoholism. Schizophrenia is sort of evenly matched but antisocial personality disorders, sometimes known as sociopathy or psychopathy, is predominantly male. And we'll turn to that a bit later.

Here are the major ones which I want to review today. I'm not going to talk about mood disorders at all because this was the topic of the superb lecture we heard last week but I want to quickly review schizophrenia, the class of disorders known as anxiety disorders, the class of disorders known as dissociative disorders, and the class of disorders known as personality disorders. And these are the main psychological problems. When a psychologist or psychiatrist does his or her work, they're predominantly focused on somebody who has one of these problems. Some of them are rare but some of them such as anxiety disorders and the mood disorders are very common.

About 1% of the world's population suffers from schizophrenia and this is the most common reason for being in a mental hospital. And the reason for that is because of its severity, because of how terrible an illness it is. Schizophrenics have been described as the lepers of the twentieth century by people who pointed out that in the last hundred years people who are schizophrenics are just--there's no place for them in society. They're shunned. They're rejected. We have no idea how to treat them or how to help them. The roots of schizophrenia come from the terms "split" and "mind" but the idea is there is a split from reality. It's important to stress the sort of etymological point because sometimes people confuse schizophrenia with something--with split personality and they somehow think schizophrenia refers to having multiple personalities. This is incorrect. A multiple personality disorder is an entirely different disorder. It's a sort of dissociative disorder. Split personality--people with schizophrenia do not have multiple personalities. What they have is a problem with relating to reality. It's roughly equally split between the genders but it strikes men earlier and it happens between--around these ages and as you could see roughly--and, as you could see, it is the sort of thing that could make its first occurrence while you're in college or university.

There are five symptoms – main symptoms of schizophrenia. Four of them are the positive symptoms, meaning things that you do, that you have that's unusual. One is a negative symptom, something that you don't have, something that a schizophrenic lacks. So, just to walk through them, a hallucination is an experience, a sensory experience, that isn't real. So, the most typical hallucinations are auditory. Schizophrenics hear voices. They hear sounds, particularly people telling them to do things, that aren't real. Sometimes there are auditory--there are visual hallucinations or hallucinations of smell and taste but a typical hallucination is auditory. Sometimes the voices are seen from coming from oneself and so you could sometimes stop the hallucinations by doing things like humming or counting or holding your mouth open. And some schizophrenics will do this in an attempt to block auditory hallucinations.

There are delusions. The difference between a hallucination and a delusion is a hallucination is a sensory experience that's wrong, that just didn't really happen. A delusion is a belief that isn't right. It's a belief that you shouldn't be having. Now, again, the question of what counts as a delusion and what counts as accuracy can be a controversial one. Richard Dawkins titled his recent book The God Delusion, describing this mass delusion that many people have that they believe there's a supernatural being who created the universe and who is watching them. Some people find that offensive, to call it a delusion and people will have different views.

The delusions schizophrenics have tend to be pretty clearly weird and wrong. They often tend to believe they are famous people. Many schizophrenics have a religious bent and believe that they are Jesus Christ. In 1959, there was a Michigan hospital that had three Jesus Christs in it and they would meet and talk. One theme of delusions is what's called "ideas of reference." And ideas of reference are you think that there's all sorts of things happening that revolve around you. You hear people whispering and you think they're talking about you. You pick up the newspaper and you believe that there's coded messages in it that are directed towards you. You might believe that there is some sort of omnipotent, powerful force conspiring against you or trying to manipulate you like aliens or the FBI, the CIA, the government. You might believe that they have some sort of evil plan in mind for you.

There is disorganized speech. Some schizophrenics babble. They talk and it's nonsense. If you listen to a schizophrenic on the street, sometimes what they're saying makes no sense at all, not merely that they're conveying ideas

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that are unreasonable but it's just garbled, it's just a mess. And sometimes there is disorganized behavior too, odd motor movements. And the most extreme cases of this are motor movements described as "catatonic" where the person doesn't move, often freezes in a position.

Those are all positive symptoms. A major negative symptom in schizophrenia is absence of normal thought or affect, affect meaning emotion. So some schizophrenics might just not talk. They might have very low emotional responses. They might not care about anything.

The basic psychological misfunction--oh, sorry. There are different subtypes of schizophrenia. There are five major subtypes but I'm going to focus on the three major ones, the three most interesting ones. The first one is paranoid schizophrenia. So, paranoid schizophrenics believe that others are spying and plotting against them. And they often have delusions of grandeur. They often believe that other people are jealous of them. They might believe they have supernatural powers. They might believe that they're God or a messiah. The catatonic schizophrenics are unresponsive to their surroundings and often they'll just repeat what people say to them, they won't generate their own speech. And finally, the disorganized schizophrenics are maybe what you most think of when you think of somebody who is insane. They make no sense. They have delusions and hallucinations. They babble. They--their actions--they could be dangerous. They could be perceived as dangerous. They're unable to help themselves. They're unable to do anything in their lives.

It's hard to pin down exactly what's at root of all of these problems but a very general summary is that there is a problem – an inability to put together your thoughts and perceptions, to sequence them and coordinate them, to impose a logical structure and a reasonable, realistic temporal sequence on your experience. This is the core thing going wrong but what happens as a result of this is you lose contact with others, you lose social contact. Losing social contact means you don't get much reality checking. If I start acting weird and nobody cares, I could just get weirder and weirder, while if I'm in a good social group of people who care about me often the situation could be brought under control. So, schizophrenia is sort of a vicious circle where you have this cognitive problem. Then you have problems losing contact with others, exaggerating the cognitive problem, and so on.

A lot of people have studied the genetics of schizophrenia. It's clear enough that there is a powerful genetic component. I could--you can tell how much at risk somebody is for becoming schizophrenic based on the schizophrenia and illness of their family members. In particular, if you have an identical twin who's schizophrenic, your odds are about a half of becoming schizophrenic yourself. At the same time, and we dealt with this as well when we talked about issues of sexual orientation, the fact that identical twins the odds are only 50% means there has to be an environmental component to it. If it was entirely genetic, it would be 100%. And so one claim--one way of looking at it is your genes make you vulnerable to schizophrenia but whether or not you become schizophrenic depends on what happens in your environment. You're sensitive to certain triggers.

Some triggers might happen early. There is some evidence that schizophrenia is associated with trauma even at the point of birth. And there's some other evidence that schizophrenia is linked to viral infections. As an example, there are more schizophrenics born in the winter, subtle--a subtle difference but there seems to be a reliable effect of more schizophrenics born in the winter. More people get sick in the winter. At times when there's been some sort of epidemic or some sort of plague, this seems to cause a jump in the frequency of schizophrenics born at that time.

There's some recent research that ties schizophrenia to the possibility of toxoplasmosis, which is a disorder carried by cat feces. The experiment basically involved asking the parents of schizophrenics one question: "Did you own a cat when your child was born?" And if the answer was "yes," it seemed to correspond to a bit higher odds for schizophrenic families than for non-schizophrenic families.

A different sort of trigger is stressful family environments. Schizophrenics seem to really have more stressful family environments than non-schizophrenics. Now, we have to be careful about this. We have to bring--we have to return to the sort of methodological cautions we had in mind when we talked about individual difference research in general. Remember we talked about the worst study in the world and one of the features of this was it was failing to pull apart cause and effect. It might be that having a difficult family environment ups your odds of becoming schizophrenic. On the other hand, it might also be that schizophrenic children or children who will become schizophrenic are difficult to deal with in certain ways causing a family environment. So, it's not clear whether the effect is from difficult family environment to later schizophrenia or from schizophrenia to difficult family environment.

There used to be a very popular theory of schizophrenia, which is that it was caused by excess dopamine. Dopamine, you'll remember, is a neurotransmitter. And there is some reason to take this seriously. Drugs that reduce dopamine provide some help in reducing symptoms. And if I give you a drug that shoots up your dopamine that will turn you into a temporary schizophrenic. You get what's called "amphetamine psychosis" and it'd give you--it can give you schizophrenic-like symptoms, hallucinations, delusions, that sort of thing. This--There might be something to this theory but we know now it can't be complete for at least two reasons. First, it doesn't explain the negative symptoms. It explains hallucinations and delusions and so on but it doesn't explain the loss of affect, the quietness, the stillness. Also, there seemed to be some sort of structural brain differences involving enlarged cerebral ventricles, involving reduced frontal lobe activity, suggesting that the problem with schizophrenia is a lot more complicated than others might have it, than the dopamine theory would have it.

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I'll end with a mystery. And this mystery is discussed nicely in the Gray textbook. The symptoms of schizophrenia, the prevalence of schizophrenics, is similar wherever you go but less industrialized countries have a better rate of recovery from schizophrenia than industrialized countries. And nobody really knows why. I listed here three possibilities. One is that the families that were--that--in a less industrialized country there's more latitude and so there's less critical- less criticism. There's less use of antipsychotic medication. Antipsychotic medications help with the symptoms but they might also impair recovery. And finally, if you think of schizophrenia as a transient disorder, maybe that will in some sense, in some way, make that more likely to actually happen.

The second sort of disorder I want to talk about, much more common than the 1% that's schizophrenia, is the classic disorders known as "anxiety disorders." The primary disturbance in anxiety disorders is anxiety; you have a lot of anxiety. It's persistent, either anxiety or maladaptive behaviors to reduce anxiety. Now, everybody experiences anxiety. If you didn't experience anxiety, you'd be a very strange person and you probably wouldn't function very well in the world, but you have an anxiety disorder when you experience too much of it, it's uncontrollable, it's unreasonable and it messes up your life. And there's quite a few anxiety disorders. The simplest one is this generalized anxiety disorders where--and this is about one in twenty people will get it at some point in their lives and you worry all the time. You're just very anxious. You're just worried all the time and it could be paralyzing. It could give you physical symptoms like headaches, stomachaches, muscle tension and irritability.

There is some evidence that generalized anxiety disorder has a genetic component, that it's somehow related to major depression. And it does seem to have its possible roots in some sort of childhood trauma. And so the model some people give for this is when you are young something really bad happens to you. This makes you hyper-vigilant. You don't trust the world, bad things could always happen around the corner. And because you're hyper-vigilant you are more prone to develop generalized anxiety disorder after a difficult life event.

A second sort of anxiety disorder, which we already discussed in class are phobias and phobias are intense, irrational fears. They could focus on objects, events, and social settings. Here's a nice diagram of different phobia, different things, and their proportion of people who are afraid of it. And the point of this diagram isn't with the details. It's really--It's rather to give you a feeling for the fact that some things most everybody is afraid of or a lot of people are afraid of and some things not many at all. The big phobic object we know from previous lectures is snakes. About 40% of the population say they're afraid of snakes. How many people here are afraid of snakes? Okay. And then there's a really terrifying thing, mice. How many people are afraid of mice? Mice are the worst things in the world. [laughter] And then cats and if you're afraid of cats that's really unusual. Not many people are afraid of cats.

There is a classical conditioning model of phobias, which we are all familiar with, but we are all familiar with why it is not a very good theory. A lot of people who are afraid of snakes have never had a bad experience with snakes. Moreover, a lot of people who have had bad experiences with things like car crashes and being electrocuted on a socket or a shooting, seeing a gun during a shooting, do not develop phobias. This lead--gives rise to a much more plausible theory known as the "preparedness theory," which says that we have evolved to be sensitive to certain phobic objects, objects that were dangerous to us in our evolutionary history. And we're prone to develop phobic responses to this.

The final anxiety disorder is obsessive-compulsive disorder. Obsessions are irrational disturbing thoughts that intrude into your consciousness. This is--hits about two to three percent of the population and it leads to compulsions, repetitive actions performed to alleviate the obsessions. For instance, you might be obsessed with the idea of being dirty, your hands are dirty, you're filthy. That might lead to compulsive washing. You might believe that God is angry at you and that might lead to compulsive prayer. Cleanliness and religion are common themes of obsessive-compulsive disorder. You often know, rationally, that these are unreasonable behaviors but you can't help yourself from doing them. Sometimes I get the worry that I left my door unlocked and I run back and checked it--check it. But I feel it's a little bit of OCD coming on because I know I locked it, but did I really lock it? And then you get--now I'm worried if I locked my door.

Checking and washing. Checking is what I'm talking about here- most common compulsions, and it seems to have a neuropsychological phenomena. At least it's related to heightened neural activity in the caudate nucleus. What's interesting is you might think obsessive-compulsive disorder is a very sort of Freudian, psychoanalytic sort of disorder but actually it's treated quite well with drugs, drugs that affect the serotonin level. Serotonin, being a neurotransmitter, can often do good work for obsessive-compulsive disorders. So, if you develop a disorder, an OCD problem, you might find yourself being cured simply with medications.

We've talked about schizophrenia and anxiety disorders. Any questions or thoughts so far? Yes. Student: What's the difference between OCD and Tourette's or are they [inaudible] Professor Paul Bloom: It's a good question. The question was the relationship between OCD and Tourette's. Tourette's is--I don't know much about it but it's a very specific neurophysiological syndrome that doesn't have--you don't have obsessive thoughts. What it leads to is involuntary tics and tremors and sometimes sort of shouted obscenities or taboo words. And it seems to be very specific to that while OCD is much broader and involves both behaviors but also the behaviors are in the service of thoughts. That's one way of thinking about the difference. Yes. Student: Can individuals have multiple disorders like be bipolar and schizophrenic?

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Professor Paul Bloom: Yes. The question is can individuals have multiple disorders? Absolutely, and in fact some disorders are "comorbid." And that's just a fancy way of saying they often go together. So, if you have a severe depression for instance, which is a mood disorder, you may also have an anxiety disorder. So yes, having one unfortunately doesn't immunize you against having another. Yes. Student: Where does superstition [inaudible] Professor Paul Bloom: The question was about superstitions. I think--it's an interesting question which I have never thought of before. I think it depends on the severity of superstitions. So, if you just have a superstition saying "Step on a crack, break your mother's back," which has never been scientifically proven, [laughter] but suppose you--and then so you're just kind of "Oh, I kind of--I just kind of--" or it's bad luck to break a mirror and that's it, you just have it and it doesn't make a big deal to you, that's harmless. On the other hand, if your superstition is such that you develop weird rituals; you might have to carefully walk so you don't step on any other--on any cracks or you might have to do--or if you do you might have to go back and start your whole walk to work over again. When it gets to that level it could creep into OCD. And often obsessive-compulsive disorders have a religious or a magical manifestation where you believe there are certain things you must do or terrible things will happen and in that way you could view them as extreme and build from superstitions, but simple superstitions don't tend to be of that type. Yes, in back. Student: [inaudible] Professor Paul Bloom: The question is "are people with schizophrenia dangerous?" As a rule statistically, it tends not to be the case. They tend to be more likely victims than harmful. They tend to be fairly helpless. You can have a case where a schizophrenic might harm somebody. A paranoid schizophrenic, for instance, might develop a delusion to harm somebody and so there are definitely such cases but for the most part, again, they are more victims than oppressors. They're more--they're very vulnerable because they aren't capable of dealing with other people. They often aren't capable of defending themselves. One more. Yes. Student: How permanent are the effects of the medications? Professor Paul Bloom: The question is, "How permanent is the effect of the medication?" Do you mean for schizophrenia? Student: Do they have to stay on the medication for [inaudible] Professor Paul Bloom: Yes. In general, I think. I can't think of any exceptions. The effects of medication are temporary. Now, that doesn't mean if you have a bout of OCD or depression you have to be on medication the rest of your life. What could happen is, for instance, somebody--if you had a mild depression, go on something like Prozac or Wellbutrin, use that time to kind of get your life back together, cheer up a bit, and then when they go off the medication they are fine. But as Professor Nolen-Hoeksema pointed out, unless they've developed coping skills they're likely to relapse and get the problem again. So, the physical effects of medication are always temporary, particularly with anybody with schizophrenia, but they can often help people get out of a problem, anxiety or depression.

Okay. Dissociative disorders. I'll show you a movie clip and then we'll go back and talk a little bit about it. [clip playing]

Let me ask you a question that might seem somewhat uncaring. How many of you think he's faking? How many of you [laughter] are confident there are many people living inside his head as--in the way it's depicted? Okay. How many of you are unsure? How many of you have two minds? There is one part of you struggling-- [laughter] It's--let's go--we'll go back to him.

Dissociative disorder are disorders involving dissociation. And what people mean by that is literally a dissociation of memory; that is, you become somehow unaware, separated from some part of your identity or history and you're unable to recall those parts of your identity and history except sometimes under special circumstances. Now, some degree of dissociation is normal. There is--I will--I have here in, actually, Dr. Nolen-Hoeksema's excellent abnormal psychology textbook a checklist of dissociative experiences many of which normal people have: "Not sure whether one has done something or only thought about it." Anybody ever have that? Common. "So involved in the fantasy that it seems real." [laughter] "Feeling as though one's body is not one's own." I will also add that experiments with pharmaceuticals can often lead to dissociative experiences. [laughter] "Driving a car and realizing that one doesn't remember part of the trip. Talking out loud to oneself when alone." Okay. "Not recognizing one's reflection in a mirror." Okay. That's not very common [laughter] but it is--it's within the normal range but then you get more severe cases and there is three different types: dissociative amnesia, dissociative fugue, and dissociative identity disorder.

Dissociative amnesia is illustrated in a story of a woman who sees something terrible and as a result her memory of that experience was no longer accessible. It's often known as "psychogenic amnesia." The only thing wrong in here is you have memory loss. And sometimes it's a selective memory loss but sometimes it could be global. It's as in these movies cases where you lose your memory because something terrible has happened and you would get it back later but you have a temporary loss of identity. The idea is that something so terrible has happened you separate yourself from your previous identity and your memory. Over half of people charged with homicide claim to have some degree of dissociative amnesia. The problem here is that many, many, many of those cases involve alcohol and drugs, which can lead to some sort of alcoholic blackout. Also, people could be lying. If you're charged with murder, it's often a reasonable thing to say, "I don't remember any of this," to just kind of--and--as a way to distance yourself from it.

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Dissociative fugue is kind of weird and interesting. The guy's wife leaves him for another man. Six months later he was discovered tending bar in Miami Beach and calling himself Martin. And he totally wiped out his past memory and developed a new identity. This is also known as "psychogenic fugue." So, it's global amnesia but there's also identity replacement. You leave home, you develop a new identity, and it's called a fugue state. This is my favorite mental disorder. If I had to get a serious mental disorder, I would get this because I'd get to travel. When it wears off your old identity comes back and your new identity is forgotten.

Then there's dissociative identity disorder and this is a story of this woman who goes back and forth from her regular personality to a personality of Donna who is only six years old. This was originally known as ""multiple personality disorder" and the idea is you have two or more distinct people in one head. It is--there are--It is a rare and controversial disorder but it includes some very famous cases and has been illustrated in many movies and books including the wonderful movie Primal Fear where--Ed Norton's first big movie, highly recommend it. And it's been tried as a criminal defense. The Hillside Strangler claimed to be two people but he was still convicted, both of them. It typically starts early, the pattern of dissociation. Mostly it's women. And mostly, it involves some sort of recollection of torture or sexual abuse. Also, and to get back to your question, can you have more than one mental disorder at the same time, people with dissociative disorder often show symptoms of posttraumatic stress disorder or PTSD.

What causes it? Well, it is often argued to be the cause--caused by severe abuse, often sexual or physical abuse. The problem is most people who get abused don't develop dissociative identity disorder. And one idea is that it's abuse plus some sort of genetic or biological predisposition to dissociate and in fact, people with dissociative identity disorder seem to be very susceptible. They're easier to hypnotize than other people. And so it might begin as sort of a self--an act of self-hypnosis. You put yourself in a hypnotic trance to cope with some terrible situation and you begin to develop new and separate and distinct personalities.

Now, of the many things I'm going to talk to you, I've talked--spoken about, some have been very controversial. One issue of controversy which we talked about was the existence in nature of so-called "repressed memories." This is another very controversial case related to the repressed memory case. In a recent poll, less than one quarter of psychiatrists believe there is such a thing as dissociative identity disorder. Why would you doubt that? Well, there are some curious statistics. Between 1930 and 1960, there were two cases in the United States. In the 1980s, there were 20,000 cases. You cannot go elsewhere from the United States and find people with dissociative identity disorder. It seems to be an American phenomena. And it varies by therapists. Some therapists, indeed some hospitals, some medical units go decades without ever seeing anybody that approaches dissociative identity disorder. Other therapists, virtually every patient they have has multiple personalities.

One worry based on these facts is dissociative identity disorder is in a sense real, that Richard really does believe he's moving from personality to personality but he didn't come in to therapy with that problem. Rather, his therapist gave it to him. The claim is that it's the result of suggestion by the therapist. The therapists, and they're typically good people who wish to help, but the therapists might be in the grips of a theory involving repression and multiple personalities and different selves and encourage, either tacitly or overtly, their patients to develop these separate personalities.

Related to this, it's not clear to what extent dissociative identity disorder is an extreme version of normal psychopathology--sorry, of normal psychology. So people, from the philosopher Dan Dennett to the psychologist Judith Harris, have pointed out that we're different selves in different situations. We can consciously play act the different selves but we could also just shift personalities depending on whether we're with our friends or our family or with strangers. The claim is that dissociative identity disorder, however dramatic it looks, might merely be an extended version of this where people as well are to some extent play acting to make their therapists and doctors happy. Any questions about dissociative identity disorder? Yes. Student: [inaudible] Professor Paul Bloom: Yes. Dissociative amnesia--the question involves the relationship between dissociative amnesia and the retrograde and anterograde amnesia discussed before. Those other amnesias are the result of brain damage. They tend to be if not permanent long lasting and severe. Dissociative amnesia is apparently caused by specific life events and can often be very short-lived. They're, of course, all brain events but in the crude sense the dissociative amnesia is more of a psychological happening than the other sorts of amnesias that we talked about involving Korsakoff syndrome and the patient "HM" and so on. Other questions. Yes, in back. Student: [inaudible] Professor Paul Bloom: Yes. What happened in 1960--There was a very famous case. I think the case was the case of Sybil. Does anybody know? The teaching fellows are nodding but there was a very famous case which I think was of Sybil which was made into a movie and discussed and had a huge influence on people and then they started to believe that it was real.

There is a type--The fourth and final type of disorder is something which is not actually discussed in the Gray textbook but it has to do with personality and this is interesting because it probably extends to some extent to many of these people--the people in this room. Personality, as you remember, is your way of dealing with the world, in particular the way you have of dealing with other people. The notion of personality disorders is that some personalities are so bad that they

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veer off into mental illness so one personality disorder is a narcissistic personality disorder. Everyone likes to talk about themselves and thinks they're terrific to some extent, some people to a little bit too much, but if it's really extreme they could talk--they--you could get labeled with a narcissistic personality disorder. You might have an avoidant personality disorder, dependent, histrionic, borderline. Borderline is really bad. When people describe you as a borderline personality disorder, that just means you're just awful to be with, you're kind of awful. [laughter] There is the paranoid personality disorder which is not that you're paranoid schizophrenic, very clearly no signs of schizophrenia, no hallucinations, nothing like that. You are just paranoid. You're just--to a greater extent than normal, you think other people are against you and plotting against you.

The most interesting personality disorders in my mind have to do with violence and crime and they have to do in particular with something called "antisocial personality disorder." Now, most murderers are not mentally ill in a medical sense. They're not mentally ill according to how clinicians categorize things. To some extent, most people who kill are just normal people being driven by normal desires, rage, jealousy, hate, just taken to an extreme. Even mass murderers do not as a rule appear to be substantively different from a psychological point of view. In every society--and honestly, I wrote the lecture on this quite a while ago but, given the recent events, they stand as a perfectly good example of what I'm going to say. In every society there is a notion of somebody who has been deeply humiliated, usually male, and he's been humiliated over and over again. He sees himself as losing status and losing status and losing status and he tries to get it all back, to gain face with one act of terrible violence where he takes his revenge over everybody and then is known as--and as a result, even though he might die, he probably will die, makes his way to a level of social status he would have never gotten before. The American term for this used to be "going postal" and--but this is an old idea. Stone Age tribes in Papua, New Guinea, had a term for this. They call it "running amok" and this is--and every society has this.

So, there's normal murderers, there's mass murderers, and then there's the interesting cases like serial killers like Dahmer or Son of Sam, Ted Bundy, John Wayne Gacy, even the imaginary Hannibal Lecter. Many of these sort of serial killers do have some sort of mental illness but the mental illnesses are all over the place. There was a guy, Jerome Brudos, who had such a severe fetish for women's feet that he killed young women and severed their feet and then kept their feet around his house. Son of Sam was pretty clearly a paranoid schizophrenic. He did his murders because a barking dog told him to. Jeffrey Dahmer is a cannibal killer and he killed people so he could eat them and then--and I asked one of my colleagues in clinical--colleagues what exactly was wrong with him and the person immediately responded, "He has a severe eating disorder." [laughter] So, it's--it was a joke. It was in very, very bad taste. [laughter] A lot of [laughter] murderers claim to have dissociative disorders, "it wasn't me who killed the guy, it was my alter ego, Fred." It's not clear how often they're telling the truth, if ever or whether this is a way of escaping responsibility.

There is a mental illness--There's an extreme, specific version of a personality disorder that revolves around violence, and this is known as "antisocial personality disorder." It is--it used to be called moral insanity. Now it's often called psychopathy. Some people make a distinction between psychopath and sociopath. For the purposes here others don't, and for the purposes here I'm going to blend them into one category. Then I'll use the term "psychopath." They're typically male. They are defined as selfish, callous, impulsive, they're sexually promiscuous. They seem to lack love, loyalty, normal feelings of affiliation and compassion, and they get into all sorts of trouble because they're easily bored and they seek out stimulation. Now, when you hear this, you've got to realize that this sort of person is not necessarily an unattractive person to imagine or think about or even under some circumstances to encounter. You have to avoid the temptation when you think about psychopath to think about a guy like this, to think about Hannibal Lecter. The most famous psychopath, of course, is James Bond who is a perfect psychopath in every regard as played by him also by Sean Connery. The Roger Moore and Timothy Dalton characters were not psychopaths. I could give a whole course on that.

Is this an illness? Well, again, this is one of the hard cases. Psychopaths don't come in for treatment. James Bond would never go to a therapist and say, "I have a problem with promiscuity and my life of adventure. [laughter] Why is it that I don't have this need to settle down and have kids and be a one-woman man?" They don't have a problem with it. Other people often have a problem with it but it's not clear that's enough to make it a mental disorder. Also, a lot of psychopaths are reasonably successful. Now, this gets complicated because psychologists study psychopaths but the psychopaths that they study are by definition unsuccessful psychopaths. And what some people have argued is the real psychopaths, the successful ones, are the ones that run the world, that excel in every field because they are successful enough that they don't look like psychopaths. They have no conscience, no compassion, love, loyalty. They are cold-blooded and ambitious but they don't go around making this so obvious that we throw them in prison. And so, it's an interesting and subtle and complicated case.

The final section – and I'll start this and we'll go five minutes into this and then move--continue it next week with the final class – concerns therapy. Now, the most interesting thing for us to deal with is the question of, "Does therapy work?" And there's a lot to be said about this. The history of therapy has been gruesome and unsuccessful. Again, to be mad was to be viewed as to be in league with the devil and so people with mental illnesses were tortured to death, burnt, sent out to sea and so on. In the eighteenth century they were thought of as degenerates and sent away from society. In the nineteenth century there was a brief blast of compassion where Pinel tried to have mental hospitals and then there were all sorts of--since then all sorts of medical treatments that were considerably less successful and this brief video will summarize some of the previous medical treatments. [video playing]

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I often wonder a hundred years from now how they're going to look at our current therapies and then whether they'll see them as equally barbaric and stupid as we look at the therapies in the past. What I'll begin next lecture with is a very quick discussion of what therapies work of the ones currently available and then I'll end the class. And this will be a somewhat short class. I'll end the class with a discussion of happiness. There is an optional thing I'll add, which is your reading responses are done and you'll have the opportunity to make comments on the class in anonymous evaluations but what I'm kind of interested in is if people could send me an e-mail, and this is entirely optional, about the most interesting thing that we've covered in this class. I'm curious what people think it is and it's something which I could try to build up on for future classes. So, again, this is optional. Just give it a subject heading "Intro Psych" and send it to me if you choose to do it and I'll see you on Wednesday.

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Lecture 20 Professor Paul Bloom: This lecture will be a some slightly shorter lecture than usual. What I first want to do is finish off the discussion of clinical psychology from last lecture and then have a little brief discussion about some very interesting research on happiness. We talked--we ended last lecture with a discussion of some early--some of the history of treating mental illness and we saw that it was rather gruesome, unsuccessful, and arbitrary. For the most part, we do better now, and Dr. Nolen-Hoeksema reviewed some of the therapies with focus on therapies for depression. The textbook talks in detail about therapies for different disorders including schizophrenia, anxiety disorders, and so on. The question which everyone is interested in is, "Does therapy work?" And this proves to be surprisingly difficult to tell. Part of the problem is if you ask people who go into therapy, "Did you get better after therapy?" for the most part they'll tell you that they did but the problem is this could be a statistical byproduct of what's called "regression to the mean."

So, the idea looks like this. This line plots how you feel from great through okay to awful and it goes up and down and in fact in everyday life you're going to--some days are going to be average, some days will be better than average, some days worse than average. You could plot your semester. You could do a plot every morning when you wake up or every night before you go to bed. You could put yourself on a graph and it'll come out to some sort of wiggly thing. Statistically, if something is above average or below average it's going to trend towards average just because that's a statistical inevitability. When do people go to therapy? Well, they go to therapy when they're feeling really crappy. They go to therapy when they're feeling unusually bad. Even if therapy then has no effect at all, if it's true that people's moods tend to go up and down after you feel really bad you'll probably improve rather than get worse. And so this could happen--the normal flow could happen just even if therapy has no effect at all.

And so, simply getting better after therapy doesn't tell you anything. On the worst day of your life you could do naked jumping jacks on the roof of your college for ten minutes. I guarantee you your next day would probably be better. That doesn't mean naked jumping jacks are helping you. Rather, it just means that the day after the worst day of your life usually is not as bad as the worst day of your life. It can get worse, but usually it just trends to average. What you've got to do then is you have to take people at the same point who would get treatment and compare them to people who do not get treatment or what we call a "control group." And this is an example of this. So, this is for people who are depressed. This is statistically equal. They start off pre-therapy. They all go for therapy but because in this example there's a limited number of therapists, some of them are put on a waiting list and others get a therapist. It's arbitrary. It's random, which is--which--making it a very good experiment. And in this example, you could see those who received cognitive training were better off. They had lower depression scores than those that received no therapy at all.

In general, in fact, we could make some general conclusions about therapy. Therapy by and large works. People in treatment do better than those who are not in treatment and that's not merely because they choose to go into treatment. Rather, it's people who are in desperate straits who seek out help. Those who get help are likely to be better off than those that don't get help. Therapy for the most part works. We can't cure a lot of things but we can often make them better.

Different sorts of therapy works best for different problems, and again, depression proves to be an illustrative example. If you have everyday unipolar depression, that is, you feel very sad and you show other symptoms associated with depression, an excellent treatment for you is some combination of cognitive behavioral therapy and possibly antidepressant medications like SSRIs. If you have bipolar depression, the cognitive behavioral therapy is useless but medication is your best bet and so on for all of the other disorders. Each disorder has some sort of optimal mode of treatment. If you suffer from an anxiety disorder, cognitive behavioral therapy can be of help. If you're a schizophrenic it's probably not going to be of much help at all. And so, different disorders go best with different sorts of therapies. Finally, some therapists do better than others. So, for reasons that nobody fully understands, there are good therapists and then there are better therapists and there are bad therapists. And there's great individual differences in the efficacy of an individual therapist.

Finally, putting aside then the difference in therapies and the difference in therapists, does it make sense to say that therapy, in general, works? And the answer is "yes." And this is in large part because of what clinical psychologists describe as "nonspecific factors." And what this just is a term meaning properties that all therapies, or virtually all therapies, share and I've listed two of them here.

One of them is "support." No matter what sort of therapy you're getting involved in, be it a psychoanalyst or a behavior therapist or a cognitive therapist or a psychiatrist who prescribes you medication or someone who makes you go through different exercises or keeps a journal, you have some sense of support, some acceptance, empathy, encouragement, guidance. You have a human touch. You have somebody who for at least some of the day really cares about you and wants you to be better and that could make a huge difference.

Also you have hope. Typically, there's an enthusiasm behind therapy. There's a sense that this might really make me get better and that hope could be powerful. Sometimes this is viewed under the rubric of a placebo effect, which is that maybe the benefits you get from therapy aren't due to anything in particular the therapist does to you but rather to the belief that things are going to get better, something is being done that will help you. And this belief can be a self-fulfilling prophecy. "Placebo effect" is often used sort of in a dismissive way, "Oh, it's just a placebo," but placebos can be powerful and even if it's useless from a real point--from a psychological theory point of view, even if the therapist runs around and dances while

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you – I have dancing on my mind now – while you sit in the chair and watch him dance; if you believe the dancing is going to make you better, it may well help. Okay. That's all I'm going to say about therapy. Any questions about therapy? Yes. Student: [inaudible] Professor Paul Bloom: Fair enough. The question is the assumption of regression to the mean seems sort of arbitrary because it depends what the mean is. Always after the fact you can apply an average to it and say, "Look. This is the average," but how do you know beforehand? It's a good point. When you talk about regression to the mean, it adopts certain assumptions. The assumption is there really is an average throughout much of your life and things go up and down within that average and for the most part that's true for things like mood. For most of us, we have an average mood and we have bad days and we have good days. It's always possible that you have a bad day and then from there on in it's just going to go down and down and down but statistically the best bet is if you have a bad day you're going to go back up to the mean. It's--in some way you don't even have to see it from a clinical point of view. You could map it out yourself. Map out your moods and the days where you're most depressed sooner or later you're likely to go up. Similarly, on the happiest day of your life odds are the next day you're going to go down and there's nothing magical about this. This is just because under the assumption that there really is an average in--built into one--each of us. If human behavior was arbitrary, it would be like a random walk but it's not. We seem to have sort of set points and aspects of us that we fall back to that make the idea of a mean a psychologically plausible claim. Yes. Student: [inaudible] Professor Paul Bloom: That's a good question. Yes. In that study it's a perfectly good hypothesis that the sort of anxiety of being told, "I see you've come here for help. We can't give it to you. Congratulations. You're a control group" [laughs] causes anxiety. In other studies the control group doesn't know they are the control group. So sometimes you can do an intervention where you say, "Congratulations, everybody in Intro Psych who did very low on the depression inventory," which many of you filled out, "We're going to do something to you." And then the rest of the people don't even know that they haven't been chosen. So, you're right. It's a perfectly good point. Knowing you're not chosen could have a deleterious effect and the way to respond to that is you have other studies that don't use that same method.

Okay. I want to end with happiness and it's a strange thing to talk about in psychology. Most of psychology focuses on human misery, most of clinical psychology. There is the psychology we spoke about through most of the semester on vision and language and social behavior, but typically when people think about interventions what they think about is people having problems and then we figure out how to make them better. They are schizophrenic, they are depressed or anxious, they are just not making it in life, and psychologists try to figure out how to make things improve. And in fact, a lot of the information I gave you at the beginning of the lecture last class where I reviewed all of the disorders is in this wonderful book called DSM-IV, The Diagnostic and Statistical Manual of Mental Disorders. If you ever really want to get--If you really [laughs] want to diagnose people and come to have a belief in your own mental instability, browsing through that book is a treat. Everything that can go wrong in mental life from Aspergers syndrome to fetishes to paranoid schizophrenia is all in that wonderful book and--but a lot of psychologists have been disturbed by the focus of our field on taking bad people, people who are broken, people who are sad, and bringing them up to normal. And they've started to ask can psychology give us any insight into human flourishing, how to take people who are--who--how to study people who are psychological successes, how to take people who are psychologically okay and make them better. And this is the movement known as "positive psychology." And it has its own handbook now, The Handbook of Positive Psychology, listing psychological strengths, listing virtues, ways--what psychology tells us about how we can be at our best.

Some of this work in positive psychology is, in my mind, real crap. A lot of it is some combination of new age banalities by people who are striving to get more grant funds and end up on Time magazine. On the other hand--and so, some of it is really bad. You could imagine this attracts every self-help huckster you could imagine. On the other hand, a lot of this work is quite neat, quite interesting and quite promising. And what I want to do is tell you what I think is the most interesting research from this movement concerning happiness.

Now, there are a lot of good books on this and I'm going to recommend books, which I haven't been doing much in this class. Marty Seligman is the pioneer of positive psychology and he's written an excellent book called Authentic Happiness. Jonathan Haidt is a brilliant young scholar who's done--also done a lot of work on disgust and morality. He did the "sex with dead chicken study" we discussed earlier. This is one of my favorite books by – Happiness by Nettle, because it's smart, it's beautifully written and it's extremely short. And Dan Gilbert's book, Stumbling on Happiness, is a very, very funny book and very smart book and is now on The New York Times bestseller list. So, there's no shortage of books on happiness.

So, the starting point is--And a lot of research on happiness starts with a basic question: How happy are you? And we're psychologists so tell us on a scale of one to ten where five is average, ten is super-duper. The most common answers, interestingly enough, are high. They're seven or eight. How many people in this room would give themselves a seven or an eight? Okay. How many a nine or a ten? All right. How many a ten? Good, good, maxed out on happiness. It turns out that most people think that they're pretty happy. There's a Lake Wobegon effect with happiness. Most people think they're very happy. In fact, most people think they're happier than most people, which shouldn't really happen.

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This question, "How happy are you from one to ten?" has been asked all over the world. So--and it turns out there are slight differences depending on how old you are. There are slight differences depending on your place within a country, California versus New York. There are slight, subtle differences between men and women at different points, somewhat paradoxically. Although women are more vulnerable to depression than men, still on average women are slightly happier than men. The country-by-country data is quite interesting. In one study they looked at forty-two countries. The happiest--well, let me see. The happiest people on earth--well, first, no country believed they were unhappy, the people in no country of these forty-two countries. I mean, you're thinking there are some really bad countries to live in and I don't know if they were tested but of these forty-two everybody seemed--said they were above average. The happiest people on earth? The Swiss. [laughter] They think--they're just like--they're just so happy. I was talking to people about this last night and they suggested chocolate. [laughter] The saddest people on this--on the sample? The sad Bulgarians. [laughter] You are wondering what about Americans. Americans are actually pretty happy, 7.71. We are a happy country full of happy people.

Now, I'm going to talk about a lot of research that's based on the data you get when you ask people how happy they are from a scale of one to ten. But I'm going to be honest and tell you there are reasons to be cautious about these numbers. And the reasons come from a couple of experiments. In one experiment they asked people inside a psychology department where there was a photocopy machine. They went up to people--the people were going up to the photocopy machine to make copies and when they were done making copies they asked them, "How happy are you with your entire life?" There were two groups. Group A, they put a dime on top of the photocopy machine so people walked over there, "I'm going to [inaudible]. Oh, a dime. Well." The other group, no dime. It turned out that when asked "How good is your whole life?" [laughter] group A reported [laughter] greater life satisfaction overall in their entire lives.

Another study asked people how happy you are with your whole life on sunny days like today and people said they were happier on sunny days than rainy days. What's interesting is you could make this effect go away if you ask immediately before "How's the weather?" These were done by phone interviews. And logically, what seems to go on is that if you're asked how's the weather, you're "Oh, it's really sunny outside," and then when people are asked "How happy are you with your whole life?" people then say, "Oh, okay. I'm going to take into account the sunny-ness when I give my answer.

Okay. So, what is happiness? What are people rating when they're answering these sort of questions? And this is an extraordinarily difficult question and one could devote a seminar to discussing it, but one simple answer from an evolutionary point of view is that happiness--forget about "what is happiness?" Ask "what's happiness for?" just like we've asked what language is for, or what laughter is for, or what hunger or lust is for. What's happiness for? And one answer is happiness is a goal state that we've evolved to pursue. It's a signal that our needs have been satisfied. Happiness is the carrot we're running towards that makes us take care of our lives. We want to be happy. An example of this is food. You're not very happy if you're starving. You want to be satiated, you want to be satisfied, so you seek out food to fill your belly. Once you've done it, you're happy.

Steven Pinker summarizes the keys to happiness in a nicely evocative passage: "We are happier when we are healthy, well-fed, comfortable, safe, prosperous, knowledgeable, respected, non-celibate, in love." How many people here have got all of those right now? Oh, come on. [laughter] Some people. Oddly enough, the person who said he was a ten didn't--does not raise his hand. Okay. [laughter] So this is- And this makes out--you get all your needs satisfied, your belly is full, people love you, you're getting sex regularly, you're smart, you're rich, you're happy, but as Pinker points out it's not that simple.

Here's the problem. You, Americans in this century, you are now healthier, better fed and so on than just about anyone in history but you're not happier. That's the puzzle. In particular, these studies asking about happiness have been around for a long time. People in the 1950s did not make as much money, did not eat as well, did not live as long, suffered from more diseases, were more vulnerable in a hundred different ways, yet they were--are as happy as you are now. You are as happy as your parents were and they were as happy as your grandparents. Moreover, in poor countries people don't have the shelter, the knowledge, the protection, the safety, yet, for the most part, there's not a huge effect on how rich a country is and--on how happy the people are.

Furthermore, there are great individual differences in happiness among people whose basic needs are met. For the most part, everybody in this room is fed and sheltered and safe. Some of you are prosperous, some of you are knowledgeable, a couple non-celibate, and-- [laughter] but even among that group you vary in your happiness, and that's kind of a puzzle. And to explain the puzzle we need to talk about a few surprising facts about happiness and I'll present three of them.

The first is happiness doesn't change as much as you think. In particular, happiness is not as sensitive to what happens--your happiness is not as sensitive to what happens in your environment as you might think it is. Part of the reason for this is that there appears to be a strong heritable basis for happiness. So, just as we talked about the domains of personality and intelligence, there is some genetic determination, not entirely but some, in how happy you are. And some people talk in terms of a genetically determined set point. So, you have a sort of natural happiness level, maybe a range. To put it in extreme form, some people are genetically predisposed to be pretty sour, others to be pretty cheerful. Well, that can't be it. Identical twins are very similar in their happiness but, as with everything else we've discussed, they're not identical.

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What about life events? Wouldn't life events change your happiness? And here we're entering one of the great discoveries of happiness research.

Think for a moment. What's the worst thing that could happen to you? And then ask how much would it change your happiness. Now, think for a moment. What's the best thing that could happen to you? And ask how much would it change your happiness. And the research in happiness suggests that your gut feelings are probably wrong. And here's a couple of case studies.

For many people a very bad thing that could happen to you is to be paralyzed from the neck down in an accident. It turns out obviously, common sense, that when this happens it makes people very unhappy. It makes them depressed, they think their life is over, they feel terribly sad, but not for that long. After about a year after being paralyzed from the neck down, people's happiness comes back up pretty much to where it was before, suggesting that there's a temporary effect but not a permanent one. Many people believe that winning many, many millions of dollars in the lottery will make you happier and it does. When you open up that winning ticket and you say, "I won one hundred million dollars," you say, "Woo, hoo!" You are honest to God very happy. You'd say, "Hell, I'm a 10.5, I am very happy." A year later you are not as happy. In fact, lottery winning may be a terrible case where people--where it goes the reverse of what you expect. What happens when you win a lot of money is it often wrenches you away from your family, your work and your friends and leads you to depression and sadness but even mundane events that would make you happy--that you think would make you happy don't seem to last.

In some research by Dan Gilbert and others, they've asked young assistant professors who are coming up for tenure, and tenure in a university system is a good thing to get because it gives you lifetime job security, "How happy would you feel if you got tenure? How happy would you feel if you didn't get tenure?" Prior to the last election, they asked people "How happy would you be if it was President Bush? How happy would you be if it was President Kerry?" And it turns out people radically overestimated the effects of these things. Having your favorite candidate win is not such a big deal. Having your favorite candidate lose is not such a big deal either. Getting tenure or not getting tenure are really big when it happens. Six months later and a year later your happiness doesn't seem to be affected.

The purchase of consumer goods, an Xbox 360, a nice flat screen TV, those sorts of things make you very happy when you open up the package and set it up but this happiness fades almost immediately. The moral of--A lot of people are shaking their heads. It's true, not for me but--the moral of a lot of this work is we think these things will have big permanent and profound effects but they need not and they often don't.

Why not? Why do we overestimate their happiness? And the technical term for this, by the way, is "affective forecasting." Again, this is Dan Gilbert's work and the idea is we are bad at affective forecasting. That is, we are bad at predicting how happy or sad we will be in the future based on what's happening to us. Why? Well, a couple of reasons. One thing is there's often a failure to appreciate the day-to-day irrelevance of certain events. So prior to the election--the election's happening tomorrow and I ask somebody who's a diehard Democrat, "How would you feel if Bush won?" and the person said, "I'll be miserable. It'll be a miserable four years afterwards." But what often isn't appreciated here is that whether or not Bush wins will make you sad or happy after it happens but for the most of your day-to-day life you aren't thinking about who the president is. I'd be very happy if I won a huge prize and I'd be "Whoa, a huge prize," the Nobel prize, a Guggenheim, a MacArthur ʻGenius' or I get them all in the same day. [laughter] "What a day. I am really happy." But then a month later I'm there and I've still got my regular insomnia and there's nothing on TV and the plumber's not coming and my kids don't respect me and I can't--and the fact that "Yeah, but I won the prize," it doesn't matter. A lot of the things in life that'll make you really--that you think will make you really happy don't have this day-to-day effect.

Also, there is the logic of the set point. And this comes to a terrible word: We adapt. Right now I'm a guy without a Nobel prize. I'm kind of used to it. If I got a Nobel prize I'd be a guy with a Nobel prize. I'd be happy but then I'd kind of get used to that too. And if I got a second one, "whoa, two!" but then I'd just get used to that too. You get used to things. You get used to bad things.

Now, I don't want to overstate this. There are some very interesting exceptions. So for instance, we don't get used to noise. A lot of research suggests that if your environment is noisy, they're doing construction around you, you can't get used to it. Your happiness drops and it doesn't come back up. Your system cannot habituate to continued noise. We adapt to good things, winning the lottery, winning a prize, getting an "A " in a course. We adapt, we get used to it, also with some surprising exceptions. One of the big--one of the other surprises from happiness research is the effects of cosmetic surgery like breast enhancement and breast reduction. One of the big surprises is it makes people happier and then they stay happier. And one explanation for this is how we look is very important. It's very important for how other people see us and how we see ourselves, and you never get used to looking in a certain way. So, if you look better it just makes you happier all the time.

So, there are these exceptions but putting aside the exceptions, the problem of adaptation is sometimes called "the hedonic treadmill" and the idea is hedonic for happy. You keep on running but no matter how fast you run you stay where you are, you get used to it. Habituation is like you put--you step into a very hot bath but you get used to it. If it's a cold bath you get used to it. A difficult environment, an easy environment, you get used to it. The story is often illustrated--It's often illustrated with a story from the Bible in Ecclesiastes of a king and this king had it all. He had gardens, parks, vineyards, castles, slaves and concubines and they were both male and female concubines. [laughter] So, he had everything, right, but

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it didn't make him happy and here's what he says: "I hated life. All this vanity and a chasing after wind and there is nothing to be gained under the sun."

Now, in these books I talked about at the beginning these authors give advice on how to deal with the hedonic treadmill. How do you deal with the fact that everything you aspire to, once you get it you'll be used to it and it will lose its value? Well, one answer is that possessions are not the key to happiness. Possessions you very quickly get used to. From there, there are two alternatives. One is endless novelty. So one guy – I forget his name – wrote a book and he says, "Look. There's the hedonic treadmill. The trick is always do something different. Next week have sex with somebody you've never had sex before. Then climb Mount Everest. You get bored with that, become an accountant. Boring. Scuba diving. Boring." He had endless ideas, and that's a possibility. You never--you--if you keep changing what you're doing you'll never get used to anything and you'll always be happy. At least he says that. Then there's the old guy alternative. Step off the treadmill. Give up--give up chasing the whole happiness thing and then seek out more substantial goods that might actually not make you happy in the simple sense of a quick fix of delight, but substantial goods like friends and family and long-term projects.

So, the first moral of the science of happiness is that your happiness is actually rather fixed. It's fixed in part genetically and it's fixed in part because what happens in your life you'll get used to, to a large extent. Are you raising your hand? No. Oh, sorry. The second one is happiness is relative. So, there's a lot of research on money, power and happiness, and remember I did say before that it doesn't matter whether you come from a rich country or a poor country. As long as your country--as long as you're not starving to death, it kind of doesn't matter how rich your country is for how happy you are. But that's not the same as saying it doesn't matter how much money you make. In fact, there's a set point or a range but there is some effect on your salary and on your job on your happiness. And if you're desperately poor, no matter where you are, no matter who's around you, you're not going to be happy. But beyond that your happiness depends on your relative circumstance. And this is an old insight. H.L. Mencken wrote, "A wealthy man is one who earns a hundred dollars more than his wife's sister's husband." The idea is what matters isn't how much you make. What matters is how much you make relative to the people around you.

And they've asked people this. "What would you rather? Do you want to make seventy thousand dollars if everybody else in your office is making sixty-five thousand or seventy-five thousand dollars if everybody else is making eighty thousand?" Does it matter how much money you bring home or does it matter how much money you make relative to other people? Well, they're both factors but relative salary--and in this example people prefer this. [pointing to the relative choice] They prefer to be making less if they're making more than the people around them. It turns out that there's research on British social servants and their happiness and their health and the quality of their relationships and how they love their lives doesn't depend on how much money they make. It depends on where they are relative to everybody else.

We are very status conscious primates and your role in a hierarchy, your level in the hierarchy plays a--has a significant effect on your level of happiness. This is not really a secret. The opera star Maria Callas and the English professor Stanley Fish had the same negotiating strategy. When Fish got hired into his department, according to urban legend at least, he said, "I don't want to talk salary. I don't have a particular number in mind. I just want to get paid one hundred dollars more than whoever is the top person in this department." And that's a guy who knows about happiness. He walks in and he states, "I'm paid more than everybody else. I don't care how much it is. It's just more." [laughter] And that's relevant to happiness.

We're now in a position to give some advice to the king, summing up. First, going back again to Dr. Nolen-Hoeksema's lecture, I think the king is suffering from mild unipolar depression so we should--he should get some SSRIs and cognitive behavior therapy. I think he needs to move his castle to a quiet part of the kingdom. The noise of a busy castle is stressful. And he needs to give up on the concubines. He needs to find a queen. He needs to develop social relationships, join a club, get involved in charity, maybe a hobby. The final finding is a bit of a jump to a different topic but--sorry. You raised--yes. Student: [inaudible] Professor Paul Bloom: The question is, "Would you become used to changes of social interaction?" An example is solitary confinement or prison. People get used to a lot of things. It could be that in those examples there is a shift in status as well and social relationships and how you think of yourself relative to others so that may be difficult to recover from. If you're popular at Yale and you go to prison you're not going to be very happy your first few days in prison probably. But then suppose you get popular in prison, people like you, you're the head of the book club and everything. [laughter] You'd rather not be in prison--been in prison but you'll probably be a pretty--if you're a cheerful guy here you'll be a cheerful guy in prison.

The final case is--involves judgments of the pleasure and pain of past events. And I mentioned the Nobel prize a little while ago as an example but the work I'm going to talk about is actually from the one psychologist who's alive who's won the Nobel prize--sorry, one of the ones who's won the Nobel prize, Daniel Kahneman. And he became interested in happiness. And you remember him from his rationality research and this is some work on happiness. Here's an example. Anybody see the movie Marathon Man? It involves a dental torture scene. Imagine you're going to the dentist and he's torturing you or it's a cleaning but it's really painful and it's terrible. You're sweaty, you're squeezing the thing, and it lasts for an hour and then when it's done the dentist leans over and says, "We're done now. If you want we could stop. But if you want, as a favor to you – I have five minutes – I could top you off with some mild pain." This may seem like a very odd thing to ask. Here's the alternative. What do you want? A dental procedure that's very painful for an hour or a dental procedure

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that's very painful for an hour--sorry about the "S" there [referring to a slide typo] --and then some additional mild pain? Who votes for A? You got to choose one. Who votes for A? Okay. Who votes for B? Okay.

Here's the big finding. The big finding is "yes," B involves more pain. It's true. "A" is an hour of pain. "B" is an hour of pain plus a few minutes of more pain. Seems like a no-brainer but when you have A or B and you have to remember it later on you'll have a much nicer memory of B than A. Kahneman's insight is when you think back on events you don't just add up the amount of pleasure or pain you experienced. Rather, your memory is highly skewed to peaks and then to endings. And you could imagine this. In the first case, "A," you leave and say, "Oh, God, that was terrible. Oh." "B," you leave and say, "Oh, that was mildly painful. There was something terrible in the middle there but it ended okay, mild pain." It turns out, in general, endings matter a lot.

Kahneman did his research with – both in a laboratory where you could make – give people mild pain by getting them to stick their hand in freezing cold water and with people undergoing extremely painful colonoscopy procedures. And it turns out that if you want to give people a good memory, or a less bad memory, of a horrible event topping them off with some mild pain will do the trick. In the end, endings matter. Both of these examples, a party that's hugely fun for ninety percent, then the last ten percent somebody slaps you in the face and pours dip on you or something-- [laughter] So, ninety percent of good stuff, ten percent bad stuff, versus ninety percent people are slapping you and pouring dip on you [laughter] but then ten percent, whoa, that was a really good--when you think back on it, if you just added it up, "A" would be much better but "B" has this huge pull because of the power of how things end so endings matter.

So, I'm going to end things now. I'm first going to do a few things. Before saying anything more, I want to thank the teaching fellows. There's Sunny Bang, Erik Cheries, Jane Erickson, Izzat Jarudi, Greg Laun, and Koleen McCrink. I think they did a superb job. [applause] We've basically reviewed all the psychology. Here is a promissory note we started with at the beginning of this semester. I think you are now in a position to answer or at least consider answers about these topics, about topics such as dreams, testimony, disgust, memory, depression, language, humor, and even a little bit about good and evil. This is an--a broad intro survey class, and the field of psychology is broad and we've just gotten started. If you're interested, this is a great department. There are some amazing scholars here and some amazing teachers and there are courses that go into detail about just about every topic I talked about. If you're interested in memory or social interaction or mental illness, I could point you to some great courses. I'm not taking any sophomore advisees next year because I'm on leave in the fall but you should feel free to come talk to me if you want any specific advice or suggestions.

Now, I know not all of you are going to end up majoring in psychology. Some of you will choose cognitive science instead [laughter] but on a more serious note I know for some of you this is the last--maybe the first but the last psychology class you'll ever take. And so I want to close this course by emphasizing two themes. The first one is a bit of humility. There are some very basic questions about the mind – and I've tried to be honest about this throughout the course--There are some very basic questions about the mind that nobody knows the answer to yet. We know the brain is the source of mental life but we don't have any understanding at all about exactly how this happens, about how a physical object, a lump of meat, can give rise to conscious experience.

We know that about half of the variants in personality, about half the differences between people, are due to genetic factors but we don't know how to explain where the other half happens. It has to be experienced but we have no real good theories of the sort of experience that makes one person adventurous and another one timid, one bitter and one satisfied. We know a lot about the social influences that can drive people to do terrible things to one another but we don't know the answer to the maybe harder question of why some of us--some people are immune to these influences, why some people do good things, perhaps even heroic things, regardless of the circumstances that they find themselves in. So, there's an enormous amount left to do. It's an exciting field just because there's just so much more we need to understand.

The second theme is more optimistic. And this is the idea that we're going to eventually come to answer these questions and many more questions through the sorts of methods we've been discussing this semester, through constructing scientific theories, evolution--evolutionary, neurological, developmental, computational and testing them through experimental and observational methods. This is the idea that, in the end, the most important and intimate aspects of ourselves, our beliefs and emotions, our capacities to make decisions, even our sense of right and wrong can be explained through constructing and testing scientific hypotheses. Now, the reason why I'm optimistic is I think there's been some success stories where we really have learned some surprising and important things about the mind and there's no reason to expect this way of proceeding to fail us in the future.

In my very--in the very first class on the brain I ended by talking about people's worries here, and I'll be honest, that some people find it a scary prospect. Some people believe that a scientific approach to the mind takes the "special-ness" away from people, that it diminishes us somehow. And I don't agree. If there's anything I've tried to persuade you through the course, it's that the more you look at the mind and how it works from a serious scientific point of view the more you come to appreciate its complexities, uniqueness, and its beauty. This has been a great course to teach. Thank you for coming and good luck on the Final. [applause]

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Bibliography

Gray, Peter. Psychology. New York: Worth Publishers, 2007. Marcus, Gary, ed. The Norton Psychology Reader. New York: W. W. Norton & Company, 2006.