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8/7/2015
1
Thinking Critically With Psychological Science
Chapter 1
Why Do Psychology?
1. How can we differentiate between uniformed opinions and examined conclusions?
2. The science of psychology helps make these examined conclusions, which leads to our understanding of how people feel, think, and act as they do!
What About Intuition & Common Sense?
Many people believe that intuition and common sense are enough to bring forth answers regarding
human nature.
Intuition and common sense may aid queries, but they are not free of error.
Limits of Intuition
Personal interviewers may rely too much on their “gut
feelings” when meeting with job applicants. (gut feelings
are often formed by common sense)
I have a feeling it is going to rain.
I have a feeling we are going to win.
I have a feeling this is my soul mate.
Taxi/ G
etty Images
Hindsight Bias is the “I-knew-it-all-along” phenomenon.
After learning the outcome of an event, many people believe they could have predicted that very
outcome.
•We only knew the dot.com stocks would plummet after they actually did plummet.
•I knew they were going to have a baby boy!
•I knew the Panthers were going to beat the Sharks
•I knew Zimmerman was going to be let go
Hindsight Bias Overconfidence
Sometimes we think we know more than we
actually know.
Anagram
BARGEGRABE
ENTRYETYRN
WATERWREAT
How long do you think it would take to unscramble
these anagrams?
Most people said it would take about 10 seconds, yet
on average they took about 3 minutes (Goranson, 1978).
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How popular are you at school?
Studies show that in a school setting that 60% of
the students rated themselves to be in the top 25%
of the popular kids.
25% of the students rated themselves in the top
1%.
As a teacher I may have a really good week in the
classroom and feel really good about how my students are
picking up the new material.
However, this overconfidence often lets me down after
seeing many low scores on a test.
Ever hear someone say after they may have had to much
to drink, I drive better when I have been drinking because I
pay closer attention to what I am doing? A little over
confident you think? Don’t let them drive!!!
By the way0Studies show that boys are tremendously over confident
in their ability to drive.
The Scientific Attitude
The scientific attitude is composed of curiosity (passion for exploration), skepticism (doubting and questioning) and humility (ability to accept
responsibility when wrong).Curiosity: without being misled, does it work? When tested, can its predictions be confirmed?
Skepticism: be open but not gullible. Scrutinizing crazy ideas sometimes prove there might be some truth behind it. Sometimes it will debunk previous thought. (Earth is flat)
Humility: awareness that being wrong is okay. Be open to other ideas and perspectives. Do not fear failure! Failures often give up and stop searching for answers.
Critical Thinking
Critical thinking does not accept arguments and conclusions blindly.
It examines assumptions, discerns hidden values, evaluates evidence and assesses conclusions.
CT asks questions like:
•How do we know that?•What is the answer based off of?•Does the answer ever change or is it always the same?
How Do Psychologists Ask & Answer Questions?
Psychologists, like all scientists, use the scientific method to construct theories that
organize, summarize and simplify observations.
Theory = a “mere hunch”- not proven
However, a scientific theory does explain through observations to allow predictions
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A theory is an explanation that integrates principles and organizes and predicts
behavior or events.
For example, low self-esteem contributes to depression.
We must test this to see if theory is even plausible.
Theory
A hypothesis is a testable prediction, often prompted by a theory, to enable us to
accept, reject or revise the theory.
People with low self-esteem are apt to feel more depressed.
It gives us direction to research. It specifies what results support our theory and what would disprove our theory.
Hypothesis
Research would require us to administer tests of self-esteem and depression.
Individuals who score low on a self-esteem test and high on a depression test would
confirm our hypothesis.
The more we replicate the same results the more confidence we gain in our theory.
Research Observations Research Process
Theories lead to the need for a hypothesis
This leads to the need for research and observe
Through this we are able to confirm, reject, or revise our theories
Description
Case Study
A technique in which one person is studied in depth to reveal underlying behavioral principles.
Is language uniquely human?
Susan Kuklin/ Photo Research
ers
Example
• The story of Genie
– This case study allows psychologists,
sociologists, linguistic professionals, etc to
study her up bringing and her disabilities in
order to compare them to others who have
been treated in similar situations. It allows the
researchers to predict the future and make a
plan of action for others.
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Survey
A technique for ascertaining the self-reported attitudes, opinions or behaviors of people
usually done by questioning a representative, random sample of people.
http://w
ww.lynnefeath
erstone.org
Survey
Wording can change the results of a survey.
Q: Should cigarette ads and pornography be allowed on television? (not allowed vs. forbid)
Wording Effects
Survey
Random Sampling
If each member of a population has an equal
chance of inclusion into a sample, it is called a
random sample (unbiased). If the survey
sample is biased, its results are not valid. The fastest way to know about the
marble color ratio is to blindly transfer a few into a smaller jar and
count them.
Lets say we want to figure out how many people in
Jacksonville who have a phone listed in the phone book
use the local beach more than twice a year.
Do we call everyone in the phone book?
Do we call a random sample? How might we go about
doing this?
Naturalistic Observation
Observing and recording the behavior of animals in the wild and recording self-seating patterns in a multiracial school lunch room constitute naturalistic observation.
Courtesy
of Gilda M
orelli
Another example Naturalistic
Observation
• A boy drops a book in the hallway
• A girl drops a book in the hallway
• Wearing a fat suit for a semester or changing the
color of your hair, or wearing off brand clothes
• Police allowing one of their own into a violent
gang for a couple years
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Naturalistic Observation
• Disadvantages– It may be difficult to determine exact cause of a
behavior
– Experimenter cannot control outside
– Different observers may draw different variables and
conclusions
– If in a situation where the group being studied knows
you are there observing, the group may behave
differently. They may also behave the way they think
the researcher wants them to behave.
Descriptive Methods
Case studies, surveys, and naturalistic observation describe behaviors.
Summary
Correlation
When one trait or behavior accompanies another, we say the two correlate. They share the same kind
of relationship.
Correlation
coefficient
Indicates direction
of relationship
(positive or negative)
Indicates strength
of relationship
(0.00 to 1.00)
r = 0.37+
Correlation Coefficient is a statistical measure of the relationship between two
variables.
Causation
• Means that one variable causes
something to happen in another variable
Perfect positivecorrelation (+1.00)
Scatterplot is a graph comprised of points that are generated by values of two variables. The slope of the points depicts the direction, while the amount of scatter depicts the strength of the relationship.
A correlation is positive if 2 sets of scores tend to rise or fall together
Scatterplots
StudyTime
Test Scores
No relationship (0.00)Perfect negativecorrelation (-1.00)
The Scatterplot on the left shows a negative correlation, while the one on the right shows no relationship between
the two variables.
A correlation is negative if 2 sets of scores relate inversely (one goes up and the other goes down)
Scatterplots
Party Time
Test Scores
Body Weight
TestScores
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Data
Data showing height and temperament in people.
Scatterplot
The Scatterplot below shows the relationship between height and temperament in people. There
is a moderate positive correlation of +0.63.
or
Correlation and CausationCorrelation does not mean causation!!!
Example
• Since Mexican Lemons and oranges have been
imported into the U.S. the nation has seen a decrease in
casualties in traffic accidents.
• 1 Study had monkey’s drive motorcycles and cars on the
highway having a bag of Mexican Citrus strapped to their
back. Since being tested over the years we have seen a
correlation of the two.
• Question. Is this causation???
• What might be the real cause of increased
Mexican citrus in the U.S.?
• What might be the real cause of fewer
accidents on the roads by motorists in the
U.S.?
• Real data could actually show the two
things being true but likely the increase in
Mexican Citrus is probably due to some
economic factor(s) while the decrease in
fatalities in traffic accidents could be due
to newer technology that helps protect the
vehicles passengers all happening in the
same time frame.
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Correlation does not mean
causation!!!Student Average minutes spent
studying
Score on first Test
1 60 78
2 63 80
3 64 84
4 65 86
5 70 90
6 73 91
7 78 95
By looking at this data it looks as if there is a relationship. If you imply there is a relationship you need to experiment to prove your results or debunk them.
The person who scored the highest may have put the most study time in but they may be stronger in the social studies area, or had tutor help, or read different sources, or have taken the same course before or may have cheated etc…
Illusory Correlation
• The perception of a relationship where no relationship actually exists. Many superstitions begin this way.
• Not only did I play
well today but my
team won. We
never win. But I
never had a hole in
my sock like I did
today. The 2 must
be correlated.
Given random data, we look for order and meaningful patterns.
Order in Random Events
Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.
Order in Random Events
Given large numbers of random outcomes, a few are likely to express order.
Angelo and Maria Gallina won two California lottery games on the same day.
Jerry Telfer/ S
an Francisco
Chronicle
Experimentation
Like other sciences, experimentation is the backbone of psychological research. Experiments
isolate causes and their effects.
Exploring Cause and Effect Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other
factors are kept under (2) control.
Effects generated by manipulated factors isolate cause and effect relationships.
Exploring Cause & Effect
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In evaluating drug therapies, patients and experimenter’s assistants should remain unaware of which patients had the real
treatment and which patients had the placebo treatment.
This is good for creating an experimental group and control group.
Evaluating Therapies
Double-blind Procedure
Assigning participants to experimental (breast-fed) and control (formula-fed) conditions by random assignment minimizes pre-existing
differences between the two groups.
Hypothesis: breast-fed babies have higher intelligence
Evaluating Therapies
Random Assignment
An independent variable is a factor manipulated by the experimenter. The effect of the independent
variable is the focus of the study.
For example, when examining the effects of breast feeding upon intelligence, breast feeding is the
independent variable.
The IV is the manipulated variable. It is the one researchers change in order to make the DV occur. Hint: look for this second. What do the researchers
hope will cause the DV in the study?
Independent Variable
A dependent variable is a factor that may change in response to an independent variable. In psychology, it is
usually a behavior or a mental process.
For example, in our study on the effect of breast feeding upon intelligence, intelligence is the dependent variable.
The DV is the measured variable. It is the variable that researchers expect will occur. Hint: look for this one first.
What is the researcher looking for or measuring in the study?
Dependent Variable
Experimentation
A summary of steps during experimentation.
Dependent and independent
variables• Lets say we wanted to find out if kids with
heavy book bags scored higher on class
grades including tests.
– Which is the independent variable?
• Weight of the book bag
– Which is the dependent variable?
• Scores on class grades and tests
• The independent variable stands alone but the
dependent variable depends on the independent
variable
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Try this one
• I have made a “magic pill” . What’s in it???
Who cares.. It cures Cancer
• Hypothesis is the “magic pill” cures cancer
• How do I set up my experiment to get results
that the FDA would approve to make me a
Trillionaire?
• Variables: what is the IV and what is the DV?
• Independent Variable – pill or placebo
• Dependent Variable – the new outcome after
receiving the pill or Placebo
How will I set this up?
• Take ½ class and give them “magic pill”
Experimental group 00. other ½ receives the
Placebo a sugar pill This would be my control
group
• Yes a sugar pill. This combats the
• Placebo effect- when someone suffers from
pain, depression, anxiety, etc. THAT if you
THINK your are receiving medication, your body
will relax, your mood will be better, and you will
even experience symptom relief.
New Example
• I am going to keep you engaged in class with a
facial expression (a wink).
• What is my independent variable?
– Wink or no wink
• What is my dependent variable?
– Being engaged in class
• Control group (½ class) on left get a the normal me
• Experimental (other ½ class) get a big wink00.boy that
worked well. You guys look really engaged
• How do we control ME seeing what I want to see???
Try to eliminate demand
characteristics• psychological term used in experiments to describe a
cue that makes the participants aware of what the
experimenter expects to find or how they should
behave0. These can change the outcome of the
experiment due to them wanting to conform to the
behavior.
• Hawthorne Effect – fact that people try to improve
behavior because they know they are being studied
• Control- single blind experiment- Experimenter knows
who got placebo and who got medicine
• Double blind- the use of numbers so neither patients nor
Dr. know who has what
Comparison
Below is a comparison of different research methods. The only type of study that can
determine cause and effect is
the experiment.
Students often miss this distinction!!!
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Statistical Reasoning
Statistical procedures analyze and interpret data allowing us to see what the unaided eye misses.
Composition of ethnicity in urban locales
Statistical Reasoning in Everyday Life
Doubt big, round, undocumented numbers as they can be misleading and
before long, become public misinformation.
Apply simple statistical reasoning in everyday life to think smarter!
Describing DataA meaningful description of data is important in
research. Misrepresentation may lead to incorrect conclusions. (Both charts are of the
same data)
Measures of Central Tendency
Mode: The most frequently occurring score in a distribution.
Mean: The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by the number of scores that were added together.
Median: The middle score in a rank-ordered distribution.
13,18,13,14,13,16,14,21,13
• Mean is the usual average:
• (13+18+13+14+13+16+14+21+13)
divide by 9 = 15
• Mean = 15
• Median is the middle value.
Rewrite the list in ascending
order
• 13,13,13,13,14,14,16,18,21
• Median = 14
• Mode is the # represented
most often.
• 13 is repeated 4 times
• 14 is repeated 2 times
• 16,18,21 are not repeated at
all
Measures of Variation
Range: The difference between the highest and lowest scores in a distribution.
Standard Deviation: A computed measure of how much scores vary around the mean.
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Measures of Central Tendency
A Skewed Distribution
$70,000 dollars is the average income per family in this area. However, only 4 families in this area even make $70,000/year or more while 26 families make $50,000 or less.
13,13,13,13,14,14,16,18,21
Revisiting our list in ascending order from a few slides ago we see that
the largest value in the list is 21 and the smallest is 13.
21-13=8
Range = 8
Normal Curve
A symmetrical, bell-shaped curve that describes the distribution of many types of data (normal distribution). Most scores fall near the mean.
Illusion of Control
1. Illusory Correlation: the perception of a relationship where no relationship actually exists.
2. Regression Toward the Mean: the tendency for extremes of unusual scores or events to regress toward the average.
That chance events are subject to personal control is an illusion of control fed by:
Making Inferences
A statistical statement of how frequently an obtained result occurred by experimental
manipulation or by chance.
Making Inferences
1. Representative samples are better than biased samples.
2. Less-variable observations are more reliable than more variable ones.
3. More cases are better than fewer cases.
When is an Observed Difference Reliable?
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Making Inferences
When sample averages are reliable and the difference between them is relatively large, we say
the difference has statistical significance. It is probably not due to chance variation.
When is a Difference Significant?
Frequently Asked Questions About Psychology
Q1. Can laboratory experiments illuminate everyday life?
Ans: Artificial laboratory conditions are created to study behavior in simplistic terms. The goal is to find underlying principles that govern behavior.
FAQQ2. Does behavior depend on one’s culture and gender?
Ans: Even when specific attitudes and behaviors vary across cultures, as they often do, the underlying processes are much
the same. Biology determines our sex, and culture further bends the genders. However, in many ways woman and
man are similarly human.
Ami Vitale/ G
etty Images
FAQQ3. Why do psychologists study animals, and is it ethical
to experiment on animals?
Ans: Studying animals gives us the understanding of many behaviors that may have common biology across animals
and humans. From animal studies, we have gained insights to devastating and fatal diseases. All researchers who deal
with animal research are required to follow ethical guidelines in caring for these animals.
D. Shapiro, © Wildlife Conservation Society
FAQ
Q4. Is it ethical to experiment on people?
Ans: Yes. Experiments that do not involve any kind of physical or psychological harm beyond normal levels encountered in daily life may be
carried out.
FAQ
Q5. Is psychology free of value judgments?
Ans: No. Psychology emerges from people who subscribe to a set of values and judgments.
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FAQ
Q6. Is psychology potentially dangerous?
Ans: It can be, but is not when practiced responsibly. The purpose of psychology is to help
humanity with problems such as war, hunger, prejudice, crime, family dysfunction, etc.