Evo Psych

World of the Mind: Evolutionary Psychology

“A science of mind and behavior without

an evolutionary perspective is incomplete.”

Evolutionary Psychology is…

“An approach to psychological inquiry that views human cognition and behavior in a

broadly Darwinian context of adaptation to evolving physical and social environments

and new intellectual challenges. It differs from sociobiology mainly in its emphasis on the effects of natural selection on information processing and the structure of the human mind.” - APA Dictionary of Psychology

Evolutionary Psychology is…

“An approach to the study of psychology that is

informed by modern principles of evolutionary

biology… an approach to exploring the mechanisms of the mind… not a branch of psychology, [but] a lens through which any psychological phenomenon can be

examined.” -David Buss

“In the distant future . . . psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.”

--Charles Darwin, 1859

“Is it not reasonable to anticipate that our understanding of the human mind

would be aided greatly by knowing the purpose for which it was designed?”

The main theme of study of Evolutionary Psychology

1. All behavior is a function of psychological mechanisms + input to those mechanisms

Core Tenets of Evolutionary Psychology

2. All psychological mechanisms, at some basic level, originate from evolutionary processes

Core Tenets of Evolutionary Psychology

3. Natural and sexual selection are the most important evolutionary processes responsible for creating psychological mechanisms

Core Tenets of Evolutionary Psychology

4. Evolved psychological mechanisms can be described as information processing devices.

Core Tenets of Evolutionary Psychology

Inputs Decision Rules Outputs

5. Evolved psychological mechanisms are instantiated in the brain.

Core Tenets of Evolutionary Psychology

6. Evolved psychological mechanisms are functional: Designed to solve statistically recurrent adaptive problems

Core Tenets of Evolutionary Psychology

The brain is a physical system.

It functions as a computer

Its circuits are designed to generate behavior appropriate to the environment circumstances.

Principle 1

Thoughts, hopes and feelings all produced by chemical reactions.

A computer made of organic compounds.

Neuron cells- transmission of information (like circuits in comp).

Circuits designed to gather information (through sensory receptors).

Output in the form of movement (behavior).

Organisms that don’t move don’t have brains.

Principle 2

Our neural circuits were designed by natural selection to solve problems that our ancestors faced during our species’ evolutionary history.

Environments don’t specify what is appropriate behavior.

Different organisms may have different appropriate behavior for same environment.

The appropriate behavior for a machine is decided by an engineer, similarly..

The appropriate behavior for a particular situation is decided by a process called “natural selection”.

What counts as appropriate behaviour?

Natural selection is the process by which heritable trait that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations.

It is a process by which a phenotypic design feature causes its own spread within a population.

Natural selection

Natural selection does not grant organisms what they need.

The way natural selection works...

Natural selection can design neural circuits only for solving adaptive problems.

Adaptive problems are the ones which came up again and again during evolution .

They are problems whose solution affects the reproduction of living organisms.

Examples of adaptation…

The solution of adaptive problem that favors reproduction leads to further evolution of the particular species.

The complex tasks we do today such as driving cars ,skating are all by-products of adaptations of our body structure during our evolution.

For all that natural selection didn't give us…

Consciousness is the tip of the iceberg :most of what goes on in our mind is hidden from us. As a result our conscious experience can mislead us into thinking that our circuitry is simpler than it really is. Most problems that seem easy to solve require very complicated neural circuitry.

Principle 3

Every human action, however trivial, effortless, natural and simple it may appear to us, is actually a lot complicated.

Each task which appears deceptively simple to us has many sub functions, performed by thousands and thousands of specialized mechanisms and we only get to know the final result, which we call our conscious experience.

Brain complexes are so complex that it has not been possible to model the apparently simple 3 D vision of humans.

Leave alone modeling , even understanding the complexities of human brain can be very difficult.

Different neural circuits are specialized for solving different adaptive problems.

Different organs performing different functions. Lungs for respiration, kidneys for waste treatment etc.

Principle 4

Mind consists of circuits that are functionally specialized.

Our modern skull house a stone age mind.

Principle 5

Human mind evolved in avery different environment

Relatively simple changes can take ten thousand years.

Natural Selection- a process that that designed our brain.

Natural selection sculptured human brain to solve day to day problems like finding mates, raising children, gathering food etc.

Modern mind are highly sophisticated

Platform has changed but we still have the hunter instict.

Behaviour requires underlying psychological mechanisms.

Evolution by selection is the causal process that creates psychological adaptations.

Evolved psychological mechanisms are functionally specialized

The human mind contains a large number of evolved psychological mechanisms

Principles according to David Buss :-

Principle-1:Behaviour requires underlying psychological mechanisms

Behaviour cannot be produced without psychological mechanisms.

All psychological theories, even the most strongly environmental ones, imply the existence of psychological mechanisms.

-> If a man responds to a public insult with violence, but a woman does not.-> If a child cries to get its way, but an adult does not.->If a human gossips and a chimpanzee does not.

It is because these different beings possess somewhat different psychological mechanisms.

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One of the best examples is of Human Mind

Rosenzweig and Krech’s experiment on rats:◦ Those living in the enriched environment

developed a thicker and heavier brain cortex.◦ Experience preserves our activated connections

while allowing the unused connections to degenerate. Use it or lose it

Experiences and Brain Development

Only two theories retain currency for the origins of complex organic mechanisms: evolution by selection and creationism.

Creationism, the idea that a supreme deity fashioned current organic mechanisms in all their glorious diversity, is regarded as a matter of religious belief. It leads to no specific scientific predictions and cannot predict or explain in a principled manner the organic forms that science has documented and discovered.

Evolution by selection, in contrast, is a powerful and well-articulated theory of the dynamics of replicating entities that has successfully organized and explained thousands of diverse facts in a principled way.

This theory unites all living forms into one grand tree of descent, accounts for the origin of new species, explains the modification in organic structures over time, and explains the functional quality of the component parts of those structures.

Other causal processes in evolution, such as mutation and genetic drift, do not produce complex functional mechanisms in the absence of selection.

Principle:-2 Evolution by selection is the causal process that creates psychological adaptations

1. Creationism

2. Seeding theory

We all are descendants of ALIENS!!!!!!

3. Evolution by natural selection

Principle :-3 Evolved psychological mechanisms are functionally specialized

A central premises of evolutionary psychology:

To understand psychological mechanisms is to articulate their functions — the specific adaptive problems they were designed to solve. Anatomists identify the liver, heart, and lungs as separate, although connected and integrated, mechanisms because they perform different functions — filter toxins, pump blood, and uptake oxygen, respectively.

Understanding the nature of these mechanisms requires understanding their functions, the adaptive problems they were designed to solve.

This ultimately reduces to the manner in which the mechanism or design feature contributed to fitness — the reproduction of the individual bearing the trait, or the reproduction of the individual's genetic relatives .

Evolutionary psychologists propose that the human mind consists primarily of functionally specialized psychological mechanisms, each designed to solve a specific adaptive

problem.

Mate preference mechanisms function to solve the problem of selecting reproductively valuable mates.

Kin-identification mechanisms function in part to solve the adaptive problem of allocating acts of altruism; and parental investment mechanisms function as devices to allocate resources to offspring.

The adaptive problems that psychological mechanisms are designed to solve have several key features.

FIRST:They must have recurred over the long course of human evolutionary history. Evolution is a slow and iterative process, resulting in the gradual accumulation of adaptations by design feature.

Second The past is the key to the present, so our current

psychological adaptations were designed to solve problems in the ancestral past.

Third There is no expectation that humans have evolved mechanisms to solve modern adaptive problems, such as avoiding dangerous electrical outlets or fast food that currently clogs arteries.

FourthAdaptive problems are those problems whose solution contributed to successful reproduction, either directly or indirectly. (Survival of the fittest)

a. If successfully climbing a status hierarchy eventually leads to success in mating, which in turn leads to success in reproduction, adaptations for status striving can be selected, even though their contribution to reproduction is distal and occurs through intermediary routes.

Fifth: Since differential reproduction is the engine of evolution by selection, only those solutions that lead to an increment in reproduction, relative to alternative variants that exist in the population at that time, can evolve.

Principle 4: The human mind contains a large number of evolved psychological mechanisms

Detailed task analyses of adaptive problems have led to the empirical discovery of evolved psychological mechanisms in many domains, such as

predator avoidance food aversions habitat selection mate choice criteria mate retention devices reciprocal altruism parental investment kin altruism, coalition formation, and many others.

Thus, the theory of the human mind depicted by evolutionary psychologists tends to be far more complex, containing many more mechanisms, than more traditional non-evolutionary theories of the mind.

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Evolutionary psychologists propose that the mind is no less complex,

and have amassed considerable empirical evidence for many functional specializations that cannot be explained on any other view.

Contrary to folk intuitions, the exquisite flexibility and context-sensitivity of human behaviour comes from having a large number of these functionally specialized mechanisms that are coordinated and integrated with each other, not from having a small number of

general or 'plastic' psychological mechanisms

Presentation By:

Nikhil Gupta Kunal Goel Ashwini Kr. Mishra Abhilash ParidaRupam Pratham

Thank You…