Evolutionary Psychology Dr. Atiqul Haq Mazumder MD (Psychiatry) Part III Student Department of Psychiatry, BSMMU Dhaka
“ 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
‘ Evolutionary psychology is the combination of two sciences -- evolutionary biology and cognitive psychology’. Introducing Evolutionary Psychology, Dylan Evans & Oscar Zarate, Totem Books, New York, 2000
Origins of Modern Humans <ul><li>Homo Erectus </li></ul><ul><ul><li>Migrated from Africa to Asia (1.8 MYA) </li></ul></ul>
Increases in brain size during evolution ardipithecus brain size: 300 ccs Australopithe-cus brain size: 310-530 ccs homo habilis brain size: 580-752 ccs homo erectus brain size: 775-1225 ccs Neandertal brain size: 1200-1450 ccs modern human brain size: 1350 ccs
Evolution Before Darwin <ul><li>Change over time in organic structures: evolution </li></ul><ul><li>Characteristics seemed to have a purpose (porcupines, turtles, skunks) </li></ul>
Darwin’s Theory of Natural Selection <ul><li>The explanatory challenge: </li></ul><ul><li>1. why change takes place </li></ul><ul><li>2. how new species emerge </li></ul><ul><li>3. what the functions are of parts </li></ul>
The answer--natural selection: Variation, inheritance, differential reproduction
The key to natural selection: Differential reproductive success because of heritable variants ; everyone has ancestors, but not everyone leaves descendants
Natural selection provided 3 key answers <ul><li>Explained change over time: descent with modification </li></ul><ul><li>Explained the apparent purposive quality of component parts: adaptive function </li></ul><ul><li>United all species into one grand tree of descent: including humans </li></ul>
Likelihood of Agreeing to Have Sex With Someone You Find Attractive as a Function of Time Known
Sexual Selection Components <ul><li>Intrasexual Competition </li></ul>
<ul><li>“ The core tenets of evolutionary psychology..” </li></ul><ul><li>- David M. Buss (2005) </li></ul>
Core Tenets of Evolutionary Psychology <ul><li>1. All behavior is a function of psychological mechanisms + input to those mechanisms </li></ul>
Core Tenets of Evolutionary Psychology <ul><li>2. All psychological mechanisms, at some basic level, originate from evolutionary processes </li></ul>
Core Tenets of Evolutionary Psychology <ul><li>3. Natural and sexual selection are the most important evolutionary processes responsible for creating psychological mechanisms </li></ul>
Core Tenets of Evolutionary Psychology … All Species have a Nature
Core Tenets of Evolutionary Psychology <ul><li>4. Evolved psychological mechanisms can be described as information processing devices. </li></ul>Inputs Decision Rules Outputs
Core Tenets of Evolutionary Psychology <ul><li>5. Evolved psychological mechanisms are instantiated in the brain. </li></ul>
Core Tenets of Evolutionary Psychology <ul><li>6. Evolved psychological mechanisms are functional : Designed to solve statistically recurrent adaptive problems </li></ul>
‘ Connection do exist: our arts, our philosophies, our literature are the product of human minds interacting with one another, and the human mind is a product of human brain, which is organized in part by the human genome and has evolved by the physical process of evolution’. -JOHN Brockman (2008)
Principle 1. The brain is a physical system. It functions as a computer. Its circuits are designed to generate behavior that is appropriate to your environmental circumstances.
Principle 2. Our neural circuits were designed by natural selection to solve problems that our ancestors faced during our species' evolutionary history.
Principle 3. Consciousness is just the tip of the iceberg; most of what goes on in your mind is hidden from you. As a result, your conscious experience can mislead you into thinking that our circuitry is simpler that it really is. Most problems that you experience as easy to solve are very difficult to solve -- they require very complicated neural circuitry.
Principle 4. Different neural circuits are specialized for solving different adaptive problems.
Principle 5. Our modern skulls house a stone age mind.
‘ The Blank Slate Theory’ - John Locke ( British Philosopher, 1632-1704 ) ‘Man is a blank slate on which culture writes’ - Emile Durkheim ( French Sociologist, 1858-1917 ), 1895
‘ For nearly all measures personality, heritability is high in western society: identical twins raised apart are much more similar than the fraternal twins raised apart.’ - William R. Clark, Michael Grunstein, 2000-11-09
‘ Two Identical twins raised apart met first’ -From Blank Slate by Steven Pinker
Psychopaths, as far we know, cannot be 'cured'. Indeed, the psychologists Marine Rice has shown that has shown that certain harebrain ideas for therapy, such as boosting their self esteem and teaching them social skills, can even make more dangerous. - Steven Pinker, 2003
presence or absence of epigenetic factors at target sites controls whether particular genes can generate proteins, the workhorses of most physiological processes. -Douglas Steinberg, Determining Nature vs. Nurture : Molecular evidence is finally emerging to inform the long-standing debate, Scientific American Mind, 17, 12 - 14 (2006)
‘ Science is discovering that while we may have fixed set of genes in Chromosomes, which of those Genes is active has great deal to do which our subjective experiences, and how we process them’ -Dawson Church, 2009
Josephine Tesauro, left, active and healthy at 92, is part of a study trying to determine why some people age better than others, even when they are closely related. Live Long? Die Young? Answer Isn’t Just in Genes, GINA KOLATA, The NewYork Times, August 31, 2006, Online link: http://www.nytimes.com/2006/08/31/health/31age.html
With no more than a change in diet, laboratory agouti mice (left) were prompted to give birth to young (right) that differed markedly in appearance and disease susceptibility. DNA Is Not Destiny, The new science of epigenetics rewrites the rules of disease, heredity, and identity; Ethan Watters, Discover Magazine, Nov. 2006 issue, Online link: http://discovermagazine.com/2006/nov/cover/?searchterm=Randy%20Jirtle
Nature vs. Nurture No Nature via nurture Yes We are the minders of our genes Evolutionary psychology describes what human nature is like - it does not prescribe what humans should do' ।