Chapter 3

The Nature and Nurture

Of Behavior

Evolutionary Psychology

Video Clip http://www.pbs.org/w

gbh/evolution/library/01/6/l_016_08.html

Sweaty T-Shirts and Human Mate Choice:

Subtle chemical signals, or pheromones, have long been known to draw pairs together within the same species, and for a specific reason.

In mice, for example, experiments showed that pheromones acted as attractants between males and females who were genetically similar except that they differed in a certain type of immune system gene.

That difference is actually a survival benefit: The combination of two individuals' different MHC (major histocompatibility locus) genes gives their offspring an advantage in beating back disease organisms.

William James, Principles of Psychology (1890)

It takes...a mind debauched by learning to carry [out] the process of making the natural seem strange…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 so upside-down? 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, that beautiful soul clad in that perfect form, so palpably and flagrantly made for all eternity to be loved!

Basic Tenets of Evolutionary Psychology

Our neural circuits were designed by natural selection to solve problems. Different neural circuits are specialized for solving different adaptive problems.

Consciousness is just the tip of the iceberg; most of what goes on in your mind is hidden.

Our modern skulls house a stone age mind, adapted to the environment of evolutionary ancestry (EEA).

Genes: Our Biological Blueprint

Chromosomes threadlike structures made of DNA that

contain the genes DNA (deoxyribonucleic acid)

complex molecule containing the genetic information that makes up the chromosomes

has two strands-forming a “double helix”- held together by bonds between pairs of nucleotides

Genes: Our Biological Blueprint

Genes biochemical units of heredity that make up the

chromosomes a segment of DNA capable of synthesizing a protein

(protein is the building block of life) Genome

the complete instructions for making an organism consisting of all the genetic material in its

chromosomes

DNA & RNA

• DNA: Deoxyribonucleic acid. One of two types of molecules that encode genetic information. The other is RNA.

• In humans DNA is the genetic material; RNA is transcribed from it. In some other organisms, RNA is the genetic material and, in reverse fashion, the DNA is transcribed from it.

DNA & RNA DNA is a double-stranded molecule held

together by weak hydrogen bonds between base pairs of nucleotides. The molecule forms a double helix in which two strands of DNA spiral about one other.

The double helix looks something like an immensely long ladder twisted into a helix, or coil. The sides of the "ladder" are formed by a backbone of sugar and phosphate molecules, and the "rungs" consist of nucleotide bases joined weakly in the middle by the hydrogen bonds.

Nucleotide Nucleotide: A subunit of DNA or

RNA. To form a DNA or RNA molecule, thousands of nucleotides are joined in a long chain

There are four nucleotides in DNA. Each nucleotide contains a base: adenine (A), guanine (G), cytosine (C), or thymine (T).

Base pairs form naturally only between A and T and between G and C.

Genetics and Behavior

Nucleus Chromosome Gene

Cell DNA

Evolutionary Psychology

Natural Selection the principle that, among the range of inherited

trait variations, those contributing to survival will most likely be passed on to succeeding generations

Mutations random errors in gene replication that lead to a

change in the sequence of nucleotides the source of all genetic diversity

Evolutionary Psychology

Evolutionary Psychology the study of the evolution of

behavior using the principles of natural selection

Gender in psychology, the

characteristics, where biologically or socially influenced, by which people define male and female

Evolutionary Psychology

Men everywhere preferred attractive physical features suggesting youth and health

For males, a question: Which woman is more attractive?

For females, a question: Which man is more attractive?

Monopolizing & Mutilating Women

Techniques across cultures: veiling, chaperoning, purdah, foot binding

“Less familiar to Westerners but more frequent are genital mutilations designed to destroy the sexual interest of young women and even their penetrability until surgically reopened…Such genital mutilations are still prevalent in 23 countries.” (Hicks 1986)