Myers’ PSYCHOLOGY (7th Ed) Chapter 3 The Nature and Nurture Of Behavior James A. McCubbin, PhD Clemson University Worth Publishers

Fact vs. Falsehood z1. If after a world wide catastrophe only Icelanders or Kenyans survived, the human species would suffer a huge reduction in its genetic diversity. z2. The majority of the American public now believes that Darwin’s evolutionary theory is supported by evidence. z3. In many places around the world, females are more likely than males to initiate sexual activity. z4. People’s differing divorce risks are about 50% attributable to genetic factors. z5. Adoptees’ traits bear more similarities to their adoptive parents than to their biological parents. z6. The most emotionally intense preschoolers tend to be relatively intense adults. z7. Two children in the same family are on average as different from one another as are pairs of children selected randomly from the population. z8. A child who hears English spoken with one accent at home and another in the neighborhood and at school invariable adopts the accent of his or her peers, not the parents. z9. Compared with Westerners, people in Japanese cultures exhibit greater concern for social harmony and loyalty. z10. Seven weeks after conception, males and female remain anatomically indistinguishable.

Genes: Our Biological Blueprint  Chromosomes  threadlike structures made of DNA that contain genes  DNA (deoxyribonucleic acid)  molecule containing the genetic information that makes up chromosomes  has two strands-forming a “double helix”--held together by bonds between pairs of nucleotides

Genes: Our Biological Blueprint  Genes  units of heredity that make up the chromosomes  a segment of DNA capable of synthesizing a protein  Genome  the complete instructions for making an organism  all the genetic material in its chromosomes

Genes: Their Location and Composition NucleusChromosomeGene CellDNA

Evolutionary Psychology  Natural Selection  the principle that, among inherited trait variations, those that lead to increased reproduction and survival will be passed on to succeeding generations  Mutations  random errors in gene replication that lead to a change; the source of all genetic diversity

Evolutionary Psychology  Evolutionary Psychology  the study of the evolution of behavior and the mind, using the principles of natural selection  Gender  in psychology, the characteristics, whether biologically or socially influenced, by which people define male and female (sex = anatomy)

Survey zComplete and discuss the Mate Charateristics survey

Evolutionary Psychology  Men preferred attractive physical features suggesting youth and health  Women preferred resources and social status

Behavior Genetics  Behavior Genetics (Nature)  study of the relative power and limits of genetic and environmental influences on behavior  Environment (Nurture)  every nongenetic influence, from prenatal nutrition to the people and things around us

Behavior Genetics  Identical Twins  develop from a single fertilized egg that splits in two, creating two genetically identical organisms  Fraternal Twins  develop from separate eggs  genetically no closer than brothers and sisters, but they share the fetal environment Identical twins Fraternal twins Same sex only Same or opposite sex

Behavior Genetics  Temperament  a person’s characteristic emotional reactivity and intensity  Heritability  the proportion of variation among individuals that we can attribute to genes  50% of personality

Behavior Genetics  Interaction  the dependence of the effect of one factor (such as environment) on another factor (such as heredity)  Molecular Genetics  the subfield of biology that studies the molecular structure and function of genes

Environmental Influence  Two placental arrangements in identical twins

Environmental Influence  Experience affects brain development Impoverished environment Rat brain cell Rat brain cell Enriched environment

Environmental Influence  Culture  the enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next  Individualistic and collectivism  Norm  an understood rule for accepted and expected behavior

Environmental Influence  Personal Space  the buffer zone we like to maintain around our bodies  Memes  self-replicating ideas, fashions, and innovations passed from person to person

The Nature and Nurture of Gender  X Chromosome  the sex chromosome found in both men and women  females have two; males have one  an X chromosome from each parent produces a female child  Y Chromosome  the sex chromosome found only in men  when paired with an X chromosome from the mother, it produces a male child

Survey zTake and discuss the Sexual Attitudes Survey

The Nature and Nurture of Gender  Testosterone  the most important of the male sex hormones  both males and females have it  additional testosterone in males stimulates  growth of male sex organs in the fetus  development of male sex characteristics during puberty  Role  a set of expectations (norms) about a social position  defining how those in the position ought to behave

The Nature and Nurture of Gender  Gender Role  a set of expected behaviors for males and females  Gender Identity  one’s sense of being male or female  Gender-typing  the acquisition of a traditional masculine or feminine role

The Nature and Nurture of Gender  Gender and Culture

The Nature and Nurture of Gender

 Social Learning Theory  theory that we learn social behavior by observing and imitating and by being rewarded or punished  Gender Schema Theory  theory that children learn from their cultures a concept of what it means to be male and female and that they adjust their behavior accordingly

The Nature and Nurture of Gender  Two theories of gender typing

Bottom Line zNature vs. Nurture = 50% each

Do you think like an evolutionary psychologist? zComplete and discuss the Evolutionary psych questions zReview the Fact or Falsehood