1 Nature, Nurture, and Human Diversity Chapter 3

2 Nature or Nurture? Behavior Genetics HeredityEnvironment

3 Behavior Genetics: Genes Terms to know: –Chromosomes –DNA –Genes –Genome

4 Behavior Genetics: Twin Studies Identical vs. fraternal => Identical more similar Identical separated at birth => many similarities: personality, intelligence, abilities, interests, brain waves, etc.

5 Behavior Genetics: Adoption Studies Adoptees tend to be different from their adoptive parents and siblings. Adoptees’ values, attitudes => adoptive parents Adoptees’ personalities = > biological parents

6 Behavior Genetics: Temperament Studies Temperament refers to a person’s stable emotional reactivity and intensity. Identical twins express similar temperaments, suggesting heredity predisposes temperament.

Behavior Genetics: Heritability Heritability: the extent to which the differences among people are attributable to genes (vs. environment). (NOT: Your high IQ is 50% attributable to your parents’ genes) BIG IDEA: Nature and Nurture - Genes are self-regulating (adaptable) - We are products of genetic predispositions & surrounding environments (Naturally outgoing kids receive more attention)

The Future: Molecular Genetics Molecular genetics: identifying functions of genes (Issues: designer babies, weeding-out disorders, etc.)

Evolutionary Psychology Evolutionary psychology: study of human similarity & the evolution of behavior and mind through natural selection (remember Darwinism?) Biologists like Belyaev and Trut (1999) were able to artificially domesticate wild foxes, selecting them for friendly traits. Any trait that is favored naturally or artificially spreads to future generations.

10 Evolutionary Psychology: Human Traits A number of human traits have resulted from natural selection. Why do infants fear strangers when they become mobile? Why are most parents so passionately devoted to their children? Why do people fear spiders and snakes and not electricity and guns?

11 Evolutionary Psychology: Human Sexuality Differences in males & females arise in regards to reproductive behaviors. (Heterosexual or Homosexual*) Gender Differences in Sexuality Question (summarized)MaleFemale Casual sex60%35% Sex for affection25%48% Think about sex everyday54%19%

Evolutionary Psychology: Mating Preferences Males: select multiple partners => best odds of producing offspring (look for youthful, fertile appearance)* VS. Females: select one, stable partner => best odds of producing offspring (look for maturity, dominance, affluence, boldness)* *Data based on 37 cultures.

Early Experiences Prenatal environment Early postnatal experiences (remember the Rhesus monkeys?) Nurture: Influences

Parental Influence Parental influence is largely genetic. Parental influence (+ & -) often overemphasized. Has most influence on: education, discipline, responsibility, charitableness, respect Nurture: Influences Peer Influence Conforming to the group Has most influence on: interacting, cooperation, gaining popularity

Cultural Influences Culture : behaviors, ideas, attitudes, values and traditions shared by a group (and passed-on) that vary across time & place Cultural Norms: rules for accepted and expected behavior Nurture: Influences Can you think of any American cultural norms?

Culture and the Self Individualism (“I”) vs. Collectivism (“We”) Nurture: Influences Westernized CulturesAsian-African Cultures Responsible for your selfResponsible to group Follow your consciencePriority to obedience Discover your giftsBe true to family-self Be true to yourselfBe loyal to your group Be independentBe interdependent

Nature and Nurture Gender Development Males Females

18 Nature and Nurture Gender Development

Males Females Y Chromosome Testosterone Solitary Play in large groups Autocratic Support war More arrests Aggressive Antisocial personality disorder Hyperactivity Alcoholism Higher suicide rate Estrogen More talkative More religious Interdependent Play in small groups Democratic* Eating disorders More depression Sense of smell Dream = of men/women Longer life span Earlier puberty More fat

Gender Identity —how a person views himself or herself in terms of gender. How is this identity formed? Nature and Nurture Gender Roles Gender = Biopsychosocial 1.Social Learning Theory: we learn gender behavior like any other behavior—reinforcement, punishment, and observation. 2.Gender Schema Theory: we learn a cultural “recipe” of how to be a male or a female, which influences us; forms a “lens” for viewing the world => male or female

21 Reflections on Nature and Nurture