Ch. 3: Nature vs. Nurture: Genes, Evolution, Environment Slides by: Wade & Tavris, 2009 Myers, 2010

Nature, Nurture, and Human Diversity Nature Behavior Genetics: Predicting Individual Differences  Genes: Our Codes for Life  Twin and Adoption Studies  Temperament and Heredity  Heritability  Gene-Environment Interaction  The New Frontier: Molecular Genetics

Nurture Parents and Peers  Parents and Early Experiences  Peer Influence

Nurture Cultural Influences  Variations Across Cultures  Variations Over Time  Culture and the Self  Culture and Child-Rearing  Developmental Similarities Across Groups

Variation Across Culture Cultures differ. Each culture develops norms – rules for accepted and expected behavior. Men holding hands in Saudi Arabia is the norm (closer personal space), but not in American culture. Jason Reed/ Reuters/Corbis

Evolutionary Psychology: Understanding Human Nature  Natural Selection and Adaptation  Evolutionary Success Helps Explain Similarities  An Evolutionary Explanation of Human Sexuality

Behavior Genetics: Predicting Individual Differences Behavior Geneticists study our differences and weigh the relative effects of heredity and environment.

Unlocking the secrets of genes Genes Functional units of heredity which are composed of DNA and specify the structure of proteins Chromosomes Within cells, rod-shaped structures that carry genes DNA (Deoxyribonucleic acid) Transfers genetics’ characteristics by way of coded instructions for the structure of proteins 3

Twin and Adoption Studies Studying the effects of heredity and environment on two sets of twins, identical and fraternal, has come in handy.

Separated Twins A number of studies compared identical twins reared separately from birth, or close thereafter, and found numerous similarities. Separated Twins Personality, Intelligence Abilities, Attitudes Interests, Fears Brain Waves, Heart Rate

Separated Twins Critics of separated twin studies note that such similarities can be found between strangers. Researchers point out that differences between fraternal twins are greater than identical twins. Bob Sacha

Biological Versus Adoptive Relatives Adoption studies, as opposed to twin studies, suggest that adoptees (who may be biologically unrelated) tend to be different from their adoptive parents and siblings.

Nature and Nurture Some human traits are fixed, such as having two eyes. However, most psychological traits are liable to change with environmental experience. Genes provide choices for the organism to change its form or traits when environmental variables change. Therefore, genes are pliable or self-regulating.

Innate human characteristics Infant reflexes Interest in novelty Desire to explore and manipulate objects Impulse to play and fool around Basic cognitive skills 3

Courtship and mating Sociobiology Interdisciplinary field that emphasizes evolutionary explanations of social behavior in animals, including humans. We behave in ways that maximize our chances of passing on our genes, and to help our close biological relatives, with whom we share genes, to do the same. 3

Mating Preferences Males look for youthful appearing females in order to pass their genes into the future. Females, on the other hand, look for maturity, dominance, affluence and boldness in males. Data based on 37 cultures.

Nature, Nurture, and Human Diversity Parents and Peers  Parents and Early Experiences  Peer Influence

Experience and Faculties Early experiences during development in humans shows remarkable improvements in music, languages and the arts. Courtesy of C. Brune

How Much Credit (or Blame) Do Parents Deserve? Parental influence is largely genetic. This support is essential in nurturing children. However, other socializing factors also play an important role. Although raised in the same family, some children are greater risk takers. Miquel L. Fairbanks

Culture and the Self

Reflections on Nature and Nurture