1 PSYCHOLOGY (8th Edition, in Modules) David Myers

2 Behavior Genetics and Evolutionary Human Diversity

3 Behavior Genetics: Predicting Individual Differences Behavior Geneticists study our differences and weigh the relative effects of heredity and environment. This used to be called the Nature vs. Nurture Debate Now it is called Nature via Nurture

4 Genes: Our Codes for Life In the nucleus of a cell chromosomes (46) containing DNA (deoxyribonucleic acid) are situated.

5 Genes: Our Codes for Life Segments within DNA constitute genes making proteins to determine our development.

6 Genome Genome is the set of complete instructions for making an organism Containing all the genes in that organism. Thus human genome makes us human and the genome for drosophila makes it a common house fly.

7 Genetics Humans have 30,000 genes. 99.9% of your DNA matches that of every other human Our genes are responsible for predisposing our appearance and behavior. Predisposition only means that the possibility of development of (x) exists.

8 How do we study the interaction of nature and nurture Twin Studies Adoption Studies

9 Twin Biology To study the effects of heredity and environment two sets of twins, identical and fraternal, have come in handy. Monozygotic Twins Dizygotic Twins

10 Twin and Procedures Behavior geneticists study the effects of shared and unique environments on total or partial genetic makeup.

11 Separated Twins A number of studies have looked at identical twins raised separately from birth or close there after and have found a number of similarities. Separated Twins Personality, Intelligence Abilities, Attitudes Interests, Fears Brain Waves, Heart Rate

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

13 Adoption Studies Opposed to twin studies, adoption studies suggest that adoptees (who may be biologically unrelated) tend to be different from their adoptive parents and siblings.

14 Adoptive Studies Adoptive studies strongly point to the simple fact that biologically related children turn out to be different in a family. So investigators ask: Do siblings have differing experiences? Do siblings, despite sharing half of their genes, have different combinations of the other half genes? Ultimate question: Does parenting have an effect?

15 Parenting Parenting does have an effect on biologically related and unrelated children. Parenting Influences children’s Attitudes, Values Manners, Beliefs Faith, Politics

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

17 Heritability Heritability refers to the extent to which the differences among people are attributable to genes.

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

19 Gene-Environment Interaction Genes can influence traits which affect responses, and environment can affect gene activity. A genetic predisposition that makes a child restless and hyperactive, evokes angry responses from his parents. A stressful environment can trigger genes to manufacture neurotransmitters leading to depression.