1. Nature and Nurture in Psychology Module 3:

2. Imagine for a moment that your adoring parents, who believe you are perfect, decide to clone you, creating a perfect genetic replica of you. Would the new baby, your identical twin, grow up to be exactly like you? What if the baby were exposed to a different prenatal environment – one polluted (or not) by drugs or viruses? What if your parents had to give the baby up for adoption or decided to move to a different part of the world?

3. Behavior Genetics  School of thought that focuses on how much our genes AND our environment influence our individual differences  Importance of both genetic and environmental factors on thoughts and behavior

4. Genes The biochemical units of heredity that make up chromosomes Many genes together make up chromosomes This is a chromosome, made up of many genes.

5. Environment Every non-genetic influence, from prenatal nutrition to the people and things around us Any influence, other than genetic, on an individual’s behavior Include: ◦ Diet (healthy vs. unhealthy) ◦ Family/home (smokers vs. non- smokers) ◦ Cultural, religious, etc. group ◦ Home location (rural, urban)

6. Nature and Nurture Debate Nature = the genetic code passed from parent to child. Nurture = all environmental influences from prenatal development on.

7. Genetics in Brief

8. Chromosomes Found in every cell in our body Made up of DNA (which contain our genes) 46 pairs of chromosomes in each cell 23 received from each parent (22 pairs of autosomes and one pair of sex chromosomes) Female sex chromosome = XX Male sex chromosome = XY Cells – nucleus – chromosomes – DNA - genes

9. Chromosomes

10. Deoxyribonucleic Acid (DNA) A complex molecule containing the genetic information The “stairs” on the DNA “ladder” are the genes Coded (to distinguish) with the letters A, T, C or G These individual lettered genes are called “nucleotides”

11. Interesting!!!!!!!!!!!! A fruit fly has about 15,000 genes A human has only about 25,000 99.9% of your 4-letter DNA sequence is the same as every other human; genetically, you are nearly identical to everyone else in the world We are each different or unique, genetically, by approximately 0.01%

12. Cellular Makeup

15. Gene Mutation Errors in gene replication that lead to a change in an individual’s genetic code The source of genetic diversity (what separates us from the 99.9%) Can be spontaneous or induced Can lead to desirable or undesirable changes 70% of genetic mutations are usually harmful to an individual, the remaining 30% are neutral or mildly beneficial For example, a butterfly may produce offspring with new mutations. The majority of these mutations will have no effect; but one might change the color of one of the butterfly's offspring, making it harder (or easier) for predators to see. If this color change is advantageous, the chance of this butterfly surviving and producing its own offspring are a little better, and over time the number of butterflies with this mutation may form a larger percentage of the population

16. Predisposition The possibility of something happening based on our genes The environment may or may not trigger the predisposition Example – disease (i.e. cancer)

17. Nature and Individual Differences

18. “But I….” Despite genetics, we, as individuals often end up very much our own person. What accounts for each of us being different from all others? Behavior geneticists study such questions using twin studies and adoption studies

19. Identical Twins Nature’s human clones Develop from a single fertilized egg that splits in two, creating two genetically identical organisms Called monozygotic twins

21. Fraternal Twins Twins who developed from separate eggs Genetically no more similar than other siblings, but they share a fetal environment Called dizygotic twins

23. Twin Studies Used to determine the heritability of a given trait Data is collected from both identical and fraternal twins on the trait Compare the data between the two groups Important not to conclude that a specific behavior is inherited

24. Evidence from Twin Studies Intelligence Personality traits Divorce rates SEE HANDOUT

25. Adoption Studies Biological parents supply the nature and adoptive parents provide the nurture Study after study reveals that adopted children share more personality trait similarities with their biological parents than with their adoptive parents

26. Environmental Factors Early Brain Development Peer Influences Cultural Influences (norms, individualism, collectivism)

27. Early Brain Development Brain development also impacts who we become; our thoughts and behaviors “Experience nurtures nature” The brain processes we use in early learning do pave the way for later learning of more complex information If you are raised in an impoverished environment you will not develop to the same capacity as someone who was; simple. Early experience is critical The brain’s pathways maintained through practice or experience will remain strong and, and neglected pathways will fade with disuse

29. Peer Influences Peer influence in adolescence is very powerful. Many studies suggest a peer group is correlated with school performance, smoking, and other behaviors.

30. Culture The shared attitudes, beliefs, norms and behaviors of a group communicated from one generation to the next