NATURE & NURTURE OF BEHAVIOR
I. genetics – nature
A. every human cell nucleus contains chromosomes- 46 total: 23rd pair = gender; X from mom/X (girl) or Y (boy) from dad
1. DNA – coils that make up chromosomes
a. genes–parts of DNA molecules w/ instructions to make proteins necessary for physical development
1. nucleotides – biochemicals that form genes
II. evolutionary psychology focuses on natural selection (certain traits, over time, prevail) – differences may grab our attention, but biological similarities are astounding! (99.95%)
III. mutations – random errors in gene replication
IV. sexuality – which gender has stronger sex drive? – gender differences in attitudes extend to differences in behavior – women are more relational, men are more recreational
A. men can reproduce more often and more widely – youthfulness is important b/c probability of babies is higher
B. women must choose wisely, often focusing on success, kindness, & generosity b/c need help raising/protecting family
V. critics of evolutionary psychology say they start with an effect or a behavior and work backwards to explain it; culture plays a greater role in behavior (ever-changing, NOT static)
VI. behavior geneticists are more concerned w/ differences
A. genes AND environment
B. identical twins – single egg/fraternal twins – two eggs
C. moderate genetic influence on certain attitudes and certain abilities– identical twins are far more similar
D. twin studies & adoption studies are best research tools
E. are adopted children more like their adoptive parents or biological parents?
1. people who grow up together are more dissimilar than many think - not that much alike personality-wise!
2. values, attitudes, manners, religion & politics are more similar than not (from environment)
VII. temperament – broad personality disposition & emotional reactivity (neuroticism) – newborns tend to develop into similar adults (stability); thought to be biologically rooted or inherited - nature
VIII. heritability – the proportion of a particular trait (intelligence, happiness, temperament) that can be attributed to genes v. environment (i.e. identical twins raised in very different environments have similar IQ high heritability)
IX. parental influence on personality is more limited than once believed – pre-natal environment, brain development, peer influence & culture are strong influences
A. placenta helps provide nutrients & block teratogens
B. early learning – repeated experiences result in stronger and more numerous neural connections (activate & preserve connections – use it or lose it!)
C. peer influence – naturally we will work with, interact with, and mate with our peers so influence is strong (i.e. accent)
D. culture – behaviors, ideas, attitudes & traditions shared by a large group (i.e. independent culture v. collectivist culture)
1. norms – the rules shared by the group
2. memes – self-replicating ideas, fashions, innovations, etc. (cultural mutations)