Nature vs. Nurture

Psych - Swenson

Nature, Nurture and Gender •  Sex differences are present at birth

•  Which long term differences are biological and which are cultural is still hotly debated.

•  Every human brain is female until 8 weeks of gestation, when a surge of testosterone leads to a change in males

•  Even at only one day old, sex differences are present. Females look longer at faces; Males look longer at mechanical mobiles.

•  At 1 year, girls prefer nurturing toys, such as dolls and tea sets, boys prefer toys that can be used or propelled such as balls, guns and trucks.

•  Interestingly, the same results hold true in a study of young monkeys

Key Differences •  Women tend to be better at empathizing,

men at systemizing (as evidenced by toy choices.

•  Women have a larger corpus collosum, allows the use of both sides of the brain. No difference in IQ scores.

•  Women attend to landmarks, facial features; Men to geometry and space. Men excel at spatial reasoning although women who had higher testosterone in the womb score higher.

•  Women tend to be more verbal; they use words more rapidly, and use both sides of the brain when processing verbal tasks, although men score equally well if given sufficient time.

•  Differences in aggression are moderate, but: females act more aggressive if they believe no one is watching. Female anger I more intense and prolonged, girls find indirect, social aggression more hurtful than physical violence.

•  Males and females are equally good at math before puberty, but at mid-teens males tend to be better at problem solving, although female scores cluster around the middle, male scores indicate more prodigies, but also more idiots

Early Experience and Genetics •  Early experience molds the way genes

work (called epigenetic imprinting)

•  Rat pups •  If licked and groomed by momma rat, grow

to be less anxious and fearful as adults (stress reaction), in turn those rats give their pups more care (evidence of power of nurture)

•  Physical differences that result: •  More active version of a gene in the

hippocampus that regulates production of a stress reducing hormone

•  Genes and hormone receptors and proteins are physically different

•  Critical Period – these changes in rats occur during the first week of life after birth

•  Survival of the fittest? Fewer nervous rats live to adulthood

•  Evidence of relationship between Nature and Nurture