Chapter 4
Nature, Nurture, and Human Diversity
Behavior Genetics: Predicting Individual Differences
:Humans typically have 46 chromosomes o 23 from mother, 23 from father o Chromosomes contain DNA
Genes are small segments of a DNA molecule
Humans have 20,000 -- 25,000 genes o Environmental events "turn on" genes
Shared Genetic Profile
Genetically speaking, the genetic makeup of humans is nearly identical
Variations found at particular gene sites in human DNA point to slight person-to. person variations from the common pattern and give clues to our uniqueness o Genetic diseases o Physical attributes o Personality/demeanor
To form us, environmental influences interact with our genetic predispositions
Twins and Adoption Studies
Identical twins vs. fraternal twins
Research studies on identical twins raised apart o Minnesota Center for Twin and Family Research
Research studies on adopted vs. biological relatives
The environment shared by a family's children has virtually no discernible impact on their personalities
Gene-Environment Interaction
Most human traits are influenced by combinations of genes For examples, no single "obesity gene" though we know heredity influences body weight Epigenetics studies that molecular mechanism by which environments can trigger or block gene expression
How Does Experience Influence Development
. Developing neural connections prepare our brain for thought, language, and other later experiences
"Use it or lose it" principle
Parental Influences
Parenting does matter, but likely not as much as we think
We see the largest effects at the extremes
"Parents should be given less credit for kids who turn out great and blamed less for kids who don't" -- Sandra Scarr, developmental psychologist
Cultural Influences
Culture is the behaviors, ideas, attitudes, values, and traditions shared by a group of people and transmitted from one generation to the next
Culture and the Self
:Individualism o Giving priority to one's own goals over group goals and defining one's identity in terms of personal attributes rather than group identifications Collectivism o Giving priority to the goals of one's group (often one's extended family or work group) and defining one's identity accordingly
Gender Development
Biological sex vs. gender Many similarities between men and women Some differences o Average woman enters puberty 1 year earlier than men and her lifespan is 5 years longer She has twice the risk of developing depression and anxiety and 10x the risk of developing an eating disorder o Average man is 4x more likely to die by suicide or develop an alcohol use disorder He is more likely to have autism spectrum disorder, colorblindness, and ADHS He is more at risk for antisocial personality disorder
Aggression o Men generally admit to more aggression and commit more acts of physical violence
Social Power o Directive vs. Democratic o Offer opinions vs. Express support
Social Connectedness o Women's brains are wired to improve social relationships while men's brains are wired to connect perception with action
How do we learn gender?
Gender Role o Describes how others expect us to think, feel, and act Gender Identity o Is our personal sense of being male, female,