Heredity, Environment, and

EvolutionMod 14 and 15

InfluencesNature vs Nurture

IntelligenceAggressionPersonality

Behavioral genetics Integrates the influences of heredity, environment

and evolution in terms of their effect on human behavior

HeredityHow the traits of parents are transmitted

biologically to their offspring

ChromosomesNucleus of each human cell contains 46 chromos23 from each parent

GenesBiochemical units of heredity that make up

chromosomesContain DNA (chainlike molecule)

EnvironmentNature vs Nurture debate

Nature – genetic or biologicalSets the possibilities for behavior

Nurture – environmental factorsDetermines how the possibilities will be realized

Most agree both contribute to influence behavior

Evolution Darwin

gradual change in genes over time because traits that allowed our ancestors to survive where passed on

Twin Studies Heritability

Proportion of variation among individuals that we can attribute to genes

Varies depending on pop. And envir. being studied

It is an estimate Applies only to the

population as a whole Not to individuals Numerical value 0 to 1

Heritability Trait with high levels of

heritability is height

If a given population has good health and nutrition, most differences regarding height will be due to differences in their genes

video

Twin Studies Monozygotic Twins

Identical 100% same genes

Dizygotic Twins Fraternal 50% same genes

Thomas Bouchard Famous Minnesota Twin

Studies Jim Twins Video

Adoption Studies Genetic relatives

Environmental relatives

Environment shared by a family’s children has virtually no impact on personality

Epigenetics Study of environmental

influences on gene expression that occurs without DNA change

video

Evolutionary Psychology

Video overview