Unit XII* Nature, Nurture, and Human Diversity *Just a reminder – there are XVII total units

The Big Question Previous units have examined the relative influences of nature and nurture in areas as diverse as intelligence, weight, language development, learning, sensation and perception. Previous units have examined the relative influences of nature and nurture in areas as diverse as intelligence, weight, language development, learning, sensation and perception. As we turn our focus to the closing units that center more on individual differences (development, personality, social psychology and disorders/therapy) it seems like a good time to consider: As we turn our focus to the closing units that center more on individual differences (development, personality, social psychology and disorders/therapy) it seems like a good time to consider: How much of who you are is a reflection of your genes, How much of who you are is a reflection of your genes,genes and how much reflects your experiences?

Genetics Behavior genetics: The study of the relative power of both genetic and environmental factors on behavior. Behavior genetics: The study of the relative power of both genetic and environmental factors on behavior. Genetic Structure Genetic Structure Chromosomes (23 pairs) Chromosomes (23 pairs) Deoxyribonucleic acid (DNA) Deoxyribonucleic acid (DNA) GATC nucleotides GATC nucleotides Genes Genes Expressed or unexpressed Expressed or unexpressed Human genome Human genome Variations between species and individuals Variations between species and individuals

Twin Studies Identical (or real) twins Fertilized egg splits Genetically identical Genetic differences? Fraternal (or fake) twins Different fertilized eggs Genetically dissimilar Twin studies Reared together Reared apart

Adoption Studies Biological relatives and environmental relatives Biological relatives and environmental relatives Research Research Environment ≠ Personality Environment ≠ Personality Environment does influence attitudes, values, faith, manners and politics Environment does influence attitudes, values, faith, manners and politics Adoptive environments demonstrate different characteristics Adoptive environments demonstrate different characteristics

Temperament, Heredity and Heritability Temperament: An in-born emotional reactivity and intensity. Temperament: An in-born emotional reactivity and intensity. Temperament varies at birth and tends to be stable Temperament varies at birth and tends to be stable Heredity predisposes us to differences in temperament Heredity predisposes us to differences in temperament Heritability: The proportion of variation among individuals that is attributable to genes. Heritability: The proportion of variation among individuals that is attributable to genes. This only works as a comparison between people This only works as a comparison between people Individual vs. group differences Individual vs. group differences Adaptive capacity – nature and nurture Adaptive capacity – nature and nurture

Nature-Nurture Interaction It is the interaction between genetic forces and environmental forces that is most important in considering this issue. Genetic predispositions impact experience Experience alters genetic possibilities Epigenetics article Molecular genetics

Evolutionary Psychology Evolutionary psychology and natural selection Evolutionary psychology and natural selection The foxy Dmitry Belyaev and unnatural selection The foxy Dmitry Belyaev and unnatural selectionfoxy Natural selection and mutation – adaptivity Natural selection and mutation – adaptivity Adaptive success explains similarities Adaptive success explains similarities Only 5% of genetic differences are between populations Only 5% of genetic differences are between populations Biological predispositions may run counter to nurture Biological predispositions may run counter to nurture Gender differences in sexuality (more on this later) Gender differences in sexuality (more on this later) Mars and Venus – natural selection and mating Mars and Venus – natural selection and mating Criticism of evolutionary psychology Criticism of evolutionary psychology

Nurture: Parent vs. Peers Parents and Family Early brain development Rosenzweig and Krech Reminder of natural and “nurtural” aspects of brain growth The parental blame game Most obvious at extremes Parenting is considered more in Unit XIII Peer-group Influence Judith Harris – The Nurture Assumption Social facilitation and peer groups The selection effect and friendships Parent and peer summation

Cultural Influences Culture: Behaviors, ideas, attitudes, values and traditions shared by a group of people and transmitted to the next generation. Seen in humans and animals Language and culture Variations between cultures Social norms Unwritten rules of conduct Personal space

Culture, continued Changes through time Changes through time Culture changes more quickly than we think Culture changes more quickly than we think Self-concept and culture Self-concept and culture Individualism Individualism Traits and info Traits and info Collectivism Collectivism Traits and info Traits and info Parenting and culture Parenting and culture “Family self” “Family self” Similarities and differences Similarities and differences

Gender Development Sex vs. Gender Sex vs. Gender G: Biological and social definitions of physiological sex G: Biological and social definitions of physiological sex 45/46 and other similarities 45/46 and other similarities Gender differences Gender differences Aggression Aggression Physical vs. relational Physical vs. relational Social power Social power Socialization Socialization Independence vs. interdependence Independence vs. interdependence

Nature and Gender We are all gender neutral until 7 weeks after conception Mom provides X Dad provides X or Y 4 th -5 th prenatal months Hormones in the brain Irregular cases Extra testosterone and females David/Brenda Reimer

Nurture and Gender Roles and Identity Roles and Identity Gender roles Gender roles Gender identity Gender identity Gender-typing Gender-typing Gender role examples Gender role examples Social learning theory Social learning theory Schemas and gender Schemas and gender Childhood and stereotypes Childhood and stereotypes

Final Reflections “Trivial and great truths” “Trivial and great truths” We are formed by genetic forces and environmental forces. We are formed by genetic forces and environmental forces. Environmental forces can include voluntary and involuntary factors Environmental forces can include voluntary and involuntary factors Environmental forces can also be influenced by genetic forces. Environmental forces can also be influenced by genetic forces. Heisenberg and N v. N Heisenberg and N v. N