Chapter 3Nature, Nurture,
and Human Development
Behavior Genetics
• Behavior Geneticists - Weigh the effects of our environment and heredity• The basics• Humans have 46 chromosomes (23 from mom/23 from dad)• Chromosomes contain DNA• Genes are small parts of the DNA• Genomes – complete instructions for making an individual (all the genetic
material)
• If specific genes can be identified with disorders, gives a biological understanding
Genetics
http://www.cbsnews.com/news/many-more-genes-linked-to-autism/
Twin & Adoption Studies• Identical twins • don’t just look the same• Come from one egg and are
“genetically” identical
• Fraternal twins• Come from two eggs• Genetically no more similar
than ordinary siblings
• Adoptive Children• Resemble biological parent
personality (thinking, feeling, acting)• Resemble adoptive parent values,
attitudes, manners, faith, politics
Temperament Studies
• Temperament • Emotional excitability
• Apparent soon after birth• Tends not to change even into adulthood• More heredity here than environment
Heritability
• Heritability• How much the difference between people can be attributed to genes
• Groups• Individual gene differences don’t necessarily explain differences in groups
Parents and peers• Prenatal (before birth) conditions can affect the child• Experience modifies the brain• Unused synapses degenerate (impoverished vs enriched environment)• Lacking visual experience early, prevents normal usage later even with
surgery
• Parents…• Influence manners, political & religious beliefs• Not so much influence on personality
• Peers…• Attempt to fit in (conformity)• Influence cooperation and interaction
Cultural Influences• Culture• Behaviors, ideas, values, traditions shared in a group
• Cultural differences• Personal space• Expressing feelings• PDA• Pace of life• Educating & rearing children
• Genes lead to culture change?• Nope – culture changes faster than genes
Cultural Influence
• Individualism (Independence) vs Collectivism (Interdependence)• US, Canada, Western Europe value the individual & personal achievement• Many part of Asia and Africa value interdependence and tradition
• Cultures may be different but genetic profiles are the same
Gender Development
• Let’s read a book…
Info about the book…
• When do you think this was published?• Published in 1970
• Intended as a satire
Gender Development
• Differences• 45 Chromosomes are unisex• Biologically
• body fat• muscle,• height,• age of puberty • life expectancy
• Psychologically • More women diagnosed w/depression• More men diagnosed antisocial personality disorder
Gender Development
• Aggression• In many cultures & ages, men tend to be more aggressive
• Social Power• Most societies are male dominant
• Social Connectedness• Women tend and befriend• Men emphasize freedom and self-reliance
• Nature of Gender• Biological sex determined by 23 pair of chromosomes• Mom=X Dad= X or Y• XX=Female XY=Male
Gender Development
Nurture of Gender• Gender Roles • Expectation of how men & women should behave
• Gender Identity • One’s sense of being male or female
• Social Learning Theory • Assumes gender behavior is learned (observed & imitated) though reward
and punishment like
• Gender Schema Theory• Proposes we learn a cultural “recipe” of how to be male/female and adjust
behavior accordingly
Got time?
• “Like a girl” videoVideos\P_G Do Things Like A Girl.mp4