Human Behavior Nature Nurture and Human Diversity Our

Human Behavior Nature, Nurture and Human Diversity

Our behavior is often characterized as “human nature. ” n What do we mean by human nature? n How might a psychologist go about identifying the traits of human nature?

In a culture that emphasizes our differences, we sometimes forget just how similar we are…

Brainstorm and list all the universal behaviors (behaviors shared among all cultures) that you can think of… communicate both verbally and nonverbally Enforce rules of etiquette Avoid incest Fear snakes / heights Exchange gifts Modesty in sexual behavior and bodily functions Labor divided by age and sex Men- more aggressive than women Women provide more child care Tools for work Belief systems- death, disease Plan for the future Taboos- crimes and legal punishments Marriage Laugh / smile / mimic / joke / flirt / sympathize / tease / dance / Music /Myths / folklore / poetry Games War

In a world of such diverse cultures, why do so many universal behaviors exist? n Genetic similarities / shared DNA

Nature, Nurture and Human Diversity Essential Question: What ultimately shapes our behavior? Topics of Study: The Influence of genes: Behavioral Genetics Evolutionary Psychology and Natural Selection Nurture and Early Development

Behavior Genetics (Text Question #1) n Study individual behavioral differences. (weigh effects of nature, nurture) Ø Chromosomes: 23 / egg, 23 / sperm (threadlike structures) ØComposed of DNA (deoxyribonucleic acid) ØGenes: 30, 000 each / self-replicating units, synthesize proteins, (the building blocks of physical development ØGene complexes: many genes acting in concert n Genes: Influence physical make-up, intelligence, aggressiveness, happiness etc.

Behavior Genetics

Fraternal, Identical Twins: What’s the difference? n Fraternal: (dizygotic) Ø Separate fertilized eggs (50% shared genes- no more genetic similarity than normal siblings) n Identical: (Monozygotic) Ø Single fertilized egg split in two = clones (100% shared genes)

Fraternal vs. Identical (#2) n Fraternal / Identical twin study findings- provide specifics for the following: Ø Alzheimer’s Ø Identical =60% / Fraternal=30% Ø Extraversion / neuroticism Ø Identical more similar than fraternal Ø Divorce rates Ø Identical x 5. 5 vs. fraternal x 1. 6 Ø Schizophrenia Ø 50, 10, 3, 1 (identical, fraternal, sibling, stranger) n What are the limitations of these studies? Ø Genetics or environment? How do we differentiate?

The Bouchard Minnesota Twin Study n “Are You a Natural”- (handout questions)

Gerald Levy and Mark Newman Separated at Birth

Levy and Newman n Bouchard’s Minnesota Twin Study Ø Ø Reunited by shared acquaintance Upon meeting for first time: Ø Same mustache, sideburns, glasses Ø Levey: college degree in forestry- Newman planned to but worked for city trimming trees Ø Levey worked installing sprinker systems, Newman installed fire alarms Ø Both were bachelors, same taste in women Ø Both only drank Budweiser (pinky wrapped underneath can, crushed can afterwards) Ø Hunting, fishing, beach, John Wayne movies, pro-wrestling, Chinese food in wee hours Ø Volunteer firefighters Ø Both raised Jewish, neither particularly religious Ø When met- same remarks, at same time, same gestures- “spooky” Ø He is he and I am I, and we are one…

Genetics and Behavior Why has genetics not been given more consideration as a determiner of personality and behavior? Ø 2 nd ½ of 20 th century: behaviorism’s dominance Ø “Experience as primary architect of human behavior” Ø “Invisible” genetics- can’t see, touch or remember the influence Ø Determinism- “compromises free will” Ø Nurture gives parents measure of confidence- “can control outcome” Ø Bad, ineffective behavior can be “unlearned” Ø “Why bother? ” Genetic argument reduces free will, cornered by determinism Ø “That boy was born to act that way!” Ø Reality: Both play critical role in who you are!

Adoption Studies (#5)

What insight has adoption studies provided regarding the influence of genetics on personality? (#5) n Environmental relatives / biological Relatives n Finding: subject’s personality reflected biological relatives, even when adopted at birth n Conclusion: people who grow up together don’t resemble each other in personality n Why are two people raised together so different? ? ? ØConfirmation of genes impact on personality

Environmental Influence n So what traits does nurture influence? ØValues ØManners ØFaith / religion ØPolitics ØSocial views

Heritability (#6) n Extent to which difference between individuals can be attributed to genes ØAs environments become more similar, heredity as a source of difference becomes more important (and vice versa) ØHeritable differences don’t often translate to group differences

Temperament (#7) n Our emotional excitability ØTemperament traits tend to remain consistent through life ØStudies confirm ØGenetic temperament helps form enduring personality ØThink of two examples of those you know.

Nature and Nurture n Genes are self-regulating (respond adapt to environment) n Individual differences almost always the result of both nature and nurture – “Gene and scene dance together” – Or, “nurture works on what nature endows”

Molecular Genetics (#8) n Identify specific genes influence on behavior Ø Weight, extraversion, sexual orientation… Ø LD, depression, schizophrenia, alcoholism… Ø Designer babies? !? !

Human Nature? 1. 2. 3. 4. Why do infants start to fear strangers about the time they become mobile? Why are most parents so passionately devoted to their children? Why do so many more people have phobias about spiders and snakes than guns and electricity? Why are men quicker to perceive friendliness as sexual interest?

Evolutionary Psychology Ø Premise Ø (Darwins’ ) natural selection shapes our behavior, thinking (over time) Ø Certain traits, behaviors that enhance survival are passed on over generations

Dmitry Belyaev: Domestication of Foxes

Belyaev’s Experiment n n n 30 males, 100 females Tamest 5% M, 20% F 30 generations Complete domestication Now sold as house pets Implications? n When certain traits are selected that give a reproductive advantage, those traits will prevail n

Evolutionary Psychology n For the most part, evolutionary psychology helps to explain our similarities. (Universal behaviors) n But it also helps explain some key differences…….

Gender and Sexuality On the issue of sex, would you characterize the attitudes and behaviors of men and women to be generally the same, or different? Explain and provide examples.

Gender and Sexual Attitudes / Behavior Studies: Ø 1978, FSU- research assistants / proposals for casual sex with strangers v 75% of men- yes 0% of women- yes Questionnaire: casual sex with different partners Ø 48% of men- yes 12 % of women- yes Ø Ø How can we explain this radical difference in sexual attitudes between the genders?

Gender Differences and Sexuality Natural selection would suggest that each gender pursued attitudes and behaviors that perpetuated their survival, and thus became part of our DNA over time. n Women- relational Ø Incubates, nurses one infant Ø Wants protection, assistance to ensure child’s survival Ø Chooses wisely n Men- recreational Ø Perpetuate his genes (spread his genes through other females) Ø Chooses widely

Gender Differences and Sexuality n Significance? n “Nature selects behaviors that increase the likelihood of sending one’s genes into the future. ”

Nature, Nurture and Gender n Gender Development ØMale, Female- What determines the gender? Ø 23 rd pair of chromosomes determine sex ØFemale=X, Male = X or Y

Boys, girls and toys… Nature or Nurture? n Why do genders choose what they do…?

Nature and Gender n Prenatal Months Ø 7 th week: develop male, female anatomical distinctions Ø 4 th, 5 th month: Ovarian hormones, testosterone influence different brain development Ø Studies Ø Hines and Alexander: Texas A&M- Velvet monkeys Ø 1 day old infants: video: friendly face or mechanical mobile Ø 1 yr. old infants: films: faces or cars Ø Evidence suggests cognitive differences upon birth

Gender Differences and the Brain ØNew evidence: structural, chemical and functional differences between genders and brains ØFemales: thicker frontal lobe (verbal fluency) ØMales: thicker parietal Cortex (space perception) ØPotential need for sex-specific treatments for addictions, depression, schizophrenia etc.

Nurture and Gender Nurture influences our sense of gender by… Gender identity (culture’s sense of being male or female) n Gender-typing: casting, assigning traditional gender roles n Gender-Schema theory: mental associations we make influence how we perceive gender in other issues n Social learning theory (Observation, imitation) n

Nurture and Early Neural Development n Early experience matters! ØFosters neural connections ØExperience preserves activated neural connections ØUnused ones degenerate (pruning) ØExcess “connectors” in youth make kids more capable of mastering certain tasks. ØExample? ØForeign language, (Accent and grammar) visual perception, musical instruments

Rat Studies n Rosenzweig and Krech Ø Isolated, impoverished vs. social, enriched environment Ø Young rats n Findings: Ø Obvious differences in behavioral activity and curiosity Ø Heavier, thicker brain cortex (brain weight increased 7 -10 percent and # of synapses increased 20%!) Impoverished environment Rat brain cell Enriched environment Rat brain cell

Premature Babies n Neonatal units ØMassage therapy stimulates growth ØSpeeds departure from hospital

Parent’s Influence Genes determine human traits (personality) n Parents’ influence helps determine how those traits are expressed! n Ø “Genome gives the basic plot, the parent gives it its tone, accent and emphasis. ” Ø IOW- “It starts with the kid, and the parents pick up on it. ” n Implications are huge for parenting… (shaping genetic traits to be productive ones…)

Nurture’s Sway… Cultural Influences n Individualism Ø Self: Independent Ø Life Task: Discover, express one’s uniqueness Ø What matters: Me, personal achievement, rights, freedoms, self-esteem Ø Coping method: change reality Ø Relationships: Many, often temporary, confrontation acceptable Ø Behavior: Reflects one’s personality, attitude n Collectivism Ø Self: Interdependent Ø Life Task: fit in, perform role, obligations Ø What matters: Us, group goals, family duty, social responsibility Ø Coping method: Accommodate to reality Ø Relationships: Few, close and long term, harmony valued Ø Behavior: social norms and roles

Cultural Influences n Individualism n Collectivism