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

Just how similar are we? (True or False) 1. Fraternal twins are no more genetically similar than normal siblings. 2. If after a worldwide catastrophe only Icelanders or Kenyans survived, the human species would suffer a huge reduction in its genetic diversity. n We share 99. 9% of our DNA with our neighbor! (Near clones!) n “We are the leaves of one tree. ”

Nature, Nurture and Human Diversity Essential Question: What ultimately shapes our behavior? Topics of Study: Genetics and Evolutionary Psychology Parents, Peers and Culture Gender

Pattern Recognition n Nature v. Nurture 1. Sugar and spice and everything nice, that’s what little girls are made of…” “Handsome is as handsome does. ” “Like father like son. ” “You can’t teach an old dog new tricks. ” “Boys will be boys. ” “You are what you eat. ” “Blood will tell. ” “All men are created equal. ” 2. 3. 4. 6. 7. 8. 9.

Genetics and Behavior Getting started…. . We know that both nature and nurture weave together to shape our behavior. Its easy to prove that nurture influences behavior, but how could we devise a way to prove that genetics influences our behavior?

Read carefully pages 95 -102 1. Identify the following and explain how they collectively influence behavior. chromosomes, DNA, genes, gene complexes 2. Explain specifically how studies contrasting fraternal and identical twins have helped prove that genetics influence individual behavior. 3. The case studies of Jim Lewis / Springer and Oscar Sohr / Jack Yufe (identical and separated at birth) provide evidence that genetics influence’s behavior. Explain specifically the strengths and weaknesses of these studies.

Behavior Genetics 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 (no more genetic similarity than normal siblings) n Identical: (Monozygotic) Ø Single fertilized egg split in two = clones

Fraternal vs. Identical

Fraternal v. Identical

Fraternal vs. Identical 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?

Twin Studies Jim Lewis / Springer n What does the study suggest?

Jim an Jim n 37 days after birth n Romantic- love notes to wife n Son James, dog Toy, wife Linda n Woodworking (same bench in front yard) n Chevy, stock car racing, Miller Lite n Vasectomy, high blood pressure, chain smoker n migraines

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

Adoption, Genetics and Behavior 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

Temperament 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.

Heritability 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

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 n Identify specific genes influence on behavior Ø Weight, extraversion, sexual orientation… Ø LD, depression, schizophrenia, alcoholism… Ø Designer babies? !? !

Questions to Consider 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…….

Evolution and Human Sexuality True or False: Males are more likely than females to initiate sexual activity.

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 Question: Why is there a difference between genders concerning attitudes and behaviors about sex?

Gender Differences and Sexuality Natural Selection 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 and Attraction Study spanned 37 cultures n Men (attracted to…) Ø Youthful, healthy, fertile Ø Waists 1/3 size of hips Ø Many children- genes to future… n Women (attracted to. . ) Ø Mature, dominant, bold, affluent Ø Support and protect Ø Long- term mating, investment in jointoffspring

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

In Conclusion… n 4 important gender differences in human sexuality (Comprehensive Study: Letitia Anne Peplau) 1. Men show greater sexual desire than women 2. Women tend to emphasize committed relationships as a context for sexuality (more so than men) 3. Aggression is more closely linked to sexuality for men than women (powerful, domineering, experienced, individualistic) 4. Women’s sexuality shows greater plasticity (attitudes, behaviors about sex more easily shaped by cultural, social factors) Ø Example: college (liberalizes women’s attitude towards sex more than men’s) Ø Chance of men identifying as gay or bisexual: x 2 Ø Chance of women identifying as lesbian or bisexual: x 900!

Evolutionary Psychology n From an evolutionary psychology perspective, how might we explain marriage?

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

Glad to be your gender? n Men Ø X 4 to commit suicide, alcoholism Ø Autism, color blindness, hyperactivity, antisocial personality disorder n Women Ø 70% more fat Ø 40% less muscle Ø 5 inches shorter Ø Puberty 2 years earlier Ø Live 5 years longer Ø X 2 for depression, anxiety Ø X 10 for eating disorders

Gender and Aggression n Males tend to be more physically aggressive ØMale-female arrest rate for murder ØU. S. 9 -1 ØCanada 7 -1

Gender and Social Power n Universal dominant pattern: Men are more socially ØMen: as leaders- more direct, autocratic, express opinions ØWomen: as leaders- more open, democratic, offer support

Gender and Social Behavior n Males Ø Individualists Ø Boys: larger play groups (activity focus) Ø Male Answer Syndrome Ø Freedom, self-reliance n Females Ø Interdependent (relationships) Ø Girls: smaller groups (often one friend) less competitive, imitate social relationships Ø 85% of greeting cards! Ø More religiously oriented

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

Nurture and Gender n Gender identity n Social learning theory n Gender Schema theory: Learning theory + cognition ØSchema, or concepts are formed by genders in developing stages- 1 yr olds: voice gender differences Ølens through which they see the world confirms roles

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.

Genes rule…? ? n In terms of personality, environmental factors typically account for less than 10% of children’s differences. (Key is how parents and peers influence those traits. )

Parenting the Genetic Code n Explain how one might address the following genetic traits for productive outcomes… sluggish, unresponsive, temperament as 3 month old 2. Imaginative, slightly hyperactive, ADD high school student 1.

What / Who has shaped you…? n List the eight behavioral traits that most reflect your personality. For each, indicate which of the following has been most influential in shaping that trait. ØParents ØPeers ØGenes Results? Which factor do you think most influential?

Prenatal Environment n Studies indicate that identical twins who share the same placenta are more similar in psychological traits than those twins that don’t.

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…)

Peer Influence n True or False “Preschoolers who disdain a certain food despite parents’ efforts will often eat the food at a table of peers who like it. ” 2. A child who hears English spoken with one accent at home and another in the neighborhood and at school will invariably adopt the accent of his peers and not his parents. 1.

Parents vs. Peers n Parents Ø Education Ø Discipline Ø Responsibility Ø Orderliness Ø Charitableness Ø Dealing with authority n Peers Ø Cooperation Ø Popularity Ø Styles of interaction

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