Human Behavior

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Human Behavior

• Nature, Nurture and Human Diversity

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Our behavior is often characterized as human
nature.

• What do we mean by human nature?
• How might a psychologist go about identifying the
  traits of human nature?

3
In a culture that emphasizes our differences, we
sometimes forget just how similar we are
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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

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In a world of such diverse cultures, why do so
many universal behaviors exist?

• Genetic similarities / shared DNA

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Just how similar are we?

• (True or False)
• Fraternal twins are no more genetically similar
  than normal siblings.
• If after a worldwide catastrophe only Icelanders
  or Kenyans survived, the human species would
  suffer a huge reduction in its genetic diversity.
• We share 99.9 of our DNA with our neighbor!
  (Near clones!)
• We are the leaves of one tree.

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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

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Nature v. Nurture

• Recognizing the difference
• Sugar and spice and everything nice, thats what
  little girls are made of
• Handsome is as handsome does.
• Like father like son.
• You cant teach an old dog new tricks.
• Boys will be boys.
• You are what you eat.
• Blood will tell.
• All men are created equal.

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Genetics and BehaviorGetting 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?

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

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Behavior Genetics(Text Question 1)

• Study individual behavioral differences. (weigh
  effects of nature, nurture)
• Chromosomes 23 / egg, 23 / sperm (threadlike
  structures)
• Composed of DNA (deoxyribonucleic acid)
• Genes 30,000 each / self-replicating units,
  synthesize proteins, (the building blocks of
  physical development
• Gene complexes many genes acting in concert
• Genes Influence physical make-up, intelligence,
  aggressiveness, happiness etc.

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Behavior Genetics
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Fraternal, Identical TwinsWhats the difference?

• Fraternal (dizygotic)
• Separate fertilized eggs (50 shared genes- no
  more genetic similarity than normal siblings)
• Identical (Monozygotic)
• Single fertilized egg split in two clones
• (100 shared genes)

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Fraternal vs. Identical
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Fraternal v. Identical
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Fraternal vs. Identical (2)

• Fraternal / Identical twin study findings-
  provide specifics for the following
• Alzheimers
• Identical 60 / Fraternal30
• Extraversion / neuroticism
• Identical more similar than fraternal
• Divorce rates
• Identical x5.5 vs. fraternal x1.6
• Schizophrenia
• 50, 10, 3, 1 (identical, fraternal, sibling,
  stranger)
• What are the limitations of these studies?
• Genetics or environment? How do we
  differentiate?

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Twin StudiesJim Lewis / Springer

• What does the study suggest? (3)

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Jim an Jim

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

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The Bouchard Minnesota Twin Study

• Are You a Natural- (handout questions)

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Gerald Levy and Mark NewmanSeparated at Birth
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Levy and Newman

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

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Genetics and Behavior

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

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Adoption Studies (5)
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What insight has adoption studies provided
regarding the influence of genetics on
personality? (5)

• Environmental relatives / biological Relatives
• Finding subjects personality reflected
  biological relatives, even when adopted at birth
• Conclusion people who grow up together dont
  resemble each other in personality
• Why are two people raised together so
  different???
• Confirmation of genes impact on personality

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Environmental Influence

• So what traits does nurture influence?
• Values
• Manners
• Faith / religion
• Politics
• Social views

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Heritability (6)

• Extent to which difference between individuals
  can be attributed to genes
• As environments become more similar, heredity as
  a source of difference becomes more important
  (and vice versa)
• Heritable differences dont often translate to
  group differences

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Temperament (7)

• Our emotional excitability
• Temperament traits tend to remain consistent
  through life
• Studies confirm
• Genetic temperament helps form enduring
  personality
• Think of two examples of those you know.

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Nature and Nurture

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

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Molecular Genetics (8)

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

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Human Nature?

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

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Evolutionary Psychology

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

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Dmitry Belyaev Domestication of Foxes
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Belyaevs Experiment

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

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Evolutionary Psychology

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

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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.

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Gender and Sexual Attitudes / Behavior

• Studies
• 1978, FSU- research assistants / proposals for
  casual sex with strangers
• 75 of men- yes 0 of women- yes
• Questionnaire casual sex with different partners
• 48 of men- yes 12 of women- yes
• How can we explain this radical difference in
  sexual attitudes between the genders?

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Gender Differences and SexualityNatural
selection would suggest that each gender pursued
attitudes and behaviors that perpetuated their
survival, and thus became part of our DNA over
time.

• Women- relational
• Incubates, nurses one infant
• Wants protection, assistance to ensure childs
  survival
• Chooses wisely

• Men- recreational
• Perpetuate his genes (spread his genes through
  other females)
• Chooses widely

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Gender and AttractionStudy spanned 37 cultures

• Men (attracted to)
• Youthful, healthy, fertile
• Waists 1/3 size of hips
• Many children- genes to future

• Women (attracted to..)
• Mature, dominant, bold, affluent
• Support and protect
• Long- term mating, investment in joint-offspring

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Gender Differences and Sexuality

• Significance?
• Nature selects behaviors that increase the
  likelihood of sending ones genes into the
  future.

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In Conclusion

• 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. Womens sexuality shows greater plasticity
  (attitudes, behaviors about sex more easily
  shaped by cultural, social factors)
• Example college (liberalizes womens attitude
  towards sex more than mens)
• Chance of men identifying as gay or bisexual x2
• Chance of women identifying as lesbian or
  bisexual x900!

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Evolutionary Psychology

• From an evolutionary psychology perspective, how
  might we explain marriage?

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Nature, Nurture and Gender

• Gender Development
• Male, Female- What determines the gender?
• 23rd pair of chromosomes determine sex
• FemaleX, Male X or Y

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Glad to be your gender?

• Men
• X4 to commit suicide, alcoholism
• Autism, color blindness, hyperactivity,
  antisocial personality disorder

• Women
• 70 more fat
• 40 less muscle
• 5 inches shorter
• Puberty 2 years earlier
• Live 5 years longer
• X2 for depression, anxiety
• X10 for eating disorders

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Gender and Aggression

• Males tend to be more physically aggressive
• Male-female arrest rate for murder
• U.S. 9-1
• Canada 7-1

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Gender and Social Power

• Universal pattern Men are more socially dominant
• Men as leaders- more direct, autocratic, express
  opinions
• Women as leaders- more open, democratic, offer
  support

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Gender and Social Behavior

• Males
• Individualists
• Boys larger play groups (activity focus)
• Male Answer Syndrome
• Freedom, self-reliance

• Females
• Interdependent (relationships)
• Girls smaller groups (often one friend) less
  competitive, imitate social relationships
• 85 of greeting cards!
• More religiously oriented

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Boys, girls and toysNature or Nurture?

• Why do genders choose what they do?

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Nature and Gender

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

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Gender Differences and the Brain

• New evidence structural, chemical and functional
  differences between genders and brains
• Females thicker frontal lobe (verbal fluency)
• Males thicker parietal Cortex (space perception)
• Potential need for sex-specific treatments for
  addictions, depression, schizophrenia etc.

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Nurture and Gender

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

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Genes rule??

• In terms of personality, environmental factors
  typically account for less than 10 of childrens
  differences. (Key is how parents and peers
  influence those traits.)

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Parenting the Genetic Code

• Explain how one might address the following
  genetic traits for productive outcomes
• sluggish, unresponsive, temperament as 3 month
  old
• Imaginative, slightly hyperactive, ADD high
  school student

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What / Who has shaped you?

• 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.
• Parents
• Peers
• Genes
• Results? Which factor do you think most
  influential?

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Prenatal Environment

• Studies indicate that identical twins who share
  the same placenta are more similar in
  psychological traits than those twins that dont.

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Nurture and Early Neural Development

• Early experience matters!
• Fosters neural connections
• Experience preserves activated neural connections
• Unused ones degenerate (pruning)
• Excess connectors in youth make kids more
  capable of mastering certain tasks.
• Example?
• Foreign language, (Accent and grammar) visual
  perception, musical instruments

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Rat Studies

• Rosenzweig and Krech
• Isolated, impoverished vs. social, enriched
  environment
• Young rats
• Findings
• Obvious differences in behavioral activity and
  curiosity
• Heavier, thicker brain cortex (brain weight
  increased 7-10 percent and of synapses
  increased 20!)

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Premature Babies

• Neonatal units
• Massage therapy stimulates growth
• Speeds departure from hospital

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Parents Influence

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

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Peer Influence

• 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.
• 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.

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Parents vs. Peers

• Parents
• Education
• Discipline
• Responsibility
• Orderliness
• Charitableness
• Dealing with authority

• Peers
• Cooperation
• Popularity
• Styles of interaction

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Nurtures SwayCultural Influences

• Individualism
• Self Independent
• Life Task Discover, express ones uniqueness
• What matters Me, personal achievement, rights,
  freedoms, self-esteem
• Coping method change reality
• Relationships Many, often temporary,
  confrontation acceptable
• Behavior Reflects ones personality, attitude

• Collectivism
• Self Interdependent
• Life Task fit in, perform role, obligations
• What matters Us, group goals, family duty,
  social responsibility
• Coping method Accommodate to reality
• Relationships Few, close and long term, harmony
  valued
• Behavior social norms and roles

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Cultural Influences

• Individualism

• Collectivism