UNIT 4 - NATURE, NURTURE, & HUMAN DIVERSITY 10.5.12.ppt

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Shared Human Nature

• _{In all cultures, we start}

fearing strangers at about 8 months

• _{We are uniquely similar as a}

human race

• _{Genes = Nature}

• _{Environments = Nurture}

– _{Both genes and environment}

play a part in shaping us

Behavior Genetics

• _{Behavior Genetics is the}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Genes

• _{Each human has 46}

chromosomes

– 23 from mother’s egg

– 23 from father’s sperm • _{Chromosomes are found}

within a cell’s nucleus

• _{DNA is found within each}

chromosome

• _{Genes are found within}

each strand of DNA

Genes

• _{Genes may be active}

(“turned on”) or inactive (“turned off”).

• _{Environmental events are}

responsible for “turning on” genes.

• _{Our DNA sequence is 96%}

the same as a chimpanzee.

• _{Our observable traits such}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Twin & Adoption Studies

• Identical Twins – develop from a single fertilized egg that

splits in two (identical genes)

– May not always have the same number of copies of those

genes

– 1 in 3 sets develop in separate placentas

• Fraternal Twins – develop from separate fertilized eggs (no more genetically similar than any other sibling)

Twin & Adoption Studies

• _{In virtually all ways,}

identical twins are more similar than fraternal twins

– _{Shared experiences} – Divorce rates

• _{Genes more than shared}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Twins

• _{Separated identical twins}

Jim Lewis and Jim Springer had amazingly similar life experiences without having contact with one another for 38 years

– _{When measuring personality,}

intelligence, heart rate, and brain waves, their results were as those of the same person tested twice!

University of Minnesota Study

• _{U of MN researcher}

Bouchard studied 80 pairs of identical twins that were raised apart

• _{Found similarities in}

personality, abilities,

attitudes, interests, fears

• _{“…the plural of anecdote is}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Biological vs Adoptive Relatives • _{Key question: Are adopted}

children more like their biological parents or their adoptive parents?

– In the area of personality, they are closer to biological parents

– _{Environments shared by}

children have NO discernible impact on personality

Biological vs Adoptive Relatives • _{Parenting has less influence}

on personality, but a greater influence on:

– _Attitudes – Values

– Manners

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Adoptions

• _{Adoptive parents are}

carefully screened; natural parents are NOT

– _{7/8 adopted children feel a}

close bond to adoptive parents

– _{Big Picture: children benefit}

from adoption

– _{Many times adopted children}

outperform their biological parents (stability, intelligence)

Temperament & Heredity

• _{Temperament = emotional}

reactivity and intensity

– _{Irritable, intense,}

unpredictable

– Cheerful, relaxed, predictable

– Temperament persists over the long haul, although some change is possible

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Temperament & Heredity

• _{“Our biologically}

rooted

temperament

helps form our

enduring

personality.”

Heritability

• _{Heritability – the extent to}

which variation among individuals can be

attributed to their differing genes.

– We can never say what % of an individual’s intelligence or personality is actually

inherited.

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Group Differences

• _{Individual differences in}

height and weight are highly heritable.

• _{Differences in males vs}

females or in people of varying ethnicities cannot be easily explained through heritability.

Nature and Nurture

• _{Humans have an enormous}

adaptive capacity.

• _{Genes are self-regulating} – _{The same gene that makes}

the African butterfly green in the summer, makes it brown in the fall

– _{Humans with very similar}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

• _{Eating disorders are}

primarily a Western cultural phenomenon

– _{Not found in most other}

cultures

– Definitely a product of both nature and nurture

• _{“Heredity deals}

the cards;

environment

plays the

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Gene-Environment Interaction • _{Baby who is attractive,}

sociable, and easy-going may attract more

affectionate and stimulating care.

• _{This in turn may lead the}

individual to be a warmer and more outgoing person, more often seeking

activities and friends.

Gene-Environment Interaction • _{Children experience being}

parented based on their own qualities.

• _{We should start thinking}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Molecular Genetics

• _Goal

– _{Find genes that influence}

human traits

– Explore mechanisms that control gene expression

Molecular Genetics

• _Procedure

– _{Seek out families that have}

had a disorder across several generations

– Draw blood from both

affected and healthy family members

– _{Examine DNA to look for}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Ethical Considerations

• _{Might early testing of}

embryonic qualities lead to discrimination?

– _{Boys valued in China}

– Some famous Americans were troubled people

– Individuals may parent

differently knowing their child is labeled “at risk”

Evolutionary Psych

• Organisms varied offspring compete for survival

• _{Biological and behavioral}

variations increase

reproductive and survival chances

• _{Offspring that survive are more}

likely to pass their genes on to next generation

• _{Over time, population}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Natural Selection & Adaptation • _{Dmitry Belyaev – Russian}

scientist who studied

possibility of domesticating foxes

– Carefully selected the most tame, docile foxes

– _{Over 30 generations of}

mating, the desired traits prevailed

Evolutionary Success

“Our shared human traits were shaped by natural selection acting over the course of human evolution.”

-Steven Pinker

-no more than 5% of genetic differences among humans arise from population group differences; 95% comes

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

• _{Women’s experience of}

nausea during the first 3 critical months of

pregnancy serves as a

protective mechanism for developing embryo. Certain bitter, strong tasting foods may be poisonous to the developing baby.

• _{Sweet and fats once helped}

our ancestors survive famines

• _{Today famine is not a}

concern in Western

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Human Sexuality

• _{In almost every human}

culture, men exhibit a stronger sex drive than women

• _{Men more often than}

women attribute a

woman’s friendliness to sexual interest

• _{Helps to explain sexual}

harassment and date rape

Mating Preferences

• _{Women’s approach to sex is}

usually more relational, and men’s more recreational

• _{Men usually find women}

attractive if they have a youthful appearance

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

• _{Men prefer}_{youth and}

health in seeking a partner

• _{Women prefer}_resources

and social status in seeking a partner

• _{Young, middle-aged, and}

older men prefer women in their child-bearing years

• _{Women of all ages prefer}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Critiquing Evolutionary Perspective • _{The sexes, having faced}

similar adaptive problems, are far more alike than

different

• _{Evolutionary perspective}

usually works from a hindsight explanation,

which makes it look more correct than it may be.

Parents & Peers

• _{Rosenweig & Krech study}

on rats:

– _{Rats living in an enriched}

environment developed a heavier and thicker brain cortex. (Brain weights and number of synapses both increased).

– _{Those living in impoverished}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Parents & Peers

• _{Stimulation by touch or}

massage help infants develop faster

neurologically and gain weight faster.

• _{Neural pathways are}

broadened or pruned, depending on their early usage.

Parents & Peers

• _{In early childhood, excess}

neural connections are available – good time to learn another language.

• _{Some language must be}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Parents & Peers

• _{In early years especially, the}

brain operates by the

principle: Use it or Lose it!

Parenting

• _{Are children easily wounded}

by normal parental mistakes?

– _{“Two children in the same}

family (are on average) as different from one another as are pairs of children selected randomly from the

population.” – Plomin &

Daniels (behavior geneticists)

– _{Children are NOT easily}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Peer Influence

• _{Especially during childhood}

and adolescence, we seek to fit into groups.

• _{Children get more of their}

culture from peers than from parents (adapt to peers characteristics).

• _{Children seek out friends}

with similar interests/habits as their own.

Peer Influence

• _{Parents influence:}

– _{Education, discipline,}

responsibility, orderliness, charitableness, and ways of interacting with authority. • _{Peers influence:}

– Cooperation, popularity, and ways of interacting with

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Cultural Influences

• _{Humans have a great ability}

to learn and to adapt.

• _{Culture is the behaviors,}

ideas, attitudes, values, and traditions shared by a group of people and passed from one generation to the next.

• _{Human culture enables}

social and economic systems that give us an edge.

Cultural Influences

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Variations Across Cultures

• _{Norms – rules for accepted}

and expected behavior

• _{Personal Space – the}

portable buffer zone we like to maintain around our

bodies

• _{Differing pace of life and}

sense of punctuality across cultures

Variation Over Time

• _{Women today are more}

likely to marry for love, and less likely to endure abusive relationships out of

economic need

• _{U.S. today has more}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Variation Over Time

• _{Compared to 1960,}

Americans spend more

hours at work, fewer hours sleeping, and fewer hours with friends and family.

Culture & Self

• Individualism- giving priority to one’s own goals over group goals and defining one’s

identity in terms of personal attributes rather than group identifications.

• _{Collectivism – giving priority to}

goals of one’s group (often one’s extended family or work group) and defining one’s

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Individualism vs Collectivism

• _{Individualism}

– _{North America, Western}

Europe, Australia, New Zealand – _{Feel a need to belong to}

groups, but less loyal to them.

• _Collectivism

– _{China, Korea, Japan}

– _{Group identifications provide a} sense of belonging, values, network of caring individuals.

Individualism vs Collectivism

• _{See Table 4.1 on pg 157} • _{Individualism has it’s}

negative effects: loneliness, divorce, homicide, stress-related disease.

• _{Individualists raise the}

demand for personal

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Culture & Child Rearing

• _{Family Self – embraced by}

many Asian and African

cultures, a feeling that what shames a child also shames the family, and what brings honor to the family brings honor to the self.

• _{Child rearing varies}

dramatically across cultures, and no one way is best.

Developmental Similarities Across Groups

• _{Nation to nation differences}

in personality traits such as conscientiousness and

extraversion vary little.

• _{Example: blood pressure}

differences between black and white men may be attributable to diet

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Gender Development

• _{Gender – the biological and}

social characteristics by which people define male or female.

• _{Males and females are in}

most ways alike.

Gender Differences

• _{Compared to the average}

man, the average woman:

– _{Enters puberty 2 years sooner} – Lives 5 years longer

– _{Carries 70% more fat} – Has 40% less muscle

– _{Is 5 inches shorter}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

• _{Women (continued):}

– _{Smell fainter odors}

– Express emotions more freely

– _{Are offered help more often} – Are vulnerable to depression

and anxiety

– _{Risk of eating disorders is 10x}

that of men

• _Men:

– _{4x more likely to commit}

suicide or suffer alcohol dependence

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Gender and Aggression

• _{Aggression – physical or}

verbal behavior intended to hurt someone

– _{Men are more aggressive with}

physical aggression (hitting)

– _{Less of a gap with relational}

aggression (excluding someone)

– _{Males outnumber females}

10-1 being arrested for murder

Gender and Social Power

• Men seen as more dominant, forceful, and independent; men place more importance on power and achievement

• _{Women seen as more}

deferential, nurturant, and affiliative

• _{Males hold advantage in}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Gender and Social Connectedness • _{In Western cultures, males}

tend to be more

individualist and females more relationship oriented (making connections)

• _{Boys usually play in larger}

groups; girls play in smaller groups or even pairs

Gender and Social Connectedness • _{Females are more}

interdependent than males

• _{Females talk longer to other}

females on the phone

• _{Males and Females average}

speaking about 16,000 words per day

• _{Women tend to be better at}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Gender and Social Connectedness • _{Bonds and feelings of}

support are stronger among women

• _{Men value freedom and}

self-reliance; men are less religious and more skeptical

• _{Women value spirituality}

more than skepticism

The Nature of Gender

• _{The 23}rd_{pair of}

chromosomes (sex):

– _{X chromosome from mother} – X or Y chromosome from

father

– _XX=girl

– XY=boy (Y-chromosome

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

• _{During 4}th_{and 5}th_{month of}

prenatal development:

– _{Sex hormones bathe the fetal}

brain and influence its wiring

– Frontal lobes become thicker in women (verbal fluency)

– Parietal cortex becomes thicker in men (spatial skills)

• _{Excess prenatal hormones}

(testosterone for females) may lead to behavioral gender differences

– Females behaving “Tomboyish”

– _{Females having more}

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

The Nurture of Gender

• _{Although biologically}

influenced, gender is also socially constructed.

• _{Gender Roles – a set of}

expected behaviors for males and for females.

• _{Gender Identity – our sense}

of being male or female.

• _{Our cultures construct}

gender roles for us.

• _{Australian and Scandinavian}

countries offer most gender equity; Middle Eastern and North African countries

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

• _{Gender ideas vary over}

time, across cultures, and across generations.

Gender and Child Rearing

• _{Gender Typing – the}

acquisition of a traditional masculine or feminine role.

• _{Social Learning Theory – we}

learn social behavior by

observing and imitating and by being rewarded or

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UNIT 4: NATURE, NURTURE, &

HUMAN DIVERSITY

Gender and Child-Rearing

• _{Schema – concepts that}

help you make sense of your world.

• _{Gender Schema – concepts}

that help us to organize our worlds on the basis of

gender.

Gender and Child-Rearing

• _{By age 3, children know to}

which sex they belong, and tend to seek out others of the same sex to play with.

• _{By age 5 or 6 the rigidity of}