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Nature versus NurtureMs. Simon

October 18, 2010

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Homework

• Read Myers pgs 95-107

Answer Questions on Website

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Do Now:

How are you like your parents?

How are you different from your parents?

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Aim: To what extent do our genes and environment contribute to our

psychology?

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Nature, Nurture, and Human Diversity

Similarities

Differences

BehaviorsLanguage

Very different languages

BiologyOrgans and body functions

Size/shape can vary, disease can change, development

Brain Same brain architecture

Asymmetry across genders

Genes Same set of chromosomes

Different alleles, mutations, X, Y

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Genes: Our Codes for LifeChromosomes

contain DNA (deoxyribonucleic acid) are situated in the nucleus of a cell.

Humans have 23pairs of chromosomefor a total of 46

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Genes: Our Codes for Life

Segments within DNA consist of genes that make proteins to determine our

development.

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Genome

Genome is the set of complete genetic instructions for making an organism

How do our genes make us who we are?

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Behavior Genetics: Predicting Individual Differences

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Twin Biology

Studying the effects of heredity and environment on two sets of twins,

identical and fraternal, has come in handy.

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Twins and Procedures

Behavior geneticists’ effects of shared and unique environments on total or

partial genetic makeup.

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Separated Twins

Separated Twins

Personality, Intelligence

Abilities, Attitudes

Interests, Fears

Brain Waves, Heart Rate

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Separated Twins

Critics of separated twin studies note that such similarities can be found

between strangers. B

ob

Sach

a

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Adoption Studies

Adoption studies, as opposed to twin studies, suggest that adoptees tend to be different from their adoptive parents and

siblings.

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Adoptive Studies

Adoptive studies strongly point to the simple fact that biologically related children turn out to be different in a

family. So investigators ask:

Do siblings have differing experiences?

Do siblings, despite sharing half of their genes, have different combinations of the other half of their genes?

Ultimate question: Does parenting have an effect?

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Parenting

Parenting does have an effect on biologically related and unrelated

children.

Parenting Influences children’s

Attitudes, Values

Manners, Beliefs

Faith, Politics

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Temperament Studies

Temperament refers to a person’s stable emotional reactivity and intensity.

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Heritability

Heritability refers to the extent to which the differences among people are

attributable to genes.

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Heritability Examples

Personality:

Mental Ability:

Schizophrenia:

Depression:

Alcoholism:

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Group Differences

If genetic influences help explain individual diversity in traits, can the

same be said about group differences?

.

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Nature and Nurture

Genes provide choices for the organism to change its form or traits when environmental variables change.

Therefore, genes are self-regulating.

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Genes self-regulate in uteru

• http://www.youtube.com/watch?v=DuWTmd4f7lo

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Gene-Environment Interaction

Genes can influence traits which affect responses, and environment can affect

gene activity.

Example: A genetic predisposition that makes a child restless and hyperactive

evokes an angry response from his parents. A stressful environment can

trigger genes to manufacture neurotransmitters leading to depression.

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Gene-Environment Interaction

Genes and environment affect our traits individually, but more important are their

interactive effects.

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What is the fundamental goal of all living things?

TO SPREAD OUR GENES!

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Evolutionary Psychology: Understanding Human Nature

Molecular genetics studies why we as organisms are distinct.

Evolutionary psychology studies why we as humans are alike. In particular, it studies the evolution of behavior and

mind using principles of natural selection.

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What is natural selection?

Natural selection is an evolutionary process through which adaptive traits are

passed on to ongoing generations

What traits would be selected for?

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Artificial Selection

Biologists like Belyaev and Trut (1999) were able to artificially rear and

domesticate wild foxes, selecting them for friendly traits.

Any trait that is favored naturally or artificiallyspreads to future generations.

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Human Traits

A number of human traits have been identified as a result of pressures

afforded by natural selection.

……Can you think of any?

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Why do infants fear strangers when they become mobile?

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Why are most parents so passionately devoted to their children?

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Why do people fear spiders and snakes and not electricity and guns?

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How do our early experiences, our family, our community and

our culture affects these differences?

We have looked at how genes influence our developmental differences. What

about the environment?

Parents and Early Experiences

We begin with the prenatal environment.

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Prenatal Environment

Identical twins who share the same placenta (b) are more alike than those

who do not (a), suggesting prenatal influences on psychological traits.

1. Intense and reactive infants become unusually anxious and

aroused when facing new or strange situations. This best illustrates the

importance of:a. the X chromosome.

b. temperament.c. personal space.d. individualism.

2. Estimates of the heritability of personality traits are most directly associated with the research efforts

of:a. social learning theorists.

b. behavior geneticists.c. evolutionary psychologists.d. gender schema theorists.

3. In emphasizing that heredity's effects on behavior depend on a

person's home environment, psychologists are highlighting the

importance of:a. the double helix.b. gene complexes.

c. collectivism.d. nature-nurture interactions.

4. Bacteria that resist a hospital's antibiotics rapidly multiply as other bacteria die off. This best illustrates:

a. collectivism.b. behavior genetics.

c. heritability.d. natural selection.

5. It has been suggested that men in all cultures tend to marry women younger than themselves because men are genetically predisposed to

seek female features associated with youthful fertility. This suggestion

best illustrates:a. social learning theory.

b. behavior genetics.c. Freudian psychology.

d. an evolutionary perspective.

6. Premature babies are especially likely to gain weight if stimulated

by:a. sound and music.b. light and colors.

c. touch and massage.d. movement and acceleration.

7. At a social gathering, Latin Americans may behave in a manner

that North Americans consider intrusive and overly expressive. This

best illustrates the importance of being sensitive to differing:

a. norms.b. gene complexes.c. gender identities.

d. heritability estimates.

8. Displays of self-effacing humility are most characteristic of those who

value:a. individualism.b. gender-typing.c. collectivism.

d. gender-schemas.

9. Over the last century, Western parents have placed ________ priority on teaching children to respect and

obey parents and ________ priority on teaching them loyalty to their

country.a. decreasing; increasingb. increasing; decreasingc. decreasing; decreasingd. increasing; increasing

10. Adolescent females spend:a. more time alone and more time praying than do adolescent males.

b. less time alone and less time praying than do adolescent males.c. more time alone and less time

praying than do adolescent males.d. less time alone and more time

praying than do adolescent males.

11. Jaquetta was exposed to excess testosterone during prenatal development. As a young girl,

Jaquetta is likely to:a. prefer toy cars over dolls.

b. exhibit superior verbal intelligence.

c. develop a male gender identity.d. demonstrate a lack of gender

schemas.

12. Concepts of masculinity and femininity that influence our

perceptions are called gender:a. types.

b. schemas.c. roles.

d. complexes.

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Evolutionary Psychologists believe that natural selection leads to

differences in our behavior and minds.

Why might this view be controversial?

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Critiquing the Evolutionary Perspective

Evolutionary psychologists take a behavior and work backward to explain it in terms of natural selection.

Evolutionary psychology proposes genetic determinism and undercuts morality in establishing society.

Where genders are unequal, gender preferences are wide, but when they are closely equal, preferences

narrow down.

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Evolutionary Psychologists Reply

Evolutionary psychologists argue that we need to test behaviors that expound evolutionary principles.

Evolutionary psychologists remind us how we have adapted, but do not dictate how we ought to be.

Males and females are more alike than different, and if we study these differences we can establish their

causes.

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The New Frontier: Molecular Genetics

Molecular genetics asks the question, “Do genes influence behavior?”

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Molecular Genetics: Promises and Perils

Molecular geneticists are trying to identify genes that put people at risk for

disorders.

What might be an ethical concern?

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• http://www.youtube.com/watch?v=o7OYCmynrRU

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Biology of Sex: 23rd pair of chromosomes

If the pair is XX, a female is produced. If the pair is XY, a male child is produced.

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Which parent determines the child’s sex?

The Father

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Sexual Differentiation

The male fetus is exposed to testosterone (because of the Y chromosome), which

leads to the development of male genitalia.

If low levels of testosterone are released in the uterus, the result is a female.

Testosterone causes developmental differences between male and female brains

….That may account for stereotyped differences in male and female behavior since infancy

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Sexual Differentiation

Sexual differentiation is not only biological, but also psychological and social.

http://video.google.com/videoplay?docid=-1376391023990365282#docid=6170255473170788798

Do Now: How do girls and boys behave differently?

AIM: Why are human males and females different?

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Gender Roles

Our culture shapes our gender roles — expectations of how men and women are

supposed to behave.

Gender Identity — means how a person views himself or herself in terms of

gender.

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Gender Roles: Theories

1. Gender Schema Theory suggests that we learn a cultural “recipe” of how to be a male or a female

example: “Girls are made of sugar spice and everything nice”

1. Social Learning Theory proposes that we learn gender-linked behaviors by imitating and being rewarded or punished

example: GI joes and Barbies

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Human Sexuality

Gender Differences in Sexuality

Question (summarized) MaleFema

le

Casual sex 60% 35%

Sex for affection 25% 48%

Think about sex everyday 54% 19%

Studies have shown that in general, across cultures and species, men

tend to be more promiscuous than females.

Evolutionary Psychology Hand-out 3-4

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Battle of the Sexes: Mating Preferences

How has natural selection resulted in different mating preferences for males and

females?

However, females select one mature and caring male because of the higher costs involved with pregnancy and nursing.

Natural selection has caused males to increase their genes by mating with

multiple females since males have lower costs involved.

What qualities do you look for in a partner?

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Mating PreferencesMales: physical

attractiveness and youthFemales: wealth, maturity, ability to care for children

Data based on 37 cultures.

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Who do you think is sexy?

Men answer: Women answer:

Do Now: Activity 3-4

AIM: How do biology and culture contribute to human differences?

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Gender Differences in Aggression

Men express themselves and behave in more aggressive ways than do women.

In males, the nature of this aggression is physical.

http://www.youtube.com/watch?v=LDYyv-

iLmRY

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Gender Differences and Connectedness

Young and old, women form more connections (friendships) with people than do men. Men emphasize freedom

and self-reliance.

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What do humans have in common?

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Experience and Brain Development

Early postnatal experiences affect brain development.

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Experience and Faculties

Early experiences during development in humans shows remarkable improvements

in music, languages and the arts. C

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Brain Development and Adulthood

Brain development does not stop when we reach adulthood. Throughout our life,

brain tissue continues to grow and change.

A well-learned finger-tapping task leads tomore motor cortical neurons (right) than baseline.

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Parental Influence

Parental influence is largely genetic. However, other socializing factors also

play an important role.

Although raised in the same family,

some children are greater risk takers.

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Peer Influence

Children, like adults, attempt to fit into a group by conforming.

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Cultural Influences

Culture is composed of behaviors, ideas, attitudes, values and traditions shared by a

group.

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Variation Across Culture

Cultures differ. Each culture develops norms – rules for accepted and expected

behavior. Ja

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Culture or Genes?

Cultures change over time. In many Western countries, culture has rapidly changed over the past 40 years or so.

This change cannot be attributed to changes in the human gene pool because

genes evolve very slowly.

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Culture and the Self

Individualist :a culture nurtures an individual’s personal

identityCollectivist: a group identity is favored

When would a collectivist system

benefit groups?

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Culture and the Self

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Culture and Child-Rearing

Individualist cultures (European) raise their children as independent individuals whereas collectivist cultures (Asian) raise

their children as interdependent.

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Culture and Child-Rearing

Westernized Cultures

Asian-African Cultures

Responsible for your self

Responsible to group

Follow your conscience

Priority to obedience

Discover your gifts Be true to family-self

Be true to yourselfBe loyal to your

group

Be independent Be interdependent

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Developmental Similarities Across Groups

Despite diverse cultural backgrounds, humans are more similar than different in

many ways. What are some things humans have in common?

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1. Intense and reactive infants become unusually anxious and

aroused when facing new or strange situations. This best illustrates the

importance of:a. the X chromosome.

b. temperament.c. personal space.d. individualism.

2. Estimates of the heritability of personality traits are most directly associated with the research efforts

of:a. social learning theorists.

b. behavior geneticists.c. evolutionary psychologists.d. gender schema theorists.

3. In emphasizing that heredity's effects on behavior depend on a

person's home environment, psychologists are highlighting the

importance of:a. the double helix.b. gene complexes.

c. collectivism.d. nature-nurture interactions.

4. Bacteria that resist a hospital's antibiotics rapidly multiply as other bacteria die off. This best illustrates:

a. collectivism.b. behavior genetics.

c. heritability.d. natural selection.

5. It has been suggested that men in all cultures tend to marry women younger than themselves because men are genetically predisposed to

seek female features associated with youthful fertility. This suggestion

best illustrates:a. social learning theory.

b. behavior genetics.c. Freudian psychology.

d. an evolutionary perspective.

6. Premature babies are especially likely to gain weight if stimulated

by:a. sound and music.b. light and colors.

c. touch and massage.d. movement and acceleration.

7. At a social gathering, Latin Americans may behave in a manner

that North Americans consider intrusive and overly expressive. This

best illustrates the importance of being sensitive to differing:

a. norms.b. gene complexes.c. gender identities.

d. heritability estimates.

8. Displays of self-effacing humility are most characteristic of those who

value:a. individualism.b. gender-typing.c. collectivism.

d. gender-schemas.

9. Over the last century, Western parents have placed ________ priority on teaching children to respect and

obey parents and ________ priority on teaching them loyalty to their

country.a. decreasing; increasingb. increasing; decreasingc. decreasing; decreasingd. increasing; increasing

10. Adolescent females spend:a. more time alone and more time praying than do adolescent males.

b. less time alone and less time praying than do adolescent males.c. more time alone and less time

praying than do adolescent males.d. less time alone and more time

praying than do adolescent males.

11. Jaquetta was exposed to excess testosterone during prenatal development. As a young girl,

Jaquetta is likely to:a. prefer toy cars over dolls.

b. exhibit superior verbal intelligence.

c. develop a male gender identity.d. demonstrate a lack of gender

schemas.

12. Concepts of masculinity and femininity that influence our

perceptions are called gender:a. types.

b. schemas.c. roles.

d. complexes.

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Reflections on Nature and Nurture