Chapter 3 - Nature and NurtureReading Map

• Thur Oct 16 99-107

• Fri Oct 17 108-113

• Mon Oct 20 113-116

• Tue Oct 21 116-125

• Wed Oct 22 in class essay

• Thur Oct 23 126-end and review

• Fri Oct 24 126 – end and review

• Mon Oct 27 Quiz/cards/study guide

Web Site

• http://bcs.worthpublishers.com/myers10e/#746145__765314__

Genes: Our Biological Blueprint (100)

• Human genome researchers know the common sequence of 3.1 billion letters within human DNA

• Humans and chimps share 95% of our letter sequences

• Humans to humans share about 99.0% of our DNA sequences

• Every cell nucleus in your body contains the genetic master code for your entire body

Chromosomes/DNA/Genes/Nucleotides• 46 chromosomes (23 from mom/23 from

dad)• Chromosomes are made of DNA

molecules• Small segments of DNA are called genes• We have about 30,000 genes• Our genes are composed of nucleotides

(ATCG) - the smallest gene (Y) has 50 million nucleotide letters - the largest has 250 million

• Nucleotide (letters) – genes (words) – DNA (pages) – Chromosomes (book)

Evolutionary Psychology (101)

• Studies how natural selection favored behavioral tendencies that contributed to the survival and spread of our ancestor’s genes

• Dead people don’t have babies!

Belyaev and Trut

• 40 year fox experiment

• selected tames foxes to breed for 30 generations

• Result- tame foxes• Principle - trait

selection

Teacher Guide References

• Handout 3-2 - Evolutionary Psychology Questionnaire

• TG 3-8 - evolution of bedtime tantrums in children

Natural Selection (102)

• The principle that, among the range of inherited trait variations, the traits that lead to increased reproduction and survival will most likely be passed on to future generations

• BUT, genes and experience (our ability to adapt) wire our brain.

Evolutionary Psychology (103)

• The study of the evolution of behavior and the mind, using principles of natural selection.

• We are predisposed to behave in ways that promoted our ancestor’s surviving and reproducing.

• See evolutionary questions on page 103

• TG 3-11 - the Coolige Effect

Sexuality and Gender Differences (104)• Gender -biologically or socially influenced characteristics

that define male/female• Baumeister, Catanese, Vohs (2001) - men think about sex,

initiate sex, make sacrifices for sex more than women• Clark and Hatfield (1989) - “average looking” researchers

approach strangers and suggest sex - all women refuse - 75% of men agree to it

• Abbey (1987) - men misperceive women’s warm responses as sexual come-ons

• Many studies show a male/female difference in sexuality ----- why?

Sexuality: An Evolutionary Explanation (104)

• Natural selection explains women’s relational approach to sex and men’s recreational approach

• Our females ancestors produced only one child at a time so they were more careful with whom they paired

• Our males ancestors could reproduce with many women at the same time

Attractiveness and Evolution (104)

• Men look for healthy, young, fertile mates

• Women look for healthy, mature, dominant, bold and rich mates

• We still advertise these qualities - check out the companions wanted ads!

Critiquing Evolutionary Theory (106)

• It starts with the effect (ex. Gender differences in sex) and works backwards to explain it

• What about alternative theories?• Fails to explain some species (ex. Chimps) where

females mate with multiple males• Could our mating preferences be more influenced

by family, culture?• Could it be used to excuse bad behavior?

Behavior Genetics (108)

• Study our individual differences

• They research genetic and environmental contributions to our various traits

• They often use twin and adoption studies to study genetic and environmental factors

Twin Studies (108)

• Identical twins - genetically identical because one egg splits

• Fraternal twins - two eggs - genetically are no more alike than normal siblings -

Identical Twin Studies (108)

• More similar in extraversion and introversion• McGue and Lykken (1992) - divorced fraternal

twin increases odd for the other twin divorcing by 1.6 times. Divorced identical twin odds go up to 5.5 times

• Loehlin and Nichols (1976) identical twins treated alike by their parents are no more similar in personality than twins treated differently

Separated Twins (109)

• Separated twins reared in different types of homes end up with similar traits, tastes, abilities, attitudes, etc

• If parents think an identical pair is fraternal, the identical pair still turns out as similar as other identical twins

• 9 min clip on separated twins http://www.youtube.com/watch?v=1gwnzW4jOMI

Twins???

Adoption Studies (111)

• Do adopted children have the traits of their biological or adoptive parents?

• Personality traits - like biological parent• Attitudes, values, manners, faith, politics -

like adoptive parents• And, siblings also tend to have unique

personalities even though raised in the same home by shared parents.

Adoption Studies (111)

• Benson (1994) - adopted children tend to thrive, especially when adopted as infants

• Sharma (1998) - adopted children score higher than their biological parents on intelligence tests. 7 out of 8 report feeling attached to 1 or both of their adopted parents. They also grow up to be more self-giving and altruistic than average

• Bohman (1990) - adopted children end up with fewer problems than those who were going to be adopted but ended up being kept by their biological parents

Temperament (112)• Temperament is our inborn emotional excitability

(reactive/easygoing; intense/quiet/; fidgety/placid)• Shows up in first weeks of life• Temperament Persistence• Goodness of Fit (parent plus infant temperament –

do they work well together?)• Genetic - identical twins are more similar in

temperament• Chess and Thomas (1970) - difficult, easy and

slow to warm temperaments

Heritability (112)

• The extent to which VARIATION among individuals can be attributed to their differing genes.

• NOTE - it doesn’t mean what % of an individual’s trait is inherited

• Ex - boys in a barrel - if their IQ’s differ we say it is nearly 100% heritability since their environments were identical.

• As environments become more similar, heredity as a source of differences necessarily becomes more important.

Group Differences (113)

• Heritable individual differences need not imply heritable group differences.

Nature Enables Nurture (113)

• Our most important similarity is our ability to adapt

• Environment reacts to and shapes what nature predisposes

• Psychological traits are usually the result of both genetic and environmental factors

• Our genetic traits (ex. good looking) evoke responses from our environment

• We select environments to suit our predispositions

Molecular Genetics (115)

• Study of specific genes and how they influence behavior

• Most traits have a team of genes

• Genetic tests reveal who is a risk for certain diseases

• Issues???????

Environmental Influences (116)

EnvironmentParents

Prenatal Nutrition

Early Stimulation

Peers Culture

Environment (117)

• Behavior geneticists find that shared environmental influences (home) account for less than 10%of children’s personality differences.

• Two children in the same family are as different as are pairs of strangers

• BUT, the environment does effect values and beliefs

Prenatal Environment (118)

• Nurture begins in the womb

• Nutrition and toxins

• Identical twins with share placenta have more similar psychological traits than those identical twins with separate placentas (Phelps 1997)

Experience and Brain Development (118)

• Experiences help develop brain’s neural connections

• Rosenzweig and Krech (1987) - rats in solitary had light and thinner brain cortexes than those raised in enriched environments

• Kolb and Whishaw (1998) after 60 days of an enriched environment rats brain weight increased 10% and the number of synapses increased 20%

Use it or Lose It (118)

• After brain maturation provides us with an abundance of neural connections, experience preserves our activated connections while allowing our unused connections to degenerate.

• Critical Period - the period in our life where we will best and most easily learn - example - early childhood language development -

Peer Influence (120)

• Harris (1998) argues that peer influence may exceed parental

• Gardner (1998) argues parents and peers are complementary. Parents shape education, discipline, responsibility. Peers shape cooperation, popularity, interaction styles.

Peer Influence

• Selection Effect - kids seek out peers with similar attitudes and interests

• Evolutionary perspective - nature predisposes teens to be heavily influenced by peers

Culture (121)

• Culture is the behaviors, ideas, attitudes and traditions shared by a large group of people and transmitted from generation to generation

Culture

• Cultural Norms - rules of accepted and expected behavior• Personal Space - buffer zone around our bodies - differs

from culture to culture• Communication style - how we say it is as important as

what we say - Iraq war comment example p 123

Culture - Variation Over Time (123)

• Meme - a self-replicating idea, fashion, innovation passed from person to person

Culture and Child Rearing (124)

• Child rearing varies from culture to culture• Child “values” also vary - do we want

obedient children or creative children?• Children of communal cultures have a

stronger sense of their “family” self (what shames the child shames the family).

• Children of western cultures have a stronger sense of their independent self

Development Similarities (124)

• Shared biology• Shared life cycle• Shared developmental

processes• Shared response to

parenting styles

Gender (126)

• We do not take on gender until 7 weeks after conception when the 23rd pair of chromosomes gives us either an XX or an XY

• Mothers contribute x

• Fathers contribute x or y

Gender

• In the 4th and 5th month the fetus’ brain development is influenced by M and F hormones

• Hines and Green (1991) Female rats and monkeys exposed to prenatal testosterone will look more masculine and act more masculine (aggressive)

Gender (127)

• Gender = biology

• Gender is also socially constructed

• Role - group of prescribed actions for a person of a certain social status

• Gender Role - expected behaviors or M and F

• Culture/Time/Generations shape gender roles

Gender Identity (128)

• Gender Identity - our sense of being male or female

• Gender Type - acquiring traditional M or F roles

Gender Theories (128)

• Social Learning Theory - We observe and imitate behavior and are rewarded or punished for certain behaviors. Through this we form our sense of gender.

Gender Theories

• Social-Cognitive Theory - we imitate and are rewarded/punished BUT we also have our own gender ideas that shape our gender

Gender Theories (129)

• Gender Schema Theory - you have a gender schema (a lens)through which you view your social world - this shapes your gender formation