Transcript Nature, Nurture, & Human Diversity

Nature, Nurture, & Human
Diversity
Chapter 3
Behavioral Genetics
• How do behavior geneticists explain
individual differences?
– Behavior genetics: the study of the relative
power and limits of genetic and environmental
influences on behavior
– Heredity interacts with our experience to
create who we are
– Every person shares 99.9% of their DNA, it’s
the .1% that makes the difference
Twin & Adoption Studies
• Identical Twins are genetically IDENTICAL,
fraternal twins are not. They are assumed to
have shared that same conception, uterus, and
cultural history (although we now know this may
not be the case)
• Fraternal Twins are genetically the same as
brothers and sisters.
• Studies have shown that identical twins are a lot
more similar in terms of behavior than fraternal
twins. Why may this be? Is it because they
have the same genes or can there be more?
Separated Twins
• The book tells the story of Jim and Jim
who were separated at birth and adopted
by blue collar families. Years later they
were reunited and were exactly the same.
• How much of it is genetic? Sometimes we
are VERY similar to a stranger.
• http://www.youtube.com/watch?v=1gwnz
W4jOMI
Biological vs Adoptive Relatives
• Are adopted kids more like their birth parents or
their adoptive parents?
• According to research conducted by behavioral
geneticists, that people who grow up together do
not resemble each other a lot in terms of
personality. In other words, they claim that
environmental factors do not have ANY influence
on personality.
• However, parents can shape attitudes, values,
manners, faith, and politics.
Temperament & Heredity
• Temperament: a person’s characteristic
emotional reactivity and intensity.
• Babies differ in temperament
• Heredity may predispose different
temperaments
Nature & Nurture
• Nature and Nurture work together like two hands
clapping
• Genes and experience INTERACT, one is not
more important than the other.
– Example: Baby #1 is very cute, while Baby#2 is not.
Baby#1 will get more attention and warmth allowing it
to become a more social person and attract more
friends than Baby#2.
– People tend to respond differently to more attractive
people. What are some examples?
– Parents may also treat their children differently. One
child elicits punishment, another does not.
Evolutionary Psychology
• How do evolutionary psychologists use natural selection
to explain behavioral tendencies?
– Evolutionary Psychology: the study of the evolution of behavior
and the mind using principles of natural selection
– Example 1: evolutionary psychologists explain men’s more
recreational approach to sex by attributing it to their ability to
“spread their genes”
– Example 2: Men judge women as more likeable if they have a
youthful appearance and smooth skin, because they are more
likely to be fertile and healthy
– Example 3: Women are more attracted to men who seem bold,
youthful, dominant, and affluent because these attributions are
related to greater protection
– Nature selects behaviors that will allow for greater reproduction
of our genes
Evolutionary Psychology and
Gender Differences
• According to Evolutionary Psychologists:
– Men desire sex more frequently, think more about sex,
masturbate more, initiate more sex, and sacrifice more for sex.
Do you agree or disagree?
– Studies:
• In 2005, college students were given the following phrase: “if two
people really like each other, it’s all right for them to have sex, even
though they’ve only known each other for a very short time.”
– 58% of men and 34% of women agreed
• They were then given the following phrase: “I can imagine myself
being comfortable enjoying casual sex.”
– 48% of men and 12% of women agreed
• In a study utilizing 18 to 59 year olds, 59% of women and 25% of
men cited affection as the reason for first intercourse.
• Gay men report more interest in uncommitted sex than lesbian
women.
• Why may this be so? Thoughts?
Critiquing the Evolutionary
Perspective
• Starts with an effect and works backwards
to find an explanation
• Doesn’t account for cultural differences or
other possible explanations.
– For instance, explains why men are not loyal,
but fails to look at men who are loyal.
Parents & Peers
• To what extent are our lives shaped by parents
and peers?
– Parental experience: Our experience with parents
begins in the womb. These experiences foster brain
development.
– As a society we credit parents with their children’s
successes and blame them for their failures.
– Parents can have great effects on achievement
(mostly school or vocational related), but may not be
very influential when it comes to personality.
– How much blame or praise do you think parents
deserve?
Peer Influences
• Preschoolers who refuse to eat a certain food
will commonly eat it if placed in a table where
the other children are eating it.
• Children who hear English with an accent at
home and a different accent at school will
eventually pick up the school accent.
• Teens who smoke typically have friends not
parents who smoke.
• Parents may be more influential when it comes
to education, values, politics, and religion, while
peers may influence music, dress, style, etc.
Cultural Influences
• Culture: the enduring behaviors, ideas,
attitudes, and traditions shared by a group
of people which is transmitted from
generation to generation.
• Each culture has its own norms (rules)
• Cultures can differ in terms of accepted
personal space
Cultural Influences
• Individualism: giving priority of one’s own
goals over that of the group. Identifying
oneself in terms of personal attributions.
– Western Society
• Collectivism: giving priority to the goals of
one’s group (often the extended family)
Culture & Childrearing
• Do you prefer children who are independent or
children who comply with what others think?
– Western Culture: “You are responsible for yourself”.
“Be true to yourself. Follow your conscience.
Discover your gifts. Think about your needs.”
– Collectivistic Culture: “Be true to your traditions. Be
loyal to your heritage and culture. Show respect to
your parents and elders.”
– Which one are you?
Cultural Differences in Childrearing
• Many Asians and Africans live in cultures that value
emotional closeness. Thus, children commonly sleep
with their parents.
• Upper-class British families traditionally handed of
routine care giving to nannies and sent their children to
boarding school at about age 10.
• The African Gusii, carry their children on their backs,
without little face-to-face interaction. Once the mother
becomes pregnant, the toddler is weaned off and
handed to an older sibling or someone else.
• What are some other cultural differences in child rearing
that you have noted?
Gender Development
• Gender Similarities and Differences:
– Men and women are similar in some aspects
and different in others
• For example: Women have less muscle and more
fat, and start puberty earlier. Men admit to more
aggression than women. Although aggression
may be expressed differently for women.
• Men are perceived as more dominant
• Men and women bond in different ways
• Gender roles: our expectations about the way men
and women should behave