Transcript Unit 10 Nature Nurture and Gender

Nature vs. Nurture
Genetic & Environmental Influences on Behavior
The Nature Argument
(is sometimes compelling)
This guy will never be….
This guy!!!
Why does Brad Pitt look the way he does?
Other Big Issues in Psychology
• Rationality vs. Irrationality.
• Stability vs. Change.
Behavior Genetics
The school of thought that focuses
on how much our genes and our
environment influence our
individual differences.
Genes: Our Biological Blueprint
Genes: Know Their Location and Composition
In the nucleus of every cell we have 46 chromosomes……
Except…
Chromosome Breakdown
Chromosomes (Books)
Genes (Words)
DNA (Pages)
Nucleotides (Letters)
What do we get from our parents?
• We inherit one set of 23
chromosomes from each
parent.
• The two sets form pairs
that contain alternate genes
for the same traits.
• Sometimes, one gene is
dominant and “overrides”
the recessive gene.
Some Dominant Traits
• Curly hair.
• Unattached earlobes.
• Farsightedness.
Genetic Diversity
• The best source of genetic
diversity comes from
genetic mutations and new
gene combinations
produced at each human
conception.
• A mutation is a random
error in gene replication
that leads to a change.
Chromosomal Abnormalities
• Gender comes from
23rd pair of
chromosomes…men
have XY…woman have
XX.
• Turner’s syndrome is
single X.
• Klinefelter’s syndrome
is extra X…XXY
• Down syndrome….extra
chromosome on 21st
pair.
Genetic Similarities
Mrs. Stout is
96%
99.9%
99.9%
Identical Twin Studies
• Best way to really study
genetics because they come
from the same zygote.
• Bouchard Study.
• .69 Correlation coefficient
for IQ tests of identical
twins raised apart.
• .88 raised together.
• What are the different
types of twins?
• Identical (Monozygotic /
from one egg) and
Fraternal (Dizygotic /
from two eggs).
Twin Studies: The Results
• To summarize the countless amount of
studies: Twins (especially identical),
whether or not they are raised in the
same environment are very much alike in
many ways. Which supports the nature
side of the nature vs. nurture debate.
Heritability
• The degree to which traits are inherited.
• It is a mathematical formula.
• Ranges from 1 (all variance due to heredity like tongue curling) to 0 (none due to
heredity – like speaking English).
• As environments become more similar,
heredity as a source of differences becomes
more important.
Temperament
• A person’s
characteristic
emotional
reactivity and
intensity.
• It remains
relatively stable
over time.
Adoption Studies
• Adoption studies also support the nature side of
the debate.
• Adopted children share more personality trait
similarities with their biological parents than with
their adoptive parents.
• Adoption studies also show that parenting plays a
vital role in the development of belief systems.
Environmental Influences on Behavior
Types of Environmental Influences
Parents
Prenatal
Experience
Peer Influence
Culture
Gender
How Much Credit (or Blame) Do
Parents Deserve?
•You and your siblings grow up in
the same environment, are you all
the same?
•Parents effect your belief
systems and values much more than
your personality (only about 10% of
our personality differences).
•Parents take too much credit for
success and too much blame for
failures.
Are children clay to
be molded by their
parents?
Lets look at perhaps our first environmental influence….
Prenatal Environment
Placental Arrangements in Identical
Twins: 2/3 share the same placenta.
Experience and Brain
Development
Parents spend a lot of $$$
sending kids to pre-school.
They just play with a lot of
toys.
The parents could use that
$$$ for a big flat screen
TV.
Is it money well spent?
Brain cells in an impoverished environment =
smaller brains & less developed cortexes.
Brain cells in an enriched environment
More well developed brains
What does this mean for humans?
• 6th graders who were given stimulating care
as infants scored higher on intelligence
tests than those who didn’t receive that
kind of care.
Use it or lose it!
Perhaps the biggest environmental influence, at
least by your age may be….
Peer Influence
•Teens are more likely to
smoke because their peers
smoke rather than their
parents smoking.
•Parents are more important
when it comes to education,
discipline and responsibility.
Culture
• Behaviors, attitudes,
traditions, etc… of a
large group that have
been passed down
from one generation
to the next.
What Culture Isn’t
• Nationality is NOT culture. Many nations
have multiple, coexisting cultures.
• Race is NOT culture. Two people of the same
race can be from different or similar
cultures.
• Your culture is a set of beliefs and behaviors
you learned from people in your environment.
Cultural Variations
• It is important to recognize our cultural
norms: an understood rule for acceptable
behavior.
• Individualistic vs. Collectivistic Cultures.
• Individualism promotes independent selves.
• Collectivism encourages the development of
the interdependent self.
• Cultural differences appear in things like
punctuality, personal space, show of
emotions, etc.
Factors Influencing Culture Development and Diversity
• Population density – higher population
requires more rules for maintaining order.
• Climate – lifestyles adapt to climate.
• Resources – scarcity or abundance of
resources influence how people work.
• Technology – also influences the way people
work in a society.
Cultural Research
• Cross-cultural research – tests
hypotheses on many groups of
people to see if principles apply
across cultures.
• Some psychological principles
are universal (i.e. language to
communicate).
• Some are culture-specific
(found only in some cultures).
Culture and Personality
• Internal Locus of
Control (control their
own fate).
• External Locus of
Control (outside
forces determine
what happens to you).
• Western nations are
more likely to have an
internal locus of
control than Asian or
African nations.
Culture and Attachment
• In the U.S. we value a “secure
attachment.”
• In Germany, this is often seen
as being “spoiled.”
• Some African tribes often
spend much time away from
their infants (left to be cared
for by others in the tribe).
Ethnocentrism
• The tendency to view the
world only through your own
cultural filters.
• When people from other
cultures behave differently
from us, we often have
strong negative reactions.
What Do We Mean By
Gender Differences?
Gender Matters
• Are there significant
physical or social
differences between
boys and girls?
Gender
• We already know the nature
differences.
• XX vs. XY
• But that focuses on SEX.
• Gender refers to our definition
of male and female, based on
socially and culturally influenced
characteristics, as well as
biology.
Physical Differences
Females:
• Larger pelvis.
• Brain receives
15% more
blood.
• 10% shorter
than males.
Males:
• Heavier bones.
• Greater grip
strength.
• Proportionately
larger hearts, lungs.
Physical Differences
Females:
• Longer life expectancy.
• Twice the body fat.
• Fewer genetic defects.
Males:
• Twice the risk of
coronary disease.
• Higher levels of
stress hormones.
More Gender Differences
Females:
• More fearful.
• More verbally aggressive.
• More social perception.
• Greater empathy.
Males:
• More active.
• More physically
aggressive.
• More competitive.
• Greater throwing
accuracy.
Differences in Throwing Ability
Social Differences
• Girls tend to play in a small group
or with a single friend.
• Boys are often more involve in a
large group with a more
competitive focus.
• Men are more likely to use
conversations to solve problems,
while women explore relationships
in conversation.
Gender Roles
• A set of expected
behaviors for males
and females.
• It’s a result of
culture, not genetics.
What gender role is she breaking?
Changing Attitudes about Gender Roles
Gender Identity
• Our own sense of male
or female.
• Personalized to us.
• We realize our gender
identity through
gender-typing: the
acquisition of a
traditional masculine or
feminine role.
Two Theories of Gender-typing
Social Learning Theory
I play baseball.
Son imitates my behavior.
I reward son.
My wife puts on
makeup.
My son copies her.
I punish my son.
Gender Schema Theory
• Schema: a concept or framework of how we organize
information.
• We develop schemas for gender which becomes the
lens through which you view your experiences.
• That concept then influences your perceptions and
behavior.
Boy’s don’t do this,
that’s for girls.
Yeah, that’s cool!!!!
I want to do that.
How and why do men and women
differ sexually?
Of course, there are other differences….
Men, Women and Sex
• Casual sex is more
accepted by men.
• When average men and
women randomly ask
strangers for sex
tonight, 75% of men
agreed, almost no women
agreed.
WHY?
Sperm is Cheap
Eggs are not
What do men and women want
when selecting a mate?
Men want:
• Attractive
• Character
• Intelligence
• Personality
Women want:
• Wealth
• Ambition
• Character
• Intelligence
Can this change?