Transcript Nature and Nurture of Behavior

Journal: Day 26
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If it were possible, would you want to take a genetic
test telling you which diseases you are likely to suffer
from later in life?
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If you or your spouse were pregnant, would you want
the unborn child tested for genetic defects?
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Do you think it should be legal for employers to use
genetic tests in deciding whom to hire?
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Handout: “Some Currently Available DNA Tests
Available”
Gene Testing
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Test for treatable disease to greatly reduce risks, 56%
Americans are “very likely” to take the test
No known treatment, 26%
“If you could have a comprehensive genetic test, which
would tell you about the likelihood that you might get several
major diseases, and it was not at all expensive, how likely do you
think you would be to have it—very likely, somewhat likely, or not
very likely?,”
39 % “very likely,” 30% “somewhat likely,” 29 % “not very likely,”
and 2 % were either not sure or refused to answer.
Who should see it?
90 % agreed that their doctor should see it, 39 % said their
health insurance company, 25 % said a life insurance company
“from whom they want to obtain a policy,” and 17 % indicated
their employer.
Journal: Day 27
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The Bell Curve – A Book about IQ
research…
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IQ’s heritability value = 0.6
Blacks score on average 15 points lower
than whites on IQ tests
Their Conclusion: blacks are genetically
inferior to whites…
DO YOU AGREE?
IF SO, WHY?
IF NOT, WHAT DOES CAUSE THIS
OBSERVED DIFFERENCE?
Journal: Day 28
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Some definitions:
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Sexual identity – sexual tendency for
males/females/both
Gender identity – internal feeling of being a
male / female
Social gender role – adherence to cultural
norms for feminine and masculine behavior
Place these on a nature / nurture
scale…(which is most influenced by nature?
nurture? middle?
Other Journal Ideas
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When looking for a future (when
you’re old enough of course) potential
mate, what 5 attributes are most
important to you? WHY?!
Other Journal Ideas
“Who has been the most important
influence in your life?”
 50% of teens say parents
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Other Journal Ideas
Imagine that you are a little older
 Women: In your relationships with
men, do you prefer them to express
their emotions fully, or to be cautious
about expressing emotion? WHY?
 Men: In your relationships with
women, do you prefer that they plan
to have careers or be homemakers?
WHY?
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Nature and Nurture
of Behavior
Chapter 3, Myers, 7th ed.
Andy Filipowicz
Introduction
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Fact or Falsehood (Handout 3-1)
F, T, F, T, F, F, T, T, T, T
?Universal human qualities?
Avoid incest, fear snakes, exchange gifts, modesty in
sexual behavior (even without clothes)
Labor divided by age / sex
Men more aggressive; women more child care
Taboos, sanctions for crimes against society (theft,
murder, rape)
Marriage defines sexual access to a fertile woman
Mimic, flirt, envy, empathize, joke, tease, dance
Myths, folklore, poetry, attempts to control or predict the
weather
Behavior Genetics:
Predicting Individual
Differences
Genes
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How many chromosomes do you get from mom? Dad?
Total??
30,000 genes
Dominant vs. Recessive
Brown eyes = Dominant
Draw a straight line on your paper
Line up ring finger to it
Does index finger reach the line?
Short indexes is recessive in females (expect less), but
dominant in males (expect more)
Punnett Squares…you know
this stuff, so try it!
?A man with red hair (recessive)
marries a woman with black hair
(dominant) whose mother had red
hair. What are the chances that their
first child will have red hair? Black
hair?
 2 in 4; 2 in 4
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More fun…
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? A man and a woman both have brown
eyes, but their first child has blue eyes.
What are the chances that their second
child will have blue eyes?
1 in 4; previous kids DO NOT MATTER
Other dominant traits: curly hair, dimples in
cheeks, unattached earlobes,
farsightedness
Twin Studies
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How alike are we?
Stand up vs. sit down using (Handout 3-2)
Jerry Levey and Mark Newman (the firemen in
your book) ID twins separated at birth
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(7) in yellow
Big Point
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Nature: 99.9% of our genes are the same and
we end up very much the same on so many
variables
Nature: identical twins are usually even more
similar! So, genes DO contribute to our
personalities and effect the outcome of our lives
Adoption Studies
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What do these studies show us?
The effect of nurture – family environment
Anyone adopted? Your personality will correlate higher with…?
Anyone have siblings? Your personalities correlate not much more than 2 randomly
drawn people from the street
?How do your parents treat you and your siblings differently from each other?
Siblings are treated differently by parents & siblings in turn react differently (nature
nurture interaction)
Big Point: Nature help shape one’s environment (nurture)
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Same nature creates a more similar nurture (ID Twins)
?SO, what do you think of your siblings?
Only 1/3 of sibling pairs show similar degrees of affection towards each other
So what?
1 study: The more negative a younger sibling is toward the older, the HIGHER the
self-esteem of the younger sibling in the long run
What is it about Baby X vs. Baby Y that shapes their environments differently?
Temperament
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Def: a person’s characteristic emotional reactivity
and intensity
Seen almost at birth and helps to predict
personality later in life
Handout 3-3: EAS Temperament Survey (see guide
pg. 8 for descriptions)
Scoring: reverse values for items 6, 18, 19 THEN,
Emotionality = intensity of emotional reactions
 Distress (4, 9, 11, 16)
 Fearfulness (3, 12, 14, 19)
 Anger (5, 8, 13, 18)
Activity = general energy level output
 Add (2, 7, 10, 17)
Sociability = tendency to affiliate and interact with
others
 Add (1, 6, 15, 20)
American Population Means
(Buss and Plomin)
Women
Men
Activity
13.40
Sociability
15.24
Emotionality
12.80
14.60
-Distress
-Fearfulness
-Anger
9.72
8.92
10.80
10.08
10.60
10.82
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Temperaments are inherited (Buss & Plomin).
ID Twins correlation coefficients
 Emotionality .63
 Activity .62
 Sociability .53
Fraternal Twins correlation coefficients
 E .12
 A -.13
 S -.03
Children are not blank slates, but obviously the environment still
contributes through conditioning
Heritability
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As environments become more similar
(MARK TWAIN’s feeding young boys
through holes in barrels until they are 12,
then compare intelligence), heredity as a
source of differences necessarily becomes
more important?? COOL??...therefore,
heritability of any trait goes up the more
similar the environments become as
long as there is any genetic contribution.
“Genetic” Has 2 Meanings
Genetic Determination: # of toes is
genetically determined b/c we all have 5
toes
Heritability: matter of the extent to which
genetic differences cause variation in
number of toes
1)
2)
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Ratio: genetically caused variation: total
variation (genes + environment)
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G / (G + E)
So, we must control for environmental
variation first if we want to make any
conclusions about the extent to which genes
determine any differences
If E is 0, G / G = 1, so heritability = 1!
Some Examples
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# of toes or fingers is genetically determined (5)
Heritability though of # of toes is almost certainly very
low…Why?
Control the environment: Most of the variation in number
of toes is environmentally caused (fetal development
problems) (so, we know what causes # of toe
differences, because we have historical evidence of it):
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Pregnant women taking thalidomide
In other words, h is low because genes are not
responsible for much of the variation. In other words,
differences caused by environment are very high!!!
Another Example
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Wearing Earrings
Some time ago in the western culture at least, heritability
was high…?WHY?
 Remember, it’s about controlling the environment
Only women used to wear them, so whether a person
wore wearing earrings was due to a genetic difference (X
vs. Y chromosome)!
Now, earrings are less gender-specific
Now, heritability for having an earring has decreased
But, the heritability for having an earring across the entire
world hasn’t decreased as much probably because men in
other cultures have worn earrings /jewelry historically.
So, wearing earings in our culture is less “genetic” today
than it used to be because the difference used to be
entirely due to a genetic cause
High Heritability WITHOUT
ANY genetic determinism!
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IQ!!!
IQ is enormously affected by normal
environmental variation
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Children from low socio-economic status
backgrounds adopted into upper socioeconomic status have dramatically higher
IQs than their biological parents
Flynn Effect: IQ has gone up about 3 points
every 10 years worldwide (better nutrition,
better health care and so forth)
IT DEPENDS ON
ENVRIONMENT
How could we lower the heritability of
IQ in any given population? (What
could we do to the people?)
 Give half of them brain damage
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This increases the environmentally
caused variation!!! Therefore, the ratio
is a smaller fraction (H = gene:total) (If
G is constant as T goes up, H goes
down)
SO H is a POPULATION
CHARACTERISTIC
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You cannot extrapolate results of heritability
outside the population you are talking about
The H very much depends on environmental
variation
The degree of H is often extremely difficult to
pinpoint and measure
So h is really only a good measure if we know
the salient qualities of a particular environment
So, do black and white people’s environments
equal each other? Are we working with the
same environmental constraints?
H of IQ goes up over the life
span
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WHY???
Environments become more similar as you
grow up
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Parents are very different
But, once away from your parents
Pretty much everybody experiences the
same generic society though
So, environments become more similar,
therefore the differences must be due to
genes, not the environment.
Heritability
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(Thomas Bouchard)
Personality
 The Big 5 (OCEAN; Openness, Conscientiousness, Extraversion,
Agreeableness; Neuroticism) = 50%
 No differences in the sexes
Mental Ability
 .22 at age 5
 .54 to . 62 at age 75+
Psychiatric Illness
 Schizophrenia .80
 Depression .40
 Anxiety disorders .20 to .40
 Alcoholism .50 to .60
 Antisocial personality disorder .41 to .46
 Anorexia nervosa .50
(http://healthpsych.psy.vanderbilt.edu/genetic_anorexia.htm)
Gene-Environment
Interaction
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Girls raised in fatherless households experience puberty earlier
 ?N/N?
Monkeys only fear snakes after watching other monkeys fear snakes
 Predisposition to learn a fear of snakes
Language Acquisition (Humans only)
 Must observe other language-speaking individuals
 Critical window
Homosexuality
 Gay men more likely than lesbians or heterosexual men to have older
brothers (not sisters)
 Also, reduced birth weight, larger placenta
 Immune reaction in mother may grow stronger with each successive
male pregnancy (may affect expression of key genes involved in brain
development
Genotype-Environment
Correlation – 3 Sub Types
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Handout – Larsen and Buss
Passive Genotype
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Reactive Genotype-Environment
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Smart Parents have lots of books
Parents pass on smart genes and create a “smart”
environment filled with books
Baby seems to enjoy cuddling, so parents cuddle with
the baby more
Sociability increases because of gene and the changed
environment
Active Genotype-Environment
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Niche picking – skydivers hang out with skydivers
“Genotype-Environment
Correlation”
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?Let’s brainstorm some others?
Evolutionary
Psychology
Evolutionary Psych
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Think back to when you were a kid…
Did you ever resist going to bed?
WHY!?
Guide 12 – pink
Handout 3-4: Evolutionary Psychology – Tough Questions!
Men and Women differ (12 – yellow)
It’s about survival of the genes!!! That’s where natural selection works,
not at the individual level!
?How close are you to your grandparents? (13 – orange)
 Rate your 4 relationships (if you know/knew them all) 0=cold or
negative feelings; 100=warm or positive feelings
?How about aunts/uncles?
Mating
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When looking for a potential mate,
what 5 attributes are most important
to you?
Mate Preferences
What You Want, Girl?
Men want: smooth skin, youthful
shape, hourglass figure
 Women want: mature, dominant, bold
(interestingly, men are 3x more likely
to die in auto crashes than women),
affluent men = capacity to support and
protect
 Sweaty Mate Choice video
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Men are Pigs
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Men are more likely to…
Think about sex
Report more frequently fantasies
Rate their own drive higher than same age females
Masturbate, begin it earlier
Homosexual couples: men have sex more than women
Put less emphasis on a committed relationship as a prerequisite for sex
 Men: physical pleasure, fantasies involve strangers, multiple partners,
focus on specific sex acts
 Women: romanticized sexual experience; fantasies involve other a
familiar partner, include affection, commitment
Be more sexually aggressive
Have less plastic sexual beliefs (adaptability to culture, social, and
situational factors)
 College doubles likelihood that man identifies as gay or bisexual
 College creates a 900% increase in the % of women identifying as gay or
bisexual
Some interesting stats
(from your book)
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80% of adults-only video store shoppers are male (1993)
55% of men, 35% of women agreed that “if 2 people
really like each other, it’s all right for them to have sex
even if they’ve known each other for a very short time.”
48% of women, 25% of men cited affection as a reason
for first intercourse
How often do you think about sex? 54 – 19 % in favor of
men said every day or several times a day
Gay men vs. lesbian women: more interest in
uncommitted sex, more responsiveness to visual stimuli,
and more concern with partner’s physical attractiveness
Attitudes and Behavior
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Casual hit and run sex is most frequent among males
with traditional masculine attitudes
Men were approached by an average-looking opposite
member and asked, ‘I have been noticing you around
campus and I find you to be very attractive. Would you
go to bed with me tonight?” said yes…
75%!
all women said no (sometimes the men even said,
“why wait until tonight?”)
Men have a lower threshold for perceiving warm
responses as a sexual come on…friendliness = sexual
interest
Infidelity
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?Would you be more distressed if you found that your
romantic partner was (1) having sexual intercourse with
someone else or (2) was becoming emotionally involved
with someone else?
Buss: 511 college students asked this question…83% of
women said 2 compared to 40% of men…60% of men
said 1, only 17% of women said 1
Infidelity
Kinsey (1940s): 36% of husbands,
25% of wives reported being unfaithful
 Marital dissatisfaction tends to be
higher among unfaithful women than
unfaithful men
 A male’s infidelity is more likely than a
female’s to be a “one night stand”
 Jealously does not appear to differ
between the sexes
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The Coolidge Effect (4 fun)
Parents and Peers
Do Parents Matter?
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Psychology through film, #6 (5:15)
Early Experience
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The Brain 1-2 (The Effects of
Hormones and Environment on Brain
Development)
Gender
Development
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Handout 3-10
Me guide 25
Why do we have these stereotypes?
Monkeys given a choice of rag dolls, trucks,
and picture books (gender neutral)
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Males: more time with trucks
Females: more time with rag dolls
1 day olds too!!! wow
Who Does Housework?
Men: 16 hrs/week (up from 12
in 1965)
 Women: 27 (down from 40)
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Handout 3-11 Gender Roles in
the Home
Abnormal Sex Chromosome
Turner’s Syndrome
 Short, immature in appearance
 Webbed necks, eyelid folds, broad
chest, receding chins
 Sterile, but very feminine
 No intellectual impairment
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Abnormal Sex Chromosome
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Kleinfelter’s Syndrome
1-2 / 1000 males
Extreme introversion
Above average height, long arms legs
Some breast development during puberty, unusually
high-pitched voice, little beard growth
Sterile
Intellectual functioning somewhat impaired
Prison pops show a slightly disproportionate number of
these guys (commit more minor crimes)
Abnormal Sex Chromosome
Double Y
 1/1000 males
 Even taller than K’s syndrome
 Large disproportionate number of
these guys in jail for nonviolent crimes
 Intellectual impairment
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Fragile x
Caused by mutation of a single gene,
intensifying over generations
Of those who carry it, 1/3 show mental
deficiency
Among males who carry it, 33% somewhat
retarded, the rest are severely retarded
About 50% of residents in homes for the
retarded have this
Sex Chromosome
Abnormalities
Not as behaviorally serious as once
believed/predicted
 Many do just fine and go on to college
 Stable families are the key
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