Download Evolutionary Psychology

The Nature and Nurture of
Behavior
CHAPTER 3
WHAT THIS CHAPTER IS!
• NATURE
• Our biological blueprint
• Evolutionary Psychology:
– natural selection
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•
•
•
Sexuality
Behavior Genetics: is it nature or is it nurture?
Eugenics
Twin studies, adoption studies, temperament,
heritability
• Gene-environment interaction
• The new frontier: molecular genetics
NURTURE
• Environmental influence
• How much credit or blame do your parents
deserve?
• The prenatal environment
• Experience and brain development
• Peer influence
• Cultural influence
Chromosomes
• Rod shaped structures found in the center of
the nucleus of every cell in the body.
• Each sperm and each ovum (egg cell)
contains 23 chromosomes.
• The chromosomes contain the genes.
• The fertilized egg (zygote) and all the body
cells that develop from it (except the sperm
cells and the ova) contain 46 chromosomes.
Karyotype
A photograph of a cell’s chromosomes
arranged in pairs according to size
http://learn.genetics.utah.edu/content/begin/traits/karyotype/
Genes
• The basic unit of genetic information
• A gene is a segment of DNA capable of
synthesizing a specific protein
– They determine the nature and the function of
the cell.
– Made up of nucleotides (A, T, C, & G)
• The human genes (about 140,000) are referred
to as the human genome.
• A genome is the full set of genes in each cell of
an organism that is made of a sequence of
nucleotides organized as coiled chains of DNA
Genotype
Phenotype
The genetic makeup of The traits that are
a given individual
expressed in the
individual
Recessive Gene
The gene pair that
determines a trait in
an individual only if
the other member of
that pair is also
recessive
Dominant Gene
One gene of a gene
pair that will cause a
particular trait to be
expressed
DNA
deoxyribonucleic acid
• The substance that genes are composed of that
determines the nature of each cell the body and
how it will function.
• At each level of the spiral or rungs of the ladder
are particular chemical pairs, “double helix.” The
arrangement of these pairs along the DNA
molecule determines which kind of proteins that
will be formed in the cell and determine our
physical development.
3.1 billion letters within human DNA
Universal Behaviors:
Evolutionary Psychology
Evolutionary Psychology
• The study of the evolution of behavior and the
mind using principles of natural selection…
adaptive qualities which have helped us survive
and spread our genes
Natural Selection
• The traits that contribute to reproduction and
survival will most likely be passed on to
succeeding generations.
• Finding one’s ecological niche
David Buss
and the International Team
(1994)
• 50 scientists studied:
10,047 people
in 37 countries
in 6 continents
• Men preferred women
thought to be youthful &
healthy
• Women preferred men
who were mature,
dominant, bold, & affluent
Evolutionary Psychology:
David Buss Research Continued
 Men preferred attractive physical features
suggesting youth and health
 Women preferred resources and social status
Human Sex Differences:
Universal
•
•
•
•
Males
Promiscuous
Undiscriminating
Competitive and
concerned about
dominance
• Prefer beauty and
health
• Like sexual novelty
•
•
•
•
Females
Devoted and faithful
Cautious
Less competitive
• Prefer resources and
social status
• Like stability and
security
All Hands on Deck
As a pair….read pgs. 106-107 & list
some of the criticisms of the
Evolutionary Psychology Perspective
Innate Human Characteristics
• Infant Reflexes
• An Attraction to Novelty
• A Desire to explore and manipulate objects
• An Impulse to be playful and fool around
• Basic arithmetic skills
The Nature and Nurture
of Gender
 Gender
 in psychology, the characteristics, whether biologically
or socially influenced, by which people define male and
female
 Testosterone
 the most important of the male sex hormones
 both males and females have it
 additional testosterone in males stimulates
 growth of male sex organs in the fetus
 development of male sex characteristics during puberty
 Role
 a set of expectations (norms) about a social position
 defining how those in the position ought to behave
All Hands on Deck: Sexuality
Textbook p. 103 & 104 Which Gender Has the Strongest Sex Drive?
1.
Segall 1990 cross-cultural study
2.
Jenish 1993 and Malamuth 1996 study
3.
Sax 2001 study of American college students
4.
Clark and Hatfield 1989 F.S.U. study
5.
Abbey 1987 and Johnson 1991 study
In early intrauterine development male and female external genitalia
(visible sex organs) are identical.
• Under the influence of the androgen
dihydrotestosterone, the external genitalia
develop in the male direction. In the absence
of androgens female external genitalia
develop.
• Mutation
A random error in
gene replication that
leads to a change in
the sequence of
nucleotides; the
source of all genetic
diversity.
– May happen as a result of
teratogens, which are
substances that can
cross the placental
barrier and harm an
unborn child
• Sometimes female
embryos are exposed to
abnormally high levels of
androgen before birth. A
small number of genetic
females are born with
ambiguous external
genitalia. The most
common cause of female
pseudohermaphroditism
is congenital adrenal
hyperplasia (CAH).
• Cortisol is released into the blood stream from
the adrenal gland, a small organ near the
kidney.
• a metabolic error causes overproduction of
androgens (e.g. testosterone) in the adrenal
gland. This androgen leads to partial
masculinization of the external genitalia
• Girls with classical CAH are born with
masculine-appearing external genitals but with
female internal sex organs.
•
His testicles were
surgically removed and an
artificial vagina created, as
is done in sex-change
operations. John became
Joan.
At 12, she was given
estrogen therapy to
complete the conversion to
a woman. She grew
breasts, but was never
accepted by other girls,
nor felt comfortable as a
woman.
Boy raised as girl discovers
happiness as a man
• In 1972 Money and Ehrhardt
reported the case of a 7 month
old baby boy - one of a pair of
twins - born in 1963 whose
penis was removed after an
operation for circumcision
damaged the child's penis. At
22 months old the child was
surgically reassigned as a girl
and brought up according to the
prevailing view at the time that
we are psychosexually neutral
at birth. This case entered the
textbooks and informed medical
opinion for several decades.
• At 14, she rebelled,
confessing to her doctor:
"I suspected I was a boy
since the second grade."
She was eventually given
a mastectomy to remove
the breasts and was
given male hormones. At
the age of 25, now John
once more, he married a
woman who already had
children.
The Nature and Nurture
of Gender
 Social Learning Theory
 theory that we learn social behavior by
observing and imitating and by being
rewarded or punished
 Gender Schema Theory
 theory that children learn from their cultures
a concept of what it means to be male and
female and that they adjust their behavior
accordingly
The Nature and Nurture
of Gender
 Gender Role
 a set of expected behaviors for males and
females
 Ex. Boys not crying
 Gender Identity
 one’s sense of being male or female
 Gender-typing
 the acquisition of a traditional masculine or
feminine role
The Nature and Nurture
of Gender
 Two theories of gender typing
The Nature and Nurture
of Gender
The Nature and Nurture
of Gender
 Gender and Culture
All Hands on Deck
• Do men and women differ in their
communication experiences?
• Who talks the most?
• Who interrupts?
• What about gender patterns in formal group
meetings?
• What about gender patterns in informal
group meetings?
• Are gender differences in communication
patterns related to power?
Who talks the most?
• In mixed-gender groups,at public gatherings,
and in many informal conversations, men spend
more time talking than do women.
Who interrupts?
• Men are more likely than women to interrupt
• A study of faculty meetings : women are more
likely than men to be interrupted.
• Women, when they interrupt, are more likely to
interrupt other women than they are to interrupt
men, according to two studies.
• Women do not resist interruptions as much as
men do
What about gender patterns in formal
group meetings?
• In meetings, men gain the "floor" more
often & keep the floor for longer periods of
time…regardless of their status in the
organization.
What are the gender patterns in informal
group meetings?
• In informal, collaborative meetings, women
display a fuller range of language ability.
What are some of the ways women are affected
by these patterns?
• Women are less likely to have confidence in
their ability to make persuasive arguments.
• Some women add to their own passive
participation -- by allowing interruptions
• Some women, when they do gain the "floor," talk
too fast as though they know they are about to
be interrupted.
Are gender differences in communication
patterns related to power?
• When people are strangers, they expect less
competence from women than from men.
• Studies have found that talking time is related
both to gender (because men spend more time
talking than women) and to organizational power
(because the more powerful spend more time
talking than the less powerful).
BODY LANGUAGE
• Men take up more physical space when sitting or standing, with
arms and legs stretched out away from their body
• Women take up less physical space, sitting with arms and legs
toward their body
• Men gesture away from the body
• Women gesture toward the body
• Men assume more reclined positions when sitting and lean
backward when listening
• Women assume more forward positions when sitting and lean
forward when listening
• Men not as sensitive to the communication cues of others
• Women have greater sensitivity and acuity toward other
people's nonverbal communication cues (picture of boss)
• Men tend to approach women more closely in terms of their
personal space
• Women do not approach men as closely in terms of their
personal space
FACIAL EXPRESSIONS
• Men: cock their head to the side and look at the
other person from an angle when listening
• Women: look at the other person directly facing
them with their head and eyes facing forward when
listening
• Men provide fewer facial expressions in feedback
and fewer reactions
• Women provide more facial expressions and more
reactions
• Men display frowning and squinting when listening
• Women display smiling and head-nodding when
listening
• Men stare more in negative interaction
• Women lower their eyes more to avert gaze in
negative interaction
GENDER DIFFERENCES
•
MEN, WOMEN, AND PUNCTUATION
• An English professor wrote the words:
• "Woman without her man is nothing" on the
blackboard and directed the
students to punctuate it correctly.
• The men wrote: "Woman, without her man, is
nothing."
• The women wrote: "Woman! Without her, man
is nothing."
• UNDERSTANDING WOMEN
(A MAN'S PERSPECTIVE)
I know I'm not going to understand women.
I'll never understand how you can take boiling
hot wax, pour it onto your upper thigh, rip the
hair out by the root,
and still be afraid of a spider.
Explaining Differences:
Behavior Genetics
Behavior Genetics
• The study of the relative power and limits of
genetic and environmental influences on
behavior
- ex. effect on personality
Environment
 every nongenetic influence, from prenatal
nutrition to the people and things around us
Language Acquisition Device
Innate Mental Module
Noam Chomsky
• Children in different cultures go through similar
stages of linguistic development.
• Children combine words in ways adults never
do.
• Adults don’t consistently correct their children’s
syntax.
• Even children with an Intellectual Deficiency
develop language.
• Infants can derive simple linguistic rules.
Where can I learn more about the
genetics of different behavioral traits?
• Online Mendelian Inheritance in Man (OMIM) is a large, searchable,
up-to-date database of human genes, genetic traits, and disorders.
Each contains bibliographic references and a summary of the
scientific literature describing what is known about a particular gene,
trait, or disorder. The following behavioral traits are included in
OMIM.
• Hand skill, relative (handedness): (139900)
• Hand clasping pattern: (139800)
• Arm folding preference: (107850)
• Ears, ability to move: (129100)
• Tongue curling, folding, or rolling: (189300)
• Musical perfect pitch: (159300)
• Novelty seeking personality trait: (601696)
• Stuttering: (184450)
• Tobacco addiction: (188890)
• Alcoholism: (103780)
• Homosexuality: (306995)
Genetic Research
• Predicting individual differences
• To determine the effects of
heredity, behavior geneticists
rely on two studies
• Twin studies
• Adoption studies
Heritability: of any trait, the
extent to which variation among
individuals can be attributed to
their differing genes
Behavior Genetics
Identical
twins
Fraternal
twins
 Identical Twins
 develop from a single
fertilized egg (by 1 sperm)
that splits in two, creating
two genetically identical
organisms
 Fraternal Twins
Same
sex only
Same or
opposite sex
 develop from separate eggs
with a separate sperm
 genetically no closer than
brothers and sisters, but
they share the fetal
environment
Twin Studies
13,000 pairs of Swedish twins, 7000 Finnish
twin pairs, 3810 Australian twin pairs
Identical twins are more similar than fraternal twins
on both extroversion & neuroticism
Battery of questionnaires to 850 U.S. twins
Identical twins are more similar in abilities,
personality traits, & interests.
Reported being treated alike
Separated Twins
• The Jim Twins
Similar in:
brain waves
voice intonation
interests
heart rate
personality
intelligence
• Gerald Levey and
Mark Newman
separated at birth,
reunited at age 38
• Both volunteer
firefighters
Adoption Studies
• People who grow up
together, whether
biologically related or not,
do not much resemble
one another in
personality.
• Adoptees’ traits bear
more similarities to their
biological parents than to
their care-giving adoptive
parents
Temperament Studies
Traits such as
emotional excitability – whether the baby is intense,
reactive, fidgety, easy going, or quiet
tend to remain steady in later years
Behavior Genetics
 Interaction
 the dependence of the effect of one factor
(such as environment) on another factor (such
as heredity)
 More like nature via nurture
 Molecular Genetics
 the subfield of biology that studies the
molecular structure and function of genes
The “Obese” Gene
• Obese gene causes
fat cells to produce
leptin.
• Leptin travels through
blood to
hypothalamus
(regulates appetite)
• Leptin reduces
appetite
Why Do People Gain Weight
Rapidly?
• Secretion of leptin is impaired
• May produce plenty of leptin but their body does
not respond to it.
• Tendency to store calories which have a survival
advantage.
Alcoholism
In 1990, psychiatrist Ernest Noble of UCLA
and pharmacologist Kenneth Blum of the
University of Texas find strong association
between alcoholism and one version of a gene
that makes the dopamine D2 receptor. this
particular gene variation is called A1. In more than
two-thirds of 35 deceased alcoholics, compared to
just one-fifth of the same number of nonalcoholics. The gene builds a receptor on the
surface of nerve cells that responds to dopamine,
a chemical messenger in the brain's "pleasure
center."
Eugenics
The science of improving the human
species through restrictive or selective
breeding
Experiments on laboratory mice and
farm animals have been used to develop
theories about ways to abolish mental
and social dysfunction by manipulating
human reproduction.
EUGENICS
• Sperm banks
• Sperm banks: medical facilities collect and store sperm.
The use of cryopreserved or frozen, donor sperm is
option for couples who have been unable to conceive
• Anonymous ,undergo rigorous medical and genetic
evaluation and testing prior to acceptance.
• donor specimen carefully analyzed for adequate sperm
count and mobility.
• choose a particular donor from a catalog describing
physical characteristics and ethnic background.
• The donor specimen selected is released to the couple's
physician for use in insemination or assisted
reproduction.
• males undergoing vasectomies, chemotherapy, other
treatments which may alter future sperm production,
sperm cryopreservation and storage facilities allow the
possibility of conceiving children in the future.
ABORTION
• In 54 countries abortions are legal.
• In 97 countries abortions are illegal.
• There are 46 million abortions conducted each year,
20 million of them obtained illegally. There are
126,000 abortions conducted each day.
• Approximately 1,370,000 abortions occur annually in
the U.S.
• In 2001, 1.31 million abortions took place.
• 43% of women will have had at least one abortion by
the time they are 45 years old.
ABORTION AND EUGENICS
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Trauma
Rape
Incest
Handicap
Mental retardation
Physical deformities
Down’s syndrome
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Social
Sex selection
Unwanted children
Economic
Medical
• To determine whether a nation is
growing or dying, we must examine
three factors: birth rate . . . death rate . .
. immigration.
• THE WEST IS DYING
• Birth Rate: This is the ultimate
determinant. In a developed nation the
average woman must bear 2.1 children
(Mean Fertility Rate) in order to maintain a
level population.
• In an undeveloped nation the rate must be
2.3 or more because of higher infant and
child mortality.
• Western World, birthrates have dropped below
replacement level.
• Europe’s population shift, in both the East and
West: demographic vacuum into which are
moving millions of Muslims and Arabs who have
large families.
• Religious shift: for the first time in history, there
will be more Muslims in the world than Catholics.
Due to contraception, sterilization, surgical
abortion and abortifacient drugs.
Population Projections
• Normal population
• Birth rate
• Adolescence- young
adult decline
• Middle aged
• Old age decline
Future Projection
• abnormal population
• Lowered birth rate
• Adolescence- young
adult decline
• Middle aged
• Increased old age
CLONING
• 1952, the first animal, a tadpole, was cloned.
• Dolly, the first mammal cloned from the cell of
an adult animal, clones were created from
embryonic cells.
• Since Dolly, researchers have cloned a number
of large and small animals including sheep,
goats, cows, mice, pigs, cats, rabbits.
3 types of cloning technologies
(1) Recombinant DNA technology or DNA cloning
• The transfer of a DNA fragment of interest from one
organism to a self-replicating genetic element such
as a bacterial plasmid.
(2) Reproductive cloning
• Reproductive cloning is a technology used to
generate an animal that has the same nuclear DNA
as another currently or previously existing animal.
(3) Therapeutic cloning.
• Therapeutic cloning, “embryo cloning,” is the
production of human embryos for use in research.
• Organs cloned for use in transplants
• therapeutic cloning can be used to generate
tissues and organs for transplants.
• DNA extracted from person in need of a
transplant and inserted into an enucleated egg.
• The stem cells would be used to generate an
organ or tissue that is a genetic match to the
recipient.
• cloned organ could then be transplanted into the
patient without the risk of tissue rejection.
• the need for organ donation could be
significantly reduced.
CLONING RISKS
• low success rates
• cloned animals have more compromised immune
function
• Zerox copy
• higher rates of infection, tumor growth, other disorders.
• Japanese studies have shown cloned mice live in poor
health and die early.
• 1/3 of cloned calves born alive have died young
-many were abnormally large.
• Clones have not lived long enough to generate good
data about how clones age.
• No long-term survival.
• Have been known to die mysteriously.
Should Humans Be Cloned?
Benefits:
• military, health, entertainment, human
services, death of loved one
Disadvantages:
• Population, the human “soul”,
(employment), ethics
Gene-Environment Interaction
“Heredity deals the cards;
environment plays the hand.”
Psychologist Charles L. Brewer (1990)
Genes? You decide!
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•
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•
This man celebrated his 113th
birthday telling reporters at his
home in southern Japan about
his joyful life and healthy
appetite.
Holds the Guinness Book of
World Records as the oldest
living male. He eats mostly
vegetables and believes the key
to longevity is not drinking
alcohol.
He lives with his son, drinks
milk every day and has no
major illnesses,
The Japanese are among the
world's longest-lived people,
with the number of those aged
100 or older at a record 36,276,
shown from a government
report ( 2008).
Japanese women have topped
the world's longevity ranks for
23 years, while men rank third
after Iceland and Hong Kong.
Environmental Influence
• Prenatal Environment
• Experience and Brain
Development
• Peer Influence
• Culture
• Gender
Prenatal Care
• Diet
• The father’s
involvement
• Age of mother
• Illness of mother
• Drug use
• Alcohol
• Teratogens
Experiences and Brain
Development
• Rosenzweig and Krech’s experiment on
rats:
– Those living in the enriched environment
developed a thicker and heavier brain cortex,
and thus more brain cells.
– Experience preserves our activated
connections
Environmental Influence
 Experience affects brain development
Impoverished
environment
Rat brain
cell
Enriched
environment
Rat brain
cell
Environmental Influence
 A trained brain
Environmental Influences:
Parents and Peers are Complementary
Howard Gardner (1998)
“Parents are more important when it comes to
education, discipline, responsibility, orderliness.
Charitableness, and ways of interacting with
authority figures.
Environmental Influences:
Peers
• Peers are more important for learning
cooperation, for finding the road to popularity, for
inventing styles of interaction among people of
the same age.
Youngsters
may find their
peers more
interesting,
but they will
look to their
parents when
contemplating
their own
futures.”
What Is the Role of Parenting?
1- Do parents really produce future adults with a
wounded child within by being irresponsible?
2- Should we blame our parents for our failings?
3- Should we shame the parents of troubled
children?
4- Should parents be given less credit for children
who turn out great?
5- What is the role of parents?
Environmental Influence: Culture
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•
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•
•
Cultural Universals
Variation Across Cultures
Variation Over Time
Cultural Relativism
Culture and Child
Rearing
- When to potty train
- Walking/talking
- Customs regarding
family
-adolescence
Environmental Influence: Culture
 Culture
 the enduring behaviors, ideas, attitudes, and
traditions shared by a large group of people
and transmitted from one generation to the
next
 Norm
 an understood rule for accepted and expected
behavior
 Mores: official rules of behavior sanctioned by
law.
 Taboos: unthinkable acts
VARIATION ACROSS CULTURES
•
•
•
•
•
Raising children
Burying the dead
Clothing styles
Use of eating utensils
Personal space
CULTURE AND CHILD-REARING
• Western cultures: individualism, independence,
true to self, marry for love: evidenced by
strollers, playpens, car seats, baby sitters
• Asian and African cultures: communal,
emotional closeness, children don’t have their
own bedrooms, not sent to daycare, stronger
sense of family self; what shames/honors family
brings same to self: spend day with close
personal contact; on mother’s back
CULTURAL RELATIVISM
• In order for behavior to be understood, it
must be judged within the context in which
it occurs;
• Sporting events
• Rock concerts
• Self-defense
• War
• Religious practices
Environmental Influence
 Personal Space
 the buffer zone we like to maintain
around our bodies; 0-12 inches:
personal, 12/18 inches-3ft: social, 3-6
feet: public
Memes
 self-replicating ideas, fashions, and
innovations passed from person to
person
VARIATION OVER TIME
• Since 1960, most western cultures have changed
with remarkable speed.
Positive changes
• The middle class fly on airplanes
• Email instead of snail-mail
• Air-conditioning for poor and middle class
• On-line shopping
• Cell phones
• Double personal income
• Eating out 2.5 more times than your parents did
Negative changes since the 60’s
• Doubled divorce rate
• Teen suicide tripled
• Quadrupled juvenile violent crime
• Quintupled prison population
• Highest depression rate in the world and rising
• More hours at work/ less hours at home
• Fewer hours sleeping
• Less time for friends
• Similar cultural changes for Britain, Canada, Australia,
New Zealand
What causes change over time?
• Events can affect fashion short/long skirts
• Inventions: microwave ovens
• Memes self-replicating ideas, fashions, and
innovations passed from person to person
 Like genes, memes compete to get copied
not into our cells but into our memories
Memes can be
• True or positive:
arithmetic, Abe Lincoln,
Bach’s music
• Neutral: new pronunciations
• False: myths, alien abductions
Culture’s Impact
• A unified culture is like bicycling with the wind.
You hardly notice it’s there
• When we try riding against the wind; we feel it’s
force!
“Genes, by themselves, are
like seeds dropped onto
pavement: powerless to
produce anything”
1. A genetically programmed action pattern is the
ethologist’s definition of:
(a) habit
(b) instinct
(c) adaptation
(d) altruism
(e) releasing merchandise
2. The result of the evolutionary process that preserves
traits that enhance the adaptation of an organism
and suppresses traits that do not is called:
(a) Habituation
(b) Accommodation
(c) Natural selection
(d) Eugenics
(e) Species assimilation
3. One's personal, private sense of maleness or
femaleness is known as
A. genital identification.
B. sexual scripting.
C. gender identity.
D. sex role perception.
4. The observable traits, mannerisms, interests, and
behaviors defined by one's culture as "male" or
"female" are one's
A. gender identity.
B. gender role.
C. genetic sex.
D. biological bias.
5.The favored pattern of behavior expected of each sex
is called
A. gender identity.
B. sexual identity.
C. gender role.
D. biological sex.
6. Sperm is to cell as DNA is to:
a. nucleotide
b. gene
c. chromosome
d. molecule
7. Which of the following is a major source of genetic
diversity?
a. Cloning
b. gender schemas
c. mutations
d. memes
8. Men judge women as especially attractive if they
appear______and women judge men as especially
attractive if they appear______.
a. mature; mature
b. youthful; youthful
c. mature; youthful
d. youthful; mature
9. The study of the relative power of genetic and
environmental influences on behavior and personality
traits is known as:
a. molecular genetics
b. evolutionary psychology
c. behavior genetics
d. human cloning
10. An infant’s temperament refers most directly to its:
a. ability to learn
b. physical attractiveness
c. temperament
d. physical health