Warm UPSet up title page- chapters 3 and 4
 Pick up and READ the article located on
the overhead


Think about 3 things about yourself that you
believe are influenced by nature and 3 that are
influences by nurture
Jim Twins
http://www.youtube.com/watch?v=qw3S35wGgT8​
 Baby Storm
http://www.youtube.com/watch?v=4olXHq5Xe78

Chapter 3: Nature and
Nurture of Behavior
Nature
Genes

Chromosomes
 threadlike
structures made of DNA that contain the
genes
 Total of 46…23 from Mom, 23 from Dad.

DNA (deoxyribonucleic acid)
 complex
molecule containing the genetic
information that makes up the chromosomes
 has two strands-forming a “double helix”- held
together by bonds between pairs of nucleotides
Genes
 Genes
 Small segments
of your
chromosomes
 Have about
30,000
 a segment of
DNA capable of
synthesizing a
protein

Genes
Nucleotides: biochemical
letters that make up genes.
Some 3 billion paired
nucleotides define the genes
that determine your individual
biological development.
Letters: A T C and G.
 Sequence of nucleotides is what
makes humans, human…pigs,
pigs, etc.

Genes

Genome
 the
complete
instructions for
making an
organism
 consisting of all
the genetic
material in its
chromosomes
Positives and Negatives of Genetic
Engineering?
Human Genome
Project: goal is to map
the human genome down
to the nucleotide and
identify all the genes
present in it.
 Reflect on Questions given
for a few minutes.

Question Reflection: Positives and
Negatives of Genetic Engineering?
1. 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?
2. If you or your spouse were pregnant, would
you want the unborn child tested for genetic
defects?
3. Do you think it should be legal for employers
to use genetic tests in deciding whom to hire?
Evolutionary Psychology
Based on the ideas of Charles Darwin and
natural selection: the principle that, among
the range of inherited trait variations, those
contributing to survival will most likely be
passed on to succeeding generations
 Mutations
 random errors in gene replication that lead to
a change in the sequence of nucleotides
 the source of all genetic diversity

Evolutionary Psychology

Evolutionary Psychology:
the study of the evolution
of behavior using the
principles of natural
selection.

Believe that nature selects
physical as well as behavioral
traits that prepare humans to
survive, reproduce, and send
genes into the future.
Evolutionary Example

Evolutionary Psychologists believe we favor
sweets and fats now since in the prehistoric era
these were harder to come by and allowed
ancestors to survive famine.

Problem today?

Complete Handout 3.2 concerning Evolutionary
Psychology.
Gender and Evolutionary Psychology

Gender: in psychology, the
characteristics, where
biologically or socially
influenced, by which people
define male and female

Evolutionary Psychologists
have found major gender
differences in both attitudes
and behaviors towards sex.
Gender Differences in Attitudes and
Behaviors
Attitudes: Males tend to have a much more
recreational approach to sex vs. women’s
relational approach.
 Behavior: Males are more likely to be
promiscuous and aggressive towards sex than
females.
Florida State Example
 Men tend to perceive a women’s friendliness as
a sexual come-on

How would Evolutionary
Psychologist Explain this
Difference?
Women most often
send their genes
into the future by
pairing wisely
 Men by pairing
widely


Complete Handout 3.3
Mate Selection
Both men and women rated mutual
attraction-love,dependable character,
emotional stability, maturity and pleasing
disposition as most important
 Least important- chastity, similar religious
backgrounds and similar political
backgrounds
 More Important to Males- good looks and
chastity
 More Important to Females- financial
security and ambitious

Preferred by Males
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Kindness
IQ
Physical Attractiveness
Exciting personality
Good Health
Adaptability
Creativity
Desire for Children
College Graduate
Good Heredity
Good Earning capacity
Good Housekeeper
Religious orientation
Preferred By Females
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Kindness
IQ
Exciting Personality
Good Health
Adaptability
Physical attractiveness
Creativity
Good earning capacity
College graduate
Desire for children
Good heredity
Good housekeeper
Religious orientation
Gender Differences and Attraction

Across the board men and women prefer
youthful appearance.
Gender Differences and Attraction
Men tend to be especially drawn to “physical
attractiveness.”
 Women are especially attracted to males who
seem mature, dominant, and affluent.

Gender Differences and
Attraction
How would Evolutionary Psychologist
Explain this?
 Men look for youth b/c young women
have more childbearing years and men
just want to send their genes into the
future
 Men prefer women who’s waists are 1/3
narrower than their hips, a sign of future
fertility
How would Evolutionary Psychologist
Explain this?
Women prefer mature, dominant and affluent
men b/c they are more able to protect and
provide for the family
 Men tend to be risk takers ( or stupid) b/c they
need to show their women “ look at me! I have
so much strength and skill that I am fearless. I
will survive no matter how much I drink or how
fast I drive.”
 Women spend more time on appearance and
money
 Men spend more time on status and dominance
 Men are constantly trying to out do other men to
compete for fertile women

Criticisms of Evolutionary
Approach: Do you Buy It?

Men and women
are a lot more
similar
 Want
single, long
term partners

Evolutionaries
focus too much
on nature
Behavior Genetics
 Behavior
Genetics
 study
of the power and limits of genetic
and environmental influences on
behavior
 Environment
 every
non-genetic influence, from
prenatal nutrition to the people and
things around us
Behavior Genetics and Use of Twin
Studies

Identical Twins
 develop
from a single
zygote (fertilized egg)
that splits in two, creating
two genetic replicas

Identical
twins
Fraternal
twins
Same
sex only
Same or
opposite sex
Fraternal Twins
 develop
from separate
zygotes
 genetically no closer than
brothers and sisters, but
they share the fetal
environment
What’s the Value of Twin Studies
to Behavior Geneticists?
Genes
Matter
 Extraversion
and neuroticism in identical twins
is more similar than in fraternal twins
 Identical twins are more similar in abilities,
personalities and interests
 Identical twins raised apart are still very
similar
Example-
Jim twins
How Have Psychologists Used
Adoption Studies?
 Genes
Matter
 Adopted
children are more similar
to their biological parents than
their adoptive parents
Especially in personality
 Parents do have an influence on
values, manners , faith and politics
Behavior Genetics
Temperament
 a person’s characteristic
emotional reactivity and
intensity
Difficultirritable,intense and
unpredictable
Easy- cheerful,relaxed
and predictable
 Hereditary
 Complete Handout 3.6.

Temperament
3
Temperaments
 Activity-
High-busybodies, like
action
 Emotionality- High-frightened and
angry easy. Quick tempered
 Sociability – High- seek out
others, enjoy company
Temperament
 1st-
reverse the number they placed
in front of items 6, 18 and 19
So… 5=1,4=2,3=3,2=4,1=5
 For Activity- add 2, 7, 10 and 17
 For Sociability- add 1, 6, 15, 20
 Emotionality- 3 parts
 Distress-
4, 9, 11, 16
 Fearfulness- 3, 12, 14, 19
 Anger- 5, 8, 13, 18
Temperament
Activity
Sociability
Emotionality
Distress
Fearfulness
Anger
Women
13.40
15.24
Men
12.80
14.60
10.08
10.60
10.28
9.72
8.92
10.80
Behavior Genetics
 Heritability:
the
proportion of variation
among individuals that
we can attribute to
genes
 Boys
raised in barrels
example
Behavior Genetics
Interaction
 the effect of one factor (such as environment)
depends on another factor (such as heredity)
 Our genes affect how people react to and
influence us
 Molecular Genetics
 the subfield of biology that studies the
molecular structure and function of genes
 Ex: Human Genome Project
 Designer babies?

Warm Up – page 3
 1. What is the nature/nurture debate?
 2.
What is an evolutionary psychologist?
 3. How do men and women differ in
their mate selection?
 4. What do behavioral geneticists
study?
 5. What is the Human Genome Project?
Nurture

Influence of Environment Starts
in the Womb

Prenatal
Environment: first
stage of nurture, when
embryos and fetuses
receive differing nutrition
and varying levels of
exposure to toxic agents.
Influence of Environment Starts
in the Womb

Two placental arrangements in identical
twins
More Environmental
Influence
 Experience
Impoverished
environment
affects brain development
Rat brain
cell
Enriched
environment
Rat brain
cell
Experience and Brain Development
More stimulation= better brain
development
 Stimulation and touch can help premature
babies
 Language development in children before
age 8
 Don’t use it, you lose it

Peer Influence
 Peer
influences
may exceed
parental influence
 Parents can help
shape
influences;schools,
neighborhoods,
etc.
Environmental Influences

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
Personal
Space
Expressions
Environmental Influences
 Memes
 self-replicating
ideas, fashions, and
innovation passed from person to
person.
Culture and Child Rearing
Western cultures
like independent
children
 Asian and
African cultures
focus on
emotional
closeness


The Nature of Gender

X Chromosome
 the
sex chromosome found in both men and
women
 females have two; males have one
 an X chromosome from each parent produces a
female

Y Chromosome
 the
sex chromosome found only in men
 when paired with an X chromosome from the
mother, it produces a male child
Nature of Gender

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
Nurture of Gender
Gender Role
 a set of expected behaviors for males
and females
 Gender Identity
 one’s sense of being male or female
 Gender-typing
 the acquisition of a traditional masculine
or feminine role

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

Nature or Nurture?

Percentage agreeing “The activities of
married women are best confined to home
and family”
70
Percentage
60
Men
50
40
30
20
10
Women
0
1967 ‘71 ‘75 ‘79 ‘83 ‘87 ‘91 ‘95
Year