Download Introduction to Psychology

Myers’ PSYCHOLOGY
For AP
Unit 3C
The Nature and Nurture
Of Behavior
3 BIG Questions
How does genetic inheritance (our nature)
and experience (nurture) influence our
development?
Continuity versus stages of development?
Stability versus Change…do our
personalities change as we age?
Genes: Our Biological
Blueprint
 Chromosomes
 threadlike structures made of DNA that
contain the genes
 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
Test Your Knowledge
If chromosomes are books of heredity – the
words are _______________ and the letters
are ___________________.
Sperm is to cell as DNA is to
_____________.
Genes: Our Biological
Blueprint
 Genes
 biochemical units of heredity that make up the
chromosomes
 a segment of DNA capable of synthesizing a protein
 Genome
 the complete instructions for making an organism
 consisting of all the genetic material in its
chromosomes
 Molecular geneticists are most interested in studying
nucleotide sequences…human genetic diversity consists of
differences in our nuclotides.
Genes: Their Location
and Composition
Nucleus
Cell
Chromosome
Gene
DNA
Evolutionary Psychology
 Natural Selection
 the principle that, among the range of
inherited trait variations, those that lead to
increased reproduction and 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
and the mind, using the principles of
natural selection
 Gender
 in psychology, the characteristics,
whether biologically or socially
influenced, by which people define male
and female
Evolutionary Psychology Con’t
EP is not about how one species evolves into
another species over time BUT is about how
genetics and environment interact leading to in
genetics to fit the environment.
Traits leading to survival are likely to be assed
along.
Predisposed to love our children, fear animals,
select healthy mates etc.
Criticisms of EP
Evolution does not imply genetic
determinism.
Behavior can be changed.
Does not assume that organisms can
compute complex math
problems/formulas.
Current adaptive mechanisms in humans
are not optimally designed.

Evolutionary Psychology
 Men preferred attractive physical features
suggesting youth and health
 Women preferred resources and social status
Behavior Genetics
 Behavior Genetics
 study of the relative power and limits of
genetic and environmental influences on
behavior
 Environment
 every nongenetic influence, from
prenatal nutrition to the people and
things around us
Behavior Genetics
Identical
twins
Fraternal
twins
Same
sex only
Same or
opposite sex
 Identical Twins (Monozygotic)
 develop from a single
fertilized egg that splits in
two, creating two
genetically identical
organisms
 Fraternal Twins
(Dizygotic)
 develop from separate eggs
 genetically no closer than
brothers and sisters, but
they share the fetal
environment
Twins
Fraternal twins are on the rise…
Fertility drugs like Clomid
Women are waiting longer to have children
Identical twins share the 100% the same genes
but can have different phenotypes…
Phenotype is how a gene expresses itself.
ie…mirror twins – differences in heritability
Personality & Interests.
 Sweden has the largest twin registry.
Behavior Genetics
 Temperament
 a person’s characteristic emotional
reactivity and intensity
 Heritability
 the proportion of variation among
individuals that we can attribute to
genes
 may vary, depending on the range of
populations and environments studied
Heritability Continued
“Herit” part of inherit – possess
something that someone has given to
you.
Ability – suffix meaning “capable” –
genetically passed on – it is capable of
showing up in children of those who
possess that quality
ie. parent to child
Behavior Genetics
 Interaction
 the dependence of the effect of one factor (such as
environment) on another factor (such as heredity)
 Example – people who are judged s attractive
physically are more likely to get a job or promotion
over someone who is less attractive.
 Molecular Genetics
 the subfield of biology that studies the molecular
structure and function of genes
Environmental
Influence
 Two placental arrangements in identical
twins
Environmental
Influence
 Experience affects brain development
Impoverished
environment
Rat brain
cell
Enriched
environment
Rat brain
cell
Environmental
Influence
 A trained brain
Environmental
Influence
 Culture
 the enduring behaviors, ideas, attitudes, and traditions
shared by a large group of people and transmitted
from one generation to the next
 Peer influence – slang, food and fashion preferences
 Parental influence - are most influential when it comes
to values, political beliefs and manners.
 Norm
 an understood rule for accepted and expected
behavior
Environmental
Influence
 Personal Space
 the buffer zone we like to maintain
around our bodies
 Memes
 self-replicating ideas, fashions, and
innovations passed from person to
person
The Nature and
Nurture 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 child
 Y Chromosome
 the sex chromosome found only in men
 when paired with an X chromosome from the
mother, it produces a male child
Sex Linked Traits
Sex linked traits are passed to child fro
mother through X chromosome.
Usually recessive so when father passes
along another X (female), his
chromosome dominates the recessive
gene.
Most sex linked traits are exhibited in
males because there’s only one X
ie. colourblindeness
The Nature and
Nurture 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
 Role
 a set of expectations (norms) about a social position
 defining how those in the position ought to behave
The Nature and
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
The Nature and
Nurture of Gender
 Gender and Culture
The Nature and
Nurture of Gender
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
 Two theories of gender typing