ch 3 Flashcards
Nativists
Emphasize genes and inborn
characteristics (Nature).
Empiricists
Focus on learning and experience
Nurture
Evolutionary Psychology
A field of psychology emphasizing evolutionary mechanisms that may help to explain human commonalities in cognition, development, emotion, social practices, and other areas of behaviour.
Behavioural Genetics
An interdisciplinary field of study
concerned with the genetic bases of
individual differences in behaviour and
personality.
Studying genetic material
Linkage studies
Genetic markers
The link between genetics and behaviour
Bi
Chromosomes
Genes
DNA (deoxyribonucleic acid)
Chromosomes Rod-shaped structures within cells that carry genes. Genes Functional units of heredity which are composed of DNA and specify the structure of proteins. DNA (deoxyribonucleic acid) Chromosomal molecule that transfers genetic characteristics by way of coded instructions for t
Genome
The full set of genes in each cell of
an organism (with the exception of
sperm and egg cells).
Linkage studies
Because genes lying close together on a
chromosome may be inherited together across
generations, researchers can look for genetic
markers in families.
Genetic markers
A segment of DNA that varies among individuals, has a known location on a chromosome, and can function as a genetic landmark for a gene.
The Link Between Genes and Behaviour
Even when researchers locate a gene on a
chromosome, they do not automatically know its role in
physical or psychological functioning.
Most human traits are influenced by more than one
gene pair.
Examples include height and eye colour.
Evolution
A change in gene frequencies within a
population over many generations.
A mechanism by which genetically influenced
characteristics of a population may change.
Changes may occur due to mutations or errors
occurring during copying of original DNA
sequence.
Changes may occur due to natural selection.
• Natural Selection
The evolutionary process in which individuals with
genetically influenced traits that are adaptive in a
particular environment tend to:
Survive; and
Reproduce in greater numbers
As a result, their traits become more common in
the population.
B
Sexual Selection
inter and intra
Intersexual selection a member of one sex chooses a mate from the other sex on the basis of certain characteristics. Intrasexual selection members of the same sex compete for a partner of the other sex. Im
Evolutionary Biologists
Start with an observation about a characteristic and try to account for it in evolutionary terms. For Example: Plumage differences in male and female peacocks.
Evolutionary Psychologists
Ask what sorts of challenges human beings might
have faced and then infer which behavioural
tendencies might have been selected to overcome
these challenges.
For example: Avoiding poisonous food and an innate
dislike for bitter tastes.
Innate Human Characteristics
Infant reflexes Interest in novelty Desire to explore and manipulate objects Impulse to play and fool around Basic cognitive skills
Phenotype Matching
An individual’s ability to assess relatedness to
another individual based on the phenotype, the
expression of gene-environment interactions.
Language
A system that combines meaningless
elements such as sounds or gestures to form
structured utterances that convey meaning.
Innate Capacity for Language
Language too complex to be learned bit by bit (Chomsky, 1957, 1980).
Sentences have surface and deep structures:
Surface structure - the way a sentence is spoken.
Deep structure - how a sentence is to be understood.
To transform surface sentence structures into deep ones, children must
apply rules of grammar (syntax).
surface structure
s
deep structure
d
Language Acquisition Device
If we do not teach syntax to toddlers, human brains must contain a
language acquisition device (Chomsky, 1957;1980), an innate module that
allows young children to develop language if they are exposed to an
adequate sampling of conversation.
Children are born with universal grammar or a sensitivity to the core
features common to all languages. Examples include nouns and verbs,
subjects and objects, and negatives.
Evidence Supporting the LAD
Combine words in ways adults never would.
Learn to speak or sign correctly although adults do not
correct syntax.
May invent their own language when not exposed to an
adult language.
Can derive simple linguistic rules from a string of sounds at
as early as 7 months of age.
Evidence for Learning and Language
Computerized neural networks can “learn” aspects of language.
Children learn the probability that any given word or syllable will follow
another.
Although there are commonalities in language acquisition, there are also
many differences.
Parents respond to children’s errors by restating or elaborating on the
phrase.
Children imitate these adult recasts and expansions
Sociobiology
Interdisciplinary field that emphasizes
evolutionary explanations of social behaviour.
Humans behave in ways that maximize our
chances of passing on our genes, and to help
our close biological relatives do the same
Evolution and Sexual Strategies
Due to different kinds of survival and mating
problems, the sexes have evolved differently in
three areas:
1. Aggressiveness
2. Physical dominance
3. Sexual Strategies
Differences in Sexual Strategies
Males
Females
Males Want sex more often. Are fickle and promiscuous. Drawn to sexual novelty and even rape. Are undiscriminating in partner choice. Concerned with competition and dominance
Females Want sex less often. Are devoted and faithful. Drawn to stability and security. Are cautious and choosy in partners Less concerned with competition and dominance.
Evolutionary Psychologists and the Question of
Gender
Evolutionary psychologists consider such analogies of
human and animal behaviours simplistic and
misleading.
Focus more on commonalities of human mating and
dating around the world.
Culture and the “Genetic Leash”
Criticisms of sociobiological and evolutionary explanations for sexual
behaviour include:
Criticisms of sociobiological and evolutionary explanations for sexual
behaviour include:
1. Evolutionary explanations of infidelity and monogamy are based on
stereotypes.
2. Actual behaviour of humans and other animals fails to conform to images
of promiscuous males and coy females.
- Human sexual behaviour is too varied to be explained solely from an
evolutionary perspective.
4. Previous Sampling Methods May not have Been Representative Prior to 2006 the U.S. Center for Disease Control (CDC) interviewed only men Male opinions often failed to conform to stereotypes
- Reporting Errors (What People Say vs. What they do)
Answers to hypothetical questions do not always
predict people’s feeling or actions in real life
situations
6. Historically, available mates for selection were much fewer than they are today. Human beings select mates based on: Similarity Proximity
The Genetics of Difference
The meaning of heritability:
A statistical estimate of the proportion of the total variance in
some trait that is attributable to genetic differences among
individuals within a group.
Expressed as proportion (.60 or 60/100)
Maximum value is 1.0
Some variables such as height are highly heritable, other variables
such as musical ability are moderately heritable.
Facts About Heritability
An estimate of heritability applies only to a particular group living in a
particular environment.
Heritability estimates do not apply to individuals, only to variations
within a group.
Even highly heritable traits can be modified by the environment
Computing Heritability
If identical twins are more alike than fraternal twins, then the increased
similarity must be due to genetic influences.
Computing Heritability
Investigators have also studied identical twins who
were separated early in life and reared apart.
Any similarities in traits between them should be
primarily genetic and should permit a direct
estimate of heritability.
Our Human Diversity: The Case of Intelligence
Genes and individual differences
Intelligence Quotient (IQ)
Intelligence Quotient (IQ)
Measure of intelligences originally computed by dividing a person’s
mental age by his or her chronological age and multiplying result by
100, now derived from norms provided for standard intelligence
tests.
The kind of intelligence that produces high IQ scores is highly heritable
.50 for children and adolescents
.60 -.80 for adults
B
Twins and Intelligence
Intelligence scores of identical twins are always more highly
correlated than those of fraternal twins.
The scores of adopted children are highly correlated with their biological
parents.
The Question of Group Differences
Genetics are used to explain differences
between groups.
These differences are used to justify
differential treatment for these groups For
example: Differences between average IQ
scores for African Americans and Caucasian
Americans.
Genetic explanations have a flaw: They use
heritability estimates based on white samples
to estimate the role of heredity in group
differences.
The Question of Group Differences
Those studies overcoming past methodological
problems fail to reveal genetic differences
between blacks and whites on IQ.
Examples:
Children fathered by black and white
American soldiers in Germany after WWII
and reared in similar German communities
did not differ significantly in IQ.
Black and white infants perform equally well
on tests for novelty.
Bi
The Environment and Intelligence
Experiences that hinder Poor prenatal care. Malnutrition. Exposure to toxins. Stressful family circumstances. Experiences that help Good health care and nutrition. Mental enrichment in home, child care, and school. Biol
Beyond Nature Versus Nurture
Heredity and environment always interact to
produce the unique mixture of qualities that
make a human.
Psychological diversity is adaptive
