ch. 4 nature, nurture, human diversity

behavior genetics

the study of differences between humans related to heredity and the enviornment

What is heredity?

The genetic transfer of characteristics from parents to offspring

What is the enviorment?

every nongenetic influence

examples of heredity

hair color, eye color, disorders & diseases

examples of environment

prenatal nutrition, influence of friends, education

What are animals and plants made up of?

genetic material, which is contained in every cell of the body

Genetic code

contains 23 sets of chromosomes composed of DND

DNA (deoxyribonucleic acid)

double-helix-shaped structures, composed of genes

What happens when genes are expressed?

they “turn on” and begin to produce proteins that serve as building blocks within the body

polygenic

no one particular gene contributes to one particular trait

identical (monozygotic)

1. form from one sperm fertilizing one egg, then splitting

2. genetically identical

3. can only be the same sex

fraternal (dizygotic)

1. formed from two sperm and fertilizing two eggs

2. genetically the same as normal siblings

3. can be the same or different sexes

Do you think people who grow up together will be more alike in personality?

1. people who grow up together are not necessarily alike in personality

2. adopted children tend to be more similar to their biological relatives in certain personality traits

3. shared family environment has little impact on someone’s personality (unless environment is extreme)

Why bother parenting at all?

parenting might not affect personality, it has been found to impact other things

temperament

is our emotional reactivity and intensity

heritability

the extent to which variation among individuals in a group can be contributed to their differing genes

What is NOT heritability?

what percent of your personality is due to genes

What IS heritability?

how much of the difference between individuals can be contributed to genetics

molecular behavior genetics

the study of how the structure and function of genes interact with environment to influence behavior

epigenetics

is the study of the molecular mechanisms by which environments can “turn on” or “block” genetic expression

Epigenetic markers

are the molecules that tell genes what to do

epigenetic effects

can be passed on to future generations

What can be changed DNA or epigenetics?

epigenetics

evolutionary psychology

the study of the evolution of behavior and the mind, using the principles of natural selection

natural selection

Inherited traits that better enable an organism to survive and reproduce in a particular environment will most likely be passed on to future generations

fitness

ability to survive and reproduce

mutation

random error in gene replication that lead to change

Where does the shared human genome come from?

according to evolutionary psychology, we are genetically predisposed to think and act in ways that promote survival and reproduction

natural brain maturation

provides us with an abundance of neural connections

experiences

activate and strengthen pathways

pruning

involves neural connections weakening from disuse

Who has the largest effects at extremes?

parenting: tends for children to share their parents politics, religion, and values

culture

the behaviors, ideas, and values shared by a group of people and passes down from generation to generation

cultural norms

understood rules for accepted and expected behaviors

tight cultures

higher obedience to norms

loose culture

more variability in behavior

culture shock

we do not understand what is expected or accepted in a new culture

How can culture change over time?

due to lifestyle and inventions

individualist cultures

• Emphasize personal goals and define identity in terms of unique personal attributes

• in groups, emphasis is placed less on group harmony and social duty

• value free will and move in and out of social groups more easily

collectivist cultures

• Prioritize the goals and needs of the group rather than individual needs and identify themselves in terms of their roles in the group

• find satisfaction in advancing the group’s interests

• emphasize norms centered around humility rather than self-importance

gender roles

the social expectations that guide people’s behaviors in relation to their gender

gender identity

is a person’s personal sense of being male or female