Genes and Environment

• intelligence

• temperament/personality

• behavioral differences

Developmental behavior genetics focus on explaining individual differences among children and study what three things?

to try to reveal the contributions of inherited genes (hereditary influences) and environmental influences

What is the goal of developmental behavior genetics?

genotype

genetic composition of individual

phenotype

visible, observable, measurable characteristic

phenotype

Psychologists cannot directly measure genotypes for complex characteristics. They can only study ___________.

observable

Our ___________ behavior is a function of both genes and environment.

1 egg and 1 sperm - the egg splits into 2 and each twin share 100% of the DNA

How are identical twins made?

100%

How much of the DNA do monozygotic twins share?

50%

How much of the DNA do dizygotic twins share?

2 eggs and 2 sperm

How are fraternal twins made?

True

True or False? Full biological siblings share the same DNA as fraternal twins

more, adopted

If intelligence is heritable:

Monozygotic twin pairs should be _____ similar in intelligence than dizygotic twin pairs.

Biological siblings should be more similar in intelligence than ________ siblings.

genetic

If we get a heritability of 60% that means that 60% of the variation in that trait in the population is due to ________ influence.

populations

Heritability applies to __________, not individuals.

Heritability is not set in stone because there are external factors controlling things.

Strong heritability does not imply a lack of modifiability meaning what?

intelligence

Heritability of ____________, based on twin and adoption studies, is estimated to be about 60%.

School: courses, location of school, student/teacher ratio, funding

Neighborhood (violent/unsafe), funding

Parents: reading to their kids, helping them with their homework

Friends: highly motivated friend has a good influence on a kid

What are some environmental factors that might influence intelligence?

30-40%

What % is heritability of personality?

intelligence

Which is MORE heritable? personality or intelligence

Yes, 60-70%

Does the environment have a significant influence on personality?

no

Are children growing up in the same household very much alike in personality?

No. The environment of siblings is different, different things affect different people

ex. abusive household could cause one kid to be shy at school and another to be more outgoing at school, maybe because they are afraid to talk at home

Are environmental influences on personality shared or not? Provide an example.

Gottesman

interested in how genes and the environment apply to our development as individuals

limits, environment

ex. genotype determines we have an outgoing personality, but environment determines how outgoing we actually are.

Gottesman: Our genotype sets _______ on the attributes or behaviors that an individual may display, but our _____________ will determine where our attributes or behaviors lie within that range.

genes; Gottesman

Who says this? Range is determined by ______; actual trait/ability within that range determined by environment

Enriched, Normal, Restricted

What are the three types of environment from greatest to least exposure that have an impact on where our traits/attributes lie within the range?

Gottesman

gene-environment correlation - Scarr and McCartney

There is a connection/association between the genes we inherit and the environment in which we grow up; our genes influence what our environment is

what is this and who says it?

passive, reactive/evocative, active/niche-picking

What are the 3 types of gene-environment correlation?

passive

type of correlation: parents (who are genetically related to their child) will provide an environment for their child which are related to their child’s genotype

ex. extroverted trait is passed on; parents create environments where they are always being social (parties, get togethers)

reactive/evocative

type of correlation: the child’s genotype (temperament/intellectual capacities) will influence how people react to him or her

ex. Ex. introverted child, people react by not talking to them too much

active/niche-picking

type of correlation: people seek out environments that they find compatible and stimulating - our choices are correlated with our motivational, personality, and intellectual attributes; we create our own environments

Ex. teens who are intellectually curious will go to college

Ex. A child who inherits “high IQ genes” will have inherited them from “high IQ parents” who will provide an intellectually stimulating environment (+ correlation between genes and environment)

Ex. highly extroverted parents pass on extroverted personality traits to the child and create an environment where they are always talking to people like inviting people over all the time, having parties, etc.

What is an example of passive correlation between genes and the environment?

Ex. extroverted child, very talkative, people react to them by being talkative back

Ex. introverted child, people react by not talking to them too much

Ex. Inquisitive students receive more instructional interactions from teachers (asking them more questions, challenging them)

What is an example of reactive/evocative correlation between genes and the environment?

Ex. teens who are intellectually curious will go to college

Ex. athletic child wants to be on a travel team, wants to go to the gym, wants to play sports; seeks out opportunities

Ex. an extroverted child wants to meet new people, go to parties, etc.

What is an example of active/niche-picking correlation between genes and the environment?

the environment parents provide is more important in infancy since infants cannot choose their own environments

Why does passive correlation decrease with development?

when children are older they move more beyond the family’s influence and seek out their own environments – their own friends, their own activities

Why does active/niche-picking correlation increase with development?

we are always eliciting responses from others based upon our own characteristics/attributes

Why does reactive/evocative correlation stay the same across development?

microsystem

interaction between the child and the child’s immediate environments

mesosystem

connections between/among the child’s immediate settings (microsystems)

exosystem

settings that affect but do not contain the child

macrosystem

values, laws, customs of culture

Microsystem, mesosystem, exosystem, macrosystem

environmental influence: Bronfenbrenner’s Ecological Systems Model

home: parents, siblings|schools: teachers, peers|church|library|museum|after-school spaces

What are some examples of microsystems?

two microsystems = parents and teachers

- parent doesn’t like the teacher, talks bad about the teacher to the child, influences the child to not follow the teacher’s rules

- OR parents and teachers have good relationships and communicate about the needs of their child, influence the child positively

- two microsystems = parents and friends

- parents don’t like the friends, forbid the child to hang out with those friends

- parents like the friends, encourage the child to hang out with the friends

What are some examples of mesosystems?

- parent workplace (parent has to work long days, has a stressful job, difficult relationship with colleagues, takes it out on the child

- schoolboard (doesn’t directly interact with the child but still has an effect on the child, ex. COVID online schooling, sports, programs)

What are some examples of exosystems?

ex. Driver’s license age, drinking laws, child labor laws, education culture

What are some examples of macrosystems?