PSYC 190 - Adoption & Behavior Genetics

Adoption Overview

In some cases biological parents who become pregnant unintentionally may feel that they’re just too young to be parents

Almost 90% of adopted children are born to never married mothers, some may be struggling with money, some may simply prefer to not have children but also not wish to terminate their pregnancy

Adoption Study on anti-social behavior

Swedish researchers examined rates of alcoholism in adopted children and how this was related to alcoholism in the biological and adoptive parents.

One study included 900 boys, in another study by the same others girls were studied with similar findings

What were the finding of the Swedish alcoholism study?

finding #1: adoptees had a significantly greater risk of alcohol abuse if their biological parents were alcoholic but that there was no effect of adoptive parents’ drinking habits

finding #2: if non biological parents drank, their adopted children were sightly less likely to develop drinking problems

finding #3: found environmental effects ( biological father alcoholism rate 34%, adopted child: 18%) → this tells us that if your biological parent drinks, you’re not necessarily doomed to drink however it doesn’t remove your added risk

What acts like a setback in adoptions studies?

most adoptions studies are not like the swedish study because most of the time the biological parents remain anonymous at least to scientists

when children are adopted, even the adoptive parents often don’t know who a child’s parents were or what their medical psychological, or criminal histories were

Why is information about biological parents important in adoption studies?

without this information, it’s almost impossible to separate effects of nature and nurture

What was the Dutch adoption study?

146 kids adopted from Sri Lanka, South Korea and Colombia

this study was important for secure attachment and how it affects children’s social and cognitive development

they also measure their social and cognitive outcomes at the age of seven

How is secure attachment measured?

it’s often measure using what’s called the strange situation task.

What is the strange situation task?

Children, generally between the ages of 12 and 18 months, are brought into a lab with their caregiver and then are left alone in the room with an unfamiliar person. The research records the infant’s response to the strange situation, whether they show anxiety and distress or a willingness to explore and interact with the new person

what are the types of attachments?

secure attachment: avoids stranger if alone, not with mother

ambivalent attachment: always avoids stranger

avoidant attachment: always plays with stranger

Statistics on attachment

60 to 70% of 12 to 18 month old infants are classified as securely attached, with the remaining infants split between ambivalent and avoidant

What are the types of mother absent/separation anxiety?

secure attachment: distressed if mother leaves

ambivalent attachment: very distressed

avoidant attachment: no distress when mother leaves

What is maternal sensitivity?

when the mother returns, the researchers recorded the mother’s response to their infant, whether they accurately perceive their infants distress and respond appropriately

In the Dutch adoption study how did they test the social and cognitive outcomes?

1. They gave the kids a test, of general intelligence (G) / intelligence quotient (IQ)

2. they asked teachers to rate whether the children were anxious, depressed, aggressive, whether they worked hard and if they had problems with attention

What were the findings of the Dutch Study?

found a series of correlations between the early measures of maternal sensitivity and attachment and the later social and cognitive outcomes

securely attached children with sensitive and responsive mothers performed better in school, had higher IQs and were less prone to behavioral problems

parenting style caused different social and cognitive outcomes

Genetic information

acts as your developmental blueprint that is stored in your cells as DNA

spread over 23 pair of chromosomes (46 in total)

What is a gene?

a sequence of DNA at a specific location on the chromosome.

the location determines what the gene control (what traits it influences).

the specific DNA sequence determines exactly what effect it has on that trait.

What are alleles?

the different possible DNA sequences for any given gene (sometimes there are two, three or more possibilities out there in the population/gene pool)

What are sex cells?

called gametes, sperm and eggs

only contain one of each chromosome

Why do sex cells only contain one of each chromosome?

when we form on of these cells, one or the other copy of each gene is passed on to that specific sex cell

its random whether each gene comes from one chromosome or the other

each gene is randomly chosen from on chromosome or the other, independent of each other gene

What is a trait?

the combination of alleles that you wind up with influences your traits

a trait is simply any attribute of an organism that’s affeccted by your genes

Behavior genetics

what are the basic factors that might cause behavioral traits to emerge in children

tries to figure out how biology, shared environment and unshared environment contribute to differences between people

What is shared environment?

The environment that the child shares with siblings when raised together

captures things within a caregiver’s control, the effect that they have as parents (bedtime, diet, discipline, etc)

what is unshared environment?

the environment that the child doesn’t share with their siblings, all the experiences that are totally unique to them

captures things that happen outside the home, all of those things that are outside the realm of control of parents (behaviors of child’s friends, teachers, media, books, etc)

How do we test behavior genetics?

studies are designed to hold constant environment so that we can see the effects of genetic differences or to hold constant genetics, so that we can see the effects of environmental variation

What is the goal of behavior genetics?

studies are designed to hold constant environment so that we can see the effects of genetic differences or to hold constant genetics, so that we can see the effects of environmental variation

What is heritability?

refers to genetic influences underlying variation in particular traits (e.g., intelligence or personality etc.)

twins are used to estimate the degree of heritability on traits

if you compare the similarity of genetically identical twins to the similarity between non-identical twins to the similarity between non-identical twins or fraternal twins, this gives us an estimate of how much the genes influence how much people differ from one to the other

What is the effect of different environments on monozygotic twins that are raised apart?

twins raised apart, particularly identical twins, come with an array of fascinating similarities

Study case on twins who grew apart

Mark and Jerry grew up about 30-40 miles apart in New Jersey. Both were 6 foot 4, had wire-rimmed glasses, big mustaches. Both were volunteer firefighters and both had studied similar topics in school. Their personalities were perfectly aligned

Does a high heritability estimate mean that most of a trait like IQ is determined by genetics?

the word determined isn’t use but rather the word influence is used.

this is due to that fact that nothing is strict when it comes to human development

heritability is not a fixed estimate, but it’ something that varies from time to time based on historical and environmental events, based on the instrument, based on the population

What is Dr. Segal’s take on parenting?

Parenting does have an effect, its a mistake to assume that it doesn’t

she believes that '“your children bring you up, you don’t bring them up”, this means that if parents are responding to children’s own genetically based inclination

Does the selection process that adoptive parents go through limit the variability in parenting of adoptive kids?

Dr.Segal believes that the reason we see fewer parenting effects than anticipated is because parents are responding to the genetic inclination of their children

what are the two types of twins?

Identical: monozygotic twins

Non-identical: dizygotic twins

Why are identical twins called monozygotic?

because they rose from the same fertilized egg or zygote, and therefore they have basically all the same genetic material

Why are non-identical called dizygotic twins?

come from two distinct eggs and share only half of their genetic material

How can we use phenotypes of twins?

We can go into the world and get some real data to see how much monozygotic twins (MZ) and dizygotic twins (DZ) actually differ, we can compare their phenotypes and whether they differ if they’re raised together or in separate homes

What did the study between MZ and DZ concordance find?

studies estimate concordance around 60% for monozygotic twins and between 10 to 20 % for dizygotic twins

What do concordance rates tells us if they change depending on the study?

when monozygotic and dizygotic twins are raised apart rather than together, if the concordance goes down when they’re raised apart this suggests that parents have an effect and it tells us how much

if environment didn’t matter at all, we’d expect a concordance of 100% between MZ twins

if parents did matter we’d expect MZ and DZ twins to look more similar to one another than predicted just from genetic differences between them

What is another type of approach for twin studies?

we can compare DZ twins who shared the same prenatal environment to siblings who are not twins and didn’t share the same uterine environment

this can tell us whether stressful events or substances during pregnancy may be related to a later autism diagnosis

what is the basic goal of behavior genetics?

to pull apart how difference between people can be explained by differences in their genes and differences in their environment

it doesn’t necessarily tell us which genes matter ,which parent practices matter, or which other specific environmental factors matter

What are heritability estimates?

Calculations of how much genetic relatedness can explain differences between people and also estimates of how shared and un shared environment affect traits and behaviors too

what are the three basic conclusions of the behavior genetics field?

1. genes impact every behavior studied

2. parents often have little to no effect on outcomes

3. the effects of parenting wear off with age

What are the big five personality traits?

these traits are considered the most important and predictive of life outcomes

1. extraversion: outgoing, decisive, enjoys leadership

2. agreeableness: warm, kind, generous

3. conscientiousness: organized, responsible, dependable

4. openness: open to new experiences, curious, original

5. neuroticism: emotional unstable, nervous, irritable

   (OCEAN)

Does behavior genetics tell us that everything is predetermined by genetics and that the environment plays no role?

No, most studies show that at least half of the variability between people is caused by environmental factors and in some cases, much more

different experiences in the world clearly cause very different behavioral outcomes

What does genetic variability explain to us?

about half of the variability in traits and behaviors, parents contribute 5 to 10% of variability and other environmental factors explain the rest

what are some of the issues with behavior genetics approach? What are some of the critics on how we interpret heritability estimates?

1. heritability estimates can change over time as environment changes ( over historical time across cultures and even within individuals)

2. behavior genetics focuses on traits

3. adoptive families aren’t very variable

4. doesn’t isolate specific causal factors

How do heritability estimates can change over time?

ex: nutrition and height tall

with better access nutrition height of a population can change therefore heritability of height would change and the genetic influence is less significant

What are stable traits?

traits that could plausibly have strong genetic components

What does behavior genetics not isolate when considering it’s findings?

it doesn’t isolate specific causal factors and it doesn’t tell us which genes matter, which parenting practice matter, or what environmental factors matter