Week 4 - Statistics and Biological Approach

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Questions and Answers

What is the primary goal of behavioural genetics?

To understand how genetic and environmental factors interact to produce a particular trait

To identify the specific environmental factors that influence a particular trait

To determine the exact genes responsible for a particular trait

To determine the percentage of individual differences resulting from genetic and environmental factors (correct)

What is the term for the effect of a variable on another variable, which is influenced by a third variable?

Mediation (correct)

Interaction

Moderation

Correlation

What is a limitation of using genetic relatedness to study the influence of genetics on a particular trait?

It is prone to bias due to shared environment (correct)

It is only applicable to twin studies

It is difficult to measure genetic relatedness

It is not applicable to human studies

What is the term for the effect of a variable on another variable, which varies depending on the levels of a third variable?

Moderation Signup and view all the answers

What is a key challenge in determining the genetic contribution to a particular trait?

Separating the effects of genes and environment Signup and view all the answers

Why is it difficult to obtain definitive evidence in behavioural genetics?

The complexity of genetic and environmental interactions Signup and view all the answers

What is heritability?

The proportion of phenotypic variance that is attributed to genotypic variance Signup and view all the answers

What is the main assumption of twin studies?

That twins have equal environments and representativeness Signup and view all the answers

What is the purpose of adoption studies?

To study the genetic influence between biological parents and adopted children Signup and view all the answers

What do behavioural geneticists try to determine?

The degree to which individual differences in personality are caused by genetic and environmental differences Signup and view all the answers

What is the limitation of heritability?

It is not applicable to single individuals Signup and view all the answers

What is the finding in twin studies that suggests heritability?

Identical twins are more similar than fraternal twins Signup and view all the answers

What is the problem with using twin studies to estimate heritability?

The assumption that twins have equal environments and representativeness may not be true Signup and view all the answers

What is the term for the proportion of observed variance in a group of people that can be attributed to environmental factors?

Environmentalality Signup and view all the answers

What is a characteristic of non-invasive methods in personality research?

They are inexpensive and easy to use Signup and view all the answers

Which personality trait is associated with sensation seeking?

Extraversion Signup and view all the answers

What is a key feature of shared environments in personality research?

They are shared by siblings in a family Signup and view all the answers

According to Galen, which bodily fluid was associated with personality?

Phlegm Signup and view all the answers

What can brain activity measurements reveal about personality?

Responses to various stimuli, including emotional and cognitive tasks Signup and view all the answers

Which personality trait is associated with emigration?

Extraversion Signup and view all the answers

What is a limitation of non-shared environments in personality research?

They are unique to each individual Signup and view all the answers

What is a common method used to measure physiological responses in personality research?

Cardiovascular activity measurements Signup and view all the answers

What is the main assumption in the nature-nurture debate?

The number of genes that are actually different between individuals is small. Signup and view all the answers

What is the purpose of the twin study in the nature-nurture debate?

To demonstrate the influence of genes on personality traits. Signup and view all the answers

What is Phineas Gage known for?

His improbably survival of an accident in which a large iron rod was driven through his head. Signup and view all the answers

What is the term for the differential responses of individuals with different genotypes to the same environment?

Genotype-environment correlation. Signup and view all the answers

What is the result of the twin study in terms of the similarity of twins reared apart?

They are still similar as adults. Signup and view all the answers

What is the main controversy in the nature-nurture debate?

The ideological concerns surrounding the debate. Signup and view all the answers

What is the term for the environment that is only relevant for the discussion of group-level variation?

Equal environment assumption. Signup and view all the answers

What is the term for parents providing both genes and environment to children?

Passive genotype-environment correlation. Signup and view all the answers

What percentage of personality traits is estimated to be heritable?

30-50% Signup and view all the answers

Which of the following personality types is associated with an abundance of yellow bile?

Choleric Signup and view all the answers

What is the effect of a woman's presence on men's testosterone levels and physical risk taking?

It increases testosterone and increases physical risk taking Signup and view all the answers

Which of the following neuroimaging techniques is used to study brain activity?

All of the above Signup and view all the answers

What is the term for the interaction between genetic and environmental factors that influences personality traits?

Genotype-environment interaction Signup and view all the answers

What type of analysis can be used to study the biological basis of personality traits?

All of the above Signup and view all the answers

Study Notes

Behavioural Genetics

The goal of behavioural genetics is to determine the percentage of individual differences that can be attributed to genes vs. environment.
Heritability is the proportion of phenotypic variance that is attributed to genotypic variance.
Heritability cannot be applied to a single individual, only at a population level.
Heritability is not a constant or immutable value, and something may have happened that has never been seen before.

Environmentality

proportion of observed variance in group of individuals attributable to environmental variance. How much can the environment explain?

Nature/Nurture

Influence of genes and of environment is only relevant for the discussion of group level variation.

Moderation and Mediation

Moderation: the effect of A on B varies depending on levels of C (e.g., 2x2 ANOVA).
Mediation: the effect of X on Y is a function of M (causal pathways/experimental condition).

How do we find out? (METHODS)

Family Studies

Similarity on trait dependent on degree of genetic relatedness
If a trait is highly heritable then family members with greater egenetic relatedness should be more similar to one another
Shared environment confounds this similar parenting style/same school/same nutrition
Not great for definitive evidence

Twin Studies

Twin studies estimate heritability by comparing identical (MZ) and fraternal (DZ) twins.
Assumptions of twin studies include: equal environments, representative samples
Can be confounded because twins have different experiences.

Adoption Studies

Adoption studies provide evidence for environmental influence by comparing adopted children and their biological parents.
Removes the equal environment assumption
selective placement of. children combined with twins reared apart - still similar as adults

Genetics and Personality

A small number of genes are different for different individuals.
These different genes include genes that indirectly code for physical traits and personality traits.
The number of genes that are actually different is small.

Shared and Non-Shared Environments

Shared environment: features shared by siblings in a family environment, which have little impact on personality.
Non-shared environment: features of the environment that differ across siblings, which have a significant impact on personality.

Physiology and Personality

Physiological measures can include: cardiovascular activity, brain activity, and biochemical analyses.
Examples of physiological measures include: heart rate, blood pressure, and EEG/PET/fMRI scans.

Historical Theories of Personality

Galen's four temperaments: phlegmatic, melancholic, choleric, and sanguine.
Each temperament was associated with an imbalance of bodily fluids (phlegm, black bile, yellow bile, and blood).

Other Factors

Presence of a woman can elevate testosterone and physical risk-taking in men.
Genotype-environment correlation: differential responses of individuals with different genotypes to the same environment.
Genotype-environment interaction: the effect of a genotype on a phenotype is dependent on the environment.

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