Midterm 2 Flashcards
Ideological concerns?
Research used.misused to make ideological point
Eugenics?
- Is the notion that we can design the future of the human species by
- Fostering the reproduction of people with certain traits
- Discouraging the reproduction of people without those traits
Heritability?
- extent to which genetics predict behaviour or trait
- How much do genetic differences among individuals cause differences in something, such as height, extraversion, or sensation seeking.
inherited?
Behaviour or trait is determined by genes alone
Heritable vs. Inherited
- Physical features (such as height) are largely heritable, but not inherited
- Example: if both your parents are 5’2”, it doesn’t mean you will be exactly 5’2”
Our genes?
- 90% of genes inherited are same across species (all human share these)
- 10% differ across species
Genotypic Variance?
Genetic variance that is responsible for individual differences in the phenotypic expression of specific traits
Environmentality?
Percentage of observed variance in a group of individuals that can be attributed to environment
Cake Metaphor?
- Cake metaphor: You bake a cake with flour, sugar, eggs, and water
Is the finished cake caused more by the flour or the eggs? - Both needed, combined and cannot be separated from finished cake
What Heritability Means?
- Heritability estimates are tied to a place and time
- If everyone in a population has exactly same environment, then influence of genotypes will tend to be greater
- If environment differs greatly across people in a population, then influence of genotypes will be less
Traits are influenced by Genotypes?
- Does not mean that genes influence behaviour directly
- Perhaps genes influence physical or physiological characteristics, which influence behaviour & personality
Selective Breeding?
- Can only occur is a desired trait is heritable
- Selective breeding studies of digs (or other animals)
- Cannot be ethically conducted with humans
- You can think different personality traits of dogs and different breeds (or other animals)
- Dog personality questionnaire
Family Studies?
- Correlates the degree of genetic overlap among family members with the degree of similarity in personality trait
- if a trait is highly heritable
- Family members with greater genetic relatedness should be more similar to one another on the trait than family members who are less closely genetically related
Family studies Limitations?
- Members of a family who share the same genes also usually share the same environment – confounds genetic with environmental influences
- This doesn’t mean people can have different environmental influences within a family
- Thus, family studies are never definitive
Twin Studies?
- Monozygotic (MZ) twins are identical twins
- Dizygotic (DZ) twins are fraternal twins
- MZ share 100% of genes
- DZ share 50% of genes that vary across species
- Same as siblings of same parentage
-If MZ twins are more similar than DZ twins, this provides evidence of heritability - Calculating heritability estimates
- Different ways to do it
Twin Heritability Estimates
- Because MZs share same genes, differences in phenotypes (traits) can only be attributed to “environment”
- Differences between Twin 1 and Twin 2 not due to genes; therefore, due to “environment” - Differences in phenotypes between pairs of DZ twins can be attributed to different genes for different “environment”
- Some of the genes are different between DZ twins
Twin Study Limitations?
- Equal environments assumption: The twin method assumes that the environments experienced by identical twins are no more similar to each other than are the environments experienced by fraternal twins
- General support for this assumption, but it is an ongoing concern with this kind of research
- Representativeness: The experience of twins is not representative of the general population (i.e., generalizability)
Adoption Studies?
- Positive correlations on traits between adopted children and adoptive parents provide evidence of environmental influence
- Positive correlations on traits between adopted children and genetic parents provide evidence of genetic influence
- Adoption studies are powerful because they can disentangle genetics and environment a bit more
- Biological parent and child: are they the same because of genetics or environment?
- Generalizability still a concern
Problem of selective placement of adopted children
Adoption Twin Studies?
- Combine twin & adoption studies
- Mz Twins raised in the same environment (reared together)
- MZ Twins raised in different environments (reared apart) - MZ reared apart unlikely to have same environments as MZ reared together
- Minnesota Study of Twins Reared Apart
- 1979 by Tom Bouchard
- Newer twin studies continue at University of Minnesota today
Sexual Orientation?
- Sexual orientation: refers to one’s sexual and/or emotional attraction to others based on their sex or gender. Identities associated with sexual orientation include gay, lesbian, bisexual, pansexual, asexual, etc
Shared environment?
- in family environment, features of the environment shared by siblings
- E.g., Kids in same family have same SES, go to same schools, share same child rearing
Nonshared environment?
- In family environment, features of the environment that differ across siblings
- E.g., different friends, different teachers, different teachers, different relationship with parents
Genotype-Environment Interaction?
- People with different genotypes can respond differently to the same environments
- Example: Task performance of introverts versus extraverts in loud versus noisy conditions - People with different genotypes exposed to different environments
- Example: How often do you go to parties or not? Extraverts may opt into these environments more often
What are the three types of Genotype-Environment correlation?
- Passive
- Reactive
- Active