Exam 2 Flashcards
(107 cards)
Define Heritability
= the proportion of variance in phenotype that can be accounted for by variance in genotype
○ conduct behavioral genetics research
○ additive genetic effects (influenced by both mother and father)
Define Sexual strategies theory
= presence of father in home affects relationships in mate preference
-perspective of resources being temporary
Ex: absent father
-more partners, children earlier, sex earlier
Example of individual differences: What is the most heritable thing we have discussed?
Height
Heritable: 90% (.90)
Environment: 10%
-diet and nutrition
Yes or no: Can the amount of heritability for specific traits be applied on a personal level?
No
Ex:
On an individual level, ones height isn’t 90% heritable and 10% environment
Define the heritability of openness
= the extent to which differences in openness can be accounted for by differences in genes
List of clarifications on heritability to know:
§ Heritability can’t be applied to a single individual
§ Heritability is not constant
§ Heritability is not precise
§ Nature vs Nurture
Define Genotype
= a person’s total collection of genes
□ Variance in genotype = people differ in which genes they have
Define Phenotype
= sum of all of a person’s observable traits
○ The outcome or what is manifested from genes
○ Things observed in the world
○ Ex: height, personality, intelligence
○ Variance in phenotype = people differ in looks, personality, IQ, etc.
(Differences between people)
To what degree is variability in language spoken due to variability in genes or in the environment?
Specific language spoken is due to culture and the environment in which someone is exposed to
Personality characteristics are 30-50% heritable. Which are the ones over 50% heritable?
- Extraversion 60%
* Neuroticism 54%
* Big Five 50%
* Temperament 50%
* Aggressiveness 50-70%
* Alcoholism 50-70%
* Violent crime 50%
Personality characteristics are 30-50% heritable. Which are the ones under 50% heritable?
- General well-being 38%
- Self-esteem 32%
Partner preferences 10%
Clarifying Nature vs. Nurture: Individual level. Which is more important, genes or the environment?
Neither one is more important; both genes and environment are necessary
® Each individual contains genes, and those genes need environments in order to be expressed
®Ex: Like asking whether a finished cake is “caused” more by the eggs or the flour
Clarifying Nature vs. Nurture: Group level. Which is more important, genes or the environment?
One may be more important than the other, on average, to explain certain characteristics
Ex: If you have 100 cakes, it makes sense to ask whether the differences among the cakes in, say, sweetness is caused more by differences in the amount of flour used or by differences in the amount of sugar used
Pros on Implications of Heritability:
□ Our genetics have real and important influences on our lives
○ Genetics research gives us important knowledge
○ Ex: When making decisions about your own health (skin cancer, problematic drinking, etc.)
○ People can be aware of/ prepare based on their genetic propensities
○ Genetics research is important because of the knowledge it gives us about truths that have practical implications for our lives.
- Adopting
- Health
- Understand themselves better
Cons on Implications of Heritability:
□ If we believe personality is predetermined by genetics…
-People may feel less responsible for harmful behavior
-People may not put in as much effort
-Eugenics- only certain people are allowed to live/reproduce
-Potential for misuse of findings from genetics research
Where do personality estimates come from? / What are the methods of behavioral genetics? (4)
-Selective breeding/ artificial selection
-Family studies
-Twin studies
-Adoption studies
Methods of behavioral genetics: Selective breeding
○ Only works if the desired traits are at least somewhat hereditary
○ physical qualities like webbed paws or behavioral/personality like friendliness
○ Artificial selection= man made
○ Labrador retriever vs. Chesapeake bay retriever
○ The fact that selective breeding has been so successful with dogs tells us that heredity must be a factor in the personality traits, such as boldness, aggressiveness, agreeableness, and desire to please, that were successfully selected.
Methods of behavioral genetics: Family studies
○ Parents, children, and siblings share 50% of their genes
○ Grandparents and grandchildren share 25%
○ First cousins share 12.5%
○ If a trait is highly heritable, then family members who possess that trait will be more similar to those to whom they are more closely related than those to whom they are more distantly related
○ Ex) If a parent is highly agreeable, then we can infer the kids might be agreeable. We cannot infer the same for nieces and nephews
What are the downsides of family studies?
○ Downside is that family members who share the same genes also typically share similar environments. Two members of a family might be similar not because a given personality characteristic is heritable, but rather because of a shared environment. For example, certain brothers and sisters may be similar on shyness not because of shared genes, but because of shared parents.
Methods of behavioral genetics: Twin studies
○ Identical twins (Monozygotic)
○ 100% of genes the same
○ Fraternal twins (Dizygotic)
○ 50% of genes the same
(like normal siblings)
○ Whether identical or fraternal, they share similar environments most of the time
○ But different level of genetic relatedness
If identical twins are more similar than fraternal twins on any given trait, then that trait is more heritable
(similarity score between 2 identical - similarity score between 2 fraternal)
Methods of behavioral genetics: Adoption studies
○ Give tests to adopted children
○ Ex: personality, IQ
○ Give the same tests to adoptive parents and biological parents
○ If children are more similar to their adoptive parents on a trait, that trait is more environmental
○ If similar to biological parents…genetic
With adoption studies tend to see adoption children are more similar to their biological parents then their adopted parents
What are the two types of environmental influence?
Shared vs non-shared environment
Define shared environment
= non-genetic influences that make siblings more alike
○ Ex: divorce, school, neighborhood, parents’ income
○ Smaller factor influencing personality
○ Traits that have a substantial shared-environment influence:
□ Religious beliefs
□ Political orientation
□ Health behaviors
◊ Smoking & drinking
□ Antisocial behavior
◊ Ex: breaking the rules
□ Depressive symptoms
Define non-shared environment
non-genetic influences that make children more different
○ Friend group, hobbies, other differences due to age difference