Problem 5 Flashcards
Heritability
Is a descriptive statistic that indicates the degree of population variation of a trait, that is due to genetic differences
Complement of heritability (1-h2)
Indicates the degree of population variation of a trait, that is due to environmental influences
What kind of studies are used to measure/ estimate the heritability of various traits ?
Twin + adoption studies
Nuisance variables
Refer to variables that are assumed to be causes of group/individual differences, but seemingly irrelevant to the theory of the investigator
–> closely related to heritability
How much does genetic vs environment influence personality traits ?
Increased genetic influence with age + decreasing shared environmental influence
–> environmental factors often decrease to 0 after adolescence
Why have personality + individual differences been neglected ?
- Cogent evolutionary theories existed for predicting + explaining sex differences
ex. : sexual selection - Assumption that natural selection has reduced/eliminated heritable individual difference because traits that are advantageous tend to spread over tome to fixation
Which theories are able to explain personality and individual differences (variation) ?
- Life history theory
- Costly signaling theory
- Environmental heterogeneity
- Frequency dependent selection
- Mutation load
- Contingent shift
Life history theory
States that we have a certain amount of energy throughout our life, that we try to allocate over the course of our life
–> some put more emphasis on kinship, some on multiple mating partners
e.g.: reproductive development and behaviors, post-reproductive behaviors, and lifespan
Costly signaling theory
States that people compete with one another by sending costly signals to others about their qualities
–> might explain conscientiousness, agreeableness, generosity etc
e.g.: to be able to be generous, one has to first have the ressources/affordances
Balancing selection
Occurs when genetic variation is maintained by selection
ex.: heterozygote advantage, where both alleles are maintained, as Aa will have a better chance of survival than AA or aa
Frequency dependent selection
Occurs when 2 or more strategies are maintained within a population at a particular frequency relative to each other, such that the fitness of each strategy decreases as it becomes increasingly common
ex.: Psychopathy, if only a few have these traits than those will consequently have an advantage, as opposed to when this is common
Role of Mutation load in heritability ?
Heritability of some traits originates from individual differences in mutation load
–> explains some harmful mental disorders
Environmental heterogeneity/ Flucturating optima
Environmental conditions can vary from time and place therefore, the traits favored by natural selection can change/fuctuate as well
–> variation in personality traits
Contingent shift
Refers the the ability to adapt psychological mechanisms in response to changes in environmental conditions
- selection favors those that are adaptive
- can occur in response to individual phenotypic qualities + environmental conditions
ex.: chef vs angestellt personality anpassen können
Stabilizing selection
Exists when selection favors a trait that is intermediate within the range represented within a population
–> most common trait is selected + continues to dominate
Adoption studies
Assessing differences in personality between pairs of genetically related individuals who don’t share a common environment
–> to assess the degree of genetic impact by looking at their similarities
Intraclass correlation coefficient
Assesses the correlation between relatives
–> variance between families, as when the variance is high between families then the similarities are high within families
Twin studies
Assesses differences in personality between twins that shared the same environment
–> to assess the degree of environmental impact by looking at the differences
Additive effects
Each gene separately contributes to personality
1 gene + 1 gene = 2 genes
Nonadditive effects
Combined effects of genes contribute to personality more than the genes individually
1 gene + 1 gene /=/ 2 genes
Combination designs
Refer to combination of different study forms
e.g.: adoption-twin, families-of-twins method
Adoption twin design
Twins adopted apart are compared to twins raised together
–> show little shared environment influences
Families-of-twins method
bla
Genotype environment interactions
The same environment influences peoples characteristics in different ways, depending on their genotype
ex.: the reason why relatives are not always similar to each other
Genotype-environment correlation (3)
Genetic tendencies cause you to be more exposed to a specific kind of environment
a) passive
- inheriting combination of genes passively, not as result of own behavior
ex. : athletic parents raise children in athletic environment passively
b) reactive
- other peoples reactions to childs genetic tendencies influence its environment
ex. : child runs around a lot; parents sign him up for soccer practices
c) active
- child actively chooses environment as a function of genetic predisposition
Contrast effect
Refers to the tendency to emphasize differences between realtives
ex.: siblings comparing each other than to general population
Assimilation effect
Refers to the tendency to emphasize similarities between relatives
ex.: father sees sister as similar
Pros vs cons of adoption studies ?
PROs
- Good way to measure the question at hand
–> only method we have
CONs
1. Assumption of representativeness
- assuming that adopted children + their parents are representative of the population
2. Prenatal environment is often not considered
3. Selective placement
- child may have been put in a family similar to the biological one
Pros vs cons of twin studies ?
PROs
- Compares mono + dizygotic twins
CONs
- Assumes that the environment is the same, which doesn’t necessarily has to be
- Assumption of representativeness
what are the life history theory strategies?
fast: (early reproduction age, shorter lifespan, many offspring with limited parental investment) favors resource allocation toward reproductive efforts -> machiavellianism and risk taking -> less related to prosocial motivations and behaviors
slow: favoring resource allocation toward continued growth and maintenance -> (+) correlated with EXACO and (-) correlated with neuroticism -> trait types of positive relationship attributes and attachment
what does allocentrism invovle?
define in reference to social entities to a great extent than idiocentrics
shows a negative correlation between O and X and shows a positive correlation between A and C
more ethnocentric
Socioecology
explain what the connections mean:
1. culture <–> personality
2. socioecology -> culture
3. socioecology -> personality
- the mutual constitution of culture and personality
- socioecology as one root of culture
- socioecology as one root of personality
Why does Variation not go away?
1) Variation has no consequence for survival & reproduction. As such, new mutations changing trait levels will persist
2) New Mutations do cause variation away from ideal levels of a trait, but natural selection does not trim mutations out faster than they appear
3) Parasitic infections spread less quickly if there is a great deal of within-species variation. See Bananas
Fluctuating Optimum
The ideal level of a trait might differ for different environments and thus be different overtime, in response to features of the current environment. The total amount of variation however will be relatively stable.
Parental Investment
In times of plenty, those who maximize quantity of offspring will be more successful
In times of shortage, its more likely for offspring to survive and thrive if the parents are there to help
Negative Frequency-Dependent Selection
When individuals having a give level of a trait become less successful when there are more of them in a population
Fluctuating Optimums and Frequency Dependence maintaing variation
1) Favoring reproductive success of individuals who have a genetic inclination towards a particular level of subject trait
2) Favoring the reproductive success of individuals whose genetic inclination is more flexible, allowing them to develop high/low levels of the trait depending on experiences in early development
Honesty-Humility throughout Life
Tends to decline during teen years and then increase through most of adulthood (60 year olds are 1 SD higher than 18 year olds on average)
Thoerized to be due to more potential gains in exploiting others during early-adulthood, declining with time
If the relatives are very similar to each other then the proportion of total variance due to within family differences is small, medium, or large? What about between family difference?
Very small - within
Very large - between
If the relatives are very different to each other then the proportion of total variance due to within family differences is small, medium, or large? What about between family differences?
Very large - within
Very small - between
Cross-national and cross-generational differences in average personality traits are usually not ____?
Very large
Socioecology complex hypothesis
The degree of personality co-variation observed within a society will be negatively associated with socioecology complexity
vertical collectivist
traditionalist and emphasizes in group cohesion, respect for in-group norms and directives of authorities
horizontal collectivist
emphasizes empathy, sociability , and cooperation
vertical individualistic
competitiveness is high one must be the “best” in order to climb hierarchy
horizontal individualistic
hierarchical difference is de-emphasized, emphasis on self-reliance, independence, and uniqueness
