Problem 5

Question 1

Heritability

Answer 1

Is a descriptive statistic that indicates the degree of population variation of a trait, that is due to genetic differences

Question 2

Complement of heritability (1-h2)

Answer 2

Indicates the degree of population variation of a trait, that is due to environmental influences

Question 3

What kind of studies are used to measure/ estimate the heritability of various traits ?

Answer 3

Twin + adoption studies

Question 4

Nuisance variables

Answer 4

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

Question 5

How much does genetic vs environment influence personality traits ?

Answer 5

Increased genetic influence with age + decreasing shared environmental influence

–> environmental factors often decrease to 0 after adolescence

Question 6

Why have personality + individual differences been neglected ?

Answer 6

1. Cogent evolutionary theories existed for predicting + explaining sex differences
   ex. : sexual selection
2. Assumption that natural selection has reduced/eliminated heritable individual difference because traits that are advantageous tend to spread over tome to fixation

Question 7

Which theories are able to explain personality and individual differences (variation) ?

Answer 7

1. Life history theory
2. Costly signaling theory
3. Environmental heterogeneity
4. Frequency dependent selection
5. Mutation load
6. Contingent shift

Question 8

Life history theory

Answer 8

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

Question 9

Costly signaling theory

Answer 9

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

Question 10

Balancing selection

Answer 10

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

Question 11

Frequency dependent selection

Answer 11

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

Question 12

Role of Mutation load in heritability ?

Answer 12

Heritability of some traits originates from individual differences in mutation load

–> explains some harmful mental disorders

Question 13

Environmental heterogeneity/ Flucturating optima

Answer 13

Environmental conditions can vary from time and place therefore, the traits favored by natural selection can change/fuctuate as well

–> variation in personality traits

Question 14

Contingent shift

Answer 14

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

Question 15

Stabilizing selection

Answer 15

Exists when selection favors a trait that is intermediate within the range represented within a population

–> most common trait is selected + continues to dominate

Question 16

Adoption studies

Answer 16

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

Question 17

Intraclass correlation coefficient

Answer 17

Assesses the correlation between relatives

–> variance between families, as when the variance is high between families then the similarities are high within families

Question 18

Twin studies

Answer 18

Assesses differences in personality between twins that shared the same environment

–> to assess the degree of environmental impact by looking at the differences

Question 19

Additive effects

Answer 19

Each gene separately contributes to personality

Question 20

Nonadditive effects

Answer 20

Combined effects of genes contribute to personality

Question 21

Combination designs

Answer 21

Refer to combination of different study forms

e.g.: adoption-twin, families-of-twins method

Question 22

Adoption twin design

Answer 22

Twins adopted apart are compared to twins raised together

–> show little shared environment influences

Question 23

Families-of-twins method

Answer 23

bla

Question 24

Genotype environment interactions

Answer 24

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

Question 25

Genotype-environment correlation

Answer 25

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

Question 26

Contrast effect

Answer 26

Refers to the tendency to emphasize differences between realtives

ex.: siblings comparing each other than to general population

Question 27

Assimilation effect

Answer 27

Refers to the tendency to emphasize similarities between relatives

ex.: father sees sister as similar

Question 28

Pros vs cons of adoption studies ?

Answer 28

PROs

1. 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

Question 29

Pros vs cons of twin studies ?

Answer 29

PROs

1. Compares mono + dizygotic twins

CONs

1. Assumes that the environment is the same, which doesn’t necessarily has to be
2. Assumption of representativeness