Task 5 - Development of Personality

Question 1

Nature vs Nurture

Answer 1

Investigation of origins of variability of differences among people
-> whether individual differences only due to environmental circumstances or due to genetic differences

Question 2

Additive Genetic Effects

Answer 2

Each gene contributing separately to making one’s level of the trait a bit higher or lowe
-> combined effects: estimated by adding together separate effects

Question 3

Non-additive genetic effects

Answer 3

Multiplicative genetic effects:
different alleles contributing to a polygenic trait in different capacities
-> harder to calculate
-> if non-additive important: identical twins would be more than twice as similar as fraternal twins

Question 4

Common shared environment influences

Answer 4

Influence of common shared environment of similarity e.g. in twins:

• aspects of household
• socioeconomic status
• strictness of parents
• > more common influences: more similar (acc. to hypothesis)

Question 5

Unique environment influences

Answer 5

Features in environment differing even for individuals living in same household:
e.g. different friends, different treatment by parents

Question 6

Twin studies results

Answer 6

Identical twins (.45) twice as similar as fraternal twins (.20)
-> suggests additive heritability: no common or shared environmental effect

Question 7

Assimilation effect

Answer 7

Tendency to emphasize similarities between related persons

Question 8

Contrast Effect

Answer 8

Under/overestimating traits by only comparing with siblings but not others

Question 9

Assortative mating

Answer 9

No particularly high levels found

-> only in beliefs, attitudes and abilities

Question 10

Equal environments assumption

Answer 10

Identical twins not just more similar due to genetic material but also due to environments being more siilar
-> e.g. parents treating identical twins more similarly

Question 11

Effects of Unique environment on personality (twins)

Answer 11

Parental treatment & peer group: weak tendencies ~.15 correlation
Birth order: negligible differences

Question 12

Genotype- environment interactions

Answer 12

Genetic tendencies causing you to be exposed to some kinds of environments more than others

Question 13

Passive genotype environment correlation

Answer 13

experienced environment influenced by genetic predispositions

Question 14

Reactive genotype-environment correlation

Answer 14

environments depending on other people’s reactions to genetic tendencies

Question 15

Active genotype-environment correlation

Answer 15

children seeking out themselves particular environment due to genetic tendencies

Question 16

Fluctuating Optimum

Answer 16

Ideal level of characteristic depending on environmental conditions
-> can change with time and might depend on place

Question 17

Frequency Dependence

Answer 17

Rough balance in population between individuals who have higher and lower levels of the characteristic
-> when there is no single ideal but balance between both extremes

Question 18

Negative-frequency dependent selection

Answer 18

When a trait is only adaptive when in minority (e.g. cuckolding)

Question 19

Frequency-dependency of personality

Answer 19

All Hexaco dimensions are frequency-dependent/fluctuating optimum
-> too many high-levels maladaptive

Question 20

Genetic influence on human psychological traits

Answer 20

Personality characteristics: 30-50% heritability

intelligence: 40-60% heritability

Question 21

Why we are not all the same

Answer 21

• no selection
• mutations
• selection is variable (over time and place)
• frequency-dependent selection
• non-additivity of genetic effect (not affected by selection)