Nature vs Nurture

Question 1

Figuring it out - Comparing Relatives, MZ together

Answer 1

Share 100% of genes

Share 100% of environment

Question 2

Figuring it out - Comparing Relatives, MZ apart

Answer 2

Share 100% of genes
Share 0% of environment

However, prenatal environment was shared so may impact heritability estimates

Question 3

Figuring it out - Comparing Relatives, DZ together

Answer 3

Share 50% of genes

Share 100% of environment

Question 4

Figuring it out - Comparing Relatives, DZ apart

Answer 4

Share 50% of genes

Share 0% of environment

Question 5

Figuring it out - Comparing Relatives, Interclass Coefficient

Answer 5

The proportion of variance due to between-family differences

Question 6

Figuring it out - Comparing Relatives, Heritability Estimate

Answer 6

h2 = 2 ( rMZ - rDZ )

Average proportion of variance for a gene trait due to geentic variation in the population

Question 7

Figuring it out - Comparing Relatives, rMZ

Answer 7

= h2 + c2

Correlation between the traits of MZ twins

Question 8

Figuring it out - Comparing Relatives, rDZ

Answer 8

= 1/2 h2 + c2

Correlation between the traits of DZ twins

Halved because DZ twins share only 50% of genes

Question 9

Figuring it out - Comparing Relatives, c2

Answer 9

= rMZ - h2

Common environment influence

Question 10

Figuring it out - Comparing Relatives, Environmental Influence

Answer 10

Unique + Common Environmental Influence

Question 11

Figuring it out - Comparing Relatives, Environmental Influence, Common

Answer 11

If MZ < 2 x DZ = Effect of the Common environment

Determine effect by compaing the traits of non-related individuals living in the same household

Question 12

Figuring it out - Comparing Relatives, Environmental Influences, Unique

Answer 12

Within-Family differences

Birth order, Parental Treatment, Peer Groups

Question 13

Figuring it out - Comparing Relatives, Environmental Influences, Unique, Birth Order

Answer 13

Adler - First born children are insecure, last born children are spoiled, middle born children are inbetween due to competition for approval

Sulloway 1995 - Later born children show increased Agreeableness and Openness to Experience and decreased Conscientiousness

Kristensen & Bjerkedual 2007 - Second-borns bought up at first-borns (as a result of adoption or death) had IQs similar to that of first-borns who tend to be 3 points higher, emphasising effect of environment as opposed to genetics

Question 14

Figuring it out - Comparing Relatives, Environmental Influences, Unique, Parental treatment

Answer 14

Loehan 1997 - Personality and Parenting correlate .15

Question 15

Figuring it out - Comparing Relatives, Environmental Influences, Unique, Peer Groups

Answer 15

Bart et al 2009 - Children that were delinquent at 14 had more delinquent peers are 17, personality determines the peers you choose NOT peers determining personality

Question 16

Figuring it out - Comparing Relatives, Genetic Influence, Additive

Answer 16

Genes will present characteristics without the need for interactions with other genes

No need for dominance or recession

Question 17

Figuring it out - Comparing Relatives, Genetic Influence, Non-Additive

Answer 17

Genes show interactions with other genes

MZ will have the same combination
DZ show the same combination 1/4 of the time

May result in MZ > 2 DZ

Question 18

Assumptions - Assortative mating

Answer 18

Genetic influence measures assume that mating is random and partners are no more similar to eachother than any other members of the population

If parents are more similar than random, genes may overlap and so heritability may be underestimated

Question 19

Assumptions - Personalities are measured independently

Answer 19

Personality measures of twins often result in the comparison of twins

Assimilation effects result in individuals being compared to the general population, making twins more similar

Contrast effects result in individuals being compared to eachother, making twins more different

Question 20

Assumptions - Early environment is separate

Answer 20

Twins and even family members will share the same womb, contributing to a shared environment that may impact personality but be ignored, overestimating heritability estimates

Question 21

Assumptions - Adoptive households are different

Answer 21

Adoptive households go through testing and monitoring to ensure they are safe for the child resulting in most adoptive households having above average treatment

Selective placement could also make the environment more similar to those that are then compared, overestimating heritability by saying any commonality is due to genes

Question 22

Assumption - Twins are treated the same

Answer 22

If the environment is 100% the same then the twins must be being treated the exact same

Tendency for MZ twins to be treated mores similarly that DZ twins

Scarri et al 1979 - Differences in treatment do not have significant effects on personality

Question 23

Separating heritability and common environments - Gene-environment Interaction

Answer 23

Different effects of the environment for people with different genotypes

People with the same genetic stress-sensitivity may show different stress levels as a result of the different environmental stressors each are exposed to

Question 24

Separating heritability and common environments - Gene-environment Correlation

Answer 24

Passive, Active / Selective or Reactive / Evocative

Question 25

Separating heritability and common environments - Gene-environment Correlation, Passive

Answer 25

The child does not choose their environment, it is a result of the parents' genetic tendencies which are then passed down Parents may have the genetic tendency to play music and have instruments in their home so the children plays these, in line with their inherited tendency

Question 26

Separating heritability and common environments - Gene-environment Correlation, Active / Selective

Answer 26

Genetic tendencies result in the selection of the environment Child may have a genetic tendency to play instruments and so chooses to go to music club at lunchtime

Question 27

Separating heritability and common environments - Gene-environment Correlation, Reactive / Evocative

Answer 27

The child selects their environment as a result of other's reaction A child may have a genetic tendency to play instruments so plays them in the home, their parents praise them and so the child decides to go to music school which further improves thier abilities

Question 28

Trait heritability - Personality

Answer 28

Minnesota Twin Study - .54 correlation between traits Riemann et al 1997 - 38% Openness to Experience, 72% Conscientiousness, 46% Agreeableness, 80% Neuroticism, 56% Extraversion, no effect of Common environment

Question 29

Trait heritability - Religiosity

Answer 29

Abrahamson, Baker & Caspi 2002 - Adult MZ from .70 to .60, Adult DZ from .60 to .40, large effect of common environment .12 heritability for adolscents

Question 30

Trait heritability - Political Attitude

Answer 30

Eaves et al 1997 - MZ .50 to .60, DZ .50 to .40, effect of environment when young, effect of genetics with age

Question 31

Trait heritability - Smoking

Answer 31

Li et al 2003 - Persistence .55 h2 Vink et al 2005 - Initiation .44 h2

Question 32

Trait heritability - Drinking

Answer 32

Alcoholism .50 - .71 h2 Drinking .21 - .56 h2

Question 33

Caspi et al 2003

Answer 33

Investigated the effect of the serotonin gene 5HTT, which has two alleles (long or short)

Question 34

Caspi et al 2003 - Findings, Depression

Answer 34

No main effect of genes Main effect of stressful life events Interaction where stressful life events predict depressive episodes in individuals with the short gene

Question 35

Caspi et al 2003 - Findings, Suicide

Answer 35

Interaction where stressful events predict suicide in individuals with short genes

Question 36

Caspi et al 2003 - Findings, Major Depressive Disorder

Answer 36

No main effect of genes Main effect of childhood maltreatment Interaction where childhood maltreatment predicts adult major depressive disorder in individuals with the short genes