Intelligence + Heritability

Question 1

Galton-Beginning of Nature VS Nurture

Answer 1

-abilities are inherited like physical traits
- close relatives of prestigious people more likely to be prestigious
- High achievers had high achieving relatives
- Acknowledge overlap of nature + nurture

Question 2

Degree of relationship terminology

Answer 2

• first degree = parent + sibling (50% shared genes)
  -2nd degree = grandparents
• Third-degree -great grandparents

Question 3

shared variability

Answer 3

• How much difference between 2 people can be explained by genes

Question 4

Beh approach to measure heritability - family studies

Answer 4

• measure intelligence of a family + correlate scores to compare performance
• similar scores can assume genetic influence
• POs: easy samples, gives basic ideas
• cons: difficult to separate genes + env = overestimate genes

Question 5

Beh approach to measure heritability - TwiN Studies

Answer 5

• compare MZ (identical) + Dz phenotypes
  -children have same env so can assume its genes
  -POs : control gene similarity
• cons: M2 treated more similarly (dressed same), don’t rep whole population, experiences aren’t identical (friends)

Question 6

Beh approach to measure heritability - Adoption studies

Answer 6

• same genes as bio, diff env
  -Best method
• POs: tease Out genes vs env
• cons: adopted family usually matched to bio, not rep, contact with bio blurs, prenatal env not controlled

Question 7

Heritability of intelligence -Ridley stats

Answer 7

• same person talking IQ test 2x = 87%
  -identical twins reared together = 86%
  -identical reared apart = 76% suggests env plays a part but genetics is a strong component

Question 8

Heritability estimates of intelligence

Answer 8

Is high
- Eysenck = 69%
-74% =Bell Curve Book

Question 9

Using DNA to explore intelligence

Answer 9

-Davis et al
- 40-50% of intelligence variation associated with common SNPs (Single Nucleotide Polymorphism)

Question 10

Using DNA to explore stability of intelligence across life span

Answer 10

• Deary et al
  -people scoring high on tests as children score similarly As adults
• More genetically similar people (SNPs in common): similar child + adult IQ, similar stability.
  -estimate genetic contribution = 38%

Question 11

is there an intelligence gene ?

Answer 11

• Not one single gene dictates
• intelligence is polygenic
• genes influence broader processes linked to intelligence (brain plasticity + synaptic dev)

Question 12

4 env influences on intelligence

Answer 12

-Biological
- family env
-school + ed
- culture
- Neisser et al

Question 13

ENV influences: Biological

Answer 13

-Not genetic
- Nutrition: stopping breast feeding early = reduced verbal intelligence
-Prenatal factors: smoking doubles woman’s risk of premature/low weight babies = lower intelligence

Question 14

ENV influences: Family eNV

Answer 14

• shared
  > socioeconomic status: 0.4% correlation
  , living condition
  > parenting style
  > family hobbies
  
  • non-shared
    > friendships
    > teachers
    > interests
    -Birth order: first higher IQ + progressively lowers As birth order increases
• family size (lower IQ with more children) -resource dilution model

Question 15

ENV Influences : school + ed

Answer 15

• Bidirectional
• intelligence predicts ed outcome (0.69) + ed quality predicts IQ
• socroeconomic status relates (high status prepare children)

Question 16

ENV Influences: culture

Answer 16

-implicit ideas of intelligence
- Types of intelligence that dev
-Different beh valved/seen as intelligent
- Decontextualisation: Western emphasise maths, science + lang
- Quantification
- Biologisation: theories grow in prominance

Question 17

complexity of gene/env interaction - genetic potential

Answer 17

-genetic potential:
> child may have genetic capacity for high intelligence
> whether this is realised depends on eNV
> High genetic potential in stimulating social ENV = reach potential
> env changes size of genetic impact

Question 18

complexity of gene/env interaction - gene-env correlation

Answer 18

• child who has genes for high intelligence might undertake beh impacting intelligence (read VS watch TV)
  -genes shape env person is in which shapes intelligence

Question 19

complexity of gene/env interaction - Differential susceptibility

Answer 19

• some genetic profiles make a child more sensitive to env
• pus env with more susceptible genes = flourish more

Question 20

complexity of gene/env interaction - Moderating factors

Answer 20

-socioeconomic status can block/ encourage gene expression
-ed can magnify genes impact
- Nutrition can magnify gene impact
-prenatal enV

Question 21

considerations of genes X env interaction

Answer 21

-estimates only tell US about groups not indiv
- genetic variation depends on dominance
- Assortative mating: assume random mating but often pick partners similar to self

Question 22

The Bell Curve

Answer 22

• Rise of cog elite: increased intelligence = more success
  -IQ tests are designed to measure g (are they valid/ reliable ?)
• cog ability is substantially heritable (40-80%)
  -intelligence is more important than socioeconomic status for predicting life outcomes
• compared to while, Asians have higher IQ+ Africans have lower

Question 23

The Bell curve- Implications

Answer 23

• lower IQ women have more children so population is slowly having lower IQ
  -Hernstein + Murray say to tackle this give extra resources to cog elite because lower IQ can’t be helped