Intelligence

Question 1

Psychometric IQ : Hierarchical structure

Answer 1

g splits into Gc and Gf
Gc (crystal intelligence) - learnt intelligence makes up to 83% to 93% of IQ tests - culture specific

Gf (fluid intelligence) - biological potential
7-17% of IQ tests

Question 2

What makes up Gc

Answer 2

Spelling
Writing
Oral style

A product of investment theory (Cattell)

Question 3

What makes up Gf

Answer 3

Reading speed
Piagetian reasoning
Sequential
Inductive reasoning

Focuses on process independent of content or knowledge domain
Seen to include executive control and working memory tasks
Seen as biologically instantiated in the prefrontal cortex

Question 4

Heritability estimates

Answer 4

48 to .62 (up to .80)
- Thus between 48% and up to 80% of the variability in IQ scores is attributed to genetic variation
- Mind the ‘heritability gap’! (Plomin & Deary, 2015)

Question 5

Heritability of g: group differences controversies

Answer 5

• Behavioural genetics assumes independence of genes and environment
• Also often assumed that fluid intelligence is fixed and crystallised intelligence less so
• Spearman’s hypothesis
• The Bell Curve (Hernstein & Murray, 1994)

Question 6

The Flynn effect

Answer 6

• Generation rise in IQ by on average of 10 points (range 5-20 IQ points; SD = 15)
• This is seen across at least 14 different countries
• It is more substantial for Gf than Gc
• Highest in the Netherlands, below average in the UK, ceased in Sweden and reversed in Norway

Question 7

The heritability paradox - Flynn Effect

Answer 7

• If heritability is so strong and environmental effect so small on IQ, how can changes in the environment create large changes in IQ?
  
  • Social Multiplier
  • Averaging
  • Gene-environment matching

Question 8

Social multipliers

Answer 8

• Environmental factors potentially contributing to an increase in IQ
  
  • Internet and access to information
  • TV?
  • Gaming (reaction times and speed)?
  • Education
  • Group learning and studying
  • Rising standards of living
  • Better nutrition
• (Rindermann et al., 2017)

Leads to better cognitive abilities

Question 9

Matching

Answer 9

• There is a gene-environment correlation
  
  • People seek out environments that match their phenotype
• The process by which the ability and the environment are matched, produces increases in that initial ability.
• Thus environment increases genetic ability

Question 10

Averaging

Answer 10

• As individuals’ ability rises, this will also influence those around them
• Such small effect over time will influence the population more widely
• The population average will increase.

Question 11

Dickens & Flynn (2001)

Answer 11

• Fluid cognition (biologically determined potential) = reflect in your measured IQ (an interaction between environment/population and biological potential)
• Intelligence is manifested via a complex interaction between genes, environments and other’s influence we’re surrounded by
• Product of interaction

Question 12

• Socio-Economic Status

Answer 12

• Heritability high for high SES
  ○ h2 = 72%
  
  • Heritability virtually zero for low SES
    ○ h2 = 10% and environment = 60%

Question 13

Heritability SES issue

Answer 13

• SES effect may reflect a gene-environment interaction. More resources in high SES to allow genes for IQ to express. SES however, is not just environmental but may reflect genetic effects also