what do sternberg and detterman define intelligence as
- higher level abilities
- valued by culture
- executive processes (regulating flow of information toward goal achievement e.g. attentional control, working memory
- intelligence comprises the mental abilities necessary for adaption to, as well as shaping and selection, of any environmental context
what is measured by an IQ test
assess IQ which is standardised to a mean score of 100 and standard deviation of 15
- norming involves administering IQ test to a representative sample of a population to obtain norms of referential scores for different sub-groups
What are the four main branches of intelligence research in Deary and Caryl model
- Predictive validity (Real-life impact)
- Psychometric studies (Structure of intelligence)
- Cognitive studies (Processing speed/Efficiency)
- Biological studies (Brain structure/Physiology)
who is associated with the concept of general intelligence represented by the letter g
charles spearman
according to the cattel-horn-carroll model shown, what does Gc stand for and what is its nature
crystallised intelligence, it represents learnt knowledge, is culture-specific, and makes up 83-93% of IQ tests
what does GF stand for in the context of psychometric IQ
fluid intelligence, it represents biological potential and makes up for 7-17% of IQ tests
list three specific abilities categorised under crystallised intelligence
- spelling
- writing
- oral style
list four specific abilities categorised under fluid intelligence
- reading speed
- piagetian reasoning
- sequential reasoning
- inductive reasoning
what is fluid intelligence
- a capacity to perceive relationships independently of previous practices or instruction related to those relationships
- focuses on process of independent content or knowledge domain
- seen to include executive control and working memory tasks
- seen as biologically instantiated in the pre-frontal cortex
- declines later in life
what is crystal intelligence
- Gc test - vocabulary etc represent acquired knowledge
- Gc is a product of Gf
- investment theory - investment of fluid intelligence in a specific body of knowledge
- knowledge increases over lifetime
what does heritability estimates for IQ range from
.42 to .62 (up to .80)
- this means between 48% and potentially up to 80% of the variability in the IQ scores is attributed to genetic variation
what do behavioural genetics assume about general intelligence
independence of genes and environment
- fluid intelligence is fixed and crystallised intelligence is less so
what is spearman’s hypothesis
- people’s performance on a cognitive test was correlated with their performance on other comparable cognitive tasks. hence, spearman proposed a comment latent factor ‘g’ that broadly represents cognitive capability
- noticed that the more strongly a test correlated with IQ, the wider the difference in black and white american’s performance on the test
- hypothesised that black and white differences on tests of cognitive ability correlate positively with a tests g-loading
what did fagan and holland find about racial group differences in IQ
no performance differences between black and white amercians given equal prior exposure to test-relevant information
- group differences reflect unequal opportunity to acquire information, not differences in cognitive processing capacity
what did nisbett et al find about racial group differences in IQ
- a review by 16 leading intelligence researchers concluded that evidence for a genetic basis for group differences is weak, and that environmental factors are sufficient to account for observed gaps
what did genome-wide evidence by bird find about racial group differences in IQ
large scale polygenic analyses find no evidence that intelligence was under divergent selection across ancestral populations, suggesting genetic differences between racial groups are not a meaningful driver of IQ gaps
what is the flynn effect
- generation rise in IQ by average of 10 percentage points
- this is seen across at least 14 countries
- it is more substantial than Gf than Gc
- stronger among adults than children
- highest in the netherlands, below average in the UK, ceased in sweden and reversed in Norway
what are social multipliers
- environmental factors potentially contribution to an increase in IQ
- internet and access to information
- TV
- gaming
- education
- group learning and studying
- rising standards of living
- better nutrition
what is averaging
- as individuals ability rises, this will also influence those around them
- small effects over time will influence the population more widely
- the population average will increase
what is matching
- 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/biological ability
what are environmental toxins
- US americans born in 60s lost up to six IQ points on average due to lead exposure
- removal of lead from petrol was followed by measurable population level IQ increases across multiple countries
how does socio-economic status affect the heritability of IQ according to turkheimer et al
- high SES - heritability is high
- low SES - heritability is virtually zero, while the environment accounts for 60%
what is meant by genetic primacy is a phenomenon of relative privilege
it means that genes can only express their potential once basic environmental conditions are met
how does heritability increase with age
- 40% in childhood, 60% in adulthood and 80% in old age
- genes need the appropriate environment to express
- high IQ people will seek out high IQ contexts and as they get older their intelligence will show
