General Intelligence Flashcards
why is factor analysis important for understanding intelligence
FA is a tool for discovering or testing the underlying structure in complex data
it identifies latent variables that explain intercorrelations between test scores etc
for this to be meaningful the data derived from tests must be valid and reliable
what is a latent variable
a variable that is not directly observable but is inferred through a mathematical model from other variables
what is the scientific process to test intelligence
form a question define the terms in the question operationalise variables formulate hypotheses collect data test hypotheses make inferences answer question
what are the problems with finding a definition of intelligence
difficult to do - need to say what it is and isn’t
requires consensus
idea that everyone intuitively knows what is meant by intelligence
we assume that intelligence is the latent variable underlying IQ scores on test
why study intelligence if we can’t define it
its an important predictor of life outcomes and justifying inequality
below a certain IQ individuals lose the right to consent
what did strenze’s 2007 meta analysis find
investigated associations between intelligence education occupation parental SES and academic performance
found that IQ is a very high predictor of educational outcome, and also occupation
there are potential confounds with genetics parent’s education, occupation and income are also good predictors but these might in part be due to their own IQ which could be inherited
what is the relationship between intelligence and longevity
associated with SES and as inequalities in health and mortality exist among different SES groups, makes sense that intelligence is linked to health and mortality
Scottish Mental Survey (1931) - children born in 1921 tested in school on the Moray House Test in 1932 and recorded survival at age 76. Found those in the highest IQ quarter were likely to live longer than those in the lowest IQ quarter although there is an WW2 effect in men where IQ made no difference to survival
Batty et al., 2007 found that risk of dying decreases by 24% per 1SD increase in IQ in an intelligence and all-cause mortality study leading to the suggestion that IQ may help to prevent disease and take fewer risks
what is the relationship between intelligence and health behaviours
Taylor et al., 2000 recorded IQ at 11 and smoking status at midlife
found that of those who have smoked, quitting is associated with higher IQ although never have smoked is associated with lower IQ
what is the relationship between intelligence and health conditions
Der et al., 2009 conducted a longitudinal survey of young people age 14-21 and found some significant negative correlations but this was not the case for all conditions
how did Galton originally conceive of intelligence
hereditary and N distributed
affects selection and competition for survival
innovative approaches to study of intelligence
histometric: figures from history who had influences sociatey to identify features of intellifence
established psychological labs as he watned real data
What were the principles of the first IQ tests developed by Binet
given it was now compulsory for al children to be educated, binet wanted to identify children with learning problems
as teacher assessments are biassed against children with discipline problems there was a need to develop objective tests
believe that as intelligence increases through childhood, older children should perform better than younger ones (validity criteria)
should not assess sensory acuity, precision, special education or training
to achieve this tests focuses on abstract reasoning rather than knowledge
performance was measure relative to age - to produce a mental age (age norming)
IQ = mental age / chronological age x100
what is the latent concept of intelligence
notion of intelligence derived from psychometric instruments that predict performance in school
intelligence directly inferred from relationship between test scores and other criteria
what are the two kinds of general intelligence (Cattel 1963; Horn, 1998)
crystallised intelligence: learning knowledge, information, content that is affecrted by experience and previous culture
fluid intelligence: is the capacity to learn new things that is biologically pure and independent of experience and culture
the capacity for knowledge vs knowledge possessed (Hemnon, 1921)
How can we test the ‘capacity for knowledge’ i.e. fluid intelligence
reaction time
visual inspection tasks
biological measures such as brain function neuronal speed and white integrity
how can we test ‘knowledge possessed’ i.e. crystallised intelligence
academic performance, college entry tests, vocabulary, information
are we testing something that is the product of fluid intelligence? is it just acquired knowledge?
are vocabulary tests good IQ tests?
measure of crystallised intelligence
number of words you can define
continues to improve until 50-60 (opportunity to learn)
IQ peaks at 20-25
SES can explain some differences, but not all
higher vocab scores in 5yo predicted time to learn new made up vocab even when children were matched for fluid intelligence (Gathercole & Baddeley, 1990)
requires inference and reasoning as most word meanings are not explicitly instructed - more complex than education and exposure
on what dimensions to intelligence tests differ from each other
scope, format, length type of tests and items included kind of intelligence group/individual administered to precision of measure and underlying structure norms, standards and biases
why is it important that intelligence tests are judged to test intelligence
need reliable tests
of difference in ability (shouldn’t be diagnostic)
differences in tests can inform the structure of intelligence
need to be sure we aren’t measuring confounds such as consientiousness
what is Raven’s Matrices
considered the purest test of intelligence & the gold standard as it doesn’t rely on education or cultural upbringing - although performance is likely to improve with experience and familiarity
must identify an abstract rule
has face validity as an IQ test
how is a task such as reading through word lists to select those with the letter ‘a’ in as quickly as possible and IQ test
scores correlate well with Raven’s matrices
tests processing speed
tells us something fundamental about the nature of intelligence despite its low face validity
remember we have a poorly defined concept of intelligence
what is the nature of the map planning test
must navigate an abstract map of a city by finding the fastest route from A-T while only passing through one number square
must weigh up options and show creativity
however clinical diagnoses can affect performance, for example people with autism struggle to see the validity of rules so can fail the task despite having very high IQ
may be a test of a more general rule following ability
how are verbal reasoning tests measures of IQ
requires a different body of knowledge - understanding the meaning of words
ability to learn word meaning and link to other words
confounded with education
how have traditional IQ tests been criticised
the traditional notion of intelligence is not comprehensive enough
there is too great a focus on mathematical and verbal reasoning - book smart intelligence
designed and developed by academics to test whether others are academically smart
more to intelligence than IQ measures
and IQ tests measure more than intelligence
perhaps multiple intelligences
other skills such as music, kinesthetics or appreciation of nature
how do individuals differ in intelligence
people often view themselves as being weaker in an aspect of intelligence
yet IQ test score differences within subject are smaller than between subject
scores from different intelligence tests positively correlate within a sample
what is spearman’s g (1904)
individual differences in basic information processing - academic performance used to establish criterion validity
product of FA g
general intelligence: latent variable explaining why scores on different IQ tests are positively correlated
could be statistical artefact - important to have a biological basis (mental energy?)
What are Thurstone’s seven factors
orthogonal FA revealed 7 primary unrelated mental abilities suggesting g doesn’t exist
verbal comprehension word fluency number facility spacial visualisation associative memory perceptual speed reasoning
g arises from tests requiring common abilities
but removing identified common factors such as speed, memory and linguistic ability doesn’t remove the effect that leads to g
possibility of individuals having their own domain of excellence, but this does not seem to be supported
what is Carroll’s 1993 hierarchical factors model
extensive multivariate analysis on structure of mental abilities
diverse sample in age and health
hierachical three stratum model of intellgence where g exists as the top level, fluid intelligence, crystallised intelligence, memory and learning, visual perception, auditory perception, retrieval ability, cognitive speed, processing speed are intermediate factors giving rise to more skills
this is supported by the fact that g explains .5 variance in any comprehensive battery of IQ tests - the unexplained variance can then be accounted for by second and third stratum factors
end up with a model where there are multiple intelligences all caused by g to some extent
what does g reflect/ give rise to
correlated with RT (-.49 IQ & RT; -.26 IQ & variability of RT, Deary et al., 2001)
correlated with inspection time (.51) - the shortest duration for which stimuli can be presented before being removed while the participant still accurately reports what the stimulus was
basic skills (unlike those used to measure IQ) free from, learning and cultural influence but high correlation
what is the relationship between brain volume and intelligence?
McDaniel (2005) meta-analysis of 37 studies found r= .33
higher for women than men
higher for adults than children
for all ages and sex groups brain volume is positively correlated with intelligence
volume of causate nucleus has been found to be related to individual differences in intelligence
what is the nature vs nurture stance on intelligence
always both
fine differences across the population make it difficult to know how much can be attributed to genes vs environment (but is undoubtedly GxE)
most likely that there is a large sample of genes which probabilistically contribute to intelligence
the more genes involved the more finely grained the variations in a given characteristic are
what is heritability
the total variation in a given characteristic in the population that can be attributed to genetic differences between members of that population - at a given time, tested with a particular test
doesn’t tell us how much genes contribute to behaviour because not GWAS
variation not attributable to genetic differences is caused by differences in the environment experienced by members of that population
not about individuals, features of environment change estimates such that standardised environments increase heritability estimates
statistical test of propensity to have a characteristic
what is H^2
the proportion of variance in a trait that is due to genetic factors (heritability statistic)
H^2= 2x (Rmz - Rdz)
1= 100% heritable 0= due to environment
what is Rmz
the correlation between scores in a population of MZ twins
what is Rdz
the correlation between scores in a population of DZ twins
what is the typical heritability of IQ
r=.25-4
g is more heritable with increasing age
At 9 years of age, the heritability was .41, at 12 it was .55, at 17 it was .66, and it continues to increase until late adulthood then drops (Bouchard, 2014; Haworth et al., 2010).
Conversely, environmental effects, which play a larger role than genetic factors at age 5, decrease rapidly in their influence as the individual approaches their late teens (Bouchard, 2014).
May be that as people mature they begin to exercise active choice over their environment, seeking out environments and activities that are based on their internal, genetically-based personal preferences and abilities.
what sex differences are there in IQ
score equally on IQ tests at a global level
the correlation of teacher ratings and test results negatively predict sex differences (higher correlation, smaller sex differences - bias in teaching?)
small advantage for girls up to age 14
revised versions of IQ tests have produced small advantages for men (Stanford-Binet, WAIS) or women (Wechsler-Bellevue) - suggests data depends on IQ test used, is this rlly valid?
sex differences in sub-tests: women do better on verbal ability, memory and perceptual speed, men do better on spatial ability, mechanical reasoning and maths
differences in fluid intelligence tested using ravens matrices show a male advantage but this is twice as large at 40 as at 18 suggesting there are environmental factors at play (such as staying in work and kind of work)
moreover male advantage seen 50-60 years ago is no longer there (effect of education)
suggestion that there is more variance in male IQ than female IQ - justification for uneven number of nobel prizes
differences in spatial reasoning
