9 - Intelligence and its Measurement p1 Flashcards
Herrnstein and Murray on Intelligence
Analysed IQ scores and admissions to universities and colleges in the US
Found:
- the most important factor in college attendance was IQ, not social class or wealth
- Intelligence is the best predictor of Job performance
- There is a cognitive elite in the US based on a separation of society through education and the workplace, based on intelligence
- Warned that intelligence would soon become the basis of the US class system, those with highest IQs at the top
- Low IQ scores are a strong precursor to poverty, more than any socioeconomic condition
Low IQ:
> predicts students dropping out of education
> related to unemployment
> associated with higher rates of divorce, lower rates of marriage, and higher rates of illegitimate births - IQ scores are a better predictor of economic and social welfare than Socio-economic status
Harrnstein and Murray on Race and IQ
On the Wechsler intelligence test, White Americans score 15 IQ points higher than black Americans
Thus they concluded:
- blacks are less intelligent than whites
- immigration is pushing down the IQ of the US
- Education can not reverse the problem of low intelligence
- programmes of affirmative action lead to a decrease of intelligence in the workplace
What does the Wechsler Intelligence test measure?
Verbal and non-verbal reasoning
6 Premises of the Herrnstein and Murray Argument
- there is a general factor of cognitive ability (g) on which humans differ
- all standardised tests of academic aptitude measure this general factor (g) to some extent, but IQ tests measure intelligence the most accurately
- IQ scores reflect what most people mean by the word intelligence
- IQ scores are stable over a person’s life
- IQ tests are not demonstrably biased against any social, economic, ethnic or racial groups
- there is a genetic heritability of intelligence between 40% and 80%
Sternberg on intelligence
The capacity to learn from experience and adapt to one’s environment
Thorndike on intelligence
Intelligent people should be defined as highly intelligent, and stupid people should be defined as lowly intelligent
Ternman on intelligence
The ability to carry on abstract thinking
Gardner on intelligence
Suggested that there are multiple different types of intelligence (physical prowess, chess ability), and that IQ tests are limited in measuring these types
Binet and Simon on intelligence
Interested in the ability to use common sense, practical sense, adapt to circumstances, comprehend well and reason well
defined this as intelligence
What 3 factors did Sternberg find that the population rated important for intelligence?
Practical Problem Solving
- the ability to be logical in regard to problems we face in various situations
Verbal Ability
- the ability to express yourself and converse with others confidently and with some eloquence
Social Competence
- the skills necessary to be accepted and fulfilled socially
Cattell on intelligence and reaction time and Wissler’s criticisms
Cattell
‘intellectual ability could be assessed by measures of sensory acuity and reaction time’
Tested:
- two-point tactile threshold
- just noticeable difference for weights
- judgement of temporal intervale
- reaction time
- letter span
- pitch perception
Wissler
- there was no correlation between any of Cattell’s mental tests
> a student could be good in one area but not in another
*therefore these tests cannot all be a general measure of intelligence (g)
Wechsler on IQ score and his equation for IQ
IQ = (actual test score x 100) / Expected score
- where the Expected score is the average score obtained by a large representative sample
- IQ score is a reflection of an individual’s relative standing with respect to others of the same age
> IQ is not an absolute score
Ternman’s equation for IQ
IQ = (Mental age / Chronological age) x 100
Mackintosh on IQ and Reaction Time
‘the size of the correlation between choice reaction time and IQ is sufficiently small that no one could seriously argue that reaction time alone provides an explanation of intelligence’
Cattell on intelligence
Two different kinds of intelligence:
- Crystallised intelligence (gc)
- Fluid intelligence (gf)
What is crystallised intelligence?
- acquired knowledge and skills, such as factual knowledge
- increases through life
- e.g:
> vocabulary size
> verbal fluency (as many words as you can think of that start with F)
> working memory (reading span - recall the last word of each sentance)
> numerical ability
What is fluid intelligence?
Primary reasoning ability
- the ability to solve abstract relational problems
- no cultural influence
- does not improve with age, slightly decreases
E.g
- analogical reasoning (coding, mapping and application)
- working memory
- executive control (intentional functions)
Central Executive Function
Carpenter
- the ability to select appropriate strategies to tackle a problem
- to deploy and manage the components and resources to address the problem
Sternberg
- 8 stages of problem solving
Thurstone’s 7 Primary mental abilities
- Associative Memory (rote memory)
- Number (mathematical operations)
- Perceptual Speed (perceiving details, anomalies and similarities in visual stimuli)
- Reasoning (inductive and deductive reasoning)
- Space (ability to transform spatial figures mentally)
- Verbal Comprehension (reading, comprehension and verbal analogies)
- Word Fluency (generate and use a large number of words effectively)
Gardner’s Multiple intelligences (9)
- Linguistic
- Logical-mathematical
- Spatial
- Musical
- Bodily Kinaesthetic
- Interpersonal
- Intrapersonal
- Naturalist (ability to interact with nature)
- Existentialist (linked to spiritual theory)
Stanford-Binet IQ Test
Binet was Tasked with figuring out whether children would perform well in school or not
- so tried to determine their mental age via his IQ test
- focussed on a series of 30 short tasks related to everyday life
Stanford adapted Binet’s test and added 40 items
Wechsler IQ Test
Commonly used here
Subsets:
- Arithmetic (addition of even numbers)
- Block design
- Comprehension (advantage of keeping money in the bank?)
- Digit Span (recall a string of numbers)
- Digit Symbol (copy across coded symbols)
- Information (general knowledge)
- Object arrangement (jigsaw puzzle)
- Picture Rearrangement (arrange cards to tell a simple story {cartoon})
- Picture completion (what’s missing from the picture)
- Similarities (in what way are a lion and tiger alike / art is to a wall as cup is to a (cupboard) )
- Vocabulary (definition test)
Ravens Progressive Matrices
- supposedly pure tests of problem solving
- study the environment to determine the ‘rule’ that needs to be applied to solve the problem
Mackintosh on General Intelligence (g)
Where different tasks that measure intelligence show a positive correlation between them all, factor analysis will yield a general factor that accounts for this positive manifold
Spearman:
- this general factor (g) provides a complete and sufficient explanation of the correlation between tests
- abilities on different factors within this test can cluster together
IQ and ageing
By the age of 8, childhood IQ predicts adult IQ well - IQ score remains reasonably stable throughout life
- IQ is a measure of relative standing among people of your age, so a high correlation between your IQ at age 10 and age 70 does not imply that your absolute level of performance remains the same
- Intelligences do not all age equally
> Fluid intelligence declines at a faster rate than Crystallised intelligence
+ (both decline with age)
Since Fluid and Crystallised intelligence change at different rates, the idea of a general measure of intelligence (g) does not hold up so well
Is Intelligence Malleable?
Hernstein and Murray thought not
- the US could not fix the intelligence gap between black and white Americans by changing the education system
Ceci (1990)
Using meta-analysis found:
- children who attend school regularly score higher on IQ tests (2.7 points higher)
- delays starting school cause intelligence to drop (5 IQ points per year missed)
Wahlsten (1997)
- An infant moved from a low socioeconomic status (SES) family to a high SES family, thier IQ score will improve 12-16 points
Genetic Basis of IQ
Francis Galton (Hereditary Genius) - found that almost half of judges appointed to the English bench from 1660-1865 had one or more relatives deemed intelligent > stated this might be due to inherited family influence, not natural intellectual gifts
Other Study:
compared sons of eminent men with adopted sons of popes
- sons that were adopted were less likely to achieve eminence than were the natural sons of eminent men
> because the social helps are the same, but the hereditary gifts are wanting
Measuring Heritability
h² = 2(rMZ - rDZ)
- there is an 86% concordance for identical twins reared together
- 55% concordance for fraternal twins
Neisser et al., (1996)
Environmental influences on IQ (3)
- Biological variables and maternal effects
- School and education
- Family environment
Influence of Biological variables and Maternal effects on IQ
- Nutrition:
> children given vitamin-mineral supplement showed an increase in IQ scores
+ Benton and Roberts (1988) - Lead exposure
- Prenatal Factors
> women who smoked 20+ cigarettes daily in late pregnancy were likely to have sons with lower IQ at 18-19y
+ Mortensen et al., (2005) - Prenatal conditions may account for 20% of the variance between twins
+ Delvin et al., (1997)
Influence of Family Environment on IQ
Socioeconomic status
Influence of School and Education on IQ
Neisser et al., (1996)
- intelligence as a dependent variable
> going to school is likely to increase your abilities, especially those relating to intelligence - intelligence as an independent variable
> intelligence is likely to influence your attendance at school and your length of schooling
Wilson effect (heritability)
Shows that the heritability of IQ increases with age
- MZ twins became increasingly concordant with age and paralleled each other in spurts and lags in development
- DZ twins became less concordant with age, and eventually matched to their singleton siblings
- Overall results suggested that the course of mental development is guided by genetic and environmental factors
- As an individual becomes a more independent age, the experiences they have (environment) become self-selected
> as you start to select the environment, your genes will have more of an influence on your phenotype, because the genes begin to influence the environment that you’re choosing to move into
What does the Wilson Effect show?
Heritability of intelligence depends entirely on the age that it’s measured
shows that heritability is dynamic
- due to the increasing ability of genes to influence environment
Flynn Effect
The average IQ score has increased at a remarkable rate in most industrialised societies throughout the 20th Century
Flynn (1994)
- we have not seen an increase in intelligence itself, but in some kind of abstract problem-solving ability
Must focus on environmental influences, because the change is far too rapid for genetic influence:
- Length of schooling has increased
> However, length of schooling predicts larger rises in verbal tests and lower rises in non-verbal tests…whereas the Flynn effect has found the reverse
+ Flynn effect found larger rises in non-verbal tests than in verbal tests - Test taking sophistication
> more time practicing, more tests generally - Child-rearing practices
> (sesame street) more engaging television
> Head Start Program (support in early years) - Culture and the age of technology
- Improvement in nutrition
If the observed variance in environment accounts for so little variance in adult IQ, how could environmental factors cause large differences?
Reciprocal causation between phenotypic IQ and environment produces gene x environment correlation
- a positive correlation between environment and genotype masks the potency of environment
> judging the size of environmental effects by the fraction of variance not explained by the genotype will understate its full magnitude
+ when measuring heritability, if the effect of the environment acts in the same direction as the genes, then we will not see the effect in the correlations
> in twin studies, we’re saying that the similarities must be due to genes, and the rest must be due to environment - There is a multiplier effect
> genes and environment can interact to inflate their effect
+ having a higher IQ may lead you into better environments which cause your IQ to grow further - Social multipliers can play an important role in determining the impact of society-wide changes
> if some external factor causes the IQ of some individuals to rise, this will improve the environment of others and cause their IQ to rise
Limitations of using IQ to predict achievement
Whalley and Deary (2001)
Found:
- people with a standard-deviation (15-point) disadvantage in IQ relative to others at age 11, were only 79% as likely to like to age 76
Possible explanations:
- High IQ is associated with more optimal health behaviours
- High IQ is predictive of educational qualifications
- High IQ may be associated with jobs with safer environments
Klemp and McCelland (1986) found that scores on standard ability tests tend to be uncorrelated with actual proficiency in managerial jobs and with performance on simulated business problems, why might this be?
Problems in IQ tests are too well-defined:
- in real life, problems are rarely so clear-cut, before figuring out a solution, one must first figure out the problem - only then can one know what kind of information to seek out in order to solve it
Deliberate Practice
Practice that gets you feedback
