Intelligence

• Francis Galton (Evolution)

  •Measure: Biological basis (e.g., skull size, reaction time)

  •Assumed: Intelligence inherited, manifests a person’s evolutionary fitness
• Alfred Binet (Education, Mental Age)

  –Measure: Problems child of a certain age can solve
• Lewis Terman (Stanford-Binet)

  •In English, mostly verbal items, single score
• David Weschler (WAIS/WISC)

  •“gold standard”, includes 

     non-verbal items, profile scores
• what Is intelligence

  Psychometric approach (Structure)

  •How people vary in abilities

   

  Cognitive processes approach (Process)

  •Why people vary in abilities
• Psychometric Approach

  •Give people diverse measures of mental abilities

  •Examine how measures correlate with each other

  •Factor analysis: create ‘clusters’ of measures

  •Issues:

  •What is measured by each cluster?

  •Can you cluster clusters?
• Psychometric Approach

  •Spearman’s g factor

  •Thurstone’s primary ability factors

  •Carroll’s three-stratum model

  •Cattell and Horn’s Gf–Gc model
• Thurstone’s Primary Abilities Model

  • verbal comprehension
  • word fluency
  • number facility
  • space
  • rote memory
  • perceptual speed
  • reasoning
• Thurstone’s Primary Abilities Model

  • fluid intelligence
  • crystallised intelligence
  • memory
  • visual perception
  • auditory perception
  • broad retrieval
  • cognitive speed
  • processing speed
• Cattell-Horn’s

  fluid intelligence vs crystallised intelligence

  fluid increases until the age of 20 and then begins to decline

  crystallised steadily increases with age
• sternberg’s trirchic theory

  3 underlying cognitive processes of intelligence

  • analytical intelligence
  • practical intelligence
  • creative intelligence
• have to develop test that are

  • reliable
  • valid
  • normed - standardised
• reliability and validity are inherently linked but distinct
• standardisation follows a bell curve most fall at the top of the bell curve, the fewer and fewer taper out either side of the curve
• Intelligence predicts occupational attainment
• intelligence predicts school and job success
• intelligence even protects you from death
• the performance diversity trade off

  increase in job performance is associated with reduced diversity

  caused by using cognitively loaded predictors with:

  • high criterion validities
  • substantial racial group differences
• intelligence is multidimensional
• different jobs have different ability profiles
• both genetics and the environment play a role in intelligence
• the more closely two individuals are genetically related the more similar their IQ scores
• people in similar environments have more similar IQ scores
• Heritability is the variation in intelligence scores (IQ) attributable to variation in genetic factors
• heritability increases with age
• early intervention helps children from disadvantaged environments more than children from more advantaged environments
• each year in education increases your IQ scores by about 1-5 points on average
• is education associated with improvements in general cognitive abiltiy or in specific skills?

  • mostly specific skills
• Flynn effect - the average IQ score of children in the US has increased by 10 points since 1930
• IQ is increasing more quickly in developing countries
• The Flynn effect is attributed to environmental factors like improved nutrition, education, and reduced exposure to toxins.