spearman's theory of central intelligence

• up until yerkes made the army tests, intelligence tests were developed for particular needs

  in 1927, spearman introduced another way of conceptualising intelligence, based on the factor analysis of data that had already been collected
• Spearman's g part 1:

  • Estimated the intelligence of 24 children in village school
  • Initially spearman set out with intelligence tests of memory, light, weight and sound in which participants were asked to identify changes in illumination, weight and pitch of spearman's instruments and perform memory tasks
  • After time and further data collections among individuals who lived further from his home and between 1904 initial experiments and experiments carried out in analysed the relations among data collected with a variety of intelligence tests and subjected them to factor analysis
• spearman's factor analysis :

  • He found that among his data there was a trend of positive correlations between intelligence tests
  • That is a person who does well on one tests, perform as well on a variety of intellectual tests
  • Equally, if a person did poorly on one intelligence test, then they also tended to do poorly on other intellectual tasks
•  general factor of intelligence

  • The first factor of intelligence was specific abilities 's'. This was the name given for each type of intelligence which was needed for performing well on each different intelligence task that spearman has observed
• G general factor of intelligence

  • The second factor was what spearman thought was underlying all the positive correlations. The thing that was underlying all the positive correlations was general ability  'g'
  • 'g' was the intelligence that was required for performance of intelligence tests of all times. Spearman envisaged g as a kind of mental energy that underlies and informed specific factors of intelligence
• The measurement of 'g'

  • Wechsler tests
  • The wechsler adult intelligence scale (WAIS), that had been standardised among 2000 adults aged between 16 and 75
  • The wechsler scale for children  (WISC) for children between 5 and 16
  • Raven progessive matrices
  • Both tests used overall scores on anumber of items to measure general intelligence
  • These scores are commonly what we refer to today as IQ
• Wechsler tests

  • Wechsler first tests were modelled on spearmans two factor model, and spearmans central position that intelligence covered a huge range of specific abilities
  • Arithmetic, block design, comprehension, digit span, digit symbol, information, object assembly, picture arrangement, picture completion, similarities and vocab
• Raven's progressive matrices

  • In his writing soearman has emphasised the abstract (theoretical thought not applied or practical) ability to see relaitonships between objects, events information and draw inferences from those relationships
  • Raven thought the best way to test this abstract reasoning was to develop a test that was free of cultural influences, particularly language

   
• what to talk about in this section:

  • yerkes army alpha and beta tests + maybe binet and therman
  • spearman's general inteligence
  • testing intelligence village children,
  • factor analysis
  • positive correlations between tests
  • specific abilities 's'
  • general abilities 'g'
  • measurement of g - WAIS and WISC
  • IQ