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intelligence change

1. The Abecedarian Project

   • Perry Preschool Project – compared to control group, intervention group had
     • Greater social responsibility: Lower juvenile delinquency,  Fewer arrests, Lower incidence of fighting / violent behaviour
     • Greater scholastic success: ×  Better grades ×  More positive attitudes to school ×  Higher proportion graduating from high school
     • Greater socioeconomic success: More likely to be employed and self-supporting, Higher earnings & home/car ownership

2. Test restandardisation

   • tests must be regularly restandardised
   • If we use old norms when comparing different populations, we may find differences that do not exist

3. rise in intelligence

   • Steady rise in test performance (e.g. Flynn, 1984; 1987): “massive IQ gains in 14 nations”
   • IQ scores increase from one generation to next

4. The Flynn Effect

   • Largest gains on tests that measure fluid intelligence (e.g., Raven’s Progressive Matrices) vs those that assess crystallised intelligence (e.g., WAIS)
   • IQ gains merely reflect increased schooling in later generations
   • It appears that the older generation have lower IQ, but they just peak later
     • IQ gains merely show that recent generations have reached their peak ability earlier

5. increase explained

   • increases in test sophistication (Cattell, 1950) ×  we have become more accustomed to taking tests ×  insufficient to explain great & continued increase
   • effect of social class changes ×  Flynn’s analysis shows insufficient - max of 30% of gain due to social class ×  would expect greater crystallised than fluid changes if this was the explanation
   • generational differences Kohn & Schooler’s (1973) complexity of life --> complexity of mind argument
   • improvements in health and nutrition large nutritionally-based increases in height have occurred over same period
   • intelligence has not increased •  Flynn’s explanation is that IQ tests do not measure intelligence. Ravens Progressive Matrices Test does not measure intelligence but rather a correlate with a weak causal link to intelligence. Flynn concludes this because he argues we do not see the real-world behaviour we would expect if people’s intelligence really was increasing at this rate. Thus, if these kind of gains are real, we would expect radical outperformance of the previous generation •  and highly visible effects