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a blog from young economists at Nova SBE

Are We All Getting Smarter and Smarter?

In endogenous growth theory, we assume that education has a positive effect on economic growth and thus development. But there also seems to be a reverse effect of development on education – this effect is called the Flynn effect!

In 1984, the political scientist James R. Flynn discovered that the results of IQ tests in industrialized countries on average have been increasing – meaning that the measured intelligence rose. Every intelligence test is standardized to an average of 100 and a standard deviation of 15 or 16 IQ points. In his 1987 published article[1] Flynn showed for 14 industrialized countries that if new participants took the old tests the IQ values increased by 5-25 points per generation. In the following he also found this effect for test results of non-verbal, culturally reduced tests (i.e. testing fluid intelligence that is necessary for all logic problem solving) – which we would not expect to see for increases due to educational factors.

The figure shows the Flynn effect for five countries throughout the 20th century from the time when standardized intelligence tests were used. It pictures that all five countries experienced a dramatic increase in IQ scores in less than 50 years. One of the tests that can be used is the Wechsler Adult Intelligence Scale (WAIS) that was first published in 1955. Only a couple of year’s later, 20 year olds taking the exact same test score an average of 115 instead of 100 as standardized before. 

The effect is mostly attributed to the improvement of surrounding conditions such as educational systems, health care, nutrition, or housing. Nevertheless there is no scientific consensus about the causes. Mingroni[2] for example argues that an increase in migration causes formerly separated subpopulations to be mixed, and thus leading to a heterotic effect.

Flynn himself has been rather astonished by the results and offered three different categories of explanations: artefacts such as an improvement in early childhood education, test sophistication, and an actual increase in intelligence. In his 1987 paper he even questioned the validity of IQ tests and argued that they do not measure intelligence but correlate with a weak link to intelligence. In his subsequent papers however he favoured environmental effects as an explanation for the test increases. 

But experimental data trying to show the impact of a better nutrition on IQ scores is mixed leading one to believe that nutrition cannot completely account for the massive gains. Education is not really believed to have a sufficient influence either as the increase can also be shown in culture-free test results. And a societal change in terms of better skills to deal with time pressure in test situations seems not to be influential either. The Flynn effect remains to be puzzling and very complex to understand…


By Julia Seither

[1] Flynn, James R. (1987): ‚Massive IQ Gains in 14 Nations: What IQ Tests Really Measure’, Psychological Bulletin 101 (2), pp. 171-191.

[2] Mingroni, Michael A. (2007): ‚Resolving the IQ Paradox: Heterosis as a Cause of the Flynn Effect and Other Trends’, Psychological Review 114 (3), pp. 806-829.


Author: studentnovasbe

Master student in Nova Sbe

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