A new meta-analysis shows that the Flynn effect is still going strong, and thus hasn’t tapered off as is sometimes claimed.
The Flynn effect refers to the global increase in intelligence test scores since about 1930, with an average increase of between two and five IQ points per decade. The effect has been known to appear and disappear in various places at various times. In Denmark, Norway, and Australia, for example, some research suggests that the effect may have already stopped, whereas it is still proceeding apace in much of the developing world.
The possible reasons behind this long-term rise in IQ scores are many. Suggestions have included better nutrition, more widespread education, and changing approaches to test-taking. These discussions have been the subject of thousands of studies and many books, several written by the eponymous James R. Flynn himself.
The new meta-analysis, published in the journal Psychological Bulletin, has taken a look at 285 studies dating back to 1951, so as to “determine the magnitude of the Flynn effect with a higher degree of precision.”
They found that the mean increase in IQ scores was 2.31 points per decade. When the studies were restricted to those conducted after 1972 using modern IQ tests (namely the Stanford-Binet and Wechsler tests), the increase amounted to 2.93 points per decade.
This rise, they conclude, “was comparable to previous estimates of about 3 points per decade but was not consistent with the hypothesis that the Flynn effect is diminishing.”
“These results supported previous estimates of the Flynn effect and its robustness across different age groups, measures, samples, and levels of performance.”