Future Bright by Martinez Michael E

Author:Martinez, Michael E.
Language: eng
Format: epub
Publisher: Oxford University Press, USA
Published: 2013-03-25T16:00:00+00:00

THE FLYNN EFFECT

A vast body of data tells us that an intergenerational shift in IQ is not a mere theoretical possibility, but rather a startling and potent reality. Starting around 1980, psychologists began to pay attention to a historical pattern in IQ data that was not completely unknown beforehand, but was certainly obscure. The object of fascination was that, around the world, IQ scores had been drifting upward for decades.54 In some cases, the upward trend of IQ extended back more than a hundred years to the time of the Industrial Revolution.55

The pattern of rising IQs around the world was presented most clearly in the writings of the philosopher James Flynn. For this reason, the worldwide escalation of IQs became widely known as the Flynn effect. The pattern held in every country, approximately 20, for which long-term data were available. Moreover, the IQ gains were large. Depending on the test, IQ scores rose as much as 15 points, a full standard deviation, per generation. On every scale the Flynn effect was measured, the magnitude of IQ change over a few brief decades was so impressive that Flynn called the effect a “brute phenomenon.”56

The trend became detectable only because IQ tests were very stable over long periods of time. As a rule, designers of IQ tests are conservative in making changes, and the resulting stability over time allows for comparisons between examinees over many decades. In 1973, for example, the Stanford-Binet was restandardized after many years but without any changes at all to the test content.57 Yet when the new test norms were obtained, it became clear to test users that the old norms were obsolete. In particular, current children’s performance was superior to that of counterparts in the 1930s and 1940s. Nine-year-old children were commonly succeeding at tasks that were previously pegged as defining a mental age of 10 years.

So profound was the upward drift in IQ scores that, at first, many psychologists doubted that the effect was real. They speculated that the intergenerational increases were spurious—artifacts, perhaps, of more widespread use of IQ tests. Or maybe the Flynn effect was no more than a statistical error based on false assumptions. In fact, psychologists advanced several possible explanations. One hypothesis—that IQ shifts resulted from changes in the genetic base of the population—was easily dismissed. Anyone who has studied high school biology knows that large shifts in the gene pool almost always occur very slowly, typically over millions of years. The timescale of the Flynn effect simply was not compatible with significant changes in population gene frequencies. Even if time were not a factor, there were reasons to doubt that the Flynn effect could arise from genetic factors. Some psychologists observed that, statistically, higher-IQ adults tended to have fewer children. This “dysgenic” pattern meant the expectable effects of reproduction would work oppositely to the Flynn effect. In any case, the hypothesis of genetic drift was easily ruled out.

Some psychologists suspected that rising IQs might simply be an artificial consequence of increasing sophistication with tests.

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