Moving Target

This Scientific American article explains Flynn's Effect, the observation that scores on IQ tests rise over time. It's a good article, and gives useful background for Eliot Gelwan's notice that the tests are being revised (as they are, apparently, every 15 to 20 years) to correct for this effect.

So if you think your child is smart, don't be disappointed if their IQ score seems lower this year...

Ceci and his current and former graduate students, Tomoe Kanaya and Matthew Scullin, found, for example, that the number of children recommended for special services for mild mental retardation tripled during the first five years of a new test compared with the final five years of an old test, despite the fact that there were no real changes in underlying intelligence.

Cornell News