American Scientist reports that the Flynn Effect—the steady increase in IQ scores from one generation to the next—has leveled off and is beginning to reverse. (Presumably this bodes ill for the thesis of Steven Johnson’s Everything Bad is Good for You, which leaned heavily on the Flynn Effect to support the argument that video games and more complex TV plots were making us smarter.) James Flynn explains the waning of his eponymous effect this way:
Flynn is convinced that the cause of his eponymous effect has to do with changes in the environment that allow children more opportunity to exercise the kinds of skills probed in today’s intelligence tests–changes like a shift to smaller family sizes, which allow parents more time to interact with each child, for example, or devotion of an ever-greater portion of kids’ leisure time to abstract, mentally demanding games. He points out that in industrialized, middle-class countries (like those of Scandinavia), such influences must be reaching a point of saturation: “You can’t really get the family much smaller than one or two kids.” And the current craze for Sudoku puzzles not withstanding, as Flynn says, “eventually, people do want to relax.”
Is there any way I can point out the other obvious factor in play without being branded a closet eugenicist? Well, here goes anyway: Dumb people have more babies. Or, to be more precise about it, it’s pretty clear that fertility varies inversely with affluence and education: rich college graduates, as a rule, do not have huge families. Obviously, income and education don’t perfectly track native intelligence, but ceteris paribus you’re probably going to find more genes coding for higher intelligence in a group of affluent and highly educated people than a group of poor dropouts. Even a recent New York Times Magazine piece whose central point was how important environment is found that when children born to parents from one group were raised by parents from another, environment made a big difference, but genetic endowment trumped it. (That is to say, kids with “rich genes” growing up in poor households still scored slightly higher on intelligence tests than kids with “poor genes” growing up in rich households.) Of course, as Mark Kleiman points out, some of that difference might have to do, not with genes, but with fetal environment, since the affluent and educated are also more likely to get good nutrition and prenatal care. That suggests you might get a few more decades of Flynn Effect by improving those factors for the poor, but in the long term the upshot is going to be the same if the fertility gap holds.
All this reminds me of a movie I heard about a while back, penned by Mike Judge of Office Space and Beavis and Butthead fame, which now appears to be in production under the title Idiocracy. The premise is that a young, utterly average young private is put into suspended animation by the Pentagon for a thousand years, and discovers upon awaking that he’s become the smartest man alive. Anyway, some commenter who knows more about genetics and demography than I do should explain why this will not, in fact, happen.