http://wired.com/wired/archive/13.05/flynn.html Though the Flynn effect is now widely accepted, its existence has in turn raised new questions. The most fundamental: Why are measures of intelligence going up? The phenomenon would seem to make no sense in light of the evidence that g is largely an inherited trait. We're certainly not evolving that quickly. Flynn has his theories, though they're still speculative. "For a long time it bothered me that g was going up without an across-the-board increase in other tests," he says. If g measured general intelligence, then a long-term increase should trickle over into other subtests. "And then I realized that society has priorities. Let's say we're too cheap to hire good high school math teachers. So while we may want to improve arithmetical reasoning skills, we just don't. On the other hand, with smaller families, more leisure, and more energy to use leisure for cognitively demanding pursuits, we may improve - without realizing it - on-the-spot problem-solving, like you see with Ravens." When you take the Ravens test, you're confronted with a series of visual grids, each containing a mix of shapes that seem vaguely related to one another. Each grid contains a missing shape; to answer the implicit question posed by the test, you need to pick the correct missing shape from a selection of eight possibilities. To "solve" these puzzles, in other words, you have to scrutinize a changing set of icons, looking for unusual patterns and correlations among them. This is not the kind of thinking that happens when you read a book or have a conversation with someone or take a history exam. But it is precisely the kind of mental work you do when you, say, struggle to program a VCR or master the interface on your new cell phone. The best example of brain-boosting media may be videogames. Mastering visual puzzles is the whole point of the exercise - whether it's the spatial geometry of Tetris, the engineering riddles of Myst, or the urban mapping of Grand Theft Auto. The ultimate test of the "cognitively demanding leisure" hypothesis may come in the next few years, as the generation raised on hypertext and massively complex game worlds starts taking adult IQ tests. This is a generation of kids who, in many cases, learned to puzzle through the visual patterns of graphic interfaces before they learned to read. Their fundamental intellectual powers weren't shaped only by coping with words on a page. They acquired an intuitive understanding of shapes and environments, all of them laced with patterns that can be detected if you think hard enough. Their parents may have enhanced their fluid intelligence by playing Tetris or learning the visual grammar of TV advertising. But that's child's play compared with Pokémon.