Why are IQ test scores rising around the globe? Steven Johnson, who we've talked about before, thinks it might have something to do with video games and other intellectual junk foods.

Interesting article, particularly the second half, which provides some hard data on IQ testing:

The classic heritability research paradigm is the twin adoption study: Look at IQ scores for thousands of individuals with various forms of shared genes and environments, and hunt for correlations. This is the sort of chart you get, with 100 being a perfect match and 0 pure randomness:

The same person tested twice: 87
Identical twins raised together: 86
Identical twins raised apart: 76
Fraternal twins raised together: 55
Biological siblings: 47
Parents and children living together: 40
Parents and children living apart: 31
Adopted children living together: 0
Unrelated people living apart: 0

After analyzing these shifting ratios of shared genes and the environment for several decades, the consensus grew, in the '90s, that heritability for IQ was around 0.6 - or about 60 percent. The two most powerful indications of this are at the top and bottom of the chart: Identical twins raised in different environments have IQs almost as similar to each other as the same person tested twice, while adopted children living together - shared environment, but no shared genes - show no correlation. When you look at a chart like that, the evidence for significant heritability looks undeniable.

But things may be more complicated than they look:

Four years ago, Flynn and William Dickens, a Brookings Institution economist, proposed another explanation, one made apparent to them by the Flynn effect. Imagine "somebody who starts out with a tiny little physiological advantage: He's just a bit taller than his friends," Dickens says. "That person is going to be just a bit better at basketball." Thanks to this minor height advantage, he tends to enjoy pickup basketball games. He goes on to play in high school, where he gets excellent coaching and accumulates more experience and skill. "And that sets up a cycle that could, say, take him all the way to the NBA," Dickens says.

Now imagine this person has an identical twin raised separately. He, too, will share the height advantage, and so be more likely to find his way into the same cycle. And when some imagined basketball geneticist surveys the data at the end of that cycle, he'll report that two identical twins raised apart share an off-the-charts ability at basketball. "If you did a genetic analysis, you'd say: Well, this guy had a gene that made him a better basketball player," Dickens says. "But the fact is, that gene is making him 1 percent better, and the other 99 percent is that because he's slightly taller, he got all this environmental support." And what goes for basketball goes for intelligence: Small genetic differences get picked up and magnified in the environment, resulting in dramatically enhanced skills. "The heritability studies weren't wrong," Flynn says. "We just misinterpreted them."

Like I said, cool article, but I still have trouble believing in the Atkins-like power of video games to make us smarter. In my life, video games have made me far more stupid, and continue to do so.

In his story from BCR #1, Michael talked about junk miles: "the mileage one accumulates without actually getting better, stronger, faster—mileage that does nothing to correct mistakes in your form." Intellectually speaking, the bulk of pop culture is junk mileage. It's doing nothing for you.

So how do I explain the Flynn effect? I'm not a psychologist, but I'd guess that people are getting better at taking IQ tests because the content of IQ tests is no longer mysterious, but a known quantity that one is prepped for from early childhood.

Then again, I'm one of those people who thinks IQ testing is bunk.