May 5, 2005

The Flynn Effect & Basketball:

Continuing iSteve's nonstop coverage of what high-IQ Steves are thinking about, in Wired, Steven Johnson writes in "Dome Improvement":

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.

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."

Flynn is, personally, a great guy, he does important research, and this explanation is not implausible. For example, it helps explain why identical twins tend to become more alike in IQ as they get older -- as they grow apart, they mold their environments to fit their genetic makeups better. Most notably, their environments are no longer distorted by having to play an unnatural role distinct from that of their identical twin (such as leader or follower, which many twin pairs adopt just so they get things done). For example, two extremely tall identical twins on one high school basketball team can cause problems because both are natural centers, but one has to play power forward. If they go to different colleges, they might both then play center -- i.e., their environments become more appropriate for their genetic codes.

Still, Flynn needs to lose this pseudo-example about NBA players. Living in New Zealand, he seems to have forgotten that NBA basketball players are not distinguished by just a 1% biological advantage over non-NBA individuals.

Now and then, I run into movie and TV stars on the street -- Tom Hanks, Robin Williams, Geena Davis, etc. -- and when dressed to be inconspicuous, they are fairly inconspicuous. Most screen stars are not obvious genetic marvels, although they are clearly above average in looks and talent. So, Flynn's 1% genetic advantage theory might, or might not, be true for Tom Hanks.

(Although it's definitely not true for Robin Williams, at least not as a stand-up comedian, where he's about seven standard deviations from the mean. Dana Carvey tells the story about how, long ago, as a young man trying to get his courage up to try comedy, he went to an open-mike night, and promised himself he'd get up on stage if he thought he was better than the other amateurs on the list before him. Dana was feeling very good about himself, until the guy before him did his act: "Oh, no, I'll never, ever be even close to him!" he lamented. That amateur was Robin Williams.)

But Flynn's assertion doesn't work at all for the NBA stars I've run into: Wilt Chamberlain, Patrick Ewing, Bill Walton, Dennis Rodman, Horace Grant, Mark Eaton, etc. These guys are astonishing physical specimens.

For example, a few years I was walking down Rush Street in Chicago on a Friday night when out of a restaurant ahead of me comes Bill Walton, the greatest white center ever. He always insisted on listing himself at 6'-11", but he's one of the rare basketball players who is considerably taller than his official height. What was more surprising is how impressive the breadth of his shoulders and his overall musculature were even at about age 50. He was going my way, so I trailed about 30 feet behind him for quite a few blocks to watch the amusing reaction of pedestrians passing him. Many seemed stunned by his size, especially women, few of whom recognized him.

More seriously, the Flynn and Dickens model is not very exciting in its implications. All it says is that people create their own environments to suit their genetic strong suits. For example, I've molded my life so I spend a lot of time crunching data and very little time with a wrench in my fumble-fingered hands. If I spent lots more time trying to repair stuff, I'd be a little bit better at it, but, so what? I'd never be as relatively good at it as I am at crunching data, so why spend my life butting my head against my genetic brick wall?

Similarly, if Flynn and Dickens are serious about altering the environments of blacks enough to put a sizable dent in the white-black IQ gap, they would call for a police state that bans all manifestations of hip-hop, that executes Jay-Z and Dr. Dre as bad examples, that puts minor rappers and black celebrities in concentration camps, etc. I doubt if that would work, but it's at least a semiserious proposal for grappling with a problem of this magnitude. But, Flynn and Dickens aren't serious at all about closing the IQ gap so they don't call for serious measures, just token ones that their own analysis shows are insufficient.

My published articles are archived at -- Steve Sailer

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