IQ 1000 versus "They've Gone About as Far as They Can Go?"

Steve Hsu and PZ Myers are apparently engaged in a bit of mutual trash talk. The subject is whether the human IQ can be significantly enhanced by genetic manipulation, with Steve, naturally, saying yea and a nay from PZ. I'm far from being a fan of Myers - he's way too dogmatic for my taste - but I would definitely give him this one on points. Myers:

Stephen Hsu thinks super intelligent humans are coming. He thinks this because he’s very impressed with genetic engineering (he’s a physicist), and believes that the way to make people more intelligent is to adjust their genes, and therefore, more gene tweaking will lead to more intelligent people, inevitably. And not just intelligent, but super-intelligent, with IQs about 1000, even though he has no idea what that means, or for that matter, even though no one really knows what an IQ of 100 means. We’re going to figure out all the genes that are involved in intelligence, and then we’ll just turn the knob on each one of them up to their maximum, and boom, super-humans.


But here’s the thing: those early modern humans were pretty much indistinguishable from us today. They were about the same size, looked about the same, had the same capabilities we do now. If we used a time machine to go back and kidnap a Cro Magnon baby, bring her to our time and raise her in an ordinary American home, she’d probably grow up to play video games, shop at the mall, get a college degree, and land a job at an investment bank, and do just fine. Most of the evolving humanity has done since seems to be focused on their immune system and adaptations to agriculture and urban living.

One has to wonder, if IQ is such a great boon to humanity, why hasn’t the biological basis for it shown much improvement in the last 100,000 years? Evolution is far better at tinkering than humans are, and has been tweaking our species for a long, long time, but super-brains haven’t emerged yet. Somehow, genetic engineering is going to find amazing new solutions to intelligence, a quality of the brain that we don’t even understand yet, and cause a great leap upward? Unlikely.

Read more:

There is a whole lot of unproven BS in that second paragraph, and I wasn't too impressed by three, either, but YMMV.

Myers makes the highly dubious claim that most differences in IQ are due to environment, but he makes the far more credible claim that tweaking all the 10,000 genes Hsu thinks influence IQ to maximize IQ would have a hella lot of unplanned side effects. Let me mention a clear example.

There is a gene known as SRGAP2 that's highly conserved in our lineage. Mice have a copy, and so do gorillas. Modern humans have four copies. Inhibiting the action of the mouse ortholog promotes some kinds of brain growth. The extra copies acquired in the human lineage seem to have been sequentially acquired just when the human brain size took it's big jumps from Chimp size to human size.

There is a punch line in the mechanism of action. The extra copies are incomplete, and seem to act only or mainly by inhibition of the original SRGAP2 A protein. Physiologically, this looks like a blunt instrument.

Steve has replied to the critique on his blog. His strongest argument seems to be that there really have been some super smart people. Would this be a great world if everybody was as smart as John von Neumann or Terry Tao? Beats the hell out of me. Would the world be any better if we could all be like Mike (Michael Jordan) or Lebron James? The extraordinary are always in some sense freaks of nature. Maybe our world needs more of one variety or another, but evolution suggests that for much of our history it wasn't so.


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