I think that a lot of people misunderstood me in this post, judging by the comments.

I'm not claiming that brain size correlates perfectly with intelligence, and that size is the only factor of interest. Obviously, there's no reason to think that a non-human brain twice the size of a human brain would be expected to be smarter. My point was that for humans, with normal brain configuration, it's a reasonable assumption that a bigger brain is generally going to be smarter than a smaller one. There's just room for more brain stuff that constitutes smarts (and I don't think that transport speeds have much relevance, relative to numbers of neurons).

With regard to Gould, yes, I did read The Mismeasure of Man, and I also read between the lines. He was a dedicated Marxist, and the very notion that there could be a correlation between "race" (and yes, I know that this is an imprecise concept, and a social rather than biological construct) and intelligence would have been anathema to him, which was why it was so important to him to debunk it. I have no particular beliefs about whether or not whites are on average smarter than blacks, or vice versa, but I think that it's absurd to claim that it's impossible for there to be any gross correlation between intelligence and melanin content. Anything that's heritable will have variability in human populations, and anyone who doesn't think that IQ, however measured or defined, doesn't have a heritable component is indulging themselves in the blank slate fallacy.

Of course, the whole issue, while it may be of scientific interest, shouldn't be so societally controversial. So what if whites are dumber, on average, than blacks, or vice versa? We don't deal with average people--we do, or at least should, deal with individuals. It doesn't matter what group I come from if I have a high IQ, and am one of the people raising the average for that group. Such research cannot rationally be used to justify any particular social policy, at least any that's congruent with the Fourteenth Amendment.