Peter Frost is an excellent race realist anthropologist. I think he is a working academic. He is as smart as the Devil. Brilliant man.
This is my post that he critiques.
Lindsay, R. (2010). The Head Size/IQ/Race Trainwreck, March 11
He sort of handwaves it away, but I think I am onto something.
I noticed certain things. First of all, Amerindian IQ is generally set at 87 all up and down the Americas. Yet their head sizes are all over the place, from large to small. OK, their heads range from large to small, but their IQ’s are all the same? Something wrong with the theory.
Here is his quote. My work is in italics below:
There has not been much comment on the Beals, Smith, and Dodd (1984) article. The most substantive one seems to be a blog post by Robert Lindsay (2010) who calls their map a “train wreck” for claims that cranial capacity correlates with IQ:
White racists like to make a big deal about the supposed correlation between head size and intelligence and race. A nice little chart showing the basically dishonest portrayal they attempt based on cherry-picking data is below.
Methinks that Lindsay takes the fine details on that map a bit too seriously. Many of the details are simply creative extrapolation and infilling; otherwise, the map roughly corresponds with world distribution of mean IQ. Furthermore, no one is claiming that cranial capacity is the only determinant of IQ. There are undoubtedly many others: cortical surface area, myelinization of nerve fibers, relative importance of domain-general thinking, etc.
But he does make a good point about the Amerindian data.
As you can see, in the Americas, there is no good evidence whatsoever for head size and IQ. I am not aware that Amerindian IQ varies in the Americas. The average is apparently 87 across the continent. If anyone can show me that it varies by latitude, please do.
Agreed. No one can, for now. But a hypothesis is not false because no one has bothered to test it.
But there are quite a few other holes in this theory. South Indians and Vietnamese have the same sized heads. South Indian IQ = 82, and Vietnamese IQ = 99. How does that work? Heads the same size and one SD difference in IQ? What?
Ugandans/ Kenyans and Italians have the same sized heads. Ugandans and Kenyans have the largest heads in Africa. Now that I think about it, Masai heads do look quite large. Ugandan/Kenyan IQ = 68, and Italian IQ = 103. OK, now we have heads of the same size and a 35 point or over 2 SD difference in IQ? Huh? I suppose you can argue that Ugandans have huge heads but there’s not a lot inside of them except maybe air. Or you can argue that the Ugandan brains are not very specialized, and Italians have much more specialized brains. I suspect this may be the case with Vietnamese too.
After all, you can have a huge car that is junk and a smaller car that is one of the finest on Earth. It’s all down to the specialization and micro-detail. And I suspect it’s not just head size alone. We know full well that certain more modern parts of the brain are correlated much more with advanced thinking than other parts of the brain are. The prefrontal cortex is one of those – it hardly exists in apes, but it’s full blown in man. And there are structures within the PFC than are even more specialized than the PFC itself. Maybe it’s not the size of the brain but the type and quality of the machinery inside of it?
This becomes quite clear when we notice that Eskimos have the biggest heads of all, yet their IQ is only 91, just above the world average of 89. 91 is not a bad IQ, but one would expect more from the people with the biggest heads on Earth, no? Usually the explanation is that a huge portion of the Eskimo brain has gone over to visuospatial, which is actually proven in experiments that show how Eskimos can find their way even in the most confusing wind, snow and ice-filled landscapes.
Aborigines also have superb visuospatial skills, some of the finest of all mankind. They got this from having evolved in the trackless desert that in terms of familiar objects and markers is probably not a whole lot different from the Arctic. So if you have a huge brain but a lot of that larger size is gone over to something like visuospatial, then that won’t do a lot for your IQ.
On the other hand, there goes your theory! We are already finding exceptions and handwaving them away.
Nevertheless, I think that the theory is good in sort of a broad and general way, possibly with a number of exceptions. The exceptions may be down to some large brains having huge areas gone over to certain specialized things that don’t do much for IQ and some small brains possibly being as good as large ones in that perhaps they are very specialized or have a lot of micro-machinery of very good quality in their heads.
All in all, not a bad theory, but beware of the exceptions minefield.