one key mutation of one key gene which accounts for the largest part of the skin color difference between Africans and Europeans, but even that only accounts for around a third of the color variation. We’ve known for decades that there are actually many different ways skin can end up “black”:
The Negritos of the islands of Luzon and Mindanao in the Philippines, for instance, superficially resemble other dark-skinned groups in Africa and Australia. Yet their overall genetic affinities turn out to be far stronger to the lighter-skinned Asian peoples who surround them.
So if you measure IQ of “black” and “white” populations, you’re not even measuring populations that have anything genetically in common. The “black” group will include people who are genetically more “white” than many people in the “white” group. So “race science” is literally garbage data in, garbage answer out.
Robert Taylor via Compfight
But let’s ignore even that problem, and imagine we are studying genetically similar people of European descent, and genetically similar people of African descent — so we’re looking at just that one key gene mutation mentioned earlier. Let’s imagine our subjects all grew up in the same cultural environment, so we can ignore all the problems with the cultural biases of the IQ test. What about then — might we expect to measure a meaningful IQ difference?
Well, skin color is a matter of small variations in genes. However, the melanin in the brain which we know to be important is a different kind to the melanin in the skin, eyes and hair. While there is eumelanin (the skin color type) in the brain, we don’t have any evidence that it serves any purpose. (As an aside, this means that the theory that black people are innately superior because of their increased melanin levels — a kind of reverse “race science” — doesn’t hold up either.)
So asking whether black skin leads to a genetic predisposition to lower intelligence is really just like asking whether blonde women are naturally more stupid, or whether gingers are naturally weak and overweight. It’s like calling for scientific research on whether green eyes mean you’re better at math.
But in fact, the genetics of human hair color have been teased out quite precisely:
Further study showed that the region of human DNA that contained the single nucleotide change associated with blondness specifically affected the expression of KITLG only in hair follicles. […]
“It’s clear that this hair color change is occurring through a regulatory mechanism that operates only in the hair. This isn’t something that also affects other traits, like intelligence or personality. The change that causes blond hair is, literally, only skin deep.”
In other words, melanin in the brain and melanin in the hair aren’t even affected by the same gene mutations. The mutation that changes hair melanin levels has literally zero effect on brain melanin. So there’s simply no plausible mechanism by which the blonde hair mutation would affect intelligence. There’s no reason to believe that skin color should be any different.
If you want further reading, PBS has links to articles. I’d also suggest reading about Theodore W. Allen’s book “The Invention of the White Race”, which sets out the history of how race — and in particular, the “white race” — was an invention of 17th Century American plantation owners, who used it to shore up slavery by creating a new division between poor white laborers and black slave laborers.
Adrian Wallett via Compfight
In summary: Race is an invented social construct that is used to distract the disenfranchised from class issues. It doesn’t correspond to genetics or to skin color. Hence studies showing that some races are genetically predisposed to higher intelligence are garbage. You can’t even get as far as discussing nature vs nurture, because you haven’t grouped by anything that corresponds to a feature of nature.
At this point you might be asking: OK, so if the differences in The Bell Curve aren’t attributable to race, or even to skin color, what causes them? The answer seems to be that we don’t yet know. There are a lot of possibilities. Ultimately, I suspect that the data are just too noisy to let us analyze them and get a clean answer. But science can tell us a few things that aren’t plausible explanations…
Hopefully soon we can move on to more serious questions, like whether gingers have souls, or whether all humans having souls is just liberal dogma. © mathew 2017
© mathew 2017