A reader writes:

Your reader says, "I come to this as a scientist...There is no "race"...at the genetic level...There is a continuum of genetic diversity...racial categories are a cultural construct."

Ok, race is cultural construct, but so what?  Does that make racial categorization somehow less real?  When we perceive color, we are looking at a continuum frequency diversity on the electromagnetic spectrum.  Somehow we still manage to call one color red and another one blue.  You don't hear people saying the difference between red and blue is meaningless and unworthy of scientific investigation, do you?  I have a hydrangea that is red and another that is blue.  I should pretend that they are the same, and not inquire as to whether there is a genetic basis for it?  (There isn't; it's a result of varying soil acidity, but how can I know that if I'm not allowed to ask the question because someone has already told me that color is just a cultural construct?)

If there is no "race" at the genetic level, then why is it that dark skinned people with very curly hair keep having children with dark skin and curly hair?  Why do children of Asians look persistently different from children of Jews?  There is something genetic happening that affects skin, hair, facial features, disease susceptibility, and a whole host of other things.  But we are powerless to examine those differences because there's no such thing as "race" at the genetic level?  The contention is absurd on its face.

Tell it to a drug company who sees differential effectiveness and side effects among blacks, Asians, and whites.  Sorry guys, you are not allowed to record race in your clinical trials anymore, because everyone knows that information has no meaning!

Another writes:

First of all, there is no controversy whatsoever that black people, on average, have lower IQ scores than white people. Second, race is a useful construct. To me, the term simply means, a very very large, very extended family.

I would also like to take issue with your readers who argue that IQ is meaningless. Precisely the opposite is true: The central message of the Bell Curve is that IQ scores have *high predictive validity* for all kinds of things, including income. Anecdotes about purportedly dumb people that have been very successful or amazingly bright individuals that have failed in some way are meaningless behind the mountain of data that point to a key role for IQ, whatever that may be, in individuals' life outcomes.

I would like to point out that there is growing evidence that one's IQ is correlated with brain regional volumes, particularly the dorsolateral prefrontal cortex, the parietal cortex, and the connections between them. This indicates that the construct called IQ has a basis in biology. See, for example, this article in Nature Reviews Neuroscience.

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