Explaining Human Variation
Statistically explaining “a little bit” about something may actually end up doing more harm than good if one begins to forget the "lack of precision" of the concept. This is the first problem when one substitutes race for human variation: one tends to forget about the 94% of variation that race fails to statistically explain. The test I now put to race-as-genetics is not statistically, but conceptually. Is race merely a poor correlate of human genetic variation or does it help to explain the underlying processes by which variation comes about? Consider the following.
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Racial definitions and boundaries change over time and place. Thus, race is an inherently unstable and unreliable concept. That is fine for local realities but not so for a scientific concept. The importance of this point is that a bio-racial generalization that appears true at one time and place is not necessarily as true in another time and place. We just don’t know. One of the first lessons of science is to not base a generalization on a shifting concept, which is exactly what race is.
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The idea of race can only divide human diversity into a small number of divisions. That is the limit. This might have been all that one could do before the advent of parametric statistics, multivariable analyses, and computers. But, now we can do so much more.
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Because race is used in medicine and other fields as a way to categorize both genetics and lived experience, what passes as the result of genetic difference may actually be due to interactions or some aspect of lived experience. Using race tends to conflate genetics and lived experience (Goodman, 2001).
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I am pessimistic about how the subtle reuses of race in genetics will eventually merge with virulent racists. This does not mean that I want to hide anything about human variation. Rather, it means that we need to study human variation precisely.
I advocate for de-racializing biological variation simply because there is always a more precise and meaningful way to characterize and explain those myriad variations.
Location, Location, Location
In the real estate industry there is a general rule that three things primarily determine housing prices: location, location and location. A similar refrain applies in the case of human genetic variation. Geographic location is the best single explanation for human genetic variation. There is no more powerful piece of information for predicting the genetic makeup of either an individual or a group than knowing from where on the map they originate. Furthermore, the degree of genetic variation between any two human groups is almost entirely explained by the geographic distance between them: Genetic and geographic distances are almost perfectly correlated (Templeton, 1998).
Although highly correlated with genetic variation, geographic location, however, is not in itself an explanation for genetic variation. Complex questions about human variation come down to specifics about our early evolution and migration out of Africa, subsequent movements of migrating populations, adaptive struggles, and stochastic events. To begin to put together these puzzle pieces, requires multiple lines of evidence and inquiry. Human diversity is the end result of two complex, interrelated and fascinating processes: evolution and history.
For example, one might ask, “Why do some individuals have sickle cell trait? Is it because of their race?” The answer to this question is clearly “no.” Race is a poor explanation for the distribution of sickle cell trait, which occurs in high frequencies only in particular regions of Africa while also occurring in high frequencies in parts of Asia and Europe. Rather, sickle cell trait can be understood as a fascinating history involving agricultural intensification, clearing of lands, breeding grounds for mosquitoes, and so on (Livingstone, 1958).
Sickle cell is but one example of how evolution and cultural history explain not only the distribution of particular traits, but how particular traits come about. This is one specific example of the profoundly biocultural processes of evolution and history. I want to propose that if we think race is an explanation or even if we use it as a statistical proxy, we are less likely to conceptually understand how variation arises and is distributed.
