Saturday, March 27, 2010

The illusion of difference

Racialist "scientists" sometimes defend their ideas about the reality of human races by invoking the "it's so obvious" argument. Look at the photo below, they might say, and you can tell immediately which person has African ancestry and which has European ancestry:

And of course it is pretty obvious that, statistically speaking, the Reverend Gary Davis, on the left, is more likely to have recent African ancestors, while the little girl on the right is more likely to have recent European ancestry.  It was sudden confrontations with people who looked and behaved very different from themselves that led Europeans to develop their ideas about "racial" differences. In the age of European exploration and conquest, Europeans for the first time boarded sailing vessels, sailed away from people who were familiar, and after long sea voyages were suddenly faced with people who were maximally unfamiliar. This experience of human diversity led to Linnaeus's taxonomic classification of humans into four distinct groups and, a few years later, Blumenbach's elaboration of five categories.

The problem, as we now know, is that the nature of biological variation does not favor the division of species into discrete subcategories (subspecies, or races). Biological traits display clinal distribution, as shown by the gradual increase in frequency of the B blood type allele as we move east across Eurasia.

The same is true for traits that we think of as diagnostic of human "races," such as skin color. There is no clear division between "black" and "white" skin colors; instead, skin color varies clinally with skin tending to be darker near the Equator and gradually becoming lighter in populations that are located farther and farther from the Equator.

We can get an idea of how this looks on actual people by examining portraits from (left to right) Scandinavia, Spain, Morocco, and Nigeria.

The concept of "races" as discrete categories is as bogus for humans as it is for any other wide-spread species, such as Puma concolor (a.k.a. cougar, mountain lion, panther, etc.). This is a fact that is increasingly accepted by biologists, but still denied by race-affirmers like J. Philippe Rushton, who divides humans into three categories: mongoloid, negroid, and caucasoid and then attributes different behavioral traits to these groups. But more about this in a future post.

1 comment:

  1. I'd like to see your future comments on this. I certainly agree with this re human beings, for a variety of reasons, but with nonhuman organisms, "giving up" subspecies may be somewhat trickier. On the one hand, if you keep subspecies in organisms like Puma concolor, you may be playing into the hands of "racialists" like J.Philippe Rushton, who could reasonably claim that if there are nonhuman subspeices, why not among humans? On the other hand, the subspecies concept may have at least some scientific validity in that some populations of some species display fairly distinct differences from other populations. For example, "black" bears have been dividied into actual "species" partly on the basis of their color. These color variations are sometimes quite dramatic: the so-called "Kermode" bears in certain British Columbia forests are white, not black, and they tend to look like rather small polar bears. But they are allUrsus amaricanus. In any case "black" bears are often not black, especially if they happen to live in areas where forest cover is discontinuous(e.g. in places like Yellowstone or Mt. Rainier National Park; I've seen a number of these color variations). I could go on, but while these genetic variations probably don't have much meaning except as some sort of enviornmental adaptation, much like variations in human skin color, they may, and I emphasize the "may" here, suggest the kind of variations in populations that could, conceivably become the basis for speciation. I think this whole concept is really something of a gray area, scientifically.


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