Genetic averaging

Genetic averaging is a the notion that people of European descent are in some way a genetic average of people of Sub-Saharan African descent and people of East Asian descent. It is promoted by J. Phillipe Rushton. Some argue that the genetic research Rushton cites has shown no biological basis for race and that his identifications of genetic groups are arbitrary - specifically, the genetic diversity found between members of a group is higher than differences between groups.

Arthur Jensen argues that, "if the differences between the means of various populations were not smaller than the mean difference between individuals within each population, it would be impossible to distinguish different populations statistically." Others assert that Jensen makes a logical error in believing that any observed genetic difference must be representative of all genetic differences - that is to say, it is possible to distinguish arbitrary groups which have minor differences between means, but more differences within those groups. For example, blue and green bags of coins may differ as groups, by 2 cents, but within groups larger amounts:

Some claim that the genetic linkage trees Luigi Luca Cavalli-Sforza provides clearly show distinct branches for all the three main races Rushton describes. Others claim that when Cavalli-Sforza applied the wholly objective mathematical procedure of principal component analysis to his genetic data, the major racial groupings Rushton describes formed very clear and unambiguous clusters. Rushton claims his focus on race is consistent with the work of forensic experts, research in bio-medicine, and biologists studying geographic variation in other species. Harvard biologist E.O. Wilson told journalist Peter Knudson. "The basic reasoning by Rushton is solid evolutionary reasoning; that is it's logically sound. If he had seen some apparent geographic variation for a non-human species-a species of sparrow or sparrow hawk, for example-no one would have batted an eye."

These claims are highly contested by other scientists and researchers, including those whom Rushton cites. Rushton's research has also been criticised by those that consider his conclusions and methods as "sloppy" and "unscientific".