From very early in the history of IQ testing, it was observed that blacks averaged lower scores than whites. That quickly raised questions of causality: Nature? Nurture? Both?
One way to falsify the genetic theory of the IQ racial gap would be if there proved to be no positive correlation among self-identifying African Americans between IQ and the proportion of white ancestry. Finding a positive correlation wouldn’t prove that the race gap was at least partly genetic — there are always more complicated explanations that can be devised. But not finding a positive correlation would be highly embarrassing to the Nature camp.
We now finally have huge databases of ~10,000 volunteers, such as the Philadelphia Neurodevelopment study and the Adolescent Brain Cognitive Development, that by combining cognitive testing with DNA data on genetic ancestry allow us to correlate IQ and racial admixture better than the studies that Mead criticized a century ago.
Of course, they are immense hot potatoes. Doing these studies helped get tenured professor Bryan Pesta fired from Cleveland State U. But very little news coverage has been given to Pesta’s firing, perhaps because writing about it would require describing his research, which is unthinkable.