Troublesome Reflection: Racism as the Blind Spot in the Scientific Critique of Race

In A Troublesome Inheritance, Nicholas Wade seeks to use advances in genomics and comparative human biology to revivify hereditarian racialist notions about the ways in which differences among human societies are shaped by evolutionary forces acting on genetic variation. The arc of the argument consists of three claims: (1) human evolution has produced some unspecified number of races; (2) differences among these races in social dispositions have a strong genetic component; and (3) an oppressive academic environment keeps this kind of research out of the intellectual mainstream. These claims form the core of a world view that I refer to as "hereditarian racialism." Recent examples of this genera include The Bell Curve (Herrnstein and Murray 1994) and Race, Evolution, and Behavior (Rushton 1995), with examples extending back for some time (e.g., Grant 1970 [1912]). None of these claims are true. The book is neither good popular science writing nor all that new or interesting by the standards of the hereditarian racialist literature. (Rushton [1995] and Miele and Sarich [2005] are far more interesting examples of this genera.) Troublesome Inheritance, however, is a useful foil for a critical examination of the mainline scientific critique of hereditarian racialism, which, as it stands, is weak and scattered. To recuperate a useful scientific critique of race, we need to come to grips with ways in which the political processes of racism have shaped human organisms over the last few hundred years.

Genomic Variation and Human Population History and Structure

Contrary to Wade's assertion, all parties to controversies surrounding human variation agree that humans show genomic and phenotypic variation that is structured in geographic space, through time, and across many social divisions. The disagreement is over how best to describe and model the evolutionary causes of this variation. Ignoring for the moment the large changes in the distribution of human genetic variation over the last few centuries (more on that below under Evolutionary Consequences of Racism), we can build a range of evolutionary models and statistically compare their fit to available genomic data.

In this idiom, racial models of variation like the one advocated in Troublesome Inheritance take the form of something like the tree diagram in Figure 1A (Hunley et al. 2009; Long and Kittles 2003). Groups within a race share common ancestry with one another more recently than they do with groups in other races. In contrast, most narrative accounts of recent human evolution feature population fissioning and founding events reflecting the movement of groups into different regions (previously occupied or not; see, e.g., Henn et al. 2012). Out-of-Africa dispersals and the spread of agriculture are two examples of these kinds of events. In this case, we might start with an estimate of a tree of patterns of common ancestry among groups under the expectation that groups with more recent common ancestry should be more genetically similar than those with distant common ancestry (Long and Kittles 2003; Long et al. 2009; Pickrell and Pritchard 2012). We can then add in admixture (episodic mixing of previously isolated groups) and gene flow between groups to produce a more elaborate model (Hunley et al. 2009; Pickrell and Pritchard 2012; Prüfer et al. 2014). The result is something like the elaborate model sketched out in Figure 1B, which is far and away the best fit to population genomic data. The relative importance of the different processes that make up these models are still a matter for further research, but it is certain that the racial model is a poor fit to the data and does not allow us to generate new and interesting questions.

Figure 1.

Models of population structure and history. Black lines indicate evolving lineages and recency of common ancestry, with time going from left to right. The numbered tips of the lineages are operationally defined groups of individuals. The length of a line segment reflects...