Biology & Philosophy

, Volume 30, Issue 1, pp 1–17 | Cite as

Race, IQ, and the search for statistical signals associated with so-called “X”-factors: environments, racism, and the “hereditarian hypothesis”

  • Jonathan Michael KaplanEmail author


Some authors defending the “hereditarian” hypothesis with respect to differences in average IQ scores between populations have argued that the sorts of environmental variation hypothesized by some researchers rejecting the hereditarian position should leave discoverable statistical traces, namely changes in the overall variance of scores or in variance–covariance matrices relating scores to other variables. In this paper, I argue that the claims regarding the discoverability of such statistical signals are broadly mistaken—there is no good reason to suspect that the hypothesized environmental causes would leave detectable traces of the sorts suggested. As there remains no way to gather evidence that would permit the direct refutation of the environmental hypotheses, and no direct evidence for the hereditarian position, it remains the case, I argue, that the hereditarian position is unsupported by current evidence.


Race IQ Intelligence Hereditarian Environmental Variance Statistical signals 



Christian Matthias and Massimo Pigliucci provided helpful comments on an early draft of this paper. I benefited from conversations with James Flynn surrounding these issues, and he provided useful comments on a draft of the paper. Two anonymous reviewers provided extensive and useful feedback on drafts. Josh Banta wrote the R scripts, and helped with the simulations.

Supplementary material

10539_2014_9428_MOESM1_ESM.docx (16 kb)
Supplementary material 1 (DOCX 16 kb)


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Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  1. 1.School of History, Philosophy, and ReligionOregon State UniversityCorvallisUSA

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