Review essay: Lynn and Vanhanen, IQ and global inequality

IQ and Global Inequality is a sequel to the authors' earlier IQ and the Wealth of Nations wherein they argued that "... national differences in intelligence are an important factor contributing to differences in national wealth and rates of economic growth" (p. 2). Or, later more precisely stated, that "... national IQ is the single most powerful explanatory variable, but because the explained part of the variation does not rise higher than 4060 percent, this explanation leaves room for other explanatory factors"(p. 13). Not surprisingly, even so qualified, this thesis triggered a "mixed reception." As the authors relate with refreshing candor, some of the reviewers denounced them for "jumping to conclusions," took issue with their "relatively weak statistical evidence and dubious presumptions," found the study "neither methodologically nor theoretically convincing," and dismissed the evidence as "virtually meaningless" (p. 3).