The Biogeography of Human Diversity in Life History Strategy

Controversial theories have been advanced (e.g., Rushton, 1985, 2000) relating "race" to human life history strategy: (a) different human populations ("races") evolved in different physical and community ecologies; (b) these ecologies should at least partially determine the selective pressures shaping the evolution of human life history strategies in different parts of the world; ergo (c) different human populations ("races") should be associated with different modal life history strategies. Although the argument seems plausible in its stark logical form, there were several limitations in operationalization: (a) the traditional "Big Three Races" used (Caucasoid, Mongoloid, and Negroid) do not correspond very closely to the five or six major population clusters identified by modern human genetics; (b) these "races" are neither discrete nor mutually exclusive, having many zones of overlap and interbreeding, making geographical boundaries fuzzy and imprecise; (c) fixing the "race" issue will still not directly address the fundamental premise of the theory that human life history strategy is largely determined by ecological factors. We therefore divided a sample of 141 national polities into zoogeographical regions instead of conventionally defined "races." We only used regions for this analysis that were still inhabited mostly by the aboriginal populations that existed there prior to the 15th century AD. Although obtained by different procedures than those used originally by Rushton, these produced results that were surprisingly convergent with the basic premise underlying the original hypotheses.