Biological approaches to human behavior got themselves a bad name from the excesses of naked ape and territorial-imperative theorising in the 1960s. Since then, palaeontology and genetics have made major advances in our understanding of the mechanisms of evolution, while neuropsychology and biological sciences have been rapidly expanding knowledge of human functioning. Parallel to these developments, evolutionary psychology has emerged as a substantially new eld (Barkow, Cosmides, & Tooby, 1992 Crawford & Krebs, 1998) seeking to escape the taints of its populist forebears by serious scholarship into the functionality of human behavior and, by implication, the subject of this paper, the processes and constraints on human action.