The insights provided by the application of evolutionary psychology to established fields of evidence has clinical relevance in areas such as fears, anxiety, and depression (Dimberg & Ohman 1996; Gilbert 1992; Marks & Nesse 1994). Certain evolved behaviours, such as the attachment behaviour of human and other primate infants, are accepted as orthodoxy. But broader notions of an evolved "human nature," that is, of specialised propensities 1 that generate functional behaviours effective in the social and material world, are still viewed with skepticism or indifference by many in the psychological and medical communities (Andersson 1993; Schaffner 1998). Among the more important reasons for this may be concern about genetic determinism or, at least, a distaste for invoking genetic factors (Crawford 1989; Daly & Wilson 1988; Plomin 1989; Tooby & Cosmides 1992), and suspicion of "Just-So Stories," that is, post hoc explanations from available evidence (Gould & Lewontin 1979). Far from endorsing the over-simple gene explanations that are sporadically revisited in psychiatry (Plomin 1989), evolutionary psychology aims to broaden our understanding of behaviour, in all its flexibility and contingency in relation to the immediate environment and the individual's learning history, by addressing the cognitive adaptations that are part of our heritage (Cronin 1991). 1. The function of pain Pain is the "final mediator" of a wide range of selection pressures (Walters 1994): sublethal injuries that may still threaten survival or reproduction are incurred during predation, intraspecific combat, and competition with conspecifics. By virtue of its aversiveness, pain serves to promote the organism's health and integrity, to the extent that congenital absence of pain on injury significantly shortens human life (Damasio 1999; Wall 1999): "Suffering offers us the best protection for survival" (Damasio 1994, p. 264). The adaptive value of experiencing pain at first seems selfevident: distinguishing harmful from harmless situations, prompting avoidance of harm and its associated cues, giving a high priority to escape from danger, and promoting healing by inhibiting other activities that might cause further tissue damage (Bateson 1991). Research in animals has focussed mainly on immediate escape from pain (e.g.,