The Emergence of Evolutionary Psychology*

Humans, like all other organisms, were created thro ugh the process of evolution. Consequently, all innate human characteristics are the products of the evolutionary process. Although the implications of this were quickly grasped in investigating human physiology, until recently there has been a marked resistance to applying this knowledge to human behavior. But evolution and the innate algorithms that regulate human behavior are related as cause and consequence: lawful relations are being discovered between the evolutionary process and the innate psychology it has shaped. These lawful relations constitute the basis for a new discipline, evolutionary psychology, which involves the exploration of the naturally selected "design" features of the mechanisms that control behavior. This synthesis between evolution and psychology has been slow in coming(see DeVore, this volume). The delay can be partly accounted for by two formidable barriers to the integration of these two fields: the initial imprecision of evolutionary theory, and the continuing imprecision in the social sciences, including psychology. The revolution in evolutionary theory began two decades ago and, gathering force, has subsequently come to dominate behavioral inquiry. Vague and intuitive notions of adaptation, frequently involving (either tacitly or explicitly) group selection, were replaced by increasingly refined and precise characterizations of The application of these more precise models of selection at the level of the gene opened the door for meaningful explorations of a series of crucial behavioral problems, such as altruism towards kin, aggression, mate choice, parental care, reciprocation, foraging, and their cumulative consequences on social structure. These theoretical advances had their most dramatic impact on field biology, quickly reorganizing research priorities, and integrating the diverse studies of animal (and plant) behavior into a larger system of evolutionarily-based behavioral ecology (or sociobiology). The heart of the recent revolution in evolutionary theory lies in the greater precision with which the concept adaptation is now used: the primary evolutionary explanation for a trait is that it was selected for; this means that it had or has the consequence of increasing the frequency of the genes that code for it in the population; if there is a correlation between a trait and its consequences, the trait can then be termed an adaptation; the means by which a trait increases the frequency of its genetic basis is called its function. There is no other legitimate meaning to adaptation or function in the evolutionary lexicon. Thus, the genes present in any given generation …