IS TIBETAN POLYANDRY ADAPTIVE - METHODOLOGICAL AND METATHEORETICAL ANALYSES

This paper addresses methodological and metatheoretical aspects of the ongoing debate over the adaptive significance of Tibetan polyandry. M ethodological contributions include a means of estimating relatedness of fraternal co-husbands given multigenerational polyandry, and use of Hamilton's rule and a member-joiner model to specify how inclusive fi tness gains of co-husbands may vary according to seniority, opportunit y costs, and group size. These methods are applied to various data set s, particularly that of Crook and Crook (1988). The metatheoretical di scussion pivots on the critique by evolutionary psychologists of adapt ationist accounts of polyandry. Contrary to this critique, I argue tha t valid adaptationist explanations of such practices do not necessitat e cognitive mechanisms evolved specifically to produce polyandry, nor that there must have been exact equivalents of Tibetan agricultural es tates and social institutions in human evolutionary history. Specific issues raised when one posits either kin selection or cultural evoluti on to explain the adaptive features of Tibetan polyandry are also disc ussed.