ABSTRACT
This chapter begins with a brief discussion of the contrast between the phenomenon labeled "reciprocity" by ethnologists and "reciprocal altruism" by behavioral ecologists. It focuses especially on food sharing among ethnographically known hunter—gatherers and subsistence cultivators to illustrate some of the patterns, the explanatory problems they present, and some of the competing hypotheses that evolutionary ecologists pose to account for them. Three models used to explore problems of sharing and collective action are introduced. The models illustrate three kinds of explanation—delayed reciprocity, mutualism, and manipulation. The chapter reviews the effects of time lags, ancillary benefits, and resource "lumpiness" on collective action. Some applications to "the sexual division of labor" are briefly discussed. Finally, ethnographic examples in which variations in patterns of food sharing have been described are summarized and examined in light of issues. Evolutionary ecologists have thus found game theory to be a particularly useful analytical tool.
