Reciprocity (cultural anthropology)
（重定向自Moral reciprocity）
In cultural anthropology, reciprocity refers to the non-market exchange of goods or labour ranging from direct barter (immediate exchange) to forms of gift exchange where a return is eventually expected (delayed exchange) as in the exchange of birthday gifts. It is thus distinct from the true gift, where no return is expected. Reciprocity is said to be the basis of most non-market exchange. David Graeber argues, "as currently used, 'reciprocity' can mean almost anything. It is very close to meaningless."