Culture: the missing piece in theories of weak and strong reciprocity.

Guala does not go far enough in his critique of the assumption that human decisions about sharing made in the context of experimental game conditions accurately reflect decision-making under real conditions. Sharing of hunted animals is constrained by cultural rules and is not "spontaneous cooperation" as assumed in models of weak and strong reciprocity. Missing in these models is the cultural basis of sharing that makes it a group property rather than an individual one.