The world about us is in a constant state of flux. The nomad in the Kalahari Desert and the Western city-dweller in front of his television set are both repeatedly confronted by changes in their natural surroundings and in the behaviour of other members of their own species. In this respect, at least, their experience is no different from that of all other organisms.

Culture endows man with exceptional flexibility in coping with his surroundings and, in consequence, human beings regularly cope with an unusual diversity of natural and social environments. As a result, the normal lifestyle of people in different parts of the world can be radically different. Yet the inherent temporal instability of these environments still poses problems and unusually severe perturbations frequently claim human lives. Shortage of food, one of the most basic and yet least reliable of the requirements for human survival, remains a common cause of loss of life. The means by which human beings secure their food supply in the face of such uncertainty are thus as central to society as the consequences of shortage are drastic and they have far-reaching ramifications throughout cultural behaviour and social life.

Human communities have developed an impressive array of cultural mechanisms for buffering variability.