Campaigning for the environment: Edited by Richard Kimber and J. J. Richardson. Routledge & Kegan Paul, London and Boston, 1974. 228 pp. 14 × 22 cm. Price: £4.95

Abstract

Incest and exogamy, though often confused in the social science literature, are two distinct phenomena. Incest avoidance, despite the fact that it is often expressed in humans through incest taboos, has an ancient phylogeny which antedates the development of human culture. Exogamy, on the other hand, is a cultural invention which appeared a few thousand years ago, together with unilineal descent and the domestication of plants and animals. It does not necessarily foster outbreeding because it is often combined with a rule of cross-cousin marriage. Anthropological alliance theory and sociobiological kin selection theory are complementary rather than conflicting analyses of human kinship systems. Humans, like other social animals maintain an optimum balance between inbreeding and outbreeding. For many horti-cultural societies, that balance seems to be produced by rules of marriage encouraging kin to mate if r≤18, but forbidding marriage when r≥14. Through unilineal descent, clan exogamy, and preferential cross-cousin marriage, many horticultural societies maximize the benefits of both kin selection and reciprocity by marrying cousins (r≤18) and establishing matrimonial alliances between exogamous clans, while reducing the genetic load of inbreeding through incest taboos against close kin (r≥14). In effect, the kinsmen “lost” through the principle of unilineal descent are regained as spouses and in-laws.