On the Origin and Extension of the Incest Taboo

This paper presents new evidence and a model which are consistent with the theory that the prohibition of familial mating became universal and may have originated because of the problem of inbreeding. The new evi dence has to do with why the incest taboo may be extended to first cousins; of all the available theories, only that of inbreeding seems to explain the cross-cultural variation in cousin marriage. The model described here gen erates estimates of reproductive rates that might have obtained in earlier hypothetical populations. These estimates suggest that the differences in re productive rates between familial and nonfamilial matings may have been great enough for people to have recognized the disadvantage of inbreeding and to have consciously prohibited it.