Blood is not always thicker than water: The limited effect of kin selection on human kinship in the traditional Chinese family

Abstract To examine the importance of kin selection in shaping human societies, this study analyzed the kinship system practiced in traditional China for two millennia and teased apart its underlying genetic and other, presumably cultural, components. The results demonstrate that, in the traditional patrilineal Chinese family, both genetic relatedness and the cultural factor of generation were important in determining kinship status for male agnates (genetically related relatives). For female agnates, however, only genetic relatedness was important. Another surprising finding was that the influence of gender was not as important as genetic relatedness. The most interesting finding in this study, however, was that kin selection and culture (i.e., seniority in generation and age) played vastly different roles in different lineages in the Chinese family: for collateral (indirect) agnates, genetic relatedness was the most important factor in determining their kinship status, but for lineal (direct) agnates, its importance was overridden by seniority in generation and age, a cultural factor. Several other bio-cultural factors also explained a considerable amount of variance in kinship status. Since kinship profoundly affected, and was often the foundation of, the legal and social systems in dynastic China, kin selection, while its strength may differ remarkably between lineal and collateral relatives, could act as a selective force in Chinese families.