Where does kinship collide?

In social and cultural anthropology, kinship is the culturally built system by which a society decides who is related to whom and what those relations require: rules of descent, marriage, and alliance that organise families, groups, and obligations. Lewis Henry Morgan mapped the kin terminologies of many peoples, and Lévi-Strauss read marriage as an exchange that binds groups through alliance. In A Critique of the Study of Kinship, David Schneider argued that kinship is itself a Western folk category that anthropologists had wrongly treated as a universal fact of nature. The referent here is a cultural construction of relatedness, one that need not follow biological descent and often does not, as with adoption, godparenthood, or clan membership.[1]

Unit

A relative recognised through a culture's rules of descent, marriage, and alliance

Recovery means

Not applicable

Measured by

Described by ethnography, by collecting a society's kin terms, and by recording its rules of descent and marriage

In evolutionary biology, kinship is measured relatedness: the coefficient r, the probability that two individuals share a given gene through common descent. W. D. Hamilton's rule, that rB exceeds C, states that a gene disposing an individual to help others can spread when the benefit B to a relative, weighted by relatedness r, outweighs the cost C to the helper. This is why altruism toward close kin, who are likely to carry the same gene, can evolve, an idea known as kin selection or inclusive fitness. Here kin is a quantity fixed by genealogy and genetics, not a status that a culture confers.[2]

Unit

The coefficient of relatedness r between two individuals, from 0 to 1

Recovery means

Not applicable

Measured by

Computed from pedigrees, or estimated from genetic markers, as the coefficient of relatedness

In the sociology of families, kinship includes fictive or chosen kin: people treated as family through bonds of care, exchange, and obligation rather than through birth or marriage. In All Our Kin, Carol Stack described how households in a poor Black community pooled resources across wide networks of related and unrelated kin in order to survive. Godparents, close friends named as aunts or uncles, and other chosen relatives show that family membership can be made and kept up socially. The referent is a bond of kinship that a genetic account of relatedness does not register at all.[3]

Unit

A person counted as family through care and obligation rather than birth

Recovery means

Not applicable

Measured by

Traced by studying households, exchange networks, and whom people name and treat as family