Ambilineality

Ambilineality is a form of kinship affiliation of cognatic descent that relies on self-defined affiliation within a given social system, meaning individuals have the choice to be affiliated with their mother's or father's group. Common features of societies that practice ambilineality are a shared set of land, communal responsibilities, and collective ownership of some segments of wealth and debt in their societies. This system of descent is distinct from more common genealogical structures in that rather than determining affiliation and descent using the standard determinants of biological and genealogical relation, it instead relies heavily on voluntary affiliation with one's group, oftentimes being determined by factors including residence.

Societies practicing ambilineal descent are especially common in Southeast Asia and the Pacific Islands. Polynesian cultures and Micronesian cultures are often ambilineal, including, for example, Samoans, Māori, Hawaiians and people of the Gilbert Islands. The indigenous peoples of Northwestern North America are also followers of ambilineality; and it is also found among the Southern Yoruba people residing in West Africa.