Cognatic Descent Systems

Unilineal kinship makes a direct and simple assignment of social statuses, rights, and duties by confining transmission to a single descent line. By contrast, nonunilineal, or cognatic, systems allow for the construction of social groups and categories through any or all of an individual's acknowledged relatives beginning with both his/her father and mother. The open nature of cognatic organization leads to greater complexities and wider variations than are normally apparent in partilineal or matrilineal forms.

Cognatic kinship structures can be classified into two basic systems: bilateral and ambilineal.

  1. Bilateral systems involve the inclusion of all of an individual's relatives within a given range. They are usually ego focused and are formed by tracing relationships from both parents throughout an everwidening network of kinship called a kindred. A less common variant form, a stock, or bilateral descent group is based on tracing descent lines back to founding ancestors.
  2. Bilateral Kinship Network (Kindred)


  3. Ambilineal systems involve an exclusive selection of membership in a father's or mother's group, usually upon adulthood. (Alternative forms are based on a choice of living with one's husband's or wife's family after marriage.) They are ancestor focused and become organized by tracing descent from either father or mother, but not both, and back through a similarly restricted string of forbearers.

    Ambilineal Kinship Group (Ramage)


    • Relatives included in Ego's ambilineal group are shaded in red.
    • Purple indicates descendants who have not been assigned membership.

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© Brian Schwimmer
University of Manitoba
Created: Sept. 1997
Last Updated: August 1998