Descent Groups

Different descent principles and marriage rules result in the formation of different types of families and larger kin based groups.  Regardless of the descent and marriage pattern used by a society, however, most people at some time in their lives are members of more than one family group.  For example, in North America and other monogamous societies with bilateral descent patterns, people usually see themselves as being members of two related nuclear click this icon to hear the preceding term pronounced families--the one in which they are a child (family of orientation click this icon to hear the preceding term pronounced) and the one in which they are a parent (family of procreation click this icon to hear the preceding term pronounced).

Diagram of nuclear families of orientation and procreation within an extended family   Photo of a North American nuclear family at the beach   Do you think that this
picture shows a nuclear
family of orientation or
of procreation?

Click the button to see
 if you are correct.

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In reality, the 21st century American family is often missing an adult male as a result of death, divorce, abandonment, or no marriage having occurred.  Such families are often referred to as being matricentric click this icon to hear the preceding term pronounced or matrifocused click this icon to hear the preceding term pronounced.  They may also include the mother's daughter's children, as in the case shown in the diagram below.  The matricentric family pattern exists in all segments of the American society today but is most common in poor urban African American communities.

Diagram of a matricentric family

In some cases, it is the wife-mother who is absent from the family.  As a result, the husband-father usually takes on both parent roles.  Another increasingly common form of family in contemporary America is the dual-family.  This occurs when children move between the separate households of their divorced or separated parents.  Since half of all marriages in the U.S. now end in divorce, it is likely that the dual-family will become a more accepted family alternative.

Unilineal Descent Groups

When a unilineal descent principle is used, people are most often members of multi-generational groups of close relatives called unilineages click this icon to hear the preceding term pronounced.  These may be matrilineages click this icon to hear the preceding term pronounced, as in the case of the green people in the diagram below, or they may be patrilineages click this icon to hear the preceding term pronounced, depending on whether the links are traced through women or men.

Diagram of 3 a matrilineage segment  

Photo of a multigenerational family in New Guinea

Three generations of a small matrilineage

Members of a unilineage in New Guinea

Societies that have unilineages also often define larger, more inclusive kin groups called clans click this icon to hear the preceding term pronounced.  These are groups of people who claim unilineal descent from a common ancestor but who cannot specify all of the actual links.   The ancestor is genealogically click this icon to hear the preceding term pronounced so remote that he or she is thought of often as a mythical being.

Diagram of a clan's relationship to its unilineages


Drawing of an English crest or coat of arms

Typical English crest
with heraldic animals

Such distant, non-human ancestors become identifying symbols of the clan.  Anthropologists often refer to these fictional clan originators as totems click this icon to hear the preceding term pronounced or totemic emblems click this icon to hear the preceding term pronounced.   Often, there are cultural rules requiring that clan members show respect for the totemic animal or plant and observe a prohibition against killing or eating it.   Medieval European heraldry also used animal representations to identify family lines.  However, such creatures were not considered to be family ancestors but rather as symbolic representations of virtues such as strength and loyalty.

Australian Aboriginal bark
painting showing totemic
ancestors in the "dreamtime"
(the mythical time when the
world was created)
  photo of a 19th century Australian Aboriginal bark painting showing totemic ancestors in the supernatural "dreamtime"  

Some societies group their clans into even larger-scale unilineal descent groups called phratries click this icon to hear the preceding term pronounced.  As with clans, the actual genealogical links are not clear and the phratry ancestors are usually mythical.

Diagram of phratries and their relationship to clans

Entire societies may be divided into two large unilineal descent groups that have reciprocal responsibilities with each other.  These groups are known as moieties click this icon to hear the preceding term pronounced (from the French word for half).  The distinction between phratries and moieties is not simply a matter of the number of groupings.  Moieties are intended to produce a balanced opposition within a society.  The constantly reinforced social and economic exchanges between moieties encourages economic equality and political stability.

Diagram of moieties and their relationship to clans and phratries


The often complex patterns of reciprocity inherent in moiety systems can be seen operating in the marriage patterns of the Kariera Aborigines of Western Australia.  They follow patrilineal descent but with a peculiar twist that is known by anthropologists as a four class system.  They have two moieties and four "marriage classes."  An individual's moitey and marriage class identity determines who he or she may marry.

Each Kariera moiety has two generational marriage class "names."  Everyone in a moiety who is in the same generation has the same marriage class identity.  For simplicity, the moieties are designated below as "A" and "B", while the marriage class "names" are "a", "b", "c", and "d" respectively.

Diagram of Australian 4-class system showing the relationship between generation, class, and moiety identity

An "a" man can only marry a "c" woman from moiety "B".  Their children will be "b's" in moiety "A".  Conversely, a "c" man can only marry a woman from moiety "A" and their children will be "d's" in moiety "B".

Diagram of Australian 4-class system showing culturally specified marriage partners and class identity of children determined by their father's identity

Ideally, Kariera men from different moieties marry each other's sisters.  This results in strong reciprocal bonds between the men and their moieties.  There is a generational alternation in class "names" among the Kariera.  People have the same class identity as their grandparents and grandchildren but not their parents and children.  It is sobering to note that as confusing as the Kariera 4-class system seems, it is not the most complex example of Australian Aboriginal kinship.

Societies with moieties usually consist of a few thousand people or less.  In contrast, societies with phratries are often larger.  As in the case of clans and phratries, moiety members usually cannot demonstrate all of the descent links back to their supposed common ancestor.

Membership in unilineages, clans, moieties, and phratries is inherited and usually continues throughout life.  As a result, these unilineal descent groups often function successfully as long-term joint property owners and economic production teams.

Bilateral Descent Groups

Bilateral descent groups tend to be more fragile and short term than unilineal ones.  Beyond the nuclear family, there usually only exists a kindred click this icon to hear the preceding term pronounced.  This is a group of relatives who are linked together by a single individual who can trace descent and/or marriage relationships to every other member of the kindred.

In North America today, a kindred group usually informally includes spouses and in-laws as well as biological relatives.  All of the people below may be part of ego's kindred.

Diagram of a bilateral kindred in which consanguines are considered relatives

This loosely defined type of kindred allows people to be part of the extended families of their spouses as well as their own.  An unfortunate consequence is divided family loyalties when an issue comes up that places consanguinal relatives and affines on opposite sides.  Conflicting interests and obligations usually prevent such expanded kindreds from functioning as efficiently as a unilineage in collective ownership and mutual aid.

North American kindreds are not only fragile but also usually short term social groupings.  When an individual dies or is divorced, the kindred that was focused on him or her is altered significantly or may even cease existing.   The only kind of bilateral kindred that regularly continues to exist after the death of its founder is a dead ancestor focused one.  For example, members of the well known, politically active Kennedy family of Massachusetts, which has included a U.S. President and several Senators, still considers themselves to be a large closely related kindred despite the fact that Joe Kennedy, the family founder, died in 1969 and many of the Kennedy kindred do not have the Kennedy name.


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This page was last updated on Friday, March 16, 2007.
Copyright 1997-2006 by Dennis O'Neil. All rights reserved.
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