For the biological concept, see tribe (biology).
Viewed historically or developmentally, a tribe consists of a social formation existing before the development of, or outside of, states. Many people use the term to refer to any non-Western or indigenous society. Some social scientists use the term to refer to societies organized largely on the basis of kinship, especially corporate descent groups (see clan and lineage). In some countries, such as the United States of America and India, tribes are polities that have been granted legal recognition and limited autonomy by the state.
Considerable debate takes place over how best to characterize tribes. Some of this debate stems from perceived differences between pre-state tribes and contemporary tribes; some of this debate reflects more general controversy over cultural evolution and colonialism. In the popular imagination, tribes reflect a way of life that predates, and is more " natural", than that in modern states. Tribes also privilege primordial social ties, are clearly bounded, homogeneous, parochial, and stable. Thus, many believed that tribes organize links between families (including clans and lineages), and provide them with a social and ideological basis for solidarity that is in some way more limited than that of an "ethnic group" or of a "nation". Anthropological and ethnohistorical research has challenged all of these notions.
In his 1972 study, The Notion of the Tribe, Morton Fried provided numerous examples of tribes the members of which spoke different languages and practised different rituals, or that shared languages and rituals with members of other tribes. Similarly, he provided examples of tribes where people followed different political leaders, or followed the same leaders as members of other tribes. He concluded that tribes in general are characterized by fluid boundaries and heterogeneity, are not parochial, and are dynamic.
Archeologists continue to explore the development of pre-state tribes. Current research suggests that tribal structures constituted one type of adaptation to situations providing plentiful yet unpredictable resources. Such structures proved flexible enough to co-ordinate production and distribution of food in times of scarcity, without limiting or constraining people during times of surplus.
Fried, however, proposed that most contemporary tribes do not have their origin in pre-state tribes, but rather in pre-state bands. Such "secondary" tribes, he suggested, actually came about as modern products of state expansion. Bands comprise small, mobile, and fluid social formations with weak leadership, that do not generate surpluses, pay no taxes and support no standing army. Fried argued that secondary tribes develop in one of two ways. First, states could set them up as means to extend administrative and economic influence in their hinterland, where direct political control costs too much. States would encourage (or require) people on their frontiers to form more clearly bounded and centralized polities, because such polities could begin producing surpluses and taxes, and would have a leadership responsive to the needs of neighboring states (the so-called "scheduled" tribes of the United States or of British India provide good examples of this). Second, bands could form "secondary" tribes as a means to defend themselves against state expansion. Members of bands would form more clearly bounded and centralized polities, because such polities could begin producing surpluses that could support a standing army that could fight against states, and they would have a leadership that could co-ordinate economic production and military activities.
See also cultural evolution
Tribes are also American Indian nations, which posses sovereignty but no state.