Endogamous groups, variously specialised in craftwork, music, hunting, and/or certain rituals, are characteristic of several regions of sub-Saharan Africa: the Western Sudanic and Sahelian zones; the central Sahel and Sahara; the Alantika and Mandara mountains; and East Africa (Sudan, Ethiopia, the Somali lands, Kenya, and the interlacustrine zone), an area that includes some twenty-five contemporary states. In some regions, specialists are subject to extreme avoidance behaviour. It is hypothesized that in all pre-industrial agricultural or pastoral societies, mainly because of the symbolic representations associated with craftwork and music (two domains that are closely linked to each other), persons who engage in them potentially form endogamous groups. However, the transition to endogamy only takes place in situations of marked political inequality: typically when (a) hunting-gathering populations are encapsulated in agricultural or pastoral societies; or (b) dynasties, especially ones with blacksmith kings, are overthrown. In some instances, the new status is deliberately put in place by the newly dominant groups. Whenever one or more endogamous groups have formed in a given area (a low-probability event), this institution is readily adopted by neighbouring populations (a high-probability event). Such groups form not at the time of the initial discovery of the techniques, but during the later phases of a conflict-ridden history marked by significant inequalities among communities. In other words: cognitive processes that operate in most cultures result, in certain historical circumstances only, in the formation of discriminated specialist groups.
