in terms of the breakdown of tribal (and therefore caste) boundaries, and the proliferation of new mixed caste groups. In other words, ethnogenesis (the construction of new ethnic identities) in tribes occurs through a fission process (where groups splinter-off as new tribes, which preserves endogamy), whereas with settled castes it usually occurs through intermixture (in violation of strict endogamy). Tribals and are often regarded as constituting egalitarian societies. However, many scholars argue that the claim that tribals are an egalitarian society in contrast to a caste-based society is a part of a larger political agenda by some to maximise any differences from tribal and urban societies. According to scholar Koenraad Elst, caste practices and social taboos among Indian tribals date back to antiquity: Other criteria Unlike castes, which form part of a complex and interrelated local economic exchange system, tribes tend to form self-sufficient economic units. For most tribal people, land-use rights traditionally derive simply from tribal membership. Tribal society tends to the egalitarian, with its leadership based on ties of kinship and personality rather than on hereditary status. Tribes typically consist of segmentary lineages whose extended families provide the basis for social organisation and control. Tribal religion recognises no authority outside the tribe. Any of these criteria may not apply in specific instances. Language does not always give an accurate indicator of tribal or caste status. Especially in regions of mixed population, many tribal groups have lost their original languages and simply speak local or regional languages. In parts of Assam—an area historically divided between warring tribes and villages—increased contact among villagers began during the colonial period, and has accelerated since independence in 1947. A pidgin Assamese developed, whereas educated tribal members learnt Hindi and, in the late twentieth century, English. Self-identification and group loyalty do not provide unfailing markers of tribal identity either. In the case of stratified tribes, the loyalties of clan, kin, and family may well predominate over those of tribe. In addition, tribes cannot always be viewed as people living apart; the degree of isolation of various tribes has varied tremendously. The Gonds, Santals, and Bhils traditionally have dominated the regions in which they have lived. Moreover, tribal society is not always more egalitarian than the rest of the rural populace; some of the larger tribes, such as the Gonds, are highly stratified. The apparently wide fluctuation in estimates of South Asia's tribal population through