In political science, Big man syndrome, also bigmanism, refers to corrupt and autocratic rule of countries by a single person, Africa has produced the most examples of these regimes by far (but the term can be used to describe any nation with a dictatorial ruler). Uganda's Idi Amin and Zaïre's Mobutu Sésé Seko are examples of leaders to whom this description has been applied. The Monitor newspaper uses this phrase in the context of the succession of Kenyan leader Daniel Arap Moi:
In anthropology, a big man refers to the most influential man in a tribe. His power is achieved through recognition (by skill, wisdom, or material possessions) and not inherited. He lacks coercive authority and his position is informal and unstable. This is commonly found in Melanesia.
The American anthropologist Marshall Sahlins in particular has been a proponent of the big-man phenomenon. In his "Poor Man, Rich Man, Big Man, Chief: Political Types in Melanesia and Polynesia" (1963) Sahlins uses analytically constructed ideal-types of hierarchy and equality to compare a larger-scale Polynesian-type hierarchical society of chiefs and sub-chiefs with a Melanesian-type big-man system.
The latter consists of segmented lineage groups, locally held together by faction-leaders who compete for power in the social structure of horisontally arranged and principally equal groupings (factions). Here, leadership is not ascribed, but rather gained through action and competition "with other ambitious men".
A big-man's position is never secured in an inherited position at the top of a hierarchy, but is always challenged by the different big-men who compete each other in an on-going process of reciprocity and (re-)distribution of material and political resources. As such the big-man is subject to a transactional order based on his ability to balance the simultaneously opposing pulls of securing his own renown through distributing resources to other big-man groups (thereby spreading the word of his power and abilities) and redistributing resources to the people of his own faction (thereby keeping them content followers of his able leadership).
1963 "Poor Man, Rich Man, Big Man, Chief: Political Types in Melanesia and Polynesia" in Comparative Studies in Society and History, 5/285-303.