Control of labour and inter-group conflict is characteristic of corporate-level or 'tribal' groups, headed by a charismatic individual; whether a 'big man' or a proto-chief, functioning as a lineage-group head. Whether a non-hierarchical system of organization existed is debatable, and there is no evidence that explicitly suggests that Neolithic societies functioned under any dominating class or individual, as was the case in the chiefdoms of the European Early Bronze Age. Theories to explain the apparent implied egalitarianism of Neolithic (and Paleolithic) societies have arisen, notably the Marxist concept of primitive communism.