Paleo-anthropologists believe that what allowed the survival of the first hominids was membership of a group; they argue that vital needs made it essential to join forces. It is therefore likely that the hunter-gatherers who formed the small tribes of prehistory were cooperators, some perhaps reluctantly. The need to divide the tasks of procuring food and caring for offspring strengthened the blood ties between group members. The balance within those proto-communities and the stability of their composition probably depended on the principle of authority. The strongest imposed the fulfilment, even by force, of the assigned tasks. If a group member violated the rules of cohabitation, a punishment would come into play, up to expulsion from the group. A convincing threat, this, in times when being abandoned to oneself was equivalent to certain death. “Immobility” was also a characteristic of the collectivist societies of antiquity, as well as of the Sumerian city-states of Mesopotamia and the pre-Columbian civilisations of Latin America, regardless of the different forms in which power was exercised by the elders.