Melanesian societies are commonly divided into those with chiefs and those with “big men”. Chieftainship was hereditary, and there was a distinction between “chiefly” and “commoner” families. This distinction was clear in some chiefly societies, blurred in others. There were sometimes rival claimants to legitimate succession, or ways in which an obviously “legitimate” successor could be passed over in favor of another man if he were judged (by enough men of power) to be unfit for the position. Chiefly societies were usually matrilineal and women had more power than in ”big man” societies. The chieftainship system was confined to some island and coastal peoples, mostly speaking Austronesian languages.
In many PNG societies, and notably in the highlands of New Guinea, leadership was exercised by “big men” who achieved their status by their own activities, though it could be an advantage to be fathered by a “big man”. A “big man” could be a fight leader (who in some societies also behaved aggressively within his own group); a man skilled in organizing such activies as trading expeditions, or the production and redistribution of food and valuables; or a successful mediator in disputes. More often than not a “big man” had a combination of these qualities. The nature of “big men” systems was not understood by early colonial administrators (looking for chiefs through whom they could govern), and by early anthropologists.
These systems of social organization survive in some parts of the country today. There are still recognized “big men” in parts of the highlands, and chiefs in the Trobriand Islands , although their influence in their societies has greatly diminished.