Social Organization. Local organization mirrors the social division into moieties, with named clans represented in many villages between whom relations are traced. The moieties are classified into "sky" ( nyaui ) and "earth" (or "mother," hnyamei ). Each moiety is responsible for carrying out the initiation for the boys of the other; thus, boys get scarified by men from the other group. Iatmul men are classified also into an age-grade system, with four to six different degrees, depending on the village. Among the eastern Iatmul there exists a second nonlocalized moiety system that works as a competitive exchange system.
Political Organization. The men's houses are not only the religious center of Iatmul life but the political center as well. There discussions are held concerning all public matters on which a decision has to be made or action taken. Discussions are usually led by influential men who occupy the structural position of being endowed with ritual knowledge, a prerequisite for political leadership. Among men there is considerable competition and rivalry for political leadership. Speech making is an important factor in the decision-making process, and oratorical skill is a necessary condition for leadership. Speeches are delivered near the ceremonial "chair," a totemic representation of a founding ancestor whose judgment is solicited as a warrant for the truth. Another means to political leadership was to have a reputation as a powerful sorcerer or to be talented as a chanter.
Social Control. Traditionally, the men's house was also the center of jurisdiction in quarrels between members of different clans. Within a clan conflicts were settled by its own influential men. Women had informal power in social affairs; for example, a wife could refuse to provide her husband with food, and in serious matters she could call on her own family, mainly her brothers. At the community level, women were feared for their supposed polluting capacities, which were considered responsible at least in part for sorcery and witchcraft.
Conflict. Warfare was an important male activity and head-hunting was part of the initiation rite. Most attacks were against other Iatmul villages, particularly in the east.