Social Organization. Each longhouse, as each bilik, is an autonomous unit. Traditionally the core of each house was a group of descendants of the founders. Houses near one another on the same river or in the same region were commonly allied, marrying among themselves, raiding together beyond their territories, and resolving disputes by peaceful means. Regionalism, deriving from these alliances, in which Iban distinguished themselves from other allied groups, persists in modern state politics. Essentially egalitarian, Iban are aware of long-standing status distinctions among themselves, recognizing the raja berani (wealthy and brave), mensia saribu (commoners), and ulun (slaves). Prestige still accrues to descendants of the first status, disdain to descendants of the third.
Political Organization. Prior to the arrival of the British adventurer James Brooke there were no permanent leaders, but the affairs of each house were directed by consultations of family leaders. Men of influence included renowned warriors, bards, augurs, and other specialists. Brooke, who became Rajah of Sarawak, and his nephew, Charles Johnson, created political positions—headman ( tuai rumah ), regional chief ( penghulu ), paramount chief ( temenggong )—to restructure Iban society for administrative control, especially for purposes of taxation and the suppression of head-hunting. The creation of permanent political positions and the establishment of political parties in the early 1960s have profoundly changed the Iban.
Social Control. Iban employ three strategies of social control. First, from childhood, they are taught to avoid conflict, and for a majority every effort is made to prevent it. Second, they are taught by story and drama of the existence of numerous spirits who vigilantly ensure observation of numerous taboos; some spirits are interested in preserving the peace, while others are responsible for any strife that arises. In these ways, the stresses and conflicts of ordinary life, especially life in the longhouse, in which one is in more or less constant sight and sound of others, have been displaced onto the spirits. Third, the headman hears disputes between members of the same house, the regional chief hears disputes between members of different houses, and government officers hear those disputes that headmen and regional chiefs cannot resolve.
Conflict. Major causes of conflict among Iban have traditionally been over land boundaries, alleged sexual improprieties, and personal affronts. Iban are a proud people and will not tolerate insult to person or property. The major cause of conflict between Iban and non-Iban, especially other tribes with whom Iban competed, was control of the most productive land. As late as the first two decades of the twentieth century, the conflict between Iban and Kayan in the upper Rejang was serious enough to require the second rajah to send a punitive expedition and expel the Iban forcefully from the Balleh River.