Marriage. Marriages within moieties are allowed, although not preferred; but marriages within sibs are discouraged. Islanders tend to marry within their own villages and districts, but they also often marry outside. Traditionally, parents and other relatives of the couple arranged the marriage. Nowadays the couples themselves often take the initiative, seeking Family approval afterwards. Brother-sister exchange is the ideal; at the least, the sib giving a woman in marriage should eventually receive one in return. Relatives still exercise some Control over a couple's marriage by contributing to the payment of bride-wealth in cash, shell rings, and store goods. A traditional "giving" of the bride accompanies a church wedding. Upon marriage, the couple establishes a new household, Usually near the households of the man's father and brothers. Although infrequent today, polygamous unions were once Common. Nowadays islanders working or studying elsewhere in Papua New Guinea also marry people of other islands. Because of Catholic strictures, divorce on Nissan is uncommon, as it was traditionally.
Domestic Unit. The nuclear family is the household unit, often combining for economic activities with other units related through the male heads of household.
Inheritance. On Nissan, men own land and movable wealth (shell rings and pigs). In some cases, a man will indicate during his lifetime the desired disposition of land and wealth upon his death. In most instances, a man's sons Inherit equally and divide the property and wealth among themselves. If a man has no sons, his brothers and brothers' sons—or, in the absence of these persons, his sisters' sons—inherit his property and wealth.
Socialization. Parents allow children to mature at their own pace. They show affection for small children primarily by physical means. Adults inculcate in children a sense of shame, considered a vital aspect of Nissan character. Preferred punishments are scolding and teasing. When not in school, children are expected to assist in the household. However, they often engage in unorganized, desultory play among themselves.