All the cultures of the Sepik River region have certain basic elements in common that appear in many local variations. These are: the men's secret society, the men's clubhouse, and the performance of spectacular ceremonies. The rites involve everywhere the use of a vast number of carved and decorated objects. These objects are of two kinds- sacred hidden ones, which may be seen only by a particular group of persons, and others that are used and seen by everyone. In both categories, representations of supernatural spirits are frequent and the sense of the dramatic is very strong. There is a sharp division among the people marking off the initiates, those who can participate actively in the rites, from the uninitiated, usually women and children, who compose the audience.

      The number of objects produced in the Sepik area is enormous. Among them are figures ranging from eight inches to eight feet, and masks measuring from a few inches to several feet. Stools, neck rests, slit-gongs and shields are decorated with human or animal design motifs. Elaborate wooden hooks of all sizes, used to hang belongings out of reach of the rats, are made in many villages. On the coast and along the rivers canoes are built, some with prows shaped realistically in form of large crocodiles. In some sections human skulls are painted and covered with clay modeling to represent heads. Even pottery, a craft that is little developed in Oceania, is found here in great variety.

      Every tribe produces a number of wood carvings of ceremonial and artistic importance and makes use of leaves, feathers, shells, furs, etc., for their decoration. The dominant color is red, in all shades from pink to maroon. It is often combined with black, white, yellow, and purplish gray. Many of the carvings are made of a heavy, close-grained wood and every time they are to figure in a ceremony they are decorated and painted anew.

      Sepik River art is for the most part the work of professional artists, or at least men of recognized skill, and in some places tradition provides opportunities for the display of connoisseurship by tribal members. All kinds of objects are constantly traded. Sometimes they are acquired from a distant tribe together with the ceremonial dances, rhythms and songs for which they were made. Often the newcomers do not understand the original meaning of the pieces or even the words of the songs pertaining to them. Such purchases can be seen as motivated by a desire to enrich local ceremonies with new objects and forms. A ceremony, whether religious or social remains in fact, fashionable for a limited time only and then is superseded by a new one. This constant trading of objects among the tribes has produced an often bewildering intermingling and diffusion of style elements.

      The variety of Sepik River art is one of its chief characteristics. Since the elaborate religious and social ceremonies required a great display of carved and painted objects there was an ever present need for new paraphernalia and this gave rise to a technical proficiency and creative interpretions of traditional forms unsurpassed in any other area of Oceania.