Published online by Cambridge University Press: 31 July 2008
The Western Abelam of Papua New Guinea display an annual cycle of social conflicts and births which is a function of a system of ritual beliefs involved in the growing of ceremonial yams. This sociorhythmic ritual complex involves adherence to various taboos which encourage a 6-month period in which social conflict is avoided and sexual activity is markedly curtailed. Conflict case studies and demographic data collected from one village over a 15-month period indicate significant seasonal variation in various areas of Abelam social life and suggest that sociorhythmic phenomena can affect both social behaviour and demographic patterns of human groups. Alternative environmental and nutritional hypotheses are also investigated.