Sago games: Cooperation and change among Sago producers of Papua New Guinea

In 1986-1987 at a small community in lowland Papua New Guinea, residents with greater rights to local land (owners) produced more sage flour than residents with fewer rights to that land (guests) and shared their produce with the latter, This behavior was interpreted as a case of reciprocal altruism on the understanding that customary patterns of settlement relocation would have the outcome that individuals would often change status as owners or guests and, hence, as donors and recipients. Recent influences resulting in greater stability of community composition and location have reduced the likelihood that individuals could expect to change status vis ci vis others, Thus, the central condition for reciprocal altruism has been lost, and we predicted that individuals would alter their behavior in relation to sage production, Four predictions regarding the expected directions of change in effort and patterns of association were supported by data obtained in 1995, and the magnitude of three of these changes was substantial, We conclude that behavior observed in 1986-1987 qualified as reciprocal altruism and discuss it in terms of the repeated prisoner's dilemma, While unable to establish the particulars of rules, mechanisms, or logistics that shaped the actual probability of reciprocation, we have established that once the potential for reciprocation was lost the ''sago game'' broke down. (C) Elsevier Science Inc., 1997.