Intergroup competition for the provision of binary public goods.

An experimental paradigm isproposed for investigating interpersonal conflicts under conditions of intergroup competition. The paradigm constitutes an n-person game with imperfect and incomplete information i which the n players arc divided into two groups, are each assigned monetary endow-ment, and must then decide independently and anonymously whether to keep the endowment or contribute it to the group's benefit. The group with the larger sum of contributions is provided with a monetary reward (binary public good), which is shared equally among all of its members egard-less of their decision. Two alternative models are proposed and their testable implications are de-rived and discussed. Both assume maximization fexpected utility, but their assumptions about he expectations each player holds about he decisions of the remaining players are different. The ef-fects of predccisional communication arc examined and several extensions of the basic paradigm are outlined. Although the interest of social psychologists in intergroup re-lations has been growing rapidly (Billi~, 1976; Brewer, 1979; Tajfel, 1982), the experimental research in this area is still sparse, especially when compared with the vast amount of re-