A PROBABILISTIC MODEL OF CRITICALITY IN A SEQUENTIAL PUBLIC GOOD DILEMMA

A public good (PG) is a commodity or service made available to all mem bers of a group: its provision depends on the voluntary contribution o f its members, Once provided, all members can enjoy the benefits of th e PG, regardless of whether they contributed or not; hence, there is a temptation to ''free-ride'' in the hope that others will contribute. Rapoport (1987) showed that an important factor that affects cooperati on (contribution) in a PG dilemma is the extent to which a group membe r is critical in providing it. Erev and Rapoport (1990) tested a game- theoretic model that yields deterministic predictions about the effect s of criticality on cooperation in public good dilemmas, Based on rese arch by Chen, An, and Komorita (1996), we propose a probabilistic mode l of criticality. The model is tested and found to fit empirical data. Extensions of the model to situations with uncertain group size or pr ovision point are discussed. (C) 1998 Academic Press.