Monetary reward, verbal reinforcement, and harvest strategy of others in the commons dilemma.

A commons dilemma arises when individuals sharing a resource act according to their short-term interests, thereby causing the long-term destruction of a slowly regnerating resource (Platt, 1973). Seventy-two American students played a computerized commons-dilemma simulation in which verbal reinforcement for conservation-oriented harvests, exploitive harvesting strategies by other participants, and monetary rewards for harvests were crossed in a between-subjects factorial design. Results are discussed in terms of competitive influences attributable to monetary rewards and others' behavior, with implications for changing reinforcement structures as a possible solution to commons dilemmas.