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 regenerating resource (Piatt, 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. As expected, verbal reinforcement decreased exploitive behavior across a variety of circumstances. However, the behavior of others with whom the commons was shared affected subjects' harvest strategy only under conditions of monetary reward. 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.