Dynamic Volunteer's Dilemmas over a Finite Horizon

Volunteer's dilemmas that evolve over time are presented and modeled as noncooperative n-person games in extensive form with symmetric players, discrete time, finite horizon, and complete information. Volunteering is costly, thereby giving rise to free riding. Reflecting on the observation that in many naturally occurring social dilemmas it is beneficial to volunteer earlier than later, the model assumes that the payoff to the volunteer and the (higher) payoff to each of the nonvolunteers decrease monotonically over time. The authors construct symmetric and asymmetric subgame perfect equilibria to the game. An experimental study shows that financially motivated subjects who are rewarded contingent on their performance volunteer more readily when the cost of volunteering is relatively low; that they largely fail to coordinate on any of the asymmetric equilibria in which only a single subject volunteers immediately; that they volunteer, on average, earlier than predicted; and that they vary considerably from one another in their inclination to free ride.