A growing literature in experimental economics examines the conditions under which cooperation can be sustained in social-dilemma settings. In particular, several recent studies contrast cooperation levels in games in which the number of decision rounds is probabilistic to games in which the number of decision rounds is finite. We contribute to this literature by contrasting the evolution of cooperation in probabilistically and finitely repeated linear voluntary-contribution public-goods games (VCM). Consistent with past results, ceteris paribus, cooperation is found to increase in the marginal value of the public good. Additionally, as the number of decision sequences increases, there is a pronounced decrease in cooperation in the final round of finite sequences compared to those with a probabilistic end round. We do not, however, find consistent evidence that overall cooperation rates are affected by whether the number of decision rounds is finite or determined probabilistically.

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This paper examines a theoretical model designed to characterize a static, individual vaccination decision environment. I identify and characterize both equilibrium and socially optimal vaccination behavior and determine how this behavior changes as the effectiveness of the vaccine changes. I also evaluate the individual and social welfare implications of a change in vaccine effectiveness. I find that under certain conditions, an increase in vaccine effectiveness can decrease the number of agents vaccinating in equilibrium due to the positive external effects of vaccination. Notably, it is also possible for individual and total welfare to decrease. This is an undesirable, and perhaps unexpected, consequence of better vaccines. Fortunately, welfare at the social optimum always increases as vaccine effectiveness increases. However, equilibrium behavior often falls short of the social optimum due to the positive externalities created by vaccinating.

This study examines the effects of initial endowment size on individual behavior in a binary choice game with no dominant strategy. Subjects make decisions in two, theoretically identical sequences, differing in initial endowment levels only. Each decision involves a choice between an option with a certain loss and an option with a loss that is increasing in the number of individuals who choose it. For the higher endowment level, all subjects are guaranteed a positive payoff. For the lower endowment level, subjects who choose the uncertain loss option could receive a negative payoff. The results indicate that in the first round of play, subjects with the higher endowment level choose the certain loss option significantly more often than subjects with the lower endowment level. There are, however, no significant differences in behavior beyond the first few rounds of play.