Relatedness and synergy affect the selection pressure on cooperation and altruism. Although early work investigated the effect of these factors independently of each other, recent efforts have been aimed at exploring their interplay. Here, we contribute to this ongoing synthesis in two distinct...

How the size of social groups affects the evolution of cooperative behaviors is a classic question in evolutionary biology. Here we investigate group size effects in evolutionary games in which individuals choose whether to cooperate or defect. We find that increasing the group size decreases...

We characterize the symmetric Nash equilibria of the symmetric voter participation game with complete information introduced by Palfrey and Rosenthal (1983). Our results confirm their conjecture on the existence, multiplicity, and comparative statics of such equilibria and yield more precise...

We characterize the symmetric Nash equilibria of the symmetric voter participation game with complete information introduced by Palfrey and Rosenthal (1983). To do so, we use methods based on polynomials in Bernstein form to determine how the probability that a voter is pivotal depends on the...

We consider how group size affects the private provision of a public good with non-refundable binary contributions. A fixed amount of the good is provided if and only if the number of contributors reaches an exogenous threshold. The threshold, the group size, and the identical, non-refundable...