Sung-Ha Hwang

Deterministic equations for stochastic spatial evolutionary games

Spatial evolutionary games model individuals who are distributed in a spa- tial domain and update their strategies upon playing a normal form game with their neighbors. We derive integro-differential equations as deterministic ap- proximations of the microscopic updating stochastic processes. This generalizes the known mean-field ordinary differential equations and provide a powerful tool to investigate the spatial effects in populations evolution. The determin- istic equations allow to identify many interesting features of the evolution of strategy profiles in a population, such as standing and traveling waves, and pattern formation, especially in replicator-type evolutions.

Conventional Contracts, Intentional behavior and Logit Choice: Equality Without Symmetry

When coordination games are played under the logit choice rule and there is intentional bias in agents’ non-best response behavior, the Egalitarian bargaining solution emerges as the long run social norm. Without intentional bias, a new solution, the Logit bargaining solution emerges as the long run norm. These results contrast with results under non-payoff dependent deviations from best response behavior, where it has previously been shown that the Kalai-Smorodinsky and Nash bargaining solutions emerge as long run norms. Experiments on human subjects suggest that non-best response play is payoff dependent and displays intentional bias. This suggests the Egalitarian solution as the most likely candidate for a long run bargaining norm.

Conventional Contracts, Intentional Behavior and Logit Choice: Equality Without Symmetry

When coordination games are played under the logit choice rule and there is intentional bias in agents’ non-best response behavior, the Egalitarian bargaining solution emerges as the long run social norm. Without intentional bias, a new solution, the Logit bargaining solution emerges as the long run norm. These results contrast with results under non-payoff dependent deviations from best response behavior, where it has previously been shown that the Kalai-Smorodinsky and Nash bargaining solutions emerge as long run norms. Experiments on human subjects suggest that non-best response play is payoff dependent and displays intentional bias. This suggests the Egalitarian solution as the most likely candidate for a long run bargaining norm.