The equilibrium outcome of a strategic interaction may depend on the weight players place on other playersʼ payoffs or, more generally, on some social payoff that depends on everyoneʼs actions. A positive, negative or zero weight represents altruism, spite or complete selfishness,...

Players in a congestion game may differ from one another in their intrinsic preferences (e.g., the benefit they get from using a specific resource), their contribution to congestion, or both. In many cases of interest, intrinsic preferences and the negative effect of congestion are (additively...

A leading solution concept in the evolutionary study of extensive-form games is Selten (1983) notion of limit ESS. This note demonstrates that a limit ESS does not imply neutral stability, and that it may be dynamically unstable (almost any small perturbation takes the population away). These...

Most existing decision-making models assume that choice behavior is based on preference maximization even when the preferences are incomplete. In this paper we study an alternative approach – “justifiable choice”: each agent has several preference relations (“justifications”), and she...

This paper analyzes the implementation of correlated equilibria that are immune to joint deviations of coalitions by cheap-talk protocols. We construct a cheap-talk protocol that is resistant to deviations of fewer than half the players, and using it, we show that a large set of correlated...