Sets closed under rational behavior were introduced by Basu and Weibull (1991) as subsets of the strategy space that contain all best replies to all strategy profiles in the set. We here consider a more restrictive notion of closure under rational behavior: a subset of the strategy space is...

We model a player's uncertainty about other player's strategy choices as probability distributions over their strategy sets. We call a strategy profile robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence of strategy profiles in each of which every...

This paper extends the concept of weak renegotiation-proof equilibrium (WRP) to allow for costly renegotiation and shows that even small renegotiation costs can have dramatic effects on the set of equilibria. More specifically, the paper analyzes the infinitely repeated Bertrand game. It is...

We study costless pre-play communication of intentions among inexperienced players. Using the level-k model of strategic thinking to describe players' beliefs, we fully characterize the effects of pre-play communication in symmetric 2×2 games. One-way communication weakly increases coordination...

Two principals simultaneously appoint one agent each and decide how much power to give to their agents. The agents' task is to bargain over the provision of a public good. Power here means the right to decide the own side's provision if negotiations break down. In equilibrium the principals...

We find that contrary to common perception, cooperation as equilibrium of the infinitely repeated discounted prisoner's dilemma is in many relevant cases not very plausible, or at least questionable: for a significant subset of the payoff-discount factor parameter space cooperation equilibria...

Why do money and markets crowd out cooperative relations? This paper characterizes the effects of intertemporal preferences, money, and markets on players' ability to cooperate in material-payoff supergames. Players' aversion to intertemporal substitution facilitates cooperation by decreasing...

In this paper I define an evolutionary stability criterion for learning rules. Using Monte Carlo simulations, I then apply this criterion to a class of learning rules that can be represented by Camerer and Ho's (1999) model of learning. This class contains perturbed versions of reinforcement and...

This is a dictionary entry forthcoming in Peter Newman, ed. The New Palgrave Dictionary of Economics and the Law, London: Macmillan, 1998.

This paper examines the effects of search costs on prices in a Bertrand duopoly. It is shown that if the search cost is lowered, the expected price goes down in a single play of the stage game. However, if the game is repeated it may be easier to sustain collusion the lower the search cost. In...