We show that for many classes of symmetric two-player games, the simple decision rule imitate-the-best can hardly be beaten by any other decision rule. We provide necessary and sufficient conditions for imitation to be unbeatable and show that it can only be beaten by much in games that are of...

We show that local potential maximizer ([15]) with constant weights is stochastically stable in the log-linear dynamics provided that the payoff function or the associated local potential function is supermodular. We illustrate and discuss, through a series of examples, the use of our main...

We report experiments designed to test between Nash equilibria that are stable and unstable under learning. The 'TASP' (Time Average of the Shapley Polygon) gives a precise prediction about what happens when there is divergence from equilibrium under fictitious play like learning processes. We...

In this paper we show that reputation formation in endogenously formed relationships is a decisive determinant for the existence and performance of credit markets. In theabsence of any third party enforcement of debt repayment the contracting parties succeed in establishing stable bilateral...

This paper deploys a novel experiment to compare four theories that explain both selfish and non-selfish cooperation. The four theories capture incomplete information (à la Kreps et al. (1982)) alongside the following four non-selfish motives: caring about others (Altruism), being conscientious...

We characterize the class of symmetric two-player games in which tit-for-tat cannot be beaten even by very sophisticated opponents in a repeated game. It turns out to be the class of exact potential games. More generally, there is a class of simple imitation rules that includes tit-for-tat but...

While there is an extensive literature on the theory of in finitely repeated games, empirical evidence on how “the shadow of the future” affects behavior is scarce and inconclusive. We simulate in finitely repeated prisoner’s dilemma games in the lab by having a random continuation rule....

This paper initiates the study of long term interactions where players' bounded rationality varies over time. Time dependent bounded rationality is reflected in part in the number $\psi(t)$ of distinct strategies in the first $t$-stages. We examine how the growth rate of $\psi_i(t)$ affects...

Neuroeconomics focuses on brain imaging studies mapping neural responses to choice behavior. Economic theory is concerned with choice behavior but it is silent on neural activities. We present a game theoretic model in which players are endowed with an additional structure - a simple ``nervous...

We study environments in which agents are randomly matched to play a Prisoner's Dilemma, and each player observes a few of the partner's past actions against previous opponents. We depart from the existing related literature by allowing a small fraction of the population to be commitment types....