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...

It is well known that the rock-paper-scissors game has no pure saddle point. We show that this holds more generally: A symmetric two-player zero-sum game has a pure saddle point if and only if it is not a generalized rock-paper-scissors game. Moreover, we show that every finite symmetric...

Internet experiments are a new and convenient way for reaching a large subject pool. Yet, providing incentives to subjects can be a tricky design issue. One cost effective and simple method is the publication of a high score (as in computer games). We test whether a high score provides adequate...

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...

Recently there has been much work on learning in games. However, learning usually means learning about behavior of opponents rather than learning about the game as such. Here we test in an experiment whether players in a repeated encounter can learn the payoff structures of their opponents by...

Recently there has been much work on learning in games. However, learning usually means "learning about behavior of opponents" rather than "learning about the game" as such. Here we test in an experiment whether players in a repeated encounter can learn the payoff structures of their opponents...

Recently there has been much theoretical and experimental work on learning in games. However, learning usually means learning about the strategic behavior of opponents rather than learning about the game as such. In contrast, here we report on an experiment designed to test whether players learn...