A Public Dilemma: Cooperation with Large Stakes and a Large Audience∗

We analyze a large stakes prisoner’s dilemma game played on a TV show. Players cooperate 40% of the time, demonstrating that social preferences are important; however, cooperation is significantly below the 50% threshold that is required for inequity aversion to sustain cooperation. Women cooperate significantly more than men, while players who have ”earned” more of the stake cooperate less. A player’s promise to cooperate is also a good predictor of his decision. Surprisingly, a player’s probability of cooperation is unrelated to the opponent’s characteristics or promise. We argue that inequity aversion alone cannot adequately explain these results; reputational concerns in a public setting might be more important. JEL Classification Numbers: C72, C93, D64.