Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We study the role of communication in a high stakes prisoner's dilemma, using data from a television game show. 40 Percent of the players voluntarily promise to cooperate, and these players are 50 percentage points more likely to cooperate than players who do not volunteer a promise. However, promises that arise in response to an explicit question by the presenter of the show are uninformative about behavior. These results augment and qualify recent experimental findings on communication--people do not want to volunteer lies but may have no compunction in lying if they feel compelled to do so.