An Examination of the Effect of Messages on Cooperation under Double-Blind and Single-Blind Payoff Procedures

Previous research has suggested that communication and especially promises in-crease cooperation in laboratory experiments. This has been taken as evidence for internal motivations such as guilt aversion or preference for promise keeping. The goals of this paper are to examine messages under a double-blind payoff procedure to test the alternative explan-ation that promise keeping is due to external influence and outside-the-lab reputational con-cerns and to assess how the impact of communication varies with social distance. Employing a 2x2 design, we find no evidence that communication increases the overall level of cooperation in our experiments with double-blind payoff procedures. However, we also find no evidence that communication impacts cooperation in our experiments with single-blind payoff proce-dures. Further, the payoff procedure does not appear to impact aggregate cooperation.