Can Honesty Oaths, Peer Interaction, or Monitoring Mitigate Lying?

We introduce several new variants of the dice experiment by Fischbacher and Föllmi-Heusi (Journal of the European Economic Association 11(3):525–547, 2013) to investigate measures to reduce lying. Hypotheses on the relative performance of these treatments are derived from a straightforward theoretical model. In line with previous research, we find that groups of two subjects lied at least to the same extent as individuals—even in a novel treatment where we assigned to one subject the role of being the other’s monitor. However, we find that our participants hardly lied if they do not benefit and only others do, even if they were in a reciprocal relationship. Thus, we conclude that collaboration on lying mostly happens for personal gain. To mitigate selfish lying, an honesty oath which aims to increase moral awareness turned out to be effective.