Bringing the four-eyes-principle to the lab

The "Four-Eyes-Principle" is considered as one of the most potent measures against corruption although it lacks both theoretical and empirical justification. We show in a laboratory experiment using a standard corruption game that introducing the 4EP increases corrupt behaviour, casting doubt on its usefulness as a general recommendation. Combining data on final choices with observations on the decision making processes in teams, including a content analysis of exchanged messages, provides insights into the dynamics of team decision making and shows that the individual profit maximizing motive dominates group decision making and crowds out altruistic arguments.