Truth-telling under Oath

A growing experimental literature has explored how monetary incentives affect truth-telling and lying behavior. We extend this literature to consider how to non-monetary incentives–a loaded environment and commitment through a truth-telling oath–affect truth-telling and lying behavior. For a loaded environment, we revise the standard lying experiment by making it explicit and clear to the person that "a lie is a lie". We then combine the lying experiment with a solemn oath procedure, by which subjects commit themselves to tell the truth before entering the laboratory. Both non-monetary incentive devices affect a person's willingness to tell the truth: subjects lie slightly less frequently in the loaded environment, and drastically less after they signed the solemn oath. Interestingly, the loaded environment and oath have distinct effects–the oath changes the incentive to lie only when truthfulness is made meaningful through the loaded environment.