Ill‐Defined versus Precise Pre‐Play Communication in the Traveler's Dilemma

This article reports results from an experiment comparing the effects of vague versus precise pre‐play communication in a highly competitive two‐player game with conflicting interests. In the classic Traveler's Dilemma, non‐binding precise messages about intent of play are pure cheap talk. We conjecture that a form of imprecise pre‐play communication whereby subjects can submit ill‐defined messages may help foster cooperation because of their vagueness. Comparing behavior both across modes of communication and to a baseline case without communication, we find that cooperation is highest when players can communicate using precise numerical messages. When communication with ill‐defined messages is allowed, then conditional on receiving a message, subjects act more cooperatively than when no message is received. However, overall, the ability to exchange ill‐defined messages does not substantially improve cooperation.