Just ask? Preference revelation and lying in a public goods experiment

This paper studies the extent to which simply asking group members to report their demand-type promotes cooperation in a public goods experiment with private, unobservable incentives. The design uses a simple public goods game, in which group members differ in both their dominant strategy contributions and socially optimal contributions. Treatments are conducted in which individuals either do not report their private payoff information, report only to group members, report to group members who can punish them, or report to a binding mechanism that charges them the socially optimal contribution for someone of their reported type. In all cases, messages are non-verifiable and participants are told that they are free to lie. When participants are able to report their type, either to their group members or to a binding mechanism, they contribute more. When reporting to a mechanism, there is a positive effect initially that fades with repetition, while reporting to group members is particularly effective at sustaining cooperation over time. Further, the misreporting of type is less frequent, considered more dishonest, and punished more harshly than free-riding. Consistent with work showing that weak punishment can backfire, the punishment mechanism is underutilized in this environment and its presence negates the positive effect of sharing information.