Two rationales have emerged for why individuals keep their promises: (a) an emotional commitment to keep actions and words consistent, a commitment rationale and (b) avoidance of guilt due to not meeting the expectations of the promisee, an expectations rationale. We propose a new dichotomy with clearer distinctions between rationales: (1) an internal consistency rationale, which is the desire to keep actions and words consistent regardless of others’ awareness of the promise and (2) a communication rationale, which captures all aspects of promise keeping that are associated with the promisee having learned of the promise, including but not limited to promisee expectations. Using an experiment that manipulates whether promises are delivered, we find no support for the internal consistency rationale; only delivered promises are relevant. In a second experiment designed to better understand what aspect of promise delivery influences promisor behavior, we manipulate whether the promise is delivered before or after the promisee is able to take a trusting action. We find late-arriving promises are relevant though not as relevant as promises delivered before the promisee chooses whether to take the trusting action. We conclude that implicit contracting does not fully explain promise keeping, because had it done so, late-arriving promises would also be irrelevant.

We analyze the effects of limited feedback on beliefs and contributions in a repeated public goods game setting. In a first experiment, we test whether exogenously determined feedback about a good example (i.e., the maximum contribution in a period) in contrast to a bad example (i.e., the minimum contribution in a period) induces higher contributions. We find that when the type of feedback is not transparent to the group members, good examples boost cooperation while bad examples hamper it. There is no difference when the type of feedback is transparent. In a second experiment, feedback is endogenously chosen by a group leader. The results show that a large majority of the group leaders count on the positive effect of providing a good example. This is true regardless whether they choose the feedback type to be transparent or non-transparent. Half of the group leaders make the type of feedback transparent. With endogenously chosen feedback about good examples no difference in contributions can be observed among transparent and non-transparent feedback selection. In both experiments feedback shapes subjects’ beliefs. With exogenously chosen feedback, transparent feedback tends to reduce beliefs when good examples are provided as feedback and tends to increase beliefs in when bad examples are provided as feedback compared to the respective non-transparent cases. Our results shed new light on the design of feedback provision in public goods settings.

We develop a mechanism based on the Colonel Blotto game to elicit (subjective) expectations in a group-based manner. In this game, two players allocate resources over possible future events. A fixed prize is awarded based on the amounts the players allocate to the realized event. We consider two payoff variations: under the proportional-prize rule, the award is split proportionally to the resources that players allocate to the realized event; under the winner-takes-all rule, the full award is given to the player who allocate the most resources to the realized event. When probabilities by which events realize are common knowledge to the players, both games are Bayesian–Nash incentive compatible in the sense that (expected) equilibrium allocations perfectly reflect the true realization probabilities. By means of a laboratory experiment, we find that in a setting where realization probabilities are common knowledge the game with the proportional-prize rule (Prop) elicits better distributions compared to both the winner-takes-all variation (Win) and a benchmark mechanism based on an individual-based proper scoring rule (Ind). Without common knowledge of realization probabilities Prop is at least as good as Ind, showing that it is possible to use a game to elicit expectations in a similar fashion to using a proper scoring rule.