Promises in group decision making

We assess in the laboratory the effect of promises on group decision-making. The gift-exchange game provides the testing ground for our experiment. When the game is played between groups, inter-group cooperation and reciprocity represent a condition for increasing total earnings as a measure of social efficiency. Our findings show that promises have positive effect on aggregate payoffs and that effect is reinforced when a group member is randomly selected as proposer to set forth an effort/transfer level that other group members can approve or reject. Promises and proposers elicit social conformity leading groups to exhibit more desirable social behavior.