Positive reciprocity and intentions in trust games

Several recent theories in behavioral game theory seek to explain the behavior of subjects in experimental bargaining games. These models can be partitioned into two classes: outcome-based and intention-based. Outcome-based models treat the intentions that players attribute to one another as unnecessary for predicting behavior. Intention-based approaches, and in particular the trust and reciprocity (TR) hypothesis, rely on this attribution of intentions in an essential way. We report laboratory data from simple two-person trust games which is inconsistent with outcome-based models, but predicted by the trust and reciprocity hypothesis.