Recently developed models of fairness can explain a wide variety of seemingly contradictory facts. The most controversial and yet unresolved issue in the modeling of fairness preferences concerns the behavioral relevance of fairness intentions. In this paper we provide clear and unambiguous experimental evidence for the behavioral relevance of fairness intentions. Our results indicate that the attribution of fairness intentions is important both in the domain of negatively reciprocal behavior and in the domain of positively reciprocal behavior. This means that reciprocal behavior cannot be fully captured by equity models that are exclusively based on preferences over the distribution of material payoffs. Models that take into account players' fairness intentions and distributional preferences are consistent with our data while models thatnfocus exclusively on intentions or on the distribution of material payoffs are not.