Societies prohibit many transactions considered morally repugnant, although potentially efficiency-enhancing. We conducted an online choice experiment to characterize preferences for the morality and efficiency of payments to kidney donors. Preferences were heterogeneous, ranging from...

We provide a test of the role of social preferences and beliefs in voluntary cooperation and its decline. We elicit individuals' cooperation preferences in one experiment and use them - as well as subjects' elicited beliefs - to explain contributions to a public good played repeatedly. We find...

Substantial evidence has accumulated in recent empirical works on the limited ability of the Nash equilibrium to rationalize observed behavior in many classes of games played by experimental subjects. This realization has led to several attempts aimed at finding tractable equilibrium concepts...

Cooperativeness among genetically unrelated humans remains a major puzzle in the social sciences. We explore the causal impact of physical distance on willingness to help. In a field setting, participants decide about supporting local refugees at the dispense of money to themselves. We vary...

Extensive research in economics explores generosity in monetary allocations. However, generosity often involves the allocation of non-monetary goods or experiences. Existing evidence suggests that generosity may be higher in such contexts, though no direct comparison exists. Here, we compare...

To investigate the external validity of laboratory results, we combine a public good experiment with three treatments in a field experiment. One treatment offers the opportunity to free-ride, the other two are placebo treatments. We compare results within subjects. In the free-riding treatment,...

Experimental and observational studies have highlighted the importance of agents being conditionally cooperative when facing a social dilemma. We formalize this mechanism in a theoretical model that portrays a small community having joint access to a common pool resource. The diffusion of norms...

In many cultures and industries gifts are given in order to influence the recipient, often at the expense of a third party. Examples include business gifts of firms and lobbyists. In a series of experiments, we show that, even without incentive or informational effects, small gifts strongly...