We study whether actions are justified by beliefs, as is usually assumed, or whether beliefs are justified by actions. In our experiment, subjects participate in a trust game, after which they have an opportunity to state their beliefs about their opponent's actions. Subsequently, subjects...

We report experimental results for a twice-played prisoners' dilemma in which the players can choose the allocation of the stakes across the two periods. Our point of departure is the assumption that some (but not all) people are principled to “do the right thing,” or cooperate, as long as...

To understand the "pure" incentives of altruism, economic laboratory research on humans almost always forbids communication between subjects. In reality, however, altruism usually requires interaction between givers and receivers, which clearly must influence choices. Charities, for example,...

This paper compares two methods to encourage socially optimal provision of a public good. We compare the efficacy of vigilante justice, as represented by peer-to-peer punishment, to delegated policing, as represented by the "hired gun" mechanism, to deter free riding and improve group welfare....

We study whether actions are justified by beliefs, as is usually assumed, or whether beliefs are justified by actions. In our experiment, subjects participate in a trust game, after which they have an opportunity to state their beliefs about their opponent's actions. Subsequently, subjects...

If people get joy from giving, then why might they avoid fundraisers? We explore this in a randomized natural field experiment during the Salvation Army's annual campaign. The familiar bell-ringers were placed at one or both of two main entrances to a supermarket, making the ask for a charitable...