I suppose that people react with anger when others show themselves not to be minimally altruistic. With heterogeneous agents, this can account for the experimental results of ultimatum and dictator games. Moreover, it can account for the surprisingly large fraction of individuals who offer an...

We combine information on social networks with medical records and survey data in order to examine how friends affect one’s decision to get vaccinated against the flu. The random assignment of undergraduates to residential halls at a large private university allows us to estimate how peer...

In this paper, we propose a decision framework where people are individually asked to either actively consent to or dissent from some pro-social behavior. We hypothesize that confronting individuals with the choice of whether to engage in a specific pro-social behavior contributes to the...

We conduct field experiments in a large real-world social network to examine why decision-makers treat their friends more generously than strangers. Subjects are asked to divide a surplus between themselves and named partners at varying social distances, but only one of these decisions is...

There is a longstanding concern that material incentives might undermine prosocial motivation, leading to a decrease in blood donations rather than an increase. This paper provides an empirical test of how material incentives affect blood donations in a large-scale field experiment spanning...

In economic situations a player often has preferences regarding not only his or her own outcome but also regarding what happens to fellow players, concerns that are entirely apart from any strategic considerations. While this can be modeled directly by simply writing down a player's final...

Consistent with nonprofit fundraising practices, donation visibility has been shown to increase giving. While concern for status is used to explain this response, the authors argue that this explanation relies on the assumption that giving signals only income or generosity. When giving signals...