this end we develop a simple dynamic principal-agent model where both players may have feelings of altruism or spite toward …

involving a commitment. The hypothesis is tested in a large-scale field experiment on blood donations. We find that this “active …

social distances, but only one of these decisions is implemented. We decompose altruistic preferences into baseline altruism … towards strangers, and directed altruism towards friends. In order to separate the motives that are altruistic from the ones … the end of the experiment which decision was selected for payment, and a non-anonymous treatment where both players are …

There is a longstanding concern that material incentives might undermine prosocial motivation, leading to a decrease in … donations in a large-scale field experiment spanning three months and involving more than 10,000 previous donors. We examine two …

results, yet it is straightforward enough to be used in many applied situations where altruism, or a baser motive, is implied. …

altruism sometimes provides a net incentive to report performance truthfully, rather than to bias evaluations upward. The …

altruism. We show that allowing for private provision of health care, parallel to (free) treatment in a National Health Service …