The shortage of transplant kidneys has spurred debate about legalizing monetary payments to donors to increase the number of available kidneys. However, buying and selling organs faces widespread disapproval. We survey a representative sample of Americans to assess disapproval for several forms...

We conduct online field experiments in large real-world social networks in order to decompose prosocial giving into three components: (1) baseline altruism toward randomly selected strangers, (2) directed altruism that favors friends over random strangers, and (3) giving motivated by the...