Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms gover...

Many of those who support organ donation do not register to become organ donors. The use of reciprocity systems, under which some degree of priority is offered to registered donors who require an organ transplant, is one suggestion for increasing registration rates. This article uses a combination of survey and focus group methodologies to explore the reaction of Canadians to a reciprocity prop...

Do people have a stronger propensity to reward or punish? When reacting to intentions, Offerman (2002) concluded that people punish more. Using the Falk and Fischbacher (2006) model, we extend Offerman’s design in two ways. First, we control for the strength of the positive/negative intentions to which an individual reacts when rewarding/punishing. Second, we can precisely compare the strength ...