We investigate the effect of a donation incentive tied to contributions to a public good when group members can decide on the size of the donation to be made. An up to 20 % donation of the public good was implemented either exogenously or endogenously by group members. In the Vote treatment,...

In three sets of experiments involving 5,432 subjects, we show that agents make more errors when doing so allows them to justify selfish behavior. We show that errors relating to addition arise when they can help to justify selfishness but are eliminated when selfish motives are removed. In...