How do people react to a mix of good deeds to a third party and bad deeds against them? A modified ultimatum game shows that previous good deeds make responders substantially more tolerant to unfair proposals.

Given that private rewards have mixed effectiveness in the realm of prosocial behaviours (Bénabou and Tirole, 2006), we explore whether a 'public' reward (denominated in additional units of public good provision) successfully encourages prosocial behaviour in the form of increased donations to...