title: Indirect punishment and generosity toward strangers.
abstract: Many people incur costs to reward strangers who have been kind to others. Theoretical and experimental evidence suggests that such "indirect rewarding" sustains cooperation between unrelated humans. Its emergence is surprising, because rewarders incur costs but receive no immediate benefits. It can prevail in the long run only if rewarders earn higher payoffs than "defectors" who ignore strangers' kindness. We provide experimental evidence regarding the payoffs received by individuals who employ these and other strategies, such as "indirect punishment," by imposing costs on unkind strangers. We find that if unkind strangers cannot be punished, defection earns most. If they can be punished, however, then indirect rewarding earns most. Indirect punishment plays this important role, even if it gives a low payoff and is rarely implemented.
authors.affiliation: Center for Research in Experimental Economics and Political Decision-Making (CREED), University of Amsterdam, Roetersstraat 11, 1018 WB Amsterdam, Netherlands. a.ule@uva.nl
authors.forename: Aljaz
authors.initials: A
authors.lastname: Ule
authors.forename: Arthur
authors.initials: A
authors.lastname: Schram
authors.forename: Arno
authors.initials: A
authors.lastname: Riedl
authors.forename: Timothy N
authors.initials: TN
authors.lastname: Cason
mesh_terms: D000533:Altruism; D003299:Cooperative Behavior; D005717:Games, Experimental; D006801:Humans; D011678:Punishment; D012201:Reward; D012919:Social Behavior