Strategic reward and altruistic punishment support cooperation in a public goods game experiment

We compare the effects of and the motivations behind voluntary punishment and reward in a finitely repeated public goods game. Our experimental results show that (1) the level of cooperation is indistinguishable between the punishment and reward treatments when group membership does not change, but the reward treatment shows stronger endgame effects and that (2) punishment is much more effective than reward when group membership changes randomly between rounds. Strategic motivations are stronger in rewarding others, whereas more intrinsic motivations drive punishment behavior. We revisit the results of several previous experimental studies that are comparable to ours and show the overall consistency of our results with those in the prior experimental research.