Jiang L-L, Perc M, Szolnoki A (2013) If Cooperation Is Likely Punish Mildly: Insights from Economic Experiments Based on the Snowdrift Game. PLoS ONE 8(5): e64677.
Punishment may deter antisocial behavior. Yet to punishis costly, and the costs often do not offset the gains that are due to elevatedlevels of cooperation. However, the effectiveness of punishment depends notonly on how costly it is, but also on the circumstances defining the socialdilemma. Using the snowdrift game as the basis, we have conducted a series of economicexperiments to determine whether severe punishment is more effective than mildpunishment. We have observed that severe punishment is not necessarily more effective,even if the cost of punishment is identical in both cases. The benefits ofsevere punishment become evident only under extremely adverse conditions, whento cooperate is highly improbable in the absence of sanctions. If cooperationis likely, mild punishment is not less effective and leads to higher averagepayoffs, and is thus the much preferred alternative. Presented results suggestthat the positive effects of punishment stem not only from imposed fines, butmay also have a psychological background. Small fines can do wonders inmotivating us to chose cooperation over defection, but without the paralyzingeffect that may be brought about by large fines. The later should be utilizedonly when absolutely necessary.