Indirect reciprocity provides a narrow margin of efficiency for costly punishment

Department of Value and Decision Science, Tokyo Institute of Technology, Tokyo 152-8552, Japan.
Nature (Impact Factor: 41.46). 02/2009; 457(7225):79-82. DOI: 10.1038/nature07601
Source: PubMed


Indirect reciprocity is a key mechanism for the evolution of human cooperation. Our behaviour towards other people depends not only on what they have done to us but also on what they have done to others. Indirect reciprocity works through reputation. The standard model of indirect reciprocity offers a binary choice: people can either cooperate or defect. Cooperation implies a cost for the donor and a benefit for the recipient. Defection has no cost and yields no benefit. Currently there is considerable interest in studying the effect of costly (or altruistic) punishment on human behaviour. Punishment implies a cost for the punished person. Costly punishment means that the punisher also pays a cost. It has been suggested that costly punishment between individuals can promote cooperation. Here we study the role of costly punishment in an explicit model of indirect reciprocity. We analyse all social norms, which depend on the action of the donor and the reputation of the recipient. We allow errors in assigning reputation and study gossip as a mechanism for establishing coherence. We characterize all strategies that allow the evolutionary stability of cooperation. Some of those strategies use costly punishment; others do not. We find that punishment strategies typically reduce the average payoff of the population. Consequently, there is only a small parameter region where costly punishment leads to an efficient equilibrium. In most cases the population does better by not using costly punishment. The efficient strategy for indirect reciprocity is to withhold help for defectors rather than punishing them.

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    • "They model the fact that the bystander observing the interaction may fail to attribute an accurate reputation to the donor, due to a myopic assess of the reputation of the potential receiver or due to a misinterpretation of the action employed. Following[10,13,14,22,23,26], and given that we are dealing with small communities, we assume that, once the reputation of an individual is assigned, it is widely and faithfully disseminated throughout the population, so that everyone shares the same opinion regarding the reputation of others. "
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    ABSTRACT: Indirect reciprocity, besides providing a convenient framework to address the evolution of moral systems, offers a simple and plausible explanation for the prevalence of cooperation among unrelated individuals. By helping someone, an individual may increase her/his reputation, which may change the pre-disposition of others to help her/him in the future. This, however, depends on what is reckoned as a good or a bad action, i.e., on the adopted social norm responsible for raising or damaging a reputation. In particular, it remains an open question which social norms are able to foster cooperation in small-scale societies, while enduring the wide plethora of stochastic affects inherent to finite populations. Here we address this problem by studying the stochastic dynamics of cooperation under distinct social norms, showing that the leading norms capable of promoting cooperation depend on the community size. However, only a single norm systematically leads to the highest cooperative standards in small communities. That simple norm dictates that only whoever cooperates with good individuals, and defects against bad ones, deserves a good reputation, a pattern that proves robust to errors, mutations and variations in the intensity of selection.
    Full-text · Article · Jan 2016 · PLoS Computational Biology
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    • "In the studies of evolutionary game theory, five specific mechanisms, namely, kin selection [7] [8], direct reciprocity [9] [10], indirect reciprocity [11] [12], group selection [13] [14] [15] and spatial reciprocity [16] [17], have been proposed to promote cooperative behavior in many different contexts. Within or intercorrelated with these mechanisms, some key factors have been discovered, which can promote cooperative behavior, including reputation [18] [19], punishment [20] [21], migration [22] [23] [24] [25] [26], memory effect [27] [28] and social diversity [29] [30] [31], to name but a few (see [32–42, 43]). Recently, the social dilemma on interdependent networks [44] [45] [46] [47] [48] [49] [50] [51] [52] has attracted extensive investigation. "

    Full-text · Dataset · Oct 2015
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    • "Punishment, an external incentive discussed by Brandt et al. [9], is a powerful resolution for social dilemmas. Although some studies [10] [11] [12] [13] have shown that a costly punishment can effectively guarantee cooperation, others [14] [15] [16] [17] [18] have shown just the opposite. Boyd et al. [19] also pointed out that the average payoff of a group significantly decreases * Corresponding author at: 3-2-16, Osaki, Shinagawa-ku, Tokyo, 141-8602, Japan. "
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    ABSTRACT: Although there is much support for the punishment system as a sophisticated approach to resolving social dilemmas, more than a few researchers have also pointed out the limitations of such an approach. Second-order free riding is a serious issue facing the punishment system. Various pioneering works have suggested that an anti-social behavior or noise stemming from a mutation may, surprisingly, be helpful for avoiding second-order freeloaders. In this work, we show through mathematical analysis and an agent-based simulation of a model extending the meta-norms game that the coercive introduction of a small number of non-cooperators can maintain a cooperative regime robustly. This paradoxical idea was inspired by the effect of a vaccine, which is a weakened pathogen injected into a human body to create antibodies and ward off infection by that pathogen. Our expectation is that the coercive introduction of a few defectors, i.e., a social vaccine, will help maintain a highly cooperative regime because it will ensure that the punishment system works.
    Full-text · Article · Oct 2015 · Physica A: Statistical Mechanics and its Applications
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