The evolution of punishment through reputation

Abstract

Punishment of non-cooperators has been observed to promote cooperation. Such punishment is an evolutionary puzzle because it is costly to the punisher while beneficial to others, for example, through increased social cohesion. Recent studies have concluded that punishing strategies usually pay less than some non-punishing strategies. These findings suggest that punishment could not have directly evolved to promote cooperation. However, while it is well established that reputation plays a key role in human cooperation, the simple threat from a reputation of being a punisher may not have been sufficiently explored yet in order to explain the evolution of costly punishment. Here, we first show analytically that punishment can lead to long-term benefits if it influences one's reputation and thereby makes the punisher more likely to receive help in future interactions. Then, in computer simulations, we incorporate up to 40 more complex strategies that use different kinds of reputations (e.g. from generous actions), or strategies that not only include punitive behaviours directed towards defectors but also towards cooperators for example. Our findings demonstrate that punishment can directly evolve through a simple reputation system. We conclude that reputation is crucial for the evolution of punishment by making a punisher more likely to receive help in future interactions, and that experiments investigating the beneficial effects of punishment in humans should include reputation as an explicit feature.

Reputation based on punishment rather than generosity allows for evolution of cooperation in sizable groups

“…So far, the evolution of cooperation and punishment through reputation was mainly investigated in dyadic interactions (dos Santos et al, 2011;Hilbe & Sigmund, 2010;Hilbe & Traulsen, 2012). A few studies considered the effects of punishment in larger group sizes but with strategies that were not directly based on individual punishment reputation, or the effect of errors in reputation assessment was not investigated (Boyd & Richerson, 1992;Brandt et al, 2003;Gardner & West, 2004).…”

“…Until recently, such costly punishment has been perceived as an evolutionary puzzle because punishers accept costs to harm others while third parties benefit from the increased cooperation levels (Dreber et al, 2008;Fehr & Gächter, 2002;Rankin et al, 2009;Sigmund, 2007;Wu et al, 2009). However, if punishers can build up a punishment reputation that affects later decisions of others, punishment can lead to long-term benefits that compensate or even outweigh the immediate costs of punishment (dos Santos et al, 2011;dos Santos et al, 2013;Hilbe & Sigmund, 2010;Hilbe & Traulsen, 2012). This holds for dyadic interactions, but it is unclear whether punishment reputation facilitates the emergence of cooperation also groups larger than 2.…”

Human punishment is motivated by both a desire for revenge and a desire for equality

“…dos Santos, Rankin, & Wedekind, 2011;Hilbe & Sigmund, 2010;McCullough et al, 2013). Under this hypothesis (hereafter the 'revenge' hypothesis), individuals should be motivated to reciprocally harm individuals that intentionally harm them, even if punishment cannot immediately equalize the payoffs between the defector and the punisher (Falk, Fehr, & Fischbacher, 2005).…”

Sistemas de Reputação: um caso de simulação social em narrativas interativas

“…Nas simulações de cooperação encontradas há algumas regras de pontuação que parecem representar estes códigos de conduta. Um determinado comportamento considerado bom recebe um valor positivo, enquanto o comportamento divergente é pontuado negativamente ou em alguns casos punido de outras formas (TANIMOTO, 2007, SANTOS, WEDEKIND, 2011. Porém, casos reais podem ser mais ambíguos.…”