Human Cooperation Based on Punishment Reputation

Abstract

The threat of punishment usually promotes cooperation. However, punishing itself is costly, rare in nonhuman animals, and humans who punish often finish with low payoffs in economic experiments. The evolution of punishment has therefore been unclear. Recent theoretical developments suggest that punishment has evolved in the context of reputation games. We tested this idea in a simple helping game with observers and with punishment and punishment reputation (experimentally controlling for other possible reputational effects). We show that punishers fully compensate their costs as they receive help more often. The more likely defection is punished within a group, the higher the level of within-group cooperation. These beneficial effects perish if the punishment reputation is removed. We conclude that reputation is key to the evolution of punishment.

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

“…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.…”

Exposure to superfluous information reduces cooperation and increases antisocial punishment in reputation-based interactions

“…When humans were put into the respective situations and in front of a screen that provided all the information necessary to play these simple strategies, they seemed to behave as predicted: reputation based on generosity or on punishment was used, and the use of reputation increased cooperation frequencies (Wedekind and Milinski, 2000;Milinski et al, 2001;Wedekind and Braithwaite, 2002;dos Santos et al, 2013). However, such experiments cannot reveal the strategies humans use.…”

“…Apart from reputation based on generosity, there are other kinds of reputational effects that influence cooperation in humans. A reputation based on punishment, for example, may have played a key role in the evolution of punishment that promotes cooperation within groups (Brandt et al, 2003;Gardner and West, 2004;Hilbe and Sigmund, 2010;dos Santos et al, 2011dos Santos et al, , 2013. Various kinds of reputation may therefore affect partner choice (Fu et al, 2008;Sylwester and Roberts, 2010) and may thereby create a biological market (Barclay, 2013).…”

“…For example, a score that reveals the number of times a social partner helped or punished others in previous interactions would be sufficient to trigger cooperation in simple repeated helping games based on indirect reciprocity (e.g., Nowak and Sigmund, 1998;dos Santos et al, 2011). Experiments that were specifically designed to test these models found the kind of reputation formation and the increased cooperation that were predicted (Wedekind and Milinski, 2000;Wedekind and Braithwaite, 2002;dos Santos et al, 2013). These experiments seemed to require comparatively little memory because all the information that theory predicted to be relevant was provided in simple graphical form on a screen (e.g., a moveable arrow that indicated a level on a scale).…”

“…We introduced this treatment into two types of reputation games, one where reputation can only be based on generosity and one where reputation can only be based on punishment. We based our analyses on experimental protocols that were successfully used before to test predictions derived from game theory (Wedekind and Braithwaite, 2002;dos Santos et al, 2013) and that can both lead to reputation-based cooperation with simple behavioral rules using the simple graphical information provided on display only (consistent with the recent theory), or with more sophisticated and potentially more memory-demanding strategies.…”