Reputation-based cooperation: empirical evidence for behavioral strategies

Abstract

Human cooperation in large groups can emerge when help is channeled towards individuals with a good reputation of helping others. Evolutionary models suggest that, for reputation-based cooperation to be stable, the recipient's reputation should be based not only on his past behavior (1st-order information) but also on the past behavior of the recipient's recipient (2nd-order information). Second-order information reflects the context of others' actions, and allows people to distinguish whether or not giving (or denying) help was justified. Little is known yet about how people actually condition their cooperation on 2nd-order information. With a behavioral experiment, we show that people actively seek 2nd-order information and take this into account in their own helping decisions. In an anonymous iterated helping game, donors learned if their recipients helped others in the past and could obtain 2nd-order information about these actions. Donors often requested this 2nd-order information and were especially interested to know why help was denied (i.e., defection). Justified defection was rewarded: help was generally directed towards those who defected against the selfish, and away from those who defected against helpful individuals. A detailed analysis of individual strategies reveals that many subjects based their decisions solely on 1st-order information about their recipients' past behavior. However, a substantial fraction of subjects consistently considered also the 2nd-order information about their recipients' behavior. Our results provide strong empirical support for the mechanisms that theoretically underpin reputation-based cooperation, and highlight pronounced individual variation in human cooperative strategies.

Indirect reciprocity with private, noisy, and incomplete information

“…So far, we have assumed that mutations are rare, such that populations are typically homogeneous. Experimental evidence, however, suggests that there is considerable variation in the social norms used by subjects (4,(7)(8)(9)(10)(11). While some subjects are best classified as unconditional defectors, others act as unconditional cooperators or use more sophisticated higher-order strategies (11).…”

“…cooperation | indirect reciprocity | social norms | evolutionary game theory H umans treat their reputations as a form of social capital (1)(2)(3). They strategically invest into their good reputation when their benevolent actions are widely observed (4)(5)(6), which in turn makes them more likely to receive benefits in subsequent interactions (7)(8)(9)(10)(11)(12). Reputations undergo constant changes in time.…”

The Evolution of Morals Under Indirect Reciprocity

“…Thus, our results indicate that the reputation mechanism known as "standing" first proposed by Sugden (1986) and identified as one of the "leading eight" by Ohtsuki and Iwasa (2004) is of particular importance for the evolution of cooperation under indirect reciprocity. Moreover, we provide an analytic foundation of recent simulation results by Yamamoto et al 2017and a rationale for recent experimental evidence (e.g., Bolton et al, 2005;Swakman et al, 2016).…”

When and How Does Mutation-Generated Variation Promote the Evolution of Cooperation?

“…Studies of the evolution of cooperation typically document behavioral variation (e.g., [8][9][10][11][12][13][14][15]), including those where behavioral strategies are explicitly assessed (e.g., [16,17]). Hence, the existence of such behavioral variation may provide a general explanation for the evolution of cooperation [3][4][5][6].…”