Abstract
Indirect reciprocity, a key concept in behavioral experiments and evolutionary game theory, provides a mechanism that allows reciprocal altruism to emerge in a population of self-regarding individuals even when repeated interactions between pairs of actors are unlikely. Recent empirical evidence show that humans typically follow complex assessment strategies involving both reciprocity and social imitation when making cooperative decisions. However, currently, we have no systematic understanding of how imitation, a mechanism that may also generate negative effects via a process of cumulative advantage, affects cooperation when repeated interactions are unlikely or information about a recipient's reputation is unavailable. Here we extend existing evolutionary models, which use an image score for reputation to track how individuals cooperate by contributing resources, by introducing a new imitative-trust score, which tracks whether actors have been the recipients of cooperation in the past. We show that imitative trust can co-exist with indirect reciprocity mechanisms up to a threshold and then cooperation reverses -revealing the elusive nature of cooperation. Moreover, we find that when information about a recipient's reputation is limited, trusting the action of third parties towards her (i.e. imitating) does favor a higher collective cooperation compared to random-trusting and share-alike mechanisms. We believe these results shed new light on the factors favoring social imitation as an adaptive mechanism in populations of cooperating social actors.
Highlights
The evolution of cooperative behavior in biological and human populations has been shown to rely critically on different forms of reciprocity [1,2,3,4,5,6]
Emergence of cooperation we investigate whether imitative trust and indirect reciprocity can co-exist and allow the emergence of reciprocal altruism
It has been argued that cultural transmission mechanisms make it possible to assign a measure of reputation or social status to specific individuals in a population, so that cooperation can emerge in human societies as a consequence of indirect reciprocity [9,10]
Summary
The evolution of cooperative behavior in biological and human populations has been shown to rely critically on different forms of reciprocity [1,2,3,4,5,6]. The trustworthiness can be assigned to actors on the basis of how many third parties signal that they endorse a given actor, and as such is used as a proxy for the attributes of an individual when there is no detailed record of how those actors have acted towards others in the past [17,18,25,26] This is to say, an actor C will extend trust to A (i.e. cooperate with A), because B previously extended trust to A, and in the absence of further information the trustworthiness of A can be used as part of a frugal heuristic or referral mechanisms by C [20,24,27,28]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
