cooperation under indirect reciprocity and imitative trust在间接互惠合作,模仿的信任.pdf

Cooperation under Indirect Reciprocity and Imitative Trust Serguei Saavedra1,2*, David Smith3,4,5, Felix Reed-Tsochas3,6 1 Northwestern Institute on Complex Systems, Northwestern University, Evanston, Illinois, United States of America, 2 Kellogg School of Management, Northwestern University, Evanston, Illinois, United States of America, 3 CABDyN Complexity Centre, Oxford University, Oxford, United Kingdom, 4 Oxford Centre for Integrated Systems Biology, Oxford University, Oxford, United Kingdom, 5 Centre for Mathematical Biology, Oxford University, Oxford, United Kingdom, 6 Institute for Science, Innovation, and ¨ Society, Saıd Business School, Oxford University, Oxford, United Kingdom 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 m