Research Article Intermediaries in Trust: Indirect Reciprocity, Incentives, and Norms Giangiacomo Bravo, 1 Flaminio Squazzoni, 2 and Károly Takács 3 1 Department of Social Studies, Linnaeus University, Universitetsplatsen 1, 35195 V¨ axj¨ o, Sweden 2 Department of Economics and Management, University of Brescia, Via San Faustino 74B, 25122 Brescia, Italy 3 MTA TK Lend¨ ulet Research Center for Educational and Network Studies (RECENS), Hungarian Academy of Sciences, Orsz´ agh´ az Utca 30, Budapest 1014, Hungary Correspondence should be addressed to Giangiacomo Bravo; giangiacomo.bravo@lnu.se Received 2 September 2014; Accepted 4 December 2014 Academic Editor: Vincent Buskens Copyright © Giangiacomo Bravo et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Any trust situation involves a certain amount of risk for trustors that trustees could abuse. In some cases, intermediaries exist who play a crucial role in the exchange by providing reputational information. To examine under what conditions intermediary opinion could have a positive impact on cooperation, we designed two experiments based on a modifed version of the investment game where intermediaries rated the behaviour of trustees under various incentive schemes and diferent role structures. We found that intermediaries can increase trust if there is room for indirect reciprocity between the involved parties. We also found that the efect of monetary incentives and social norms cannot be clearly separable in these situations. If properly designed, monetary incentives for intermediaries can have a positive efect. On the one hand, when intermediary rewards are aligned with the trustor’s interest, investments and returns tend to increase. On the other hand, fxed monetary incentives perform less than any other incentive schemes and endogenous social norms in ensuring trust and fairness. Tese fndings should make us reconsider the mantra of incentivization of social and public conventional policy. 1. Introduction A trust relationship is an exchange where at least two parties interact, that is, a trustor and a trustee, and in which there is a certain amount of risk for the former. If the trustor decides to place trust, the trustee can honour or abuse it. If honouring trust is costly, as what happened in one-shot interactions and sometimes even in repeated exchanges, the trustee will have no rational incentive to be trustworthy. Knowing this, the trustor is hardly likely to make the frst move [1]. Understanding how trust can be established in such hos- tile situations is of paramount importance. One of the most interesting sociological explanations suggests that social and economic exchanges are embedded in social contexts where certain norms and roles have evolved to mediate between individual interests. For instance, intermediaries might act as advisories and mediators between the parties involved and reputation or gossip can help to spread information about unknown partners that helps trustors to take the risk of inter- action [1–3]. Recent experimental results have shown that individuals can overcome distrust and cooperate more frequently if behaviour in the exchange is observed by a third party [4– 8]. Tis happens even when the opinion of a third party has no consequence on the payofs of the individuals and repu- tational building strategies are ruled out [9]. Tis indicates that, in many real situations, third parties can reduce infor- mation asymmetry and temptations of free riding, induce mutual trust, and ensure collective beneft. Tis requires understanding why and under which conditions information from third parties should be trusted by trustors and what type of incentives can make judgements or recommendations by third parties credible to the eyes of trustors. Indeed, frst, intermediaries’ opinion is ofen subjective. Secondly, Hindawi Publishing Corporation Journal of Applied Mathematics Article ID 234528