Sufficiently frequent interaction between partners has been identified by, a.o., Axelrod as a more-or-less sufficient condition for stable cooperation. The underlying argument is that rational cooperation is ensured if short-term benefits from opportunistic behavior are offset by the long-term costs of sanctions imposed on the culprit. In this paper, we develop a model for ‘embedded trust’ in which a trustee interacts with a number of trustors who may communicate via a social network with each other about the behavior of the (...) trustor. The analysis reconfirms the standard predictions about how the level of trust depends on the payoffs and shadow of the future. We provide new predictions both on between-network effects (“which network is more favorable for cooperation?”) and on within-network effects (“in what network position can you trust more?”). (shrink)

Conditional cooperation of selfish and rational actors is feasible in repeated encounters. We stress an important alternative for conditional cooperation: credible commitments that can be incurred via voluntary hostage posting (in the sense of pledging a bond). Hostages may facilitate cooperation in different ways. First, they reduce incentives to behave uncooperatively. Second, by offering some compensation for losses, hostages reduce the costs of suffering from uncooperative behavior of the partner. Finally, hostages may serve as signals about characteristics of the partner (...) that are related to his opportunities and incentives to behave uncooperatively. We show that signalling hostages may have lasting effects in durable relations. (shrink)

This paper derives hypotheses on how dyadic social support is affected by heterogeneity of the actors. We distinguish heterogeneity with respect to three parameters. First, the likelihood of needing support; second, the benefits from support relative to the costs for providing support; and, third, time preferences. The hypotheses are based on a game theoretic analysis of an iterated Support Game. We predict that, given homogeneity in two of these parameters, the prospect for mutual support is optimal if actors are homogeneous (...) with respect to the third parameter as well. Second, under heterogeneity with respect to two of the parameters, support is most likely if there is a specific heterogeneous distribution with respect to the other parameter that ‘compensates’ for the original heterogeneity. Third, under weak conditions, the overall optimal condition for mutual support is full homogeneity of the actors. (shrink)