The effect of social distancing on the reach of an epidemic in social networks

How does social distancing affect the reach of an epidemic in social networks? We present Monte Carlo simulation results of a susceptible–infected–removed with social distancing model. The key feature of the model is that individuals are limited in the number of acquaintances that they can interact with, thereby constraining disease transmission to an infectious subnetwork of the original social network. While increased social distancing typically reduces the spread of an infectious disease, the magnitude varies greatly depending on the topology of the network, indicating the need for policies that are network dependent. Our results also reveal the importance of coordinating policies at the ‘global’ level. In particular, the public health benefits from social distancing to a group (e.g. a country) may be completely undone if that group maintains connections with outside groups that are not following suit.

     

Social preferences and public economics: Mechanism design when social preferences depend on incentives

Social preferences such as altruism, reciprocity, intrinsic motivation and a desire to uphold ethical norms are essential to good government, often facilitating socially desirable allocations that would be unattainable by incentives that appeal solely to self-interest. But experimental and other evidence indicates that conventional economic incentives and social preferences may be either complements or substitutes, explicit incentives crowding in or crowding out social preferences. We investigate the design of optimal incentives to contribute to a public good under these effects would make either more or less use of explicit incentives, by comparison to a naive planner who assumes they are absent.     

Strong reciprocity and team production: Theory and evidence

Punishment of shirkers is often an effective means of attenuating incentive problems and sustaining coordination in work teams. Explanations of the motivation to punish generally rely either on small group size or on a Folk theorem that requires coordinated punishment and, hence, highly accurate information concerning the behavior of each player. We provide a model of team production in which the punishment of shirkers depends on strong reciprocity: the willingness of some team members to contribute altruistically to a joint project and also to bear costs in order to discipline fellow members who do not contribute. This alternative does not require small group size, complex coordinated punishing activities, or implausible informational assumptions. An experimental public goods game provides evidence for the behavioral relevance of strong reciprocity and how it differs from unconditional altruism.