We study learning and influence in a setting where agents communicate according to an arbitrary social network and naively update their beliefs by repeatedly taking weighted averages of their neighbors' opinions. A focus is on conditions under which beliefs of all agents in large societies...

We examine how the speed of learning and best-response processes depends on homophily: the tendency of agents to associate disproportionately with those having similar traits. When agents' beliefs or behaviors are developed by averaging what they see among their neighbors, then convergence to a...

We investigate the role of networks of alliances in preventing (multilateral) interstate wars. We first show that, in the absence of international trade, no network of alliances is peaceful and stable. We then show that international trade induces peaceful and stable networks: trade increases...

We study the bilateral exchange of information in the context of linear quadratic games. An information structure is here represented by a non directed network, whose nodes are agents and whose links represent sharing agreements. We first study the equilibrium use of information in any given...

Many types of economic and social activities involve significant behavioral complementarities (peer effects) with neighbors in the social network. The same activities often exert externalities that cummulate in 'stocks' affecting agents' welfare and incentives. For instance, smoking is subject...

Recent research in the field of network economics has shown how explicitly modelling the network structure of social and economic relations can provide significant theoretical insights, as well as account for previously unexplained empirical evidence. Despite their critical importance to many...

Many Social Interactions display either or both of the following well documented phenomena. People tend to interact with similar others (homophily). And they tend to treat others more favorably if they are perceived to share the same identity (in-group bias). While both phenomena involve some...

This paper proposes a formulation of coalitional payoff possibilities in games with externalities, based on the assumption that forming coalitions can exploit a first mover advantage. We derive a characteristic function and show that when outside players play their best response...

We consider a game of information transmission, with one informed decision maker gathering information from one or more informed senders. Private information is (conditionally) correlated across players, and communication is cheap talk. For the one sender case, we show that correlation...

This paper establishes sufficient conditions for the existence of a stable coalition structure in the "coalition unanimity" game of coalition formation, first defined by Hart and Kurz (1983) and more recently studied by Yi (1997, 2000). Our conditions are defined on the strategic form game used...