The science of social networks is a central field of sociological study, a major application of random graph theory, and an emerging area of study by economists, statistical physicists and computer scientists. While these literatures are (slowly) becoming aware of each other, and on occasion drawing from one another, they are still largely distinct in their methods, interests, and goals. Here, my aim is to provide some perspective on the research from these literatures, with a focus on the formal modeling of social networks and the two major types of models: those based on random graphs and those based on game theoretic reasoning. I highlight some of the strengths, weaknesses, and potential synergies between these two network modeling approaches.

Abstract: We explore play between groups where one member of each 2-person group dictates the play of that group and is therefore responsible for the payoff of the other group member. We compare this to play when the game is the same, but each person is playing only for herself. Consistent with the principle of responsibility-alleviation described in Charness (2000), we find that a sense of responsibility for the welfare of others has an effect. While the issue of responsibility does not appear to influence the decisions of 2/3 of the population, almost 90 percent of the remaining 1/3 of the population plays a less risky strategy when choosing for a group than when playing only for herself.

Abstract: Networks can affect a group’s ability to solve a coordination problem. We utilize laboratory experiments to study the conditions under which groups of subjects can solve coordination games. We investigate a variety of different network structures, and we also investigate coordination games with symmetric and asymmetric payoffs. Our results show that network connections facilitate coordination in both symmetric and asymmetric games. Most significantly, we find that increases in the number of network connections encourage coordination even when payoffs are highly asymmetric. These results shed light on the conditions that may facilitate coordination in real-world networks. 1

We examine how groups of agents form trading networks in the presence of idiosyncratic risk and the possibility of contagion. Specifically, four agents play a two-stage finite repeated game. In the first stage, the network structure is endogenously determined through a noncooperative proposal game. In the second stage, agents play multiple rounds of a coordination game against all of their chosen ‘neighbors ’ after the realization of a payoff relevant shock. While parsimonious, our four agent environment is rich enough to capture all of the important interaction structures in the networks literature: bilateral (marriage), local interaction, star, and uniform matching. Consistent with our theory, marriage networks are the most frequent and stable network structures in our experiments. We find that payoff efficiency is around 90 percent of the ex-ante, payoff dominant strategies and the distribution of network structures is significantly different from that which would result from random play.

sophistication of individuals and teams in experimental

versus individual decision-making:

The focus for the Centre is research into individual and strategic decision‐making using a combination of theoretical and experimental methods. On the theory side, members of the Centre investigate individual choice under uncertainty, cooperative and non‐cooperative game theory, as well as theories of psychology, bounded rationality and evolutionary game theory. Members of the Centre have applied experimental methods in the fields of public economics, individual choice under risk and uncertainty, strategic interaction, and the performance of auctions, markets and other economic institutions. Much of the Centre's research involves collaborative projects with researchers from other departments in the UK and overseas. Please visit

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This paper studies the conditions under which intra-elite con‡ict leads to a democracy. There are two risk averse elites competing for the appropriation of a unit of social surplus, with an ex-ante uncertainty about their future relative bargaining power, and a large non-elite class unable to act collectively. We characterize a democracy as consistng of both franchise extension to, and lowering the cost of collective political activity for, individuals in the non-elite. In the absence of democracy, the stronger elite is always able to appropriate the entire surplus. We show that in a democracy, the newly enfranchised non-elite organize and always prefer to form a coalition with weaker elite against the stronger resulting in a more balanced surplus allocation between the two elites. Accordingly, the elites choose to democratize if they are suf-…ciently risk averse. Our formal analysis can account for stylized facts that emerge from a comparative analysis of Indian and Western European democracies.