Essays in the Economic Theory of Social Networks
Open Access
- Author:
- Xiang, Wang
- Graduate Program:
- Economics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- May 25, 2017
- Committee Members:
- Kalyan Chatterjee, Dissertation Advisor/Co-Advisor
Kalyan Chatterjee, Committee Chair/Co-Chair
Vijay Krishna, Committee Member
James Schuyler Jordan, Committee Member
Reka Z Albert, Outside Member - Keywords:
- Network
Structural Hole
Strong Tie
Monitoring
Percolation - Abstract:
- In this dissertation, I provide three social network models addressing different aspects of the economy. First, I consider the issue of social network formation. Meeting with strangers and meeting with friends’ friends are two common patterns when observing the formation of social networks and thus are widely adopted in many statistical network formation settings. I establish a network formation model trying to find the individual level incentive behind the two patterns. Each agent enters the network sequentially choosing between forming global random links or connecting with friends' friends, knowing that his payoff depends on the distance between the player with valuable information and himself. I find that the distance between players in the resulting network asymptotically follows a Weibull distribution and the link formation decision depends on how easily information can be transmitted under the network. When the transmission is relatively easy and information can be received from far away, players prefer to meet with strangers. Otherwise they prefer to connect with friends’ friends. The second model considers a moral hazard scenario in which a monitor must detect deviations so as to provide proper incentives to attain an efficient outcome. What if the monitor himself were to deviate after being bribed by his monitored subject? I explore a multi-agent public-good provision game in which each player prefers shirking to working in the absence of exogenous enforcement and can bribe those assigned to monitor him. I find that when players agree to cooperate in choosing an optimally designed monitoring network, a core-periphery monitoring network results, with a small group of heavily monitored players who monitor all others. Under this network, a perfect Bayesian equilibrium (PBE) is supported in which shirking is prevented, bribing among players ceases and total monitoring costs are minimized. Further, the efficiency of this core-periphery structure is robust under various settings, including the dynamic spread of bribing, and under different punishments and monitoring schedules. Lastly, I consider a phenomenon of innovation adoption and diffusion. Innovations are crucial to the long run economic growth; however, not all new ideas are adopted by the majority of the society even though similar ones which appear later turn out to be commercial successes. I establish a model in which multiple potential entrants each can bring a new technology into a market with consumers connected under a social network. Technology has the character of network externality and entrants must rely on the word-of-mouth communication under the social network to promote their products. I find that high quality innovations are not guaranteed to perform better than low quality ones under the scenario and timing is a crucial determinant of their commercial performances. Low quality innovation firms are likely to enter the market whenever possible but high quality ones might strategically wait for a proper time to acquire a better market share.