The swing voter's curse in social networks

We study communication in social networks prior to a majority vote on two alternative policies. Some agents receive a private imperfect signal about which policy is correct. They can recommend a policy to their neighbors in the social network prior to the vote. We show theoretically and empirically that communication can undermine efficiency and hence reduce welfare in a common-interest setting. Both efficiency and existence of fully informative equilibria in which vote recommendations are truthfully given and followed hinge on the structure of the network. If some voters have distinctly larger audiences than others, their neighbors should not follow their vote recommendation; however, they may do so in equilibrium. We test the model in a laboratory experiment and find rather inefficient equilibrium selection. Based on this result, there is support for the comparative statics of our model and, more generally, for the importance of the network structure for voting behavior.