Ulric B. and Evelyn L. Bray Social Sciences Seminar

Abstract: Finite players gather information about an uncertain state before making decisions. Each player allocates his limited attention capacity between biased sources and the other players, and the resulting stochastic attention network facilitates the transmission of information from primary sources to him either directly or indirectly through the other players. The scarcity of attention leads the player to focus on his own-biased source, resulting in occasional cross-cutting exposures but most of the time a reinforcement of his predisposition. It also limits his attention to like-minded friends who, by attending to the same primary source as his, serve as secondary sources in case the information transmission from the primary source to him is disrupted. A mandate on impartial exposures to all biased sources disrupts echo chambers but entails ambiguous welfare consequences. Inside an echo chamber, even a small amount of heterogeneity between players can generate fat-tailed distributions of public opinion, and factors affecting the visibility of sources and players could have unintended consequences for public opinion and consumer welfare.

Written with Lin Hu and Xu Tan.