Endogenous Attention and the Spread of False News

Abstract

We study the impact of endogenous attention in a dynamic social media model. Each period, a user observes a random story and decides whether to share it. Users like sharing true and interesting stories, but identifying false stories requires costly attention. Depending on parameters, the system exhibits either a unique limit or strong path dependence. Endogenous attention responds to changes in false story credibility, so reducing credibility can boost their prevalence. Increases in the exogenous production rate of false stories can be amplified by users' sharing decisions. Increasing users' capacity to reach others amplifies both true and false stories; we identify conditions under which the net effect favors truth over falsehood.