The battle of opinion: dynamic information revelation by ideological senders

Two informed and interested parties (senders) repeatedly send messages to an uninformed party (public). Senders face a trade-off between propagating their favoured opinions, possibly by lying, and maintaining a high audience (or market share), as the state is occasionally revealed and lies cause audiences to switch to the competitor. We fully characterize a focal Markov perfect equilibrium of this game and discuss the impact of exogenous parameters on the truthfulness of equilibrium reporting. In particular, we find that senders’ lying propensities are strategic complements so that increasing one sender’s bias decreases both senders’ truthfulness. We also analyse the role of polarization across senders.