The Supply of Motivated Beliefs

When people choose how to communicate, they must consider how their audience will interpret their messages. In many settings, senders may expect receivers to engage in motivated reasoning — trusting good news more than bad news, relative to a Bayesian. This paper experimentally examines how motivated reasoning affects information transmission in political settings. Senders are randomly matched with receivers whose political parties’ stances happen to be aligned or misaligned with a truthful statement, and either face incentives to be rated as truthful or face no incentives. Incentives for senders to be rated as truthful backfire, causing senders to be less truthful. Backfiring occurs because incentivized senders believe receivers will engage in motivated reasoning, and send false messages in order to better align with receivers’ politically-motivated beliefs. Receivers are naive to the adverse effects of senders’ incentives.