Deception and the marketplace of ideas

American democracy is built, in part, on the ideal of a “free marketplace of ideas.” Consumers are assumed to have access to the same arguments, and through deliberation, come to a consensus about which arguments are true, and therefore, best. In this article, we explain how deceptive communication undermines this ideal. We focus on two key dimensions—the motive of deception and the perception of dishonesty—that influence people's propensity to deceive and the social rewards of doing so. Deception is seen as the most justified when it is morally motivated and when it involves indirect tactics that are not perceived as particularly dishonest. We argue, therefore, that morally motivated half-truths, rather than blatantly selfish lies, may do the greatest damage to the marketplace of ideas. Ultimately, this article advances our understanding of the causes and consequences of deception and helps to explain the dynamics that lead to widespread misinformation in our social world.