Proceedings of the Annual Meeting of the Cognitive Science Society

We rely heavily on information from the social world to inform our real-world beliefs. How is this social information used, and when is it most influential? We assess the role of one kind of social information, the prevalence of a belief, in belief updating. Using real-world pseudoscientific and conspiratorial claims, we show that increases in people’s estimates of the prevalence of a belief led to increases in their endorsement of said belief. Prevalence information elicited the strongest belief change when people were most uncertain of their initial belief, suggesting that people weigh social information rationally according to the strength of their initial evidence. We discuss the implications of our results in the context of the present misinformation epidemic.