Persuading skeptics and reaffirming believers

In a world where rational individuals may hold different prior beliefs, a sender can influence the behavior of a receiver by controlling the informativeness of a signal. We characterize the set of distributions of posterior beliefs that can be induced by a signal, and provide necessary and sufficient conditions for a sender to benefit from information control. We examine a class of models with no value of information control under common priors, and show that a sender generically benefits from information control under heterogeneous priors. We extend our analysis to cases where the receiver’s prior is unknown to the sender.