Why are people so often overconfident? We conduct an experiment to test the hypothesis that people become overconfident to more effectively persuade or deceive others. After performing a cognitively challenging task, half of our subjects are informed that they can earn money by convincing others...

Laboratory evidence shows that when people have to argue for a given position, they persuade themselves about the position's factual and moral superiority. Such self-persuasion limits the potential of communication to resolve conflict and reduce polarization. We test for this phenomenon in a...