Rational Reasons for Irrational Beliefs

According to many, we live in “post-truth” times, with the pervasiveness of falsehoods being an existential threat to democracy and the functioning of free societies. Why do people believe and propagate falsehoods? Current accounts focus on psychological deficiencies, heuristic errors, self-enhancing motivations, or motivations to sow chaos. Here, we advance a complementary, outwardly (versus inwardly)-oriented and ultimate (versus proximate) account—that people often believe and spread falsehoods for socially functional reasons. Under this view, falsehoods may serve as rare and valued information with which to rise in prestige, as signals of group commitment and loyalty tests, as ammunition with which to derogate rivals, or as outrages with which to mobilize the group. Thus, although people may generate and defend falsehoods through processes that are epistemically irrational, doing so may be rational from the perspective of the functions falsehoods serve. We discuss the implications of this view for puzzling theoretical phenomena and for changing problematic beliefs.