Illusory Truth Effect
Illusion of Truth Effect
The notion that one is more likely to identify as true statements those they have previously heard (even if they cannot consciously remember having heard them), regardless of the actual validity of the statement. In other words, a person is more likely to believe a familiar statement than an unfamiliar one.
Origin
The illusory truth effect was first documented by Lynn Hasher, David Goldstein, and Thomas Toppino in a 1977 paper in the Journal of Verbal Learning and Verbal Behavior, showing that college students rated repeated statements — true and false alike — as more credible after just two additional exposures over six weeks. The label "illusory truth effect" was adopted by subsequent researchers. A landmark 2015 study by Lisa Fazio and colleagues confirmed the effect persists even when people already know a statement is false.