Imagination or exposure causes imagination inflation.

To examine the effects of exposure to complex autobiographical events on imagination inflation, subjects performed a 3-stage procedure. First, they rated their confidence that a list of events had happened in their childhood. Second, subjects imagined and paraphrased complex fictitious events 0, 1, 3, or 5 times. Finally, they rated their confidence for the childhood events a second time. We found that subjects became more confident that the fictitious events really did happen in childhood, regardless of whether they were imagined or paraphrased. There was no repetition effect beyond that of a single exposure. Taken together with the results of other research, our data suggest that the greater processing fluency associated with the target events drives imagination inflation.