Prior exposure increases judged truth even during periods of mind wandering.

Much of our day is spent mind-wandering-periods of inattention characterized by a lack of awareness of external stimuli and information. Whether we are paying attention or not, information surrounds us constantly-some true and some false. The proliferation of false information in news and social media highlights the critical need to understand the psychological mechanisms underlying our beliefs about what is true. People often rely on heuristics to judge the truth of information. For example, repeated information is more likely to be judged as true than new information (i.e., the illusory truth effect). However, despite the prevalence of mind wandering in our daily lives, current research on the contributing factors to the illusory truth effect have largely ignored periods of inattention as experimentally informative. Here, we aim to address this gap in our knowledge, investigating whether mind wandering during initial exposure to information has an effect on later belief in the truth of that information. That is, does the illusory truth effect occur even when people report not paying attention to the information at hand. Across three studies we demonstrate that even during periods of mind wandering, the repetition of information increases truth judgments. Further, our results suggest that the severity of mind wandering moderated truth ratings, such that greater levels of mind wandering decreased truth judgements for previously presented information.