Illusory implications: incidental exposure to ideas can induce beliefs.

Numerous psychological findings have shown that incidental exposure to ideas makes those ideas seem more true, a finding commonly referred to as the 'illusory truth' effect. Under many accounts of the illusory truth effect, initial exposure to a statement provides a metacognitive feeling of 'fluency' or familiarity that, upon subsequent exposure, leads people to infer that the statement is more likely to be true. However, genuine beliefs do not only affect truth judgements about individual statements, they also imply other beliefs and drive decision-making. Here, we consider whether exposure to 'premise' statements affects people's truth ratings for novel 'implied' statements, a pattern of findings we call the 'illusory implication' effect. We argue these effects would constitute evidence for genuine belief change from incidental exposure and identify a handful of existing findings that offer preliminary support for this claim. Building upon these, we conduct three new preregistered experiments to further test this hypothesis, finding additional evidence that exposure to 'premise' statements affected participants' truth ratings for novel 'implied' statements, including for considerably more distant implications than those previously explored. Our findings suggest that the effects of incidental exposure reach further than previously thought, with potentially consequential implications for concerns around mis- and dis-information.