The illusory-truth effect and its absence under accuracy-focused processing are robust across contexts of low and high advertising exposure.

In present-day digital environments, people frequently encounter content from sources of questionable trustworthiness. Advertising is an untrustworthy source because its purpose is to persuade consumers rather than to provide impartial information. One factor known to enhance the perceived truth of advertising claims is repetition: Repeated advertising claims receive higher truth ratings than novel advertising claims. The phenomenon that repetition enhances processing fluency which enhances truth judgments is known as the illusory-truth effect. Does repetition always enhance truth judgments? For instance, does repetition enhance truth judgments even in contexts with extensive advertising exposure in which enhanced processing fluency could be used to classify a statement as likely coming from an untrustworthy source? In two experiments, we examined the illusory-truth effect by presenting participants with product statements in an exposure phase and collecting truth judgments for both repeated and new statements in a test phase. In a low-advertising-exposure condition, most of the statements were labeled as scientific studies while in the high-advertising-exposure condition, most of the statements were labeled as advertising. When participants read the product statements in the exposure phase, a typical illusory-truth effect was obtained: In the test phase, repeated statements received higher truth ratings than new statements. However, when participants were instructed to adopt an accuracy focus at encoding by judging the truth of the product statements, new statements were judged to be as true as repeated statements. Both the illusory-truth effect and its absence under accuracy-focus instructions were found to be robust across different levels of advertising exposure.