The Role of Motivation and Prior Knowledge in the Illusory Truth Effect

Abstract

Repeated exposure to false claims increases their perceived accuracy, a cognitive bias known as the illusory truth (IT) effect. Incorporating the framework of the Motivation and Opportunity as Determinants (MODE) model, a 2 × 2 mixed design with 668 participants tested the effects of motivational instructions (motivated vs. control) and repetition (repeated vs. novel) on perceived accuracy of false trivia claims that are commonly known. We hypothesized that participants with the motivation cue would rate repeated (easy) false claims as less accurate than the control group, which was not exposed to the motivation cue. Results showed a robust main effect of repetition, with repeated claims rated as more accurate than novel claims, regardless of condition. No effect of condition was observed, indicating that our motivational cue was insufficient to disrupt reliance on fluency-based judgments, even when individuals had accessible prior knowledge. These findings highlight the persistence of the IT effect and underscore the challenges of addressing misinformation. Implications for interventions, such as enhanced motivational strategies and structured feedback mechanisms, are discussed.