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The "Illusory Truth Effect"

The "illusory truth effect" describes the psychological phenomenon that repeatedly presented statements are more likely to be judged as true than statements presented once. The content of a statement can be very diverse and has a high practical relevance especially in the context of the question of how knowledge about the truth of a statement changes. In times of fast and easy information dissemination through social media, we also increasingly experience polarizing reporting from both reputable and less reputable sources. Scientific research on the Illusory Truth Effect offers the potential to identify and understand cognitive mechanisms in the emergence of "fake news" and to develop effective ways to counter the spread of false information.

There are numerous different explanations for the Illusory Truth Effect. In addition to the prior knowledge of subjects, we are interested in investigating the underlying cognitive processes, such as processing fluency, coherence, and familiarity, which may influence the effect.

Relevant publications:

• Schmidt, O., & Heck, D. W. (in press). Multinomial models of the repetition-based truth effect: Investigating the role of prior knowledge. Memory & Cognition. https://doi.org/10.3758/s13421-025-01821-x  [Preprint: https://doi.org/10.31234/osf.io/rdegq]
• Aktepe, S. C., & Heck, D. W. (2025). Modeling the link between the plausibility of statements and the truth effect. Psychonomic Bulletin & Review, 32(4), 1504–1520. https://doi.org/10.3758/s13423-025-02647-z
• Aktepe, S. C., & Heck, D. W. (2025). Revisiting the effect of discrepant perceptual fluency on truth judgments. Journal of Experimental Social Psychology. https://doi.org/10.1016/j.jesp.2025.104774
• Schmidt, O. & Heck, D. W. (2024). The relevance of syntactic complexity for truth judgments: A registered report. Consciousness and Cognition, 117, 103623. https://doi.org/10.1016/j.concog.2023.103623