Illusory Truth Effect
The illusory truth effect is the tendency to judge a repeated statement as more true than a comparable unfamiliar statement. Research examines how prior exposure affects truth judgments under specified conditions. The effect does not mean repetition makes every claim believable, and it is distinct from simply remembering that a statement has been encountered before.
Term statusEstablished Concept
A concept used in academic or professional literature. This label does not mean every claim about it is settled. About these labels.
Evidence for the claims on this page: Experimental evidence within defined tasks
The cited study tests repetition and truth judgments. It does not establish that all repeated claims are believed or that knowledge never helps.
How to read this assessmentWhat it is
The illusory truth effect is an increase in perceived truth associated with prior exposure to a statement. Researchers measure it by comparing truth judgments for repeated and new statements under controlled conditions. (Fazio et al., 2015)
In everyday language
Hearing something again can make it feel more credible, even when the repetition adds no evidence. Familiarity can be mistaken for a reason to believe.
What it isn't
It does not mean that repetition makes every claim believable or changes everyone's mind. Repetition, prior knowledge, plausibility, and attention can interact.
An example
Hypothetical example: the same unsupported claim appears in several generated summaries. A reader begins to rate it as more plausible because it sounds familiar.
Key features
- Concerns judged truth rather than objective accuracy
- Can arise without new supporting evidence
- Is usually measured by comparing repeated and unfamiliar statements
How it relates to synthetic imprinting
It offers an existing explanation to test when repeated synthetic messages affect belief. A later follow-up is needed to determine whether any change persists.
Research context
Fazio and colleagues found that prior knowledge did not eliminate repetition-related truth judgments in their experiments. That result does not establish that knowledge or careful checking is always ineffective. (Fazio et al., 2015)
Related terms
Sources and what they support
- Knowledge does not protect against illusory truth. — Lisa K. Fazio, Nadia M. Brashier, B. Keith Payne, Elizabeth J. Marsh (2015). Journal of Experimental Psychology: General.
Peer-reviewed research. Tests repetition and truth judgments, including cases where participants have relevant prior knowledge.
Cite this definition
SyntheticImprinting.com Editorial Project. (2026-09-27). Illusory Truth Effect. Version 1.4. SyntheticImprinting.com. https://syntheticimprinting.com/terms/illusory-truth-effect/
APA: SyntheticImprinting.com. (2026). Illusory Truth Effect. https://syntheticimprinting.com/terms/illusory-truth-effect/
MLA: “Illusory Truth Effect.” SyntheticImprinting.com, 2026, https://syntheticimprinting.com/terms/illusory-truth-effect/. Accessed November 12, 2026.
Chicago: SyntheticImprinting.com. “Illusory Truth Effect.” Last modified 2026-09-27. https://syntheticimprinting.com/terms/illusory-truth-effect/.
Revision history
- Version 1.4 · Current
Added claim-level citations and a separate assessment of evidence support. The opening definition is unchanged.
Read this version’s definition
The illusory truth effect is the tendency to judge a repeated statement as more true than a comparable unfamiliar statement. Research examines how prior exposure affects truth judgments under specified conditions. The effect does not mean repetition makes every claim believable, and it is distinct from simply remembering that a statement has been encountered before.
- Version 1.3
Expanded the opening definition; added explicit boundaries, source context, related-term cards, and linked editorial attribution.
Read the previous definition
The illusory truth effect is the tendency to judge a repeated statement as more true than a comparable unfamiliar statement. Research examines how prior exposure affects truth judgments under specified conditions. The effect does not mean repetition makes every claim believable, and it is distinct from simply remembering that a statement has been encountered before.
- Version 1.0
Definition recorded in the previous release. Earlier edits are not reconstructed here.
Read the previous definition
The illusory truth effect is the tendency to judge a repeated statement as more true than a comparable unfamiliar statement.
What the status means
Established Concept
A concept used in academic or professional literature. This label does not mean every claim about it is settled.
How evidence labels workHelp improve this entry
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