Repeating a claim makes the person who said it seem more credible too

Across four preregistered experiments with 770 participants, people rated sources as more credible when their statements had been repeated, and that boost carried over to new statements from the same sources.

A speaker’s speech bubble echoes several times across a room, and the listeners’ trust in the speaker grows with each echo.
Share this:

Hearing a statement again makes it feel more true. That much psychologists have known for decades. A new set of experiments shows the effect spills over onto the messenger: people who make repeated statements come to seem more credible themselves.

The study, “Repeating Statements Increases Source Credibility”, is by Simone Mattavelli, Marco Brambilla and Christian Unkelbach. It was published online in Personality and Social Psychology Bulletin on June 26, 2025.

Four preregistered experiments

The authors set out to test what they call a repetition-induced source credibility effect, using four preregistered experiments.

In the first, 90 participants saw 20 statements once and 20 statements repeated, each attributed to one of 40 different people. Repetition raised both how true the statements seemed and how credible their sources appeared.

The second experiment, with 65 participants, asked whether that credibility boost travels. After rating repeated and unrepeated statements paired with different sources, participants judged brand new statements from the same people. Sources previously tied to repeated statements were seen as more credible, even when saying something new.

A failed replication, then a resolution

The third experiment, with 180 participants, did not reproduce the effect when people were not first asked to rate the statements’ truth. That raised the possibility that the effect depended on participants actively judging truth during the pairing phase.

The fourth and largest experiment, with 435 participants, settled the question. It found the repetition-induced credibility effect regardless of what task participants were doing while they saw the sources and statements together.

The authors say the findings matter for research on the illusory truth effect and for persuasion and communication management. Their results suggest that repetition can build up the standing of a speaker, not only the plausibility of the words.

Study Details:

  • Title: Repeating Statements Increases Source Credibility
  • Authors: Simone Mattavelli, Marco Brambilla, Christian Unkelbach
  • Journal: Personality and Social Psychology Bulletin, Vol. 52, No. 9, pp. 2724-2737
  • Publication Date: June 26, 2025
  • DOI: 10.1177/01461672251347420