Claiming that Listerine alleviates cold symptoms is false: To repeat or not to repeat the myth during debunking?

With terms such as “post-truth” and “fake news” becoming increasingly prominent in the media and public discourse, the ability to effectively correct inaccurate information has never been more pertinent. Unfortunately, the task of correcting misinformation is far from trivial. In many instances, issuing corrections remains only partially effective and people often continue to rely on outdated information. This is known as the continued-influence effect

But this does not mean that debunking of misinformation is necessarily impossible: On the contrary, there are some known techniques that can help make a correction more effective, which John Cook and I summarized in the Debunking Handbook some time ago.

One recommendation in the Debunking Handbook is that it is best to avoid repeating the initial misconception while issuing a correction. This recommendation was based on data available at the time of writing, which suggested that the repetition of the misconception — even when it is corrected in the same sentence — increase its familiarity. For example, the statement “It is false to claim that Listerine alleviates cold symptoms” unavoidably strengthens the link between the two concepts, namely Listerine and alleviating colds, even though the statement seeks to correct that myth.

The potential problem that arises from repeating the myth to correct it is that people are more likely to think that familiar information is true. In consequence, correcting the myth may ironically strengthen its prominence in people’s minds, a phenomenon known as the familiarity backfire effect. 

Recent research, however, has not found a familiarity backfire effect under conditions where it was expected. In a nutshell, two articles published by colleagues and I (with Ullrich Ecker and Briony Swire, respectively, as lead authors) found evidence for familiarity-based processing but failed to find a familiarity backfire effect.

You can read more about this latest research in a series of three blog posts on Shaping Tomorrow's World:

What is the upshot of this latest research?

Although our experiments showed that familiarity-based processing does not lead to a backfire effect in some cases (even when it is expected to occur), our studies remain moot on whether familiarity backfire effects will occur in other circumstances. 

Based on prior theory, we would still expect to observe a familiarity backfire effect when people are distracted while processing corrective information (e.g., driving while listening to a corrective message on the radio). Those expectations remain to be examined by experimentation.

The recommendation to communicators has therefore changed little: As a precaution, avoid repeating the myth when trying to correct it and state the correct information in the affirmative.

Listerine freshens your breath and nothing else.

DBH-AnnotationsFigure 1: Section of the Debunking Handbook with annotations outlining where the wording would change slightly due to the new findings

Posted by Stephan Lewandowsky on Thursday, 22 June, 2017

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