This blog post, written by Dr. Terry Flynn and Tim Li, is based on a research paper by Gordon Pennycook, Assistant Professor at the University of Regina; Tyrone Cannon, Professor of Psychiatry at Yale University; and David G. Rand, Associate Professor of Management Science and Brain and Cognitive Sciences at Massachusetts Institute of Technology. 

Key Findings

  • People are more likely to believe that a statement is accurate if they have encountered it before. Even a single prior encounter can increase the perceived accuracy of a false claim.
  • Misinformation is still perceived as more accurate after prior exposure even if it included warnings that the claims were disputed by other sources.
  • Exposure to misinformation that is unlikely to be true can still result in increased misperceptions. Only exceedingly implausible claims are not believed, even if they seem familiar.

Implications for Public Relations

Public relations should be vigilant of rumours and false claims, even if they sound preposterous. Belief in misinformation can be fostered through exposure and increased familiarity even for claims that appear implausible. Addressing misinformation quickly, including outrageous claims, is paramount to limiting the impact on an organization’s reputation or credibility. Even a single exposure to misleading claims is enough to bias belief and the longer the misinformation goes uncorrected, the more likely people are going to encounter it again.

The findings of this study also show that misperceptions can develop despite labels that the information is false, suggesting that more involved correction strategies should be considered. Although it is difficult with today’s availability of information and rapid sharing, it may be best to prevent people from encountering misinformation in the first place, or at least reduce exposure.

People are more likely to believe in something if they heard it before. This “illusory truth effect” occurs because people use familiarity as a mental shortcut for evaluating the information accuracy. Pennycook and colleagues examined this effect for “fake news” headlines on Facebook, a common way that misinformation is now shared, and the role of plausibility, fact-checking, and partisanship.

To test plausibility, they showed participants various known and unknown trivia statements, including extremely implausible false claims like “A single elephant weighs less than a single ant”. After a filler task, participants were asked to rate how accurate various statements were. All the statements, except the ones that were obviously wrong, were rated as truer if the participants had seen them previously, including false ones. These findings demonstrate that exposure to ambiguous information increased perceptions of accuracy. Statements need to be extremely implausible for the illusory truth effect to not occur.

To examine how the illusory truth effect can occur in a more natural, real-world setting, the authors conducted another study where participants were presented with real and fake political news headlines as they would appear on Facebook. Some of these headlines were accompanied with a warning stating that the headline was “disputed by third-party fact-checkers”, or in other words, misleading. Again, the authors observed that previous exposure to information increased their perceived accuracy. This effect occurred even when presented with a warning and regardless of if the headline aligned with the participants’ political partisanship or not. The illusory truth effect also persisted in a repeated study with a one-week delay between presenting the headlines and surveying participant perception of accuracy.

Together, these results demonstrate that the repetition of misinformation increased perceptions of its accuracy, except for when the claims are entirely implausible. Warnings of deception were not able to prevent misinformation from biasing beliefs, suggesting that people instinctually rely on familiarity to infer accuracy instead of recalling on their knowledge.

Blog post compiled by Dr. Terry Flynn and Tim Li of McMaster University.

Pennycook, Gordon, Cannon, Tyrone D., & Rand, David G. (2018). Prior exposure increases perceived accuracy of fake news. Journal of Experimental Psychology: General, 147(12), 1865-1880.

Heidy Modarelli handles Growth & Marketing for IPR. She has previously written for Entrepreneur, TechCrunch, The Next Web, and VentureBeat.
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