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Repetition Makes Fact


Read it & weep, Wakefield!

In 1998, Andrew Wakefield caused quite a stir when he published a dubious study in a renowned medical journal suggesting the Measles, Mumps, and Rubella (MMR) vaccine was linked to the development of autism (Rao and Andrade, 2011). This study terrified parents and, consequently, led to a sharp decline in MMR vaccination rates among children. Shortly after Wakefield’s article was published, numerous scientific studies were conducted that refuted and, ultimately, debunked Wakefield’s fictitious claims. However, it took 12 whole years for the Lancet, the medical journal in which Wakefield’s study was initially published, to issue a formal retraction of Wakefield’s article on the grounds of deliberate fraud (Rao and Andrade, 2011). In 2008 and 2009, while vaccination rates were on the decline, the measles came back in full force, plaguing the UK, United States, and Canada (Rao and Andrade, 2011). As a result of the chaos that ensued following his erroneous declaration, Andrew Wakefield lost his medical license. How could such an unfounded claim inspire so much mistrust? Good question. A prime culprit in perpetuating the belief in Wakefield’s false claim was repetition.

The mind is the most powerful, albeit malleable, tool known to man. Despite its complexity, the mind is highly prone to making errors. Cognitive biases are mental errors that can affect our everyday decision and judgment making. The Illusory Truth Effect is a cognitive bias where repetition of a statement makes one more likely to believe it (Hasher et al. 1977; Dechêne et al. 2009; Fazio et al. 2015; Wang et al. 2016; Majin 2019). Repetition results in increased processing fluency, which is often misinterpreted as increased trust (Hasher et al. 1977; Dechêne et al. 2009; Fazio et al. 2015; Wang et al. 2016). Processing fluency is a function of the relative ease and sense of familiarity that arises when analyzing a statement. When one encounters a statement over and over, true or not, processing it and retrieving it from memory becomes easier and easier (Hasher et al. 1977; Dechêne et al. 2009; Fazio et al. 2015; Wang et al. 2016). Repetition exerts its powerful cognitive effects whether one hears information repeated auditorily or sees it over and over visually (Dechêne et al. 2009). We’ve all heard the catchphrase that practice makes perfect, in this case, repetition makes fact.

As was the case in the constant media coverage of Wakefield’s faulty claim about the MMR vaccine, the Illusory Truth Effect can, unfortunately, wreak havoc when misleading or untruthful statements are constantly being repeated and subsequently influencing important behavioral decisions (Dechêne et al. 2009). It was the frequency in which Wakefield’s study was repeatedly covered, refuted, discussed, and disseminated through mass media that fortified its erroneous validity. Despite Wakefield’s conclusion having been soundly disproven, research has shown that the masses have trouble recognizing the syntax of negations (e.g. Wakefield’s claim is not credible) (Mayo et al. 2004; Majin 2019). It was the frequency coupled with the nature of how the media attempted to dispel Wakefield’s claims that kept the faulty unfounded link between the MMR vaccine and autism in the forefront of peoples’ minds.

You, like many others, might be sitting there thinking, yeah, well just because I hear something over and over doesn’t mean I’m going to believe it’s true- I’m way smarter than that. I hate to burst your bubble, but a recent study revealed that a large knowledge base and even expertise in a subject do not protect one from falling prey to this cognitive trickery of the Illusory Truth Effect (Fazio et al. 2015).

Until recently, it was believed that people first made truth judgements based on stored knowledge, and only when stored knowledge was unavailable did they rely on easy recall and general familiarity to inform their decisions (Fazio et al. 2015). However, recent studies have discredited this assumption. Regardless of whether we have enough general information stored in our memory to determine if a statement is true or not, we tend to rely on familiarity first to inform our judgements. When familiarity overpowers preexisting knowledge in a decision-making process, the phenomenon is known as Knowledge Neglect (Fazio et al. 2015). Knowledge Neglect is what enables repetition to be such a powerful cognitive tool when it comes to bolstering familiarity in the context of the Illusory Truth Effect.

A day in the life of a fact checker.

Processing fluency and familiarity are cues we encounter on a daily basis and rely upon as heuristics – mental shortcuts – when it comes to decision making (Fazio et al. 2015). Similar to its cousin, the Mere Exposure Effect (where likability increases as a function of greater exposure to the same object or thing), in the Illusory Truth Effect, truthfulness increases as a function of statement repetition. Since cognitive resources are limited, it is no wonder that our minds rely on fluency as a crutch to inform judgments (Fazio et al. 2015).  Just like our physical bodies, our minds get lazy and take the easy way out by relying on shortcuts unless we are in a context that promotes deep processing. Deep processing (paying attention to meaning) of statements in a truth judgment task has been shown to minimize the effects of the Illusory Truth Effect (Dechêne et al. 2009; Fazio et al. 2015). For example, a fact checker at a newspaper, whose career hinges upon their ability to accurately assess truthfulness of claims, will engage in deep processing more often than your average newspaper reader, who is taking the articles at face value, and, therefore, be less susceptible to the consequences of the Illusory Truth Effect.

So how does the Illusory Truth Effect influence your life? Well, with the explosion of digital and social media, our minds have become fertile grounds for exploitation (Kbstage, 2019). Rare is the person today who is without hand-held access to multiple feeds of news and social media inputs that they themselves have established filters to align with and satiate their pre-ordained biases (Kbstage, 2019). Moreover, artificial intelligence algorithms that produce curated news feeds serve as echo chambers that increase both the frequency and repetition of similarly sourced statements. Customizable and polarized social media platforms pave the way for there to be robust Illusory Truth Effects that influence all facets of our society (consumer behavior, election processes, health decisions, and more).

Strikingly, politicians on both sides of the aisle seem to recognize the power of the Illusory Truth Effect and appear to be using it to their advantage, asserting less-than-truthful talking points at every news cycle. While this may be an advantageous strategy to achieve a political gain, it is hurtful to the American electorate. While this may be shrewd politics, it is wrong.

Knowingly and intentionally restating a falsehood because you know that with more and more repetition your audience will come to believe that it is true does not, no matter one’s purpose (e.g. to advance a policy; to assert guilt or innocence; or sell more product), make it right. It is up to us, an audience for countless messages, to be cautious when consuming media and vigilant when analyzing the veracity of claims. The best approach when hearing or reading a repeated idea over and over again is to seek out and evaluate a conflicting point of view about the subject before formulating a conclusion. The truth is almost always someplace in between. The truth is almost always someplace in between.


Coane, J. (2019). Slides from 9.24.19 Attention I [PowerPoint Slides]. Retrieved from https://moodle.colby.edu/pluginfile.php

Dechêne, A., Stahl, C., Hansen, J., & Wänke, M. (2009). The truth about the truth: A meta-analytic review of the truth effect. Personality and Social Psychology Review14(2), 238–257. doi: 10.1177/1088868309352251

Fazio, L. K., Marsh, E. J., Brashier, N. M., & Payne, K. B. (2015). Knowledge does not protect against illusory truth effects. Journal of Experimental Psychology144(5), 993–1002. doi: 10.1037/e520562012-049

Hasher, L., Goldstein, D., & Toppino, T. (1977). Frequency and the conference of referential validity. Journal of Verbal Learning and Verbal Behavior16(1), 107–112. doi: 10.1016/s0022-5371(77)80012-1

Kbstage (2019). The illusory truth effect on social media: How it affects your marketing.” KUB. Retrieved from https://www.kub-uk.net/illusory-truth-effect/.

Majin, G. (2019). A catastrophic media failure? Russiagate, Trump and the illusion of truth: The dangers of innuendo and narrative repetition. Journalism, 146488491987800. doi: 10.1177/1464884919878007

Mayo, R., Schul, Y., & Burnstein, E. (2004). ‘‘I am not guilty’’ vs ‘‘I am innocent’’: Successful negation may depend on the schema used for its encoding. Journal of Experimental Social Psychology40, 433–449.

Rao, T. S., & Andrade, C. (2011). The MMR vaccine and autism: Sensation, refutation, retraction, and fraud. Indian Journal of Psychiatry53(2), 95. doi: 10.4103/0019-5545.82529

Wang, W.-C., Brashier, N. M., Wing, E. A., Marsh, E. J., & Cabeza, R. (2016). On known unknowns: Fluency and the neural mechanisms of illusory truth. Journal of Cognitive Neuroscience28(5), 739–746. doi: 10.1162/jocn_a_00923

  1. December 3rd, 2019 at 22:44 | #1

    Hi Julia, I enjoyed reading about the Illusory Truth Effect. I had some knowledge about the significance of repetition in impacting one’s beliefs. I realized that top down processing is not the only contributor in forming truth judgements, since you provided evidence of how people rely on fluency and familiarity. Your post allowed me to connect Illusory Truth Effect to the impact of leading questions on eyewitness testimonies. Leading questions include some suggestible information, which may also influence people’s beliefs about an incident. If the same types of questions are constantly asked, wouldn’t people begin to believe the suggestible information even though it may not be true due to their familiarity to it? On another note, I liked how you gave social media as an example because I understood how the Illusory Truth Effect plays a role in my life.

  2. December 10th, 2019 at 17:32 | #2

    Hello Julia! I found this blog to be interesting and thought provoking. When you talked about how we spontaneously recall information whether we know the source or not, it reminded me of when we talked about suggestibility from the seven sins of memory because our memories can be reconstructed from outside sources. So, if we are exposed to misinformation many separate times, this information will help reconstruct our memory and will be included in the new memory. What I found particularly interesting in your post then, was that even when there is information discrediting what we think we know, the fact that we have almost “rehearsed” this knowledge into memory so many times makes it hard to integrate completely new information or “fix” it. I wonder if this is because we tend to be overconfident in our memories in addition to being a result of processing fluency? Really nice job!

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