Falling for Fake News is Easier Than We Think

In the past few years, misinformation has been running more rampant than ever. From politics to Covid-19, fake news is ever-present online, particularly on social media. It’s easy to brush this aside: “I would never fall for these lies”, we may think. However, studies on the psychology of truth and belief suggest something different. Namely, that any of us can fall for misinformation—and it happens a lot faster, and with more ease, than we might expect. This is often due to the illusory truth effect.

What is the Illusory Truth effect?

Also known as the “Truth by Repetition Effect” or the “Mere Exposure Effect”, this phenomenon happens when we are exposed to an idea multiple times. When presented with something enough times (true or false), we start to believe it’s true. The illusory truth effect happens when you believe something is true despite it being false, after seeing it enough times—hence the truth becoming merely an “illusion”.

Not only does this effect work if the information is implausible, it even works if you already know that the information is not true. The effect also works similarly across developmental groups—anyone from a five year old to a fify-five year old are similarly impacted by the repetition of false statements.

One study showed that a statement only has to be repeated twice to dramatically increase its believability. After the second repetition, the statement still becomes more believable, but there are diminishing returns on its believability.

In his book Thinking, Fast and Slow, author Daniel Kahneman writes that even an incomplete statement can increase the believability of a completed statement. For example, “people…repeatedly exposed to the phrase “the body temperature of a chicken”” were more likely to believe a statement of the form “the body temperature of a chicken is X degrees”—showing that “partial familiarity” is enough to increase believability.

Why is it important?

Groups trying to push a certain message (ranging from advertisers to conspiracy theorists) are definitely well aware of this effect. The use of this effect can be fairly innocuous, like trying to get you to buy a hamburger. However, when used in conjunction with misinformation, the illusory truth effect can be detrimental to the public’s understanding of important topics, such as public health information.

The illusory truth effect does not have to be used intentionally to work: even unintentionally sharing misinformation increases the believability of a claim. This is why it’s important to check sources and facts before sharing information—or even choosing to not share at all.

How can you combat it?

According to research conducted by professors of psychology at Harvard and Duke University, one of the best ways to combat the illusory truth effect is by fact checking the first time you see a new piece of information. Initially asking ourselves “is this true?” and seeking out this information prevents the illusory truth effect from taking effect.

Questions to consider

Have you encountered the illusory truth effect? Were you able to avoid believing the false information?
Can you think of ways the illusory truth could be used in malicious ways? Could there be benefits to the illusory truth effect?
What could encourage us to fact check the first time we see a dubious piece of information?