The illusion of truth thinking

When your brain comes across “information”, it has to judge if this information is true or false.

Unfortunately, your brain can be quite “lazy” when it has to analyse information. It “prefers” to analyse information it has seen before as analysing such information needs much less effort than that needed to analyse new information. This preference of your brain for information it has seen before can make it believe that such information must be true, even when it has no real evidence to make that judgement.

This stupid tendency for one’s brain to blindly consider information it has seen before to be true is called, by psychologists, “illusion of truth” thinking.

Below is an example of how illusion of truth thinking can be harmful.


You are probably aware that “fake news” has become a big problem in our world. This example will show you how illusion of truth thinking plays an important role in “fake news”.

Imagine that someone, as a joke, makes an online video saying that because bananas are yellow, that they are bad for your health. In this video, the person mentions fake studies to support his theory. Of course the information in the video is not at all true.

Now imagine that a person, who we will call Mary, sees the banana video. Also imagine that around the same time Mary sees the video, that many of her family members and friends also see the same video in their own homes. Over the next few days, when Mary meets her family and friends, she repeatedly hears from them about their opinion of the video. All of them repeat the message of the video, saying that yellow bananas are bad for one’s health.

As Mary repeatedly keeps hearing that yellow bananas are bad, her brain does the illusion of truth type of stupid thinking and thinks, “I have heard it before that yellow bananas are bad, so this information must be true”. Soon this thinking makes Mary stop buying bananas, unnecessarily depriving herself a fruit she used to enjoy.


Politicians, advertising agencies, and fake news outlets all use the brain’s susceptibility to illusion of truth type of stupid thinking to convince you that what they are saying is true. So when you see information that is repeated everywhere, don’t just assume that it is true. Do some basic research / enquiries before you make that judgment.