The more we see a piece of information, maybe a rumour or a fact out there, the more easy it becomes to believe it, even if that piece of information is completely wrong. What I've just described is simply known as the illusory truth effect.
Why can wrong information feel correct?
It's strange and scary to think about, the things you thought were correct had actually deceived you, and this whole time you hadn't realised.
The reason why this is occurs is actually quite simple. According to a 2026 meta-analysis, the reason that the illusory truth effect occurs is due to two key reasons.
- Repetition
- Processing fluency
These two reasons are essential to understand why the illusory truth effect affects virtually everyone
Why repetition? Isn't it good to repeat information?
Yes! It is good to repeat information, however, it's bad to excessively repeat information. Furthermore, it shouldn't be false information.
The reason why repetition can cause the illusory truth effect is because of how the mind gets familiar with that sort of information, whether it was true or false. When your mind if familiar and comfortable with something, it doesn't like to step out of that comfort zone.
Why processing fluency? What even is that?
Processing fluency is the ease with which information is mentally processed, according to the American Psychological Association.
At first, processing fluency doesn't sound that terrible, how could it be linked to making wrong things sound right? But you'd be wrong! Think about it, if the wrong information is easy to mentally process, then your mind would rather mentally process that wrong information than having to do the extra work to see if it's actually true.
Combine this with repetition, and you have absolute chaos, repeatedly consuming information that you'd rather believe because it sounds nice and perfect, or it's just easier to consume it rather than having to do the work and research.
What can I do?
Well, the first thing you can do is to simply research. It's a powerful yet effective method in finding whether the information you're actually hearing or seeing about is true, and it would absolutely change your mindset, you might even discover things that you once thought were true, but actually weren't true in the first place!
The second thing you can do is to fact check the claim and/or the source. Compare the source that the rumour/fact links to, and check if it aligns with other sources or things that are true. This is what errata does, the website that checks if you have the illusory truth effect! It takes in your study materials, and challenges you to find and replace the deliberate mistakes in the answer it makes, making you, the student, become the teacher, also checking whether the replacements you're trying to make aligns with the sources.