Just keep lying. It’ll work eventually. (Picture: Getty)

Want to convince someone of something entirely untrue? Just keep repeating it. Over and over.

The illusory truth effect has been flying around the world of psychology since 1977. But recently, more and more evidence has arrived to back it up.

The illusory truth effect is the idea that if you repeat something often enough, people will slowly start to believe it’s true. Sounds about right, considering all the times we’ve blindly trusted an old wives’ tale or a much-retweeted factoid.

But a new study has revealed that the illusory truth effect is much stronger than we imagined. Because it turns out that even if a person has prior knowledge disproving a lie they’re being told, they’ll still believe the lie if it’s repeated enough.




In an experiment published in the Journal of Experimental Psychology, researchers asked a group of students to read through a list of statements – some of which were obviously true or false, and others that were a little trickier to judge. The students had to rate each statement from 1, meaning definitely false, to 6, meaning definitely true.

Then they were asked to do the same rating task on another list, which included some of the same statements from the first.

New trick helps you spot liars FAR more accurately

Finally, the students were given multiple choice questionnaires to judge their actual knowledge of some of the statements on the list.

What’s worrying is that even when students knew the correct answer to one of the multiple choice questions, they were still likely to rate false statements contradicting their knowledge as true, as long as they had been repeated on the lists.

So for example, even when a student knew that ‘the short pleated skirt worn by Scots’ was called a kilt, they would rate the statement ‘a sari is the name of the short plaid skirt worn by Scots’ as more true after they had read it multiple times.

This indicates that being told something enough – even when you KNOW it’s incorrect – can make you believe it to be true.

This might also apply to the person repeating the lie. The more you say something, the more you, too, will believe it’s the truth.

Bit scary, no?

MORE: Couples share the silliest things they’ve had serious arguments over

MORE: 17 lies your anxiety is telling you

Advertisement Advertisement