The illusion of truth is a mechanism by which one comes to believe something is true when it’s not. In fact, they don’t just believe it; they also defend it as true. Also, they close themselves off to the possibility that it might be false.
The illusion of truth, also called the illusory truth effect, occurs because there’s a flaw in the processing of reality. As humans, we have the tendency to say that familiar things are true.
In 1977, a study was done on it. A group of volunteers was presented with 60 statements. Researchers asked them to say if they were true or false. The same exercise was repeated later. The researchers noticed that these people deemed the statements they had already read before as true, regardless of how reasonable they were.
“A lie would have no sense unless the truth were felt dangerous.”