The Illusory Truth Effect: Separating truth from fiction

Not everything we believe is true. We may act like it is and it may be uncomfortable to think otherwise, but it’s inevitable that we all hold a substantial number of beliefs that aren’t objectively true. It’s not about opinions or different perspectives. We can pick up false beliefs for the simple reason that we’ve heard them a lot. If I say that the moon is made of cheese, no one reading this is going to believe that, no matter how many times I repeat it. That statement is too ludicrous. But what about something a little more plausible? What if I said that moon rock has the same density as cheddar cheese? And what if I wasn’t the only one saying it? What if you’d also seen a tweet touting this amazing factoid, perhaps also heard it from a friend at some point, and read it in a blog post?

Farnam Street