The misinformation effect is when misleading information changes your recollection of a certain event.
About a month ago I was talking with a friend about life from high school. He starting telling a story about something that had occurred while I was away on vacation…but he told the story having added me into it. I started asking him why he thought it was me who had said certain things in his retelling of this story, or why he even thought I was there, because I was sure I was not.
Eventually as I was talking to another friend who had been at this event, I realized that he had rehearsed this version of the event (where I am present) with my other friend. He was able to remember that indeed, I had been on vacation and could not have taken part in this event, but my original friend could not shake the notion that I had been there. The mistelling of this story over years had caused the event to change in my friend’s mind, and he was sure that that was how it had always been. Misinformation.