"As humans, we are so prone to false memories that you can sometimes induce one simply by casually telling a person about an incident that didn't really happen. Over time, that person may 'remember' the incident but forget the source of the memory. As a result, he or she will confuse the imagined event with his or her actual past."
"3 Remembering and Forgetting"
Subliminal: How Your Unconscious Mind Rules Your Behavior