Source confusion occurs when someone does not remember where certain memories come from. This is because it can be difficult to distinguish thoughts from perceptions. Therefore, if someone describes an event, or asks you to imagine an event, it is possible to believe that the event occurred. This has important applications in witness testimony; did you see the gun or did the officer tell you there was a gun? It also applies to how we construct our understanding of the world; we disassociate the content of our knowledge from the source, so we are similarly confident in the content despite not being similarly confident in the source. This effect can be especially strong with childhood memories.
A woman named Nadean Cool went to therapy, and with the use of hypnosis and other techniques, realized that she had repressed childhood memories of being in a satanic cult, being raped, as well as a variety of other horrible experiences. These memories were false, and had been planted by her psychologist. However, due to source confusion, Cool was unable to distinguish these suggestions from memories.