Also known as "source misattribution."
A concept in psychology where a person retains a vivid memory from an utterly fictional source. As memory gets encoded, parts get distributed to different areas of the brain and the source gets separated from the actual memory. As time passes from the original inception of the memory, the further that memory moves from its source. In other words, it can be difficult to attribute a source to a memory encoded in the distant past.
Sometimes, through either suggestion or imagination, we create a new source for existing memory. This process of dynamic fiction is called source amnesia.
Examples: you remember someone's face but not ever meeting the person. You love rocky road ice cream because your favorite cousin would always take you to the corner ice cream shop on saturday mornings as a kid, but it was actually your babysitter who did this. You recall a vivid childhood occasion in which you accidentally back the car out of the driveway into the street, but it was actually the neighbor's kid who did this. You remember getting kidnapped with your sister in a van and escaping to tell the authorities, but it was actually an episode of Diff'rent Strokes.
Also very closely related to source amnesia is the misinformation effect: the power of suggestibility on distant memories. For example, person A and person B were both witnesses to the same jumper suicide. Person A is told that Bob fell ten stories while person B is told that Bob plummetted ten stories. Person B is more likely to remember more aftermath gore and carnage based upon the violence of the word "plummet" versus the neutrality of the basic verb "fall." In this way, distant memories can be subtly altered.
The implications of these phenomena are terribly significant in the arena of courtroom science. How reliable is a courtroom testimony from an abuse survivor who has, with the help of suggestive clinical treatment, "recovered" repressed memory of the event? Unfortunately, some witnesses and victims present false memories condemning the innocent accused as a product of source amnesia and the misinformation effect. This problem is tracked by the False Memory Syndrome Foundation, an organization that examines subjects fixated on a false memory yet who meet good-natured resistance from siblings, family, and/or the accused.
The ability to forget is a useful and underrated part of how human memory works. In this process, the source of a memory is usually the most fragile part and therefore the first to go. It is when we try to bring this forgotten part back under pressure and suggestion that we run into trouble.
source: Myers, David G. Exploring Psychology. Worth Publishers, New York. 1999.