Cryptomnesia

All the witnesses of Mlle. [Hélène] Smith's Hindoo somnambulisms who are of the same opinion on that subject (several refrain from having any) unite in seeing in it a curious phenomenon of cryptomnesia, of reappearances of memories profoundly buried beneath the normal waking state, together with an indeterminate amount of imaginative exaggeration upon the canvas of actual facts. But by this name of cryptomnesia or resurrection of latent memories, two singularly different things are understood.

How much is cryptamnesia-confabulation, how much frontal-lobe indifference-equalisation, how much some strange schizophrenic disintegration and shattering-flattening?

The path analysis suggests that cryptomnesia is rooted in a lack of trusting relationships. […] This lack of trust leads to feelings of anomie and anxiety that make the individual more likely to construct false memories out of information stored in the unconscious mind. People who think in this way are susceptible to belief in conspiracy theories, since these theories help them to make sense of an otherwise incoherent world.

And although [Sigmund] Freud claimed that others’ ideas were of no use to him unless they came at a time when he was ready for them, he proved enormously susceptible to their influence and even noted his own tendency to ‘cryptamnesia’, by which he ‘unconsciously’ contrived to forget his intellectual debts.

Apparently lacking the time or patience to reveal a comprehensive system of cryptomnesias in his medium, Fräulein SW, [Carl] Jung strenuously asserts the importance of this unconscious device […]

While apparent regressions into past lives can often easily be shown to be constructions based on cryptamnesia[…], this is by no means always the case. In 1987, one hypnotherapy client experienced an apparent 'past life' as a submariner who died with his ship in 1942; he provided detailed names and dates that could be confirmed from the records of the naval base where he was supposed to have served[…]. If we insist on a Darwinian account, these phenomena must be examples of cryptamnesia, suggestion or fraud.

In dreams, therefore, cryptomnesias may appear, that is, impressions, elements, thoughts, a piece of knowledge that the dreamer once had, which then vanishes completely and cannot be reproduced, until it suddenly reemerges in its original form on some particular occasion.

Some plagiarism is unconscious and unintentional. It occurs when people come up with ideas that they believe are their own but in fact were encountered in the past. This unconscious plagiarism is cryptomnesia[…]. One theory of cryptomnesia is that it is a reality monitoring error. People retain the content information, but after some time has passed, and/or because little attention was paid during encoding, the source memory is weak and has no influence.