Cryptomnesia is a term that was first coined by Théodore Flournoy (1854 - 1920) and is used to describe the phenomena of misperception of information often believed to have been derived from supernatural sources.
Flourney, a former Professor of Psychology and an author of two books on parapsychology and spiritism, coined the term in order to explain the phenomenon experienced by the medium Hélène Smith as "romances of the subliminal
imagination, derived largely from forgotten sources". That is, the information either comes from forgotten memories (perhaps from books read as a child) or from information which has been absorbed subconsciously in the past without the subject's awareness (subconscious recall). In laymen's terms, the word cryptomnesia translates to hidden memories.
It's true that the subconscious mind is capable of recalling finer details about events than a person can consciously remember and this has been confirmed through hypnosis. For those who believe that hypnosis is ineffective or is pseudoscience, hypnosis has already been scientifically proven to work by measuring brain activity with EEG (ElectroEncephaloGram) during hypnosis sessions. It's also true that due to the way our internal representational systems work, our subconscious knows the meaning of our dreams and they make perfect sense when in a hypnotic trance although consciously our dreams may sometimes seem a bit odd or peculiar.
The phenomenon of cryptomnesia may very well be responsible for false memories and inaccurate information derived from unknown sources such as those believed to have been accessed during processes like channeling, past life regression and spirit writing. Whilst cryptomnesia is often used as an explanation for seemingly supernatural phenomena, it may also tie with with the placebo effect, ideomotion (responsible for the Ouija board effect) and the true power of the subconscious mind and therefore although cryptomnesia does happen, it does not rule out the possibility of supernatural phenomena happening in some cases.
[ Image: Geralt at Pixabay - Public Domain - https://pixabay.com/en/face-soul-head-smoke-light-sad-658678/ ]