A forgotten memory that resurfaces without its 'I've met this before' tag, so it arrives feeling original — plagiarism with no intent to plagiarise.
Théodore Flournoy, as the French cryptomnésie, in Des Indes à la planète Mars — his study of the medium Hélène Smith, dated 1899 or 1900 depending on the printing.
// Where it sits
Confidence is not evidence of origin — which is the whole problem.
What it really means
Memory stores two separate things: the content, and where you got it.
The second one is far more fragile than anyone assumes, and when it fails while the first survives, you are left holding something you genuinely remember — with no label saying it came from outside.
So it arrives feeling original. Because from the inside, that is exactly what an original idea feels like.
Théodore Flournoy named this in 1900. He was studying a Geneva medium who produced elaborate accounts of Mars and of past lives, and he concluded she was neither lying nor channelling: she was recovering, in Daniel B. Vermilye's 1900 English translation, “memories profoundly buried beneath the normal waking state”, stripped of their source. He called it cryptomnésie — hidden memory.
The reason the word matters outside psychology is the 1976 case.
George Harrison's My Sweet Lord was found to infringe the Chiffons' He's So Fine. What makes the judgment remarkable is that the court accepted Harrison had not deliberately copied anything — the phrase in the decision is that the copying was subconsciously accomplished — and found infringement anyway. Damages of $1,599,987, later reduced to $587,000 in 1981.
That is the legal position, and it is worth stating plainly because people reach for cryptomnesia as a defence: US copyright law treats subconscious copying identically to deliberate copying. Intent is not an element. Cryptomnesia is an explanation, and explanations are not exculpations.
And it is not rare. Laboratory studies in 1989 found people inadvertently plagiarised roughly 3 to 9 per cent of the time in simple idea-generation tasks — and the slips came less in the group round itself than afterwards, when people tried to sort which ideas had been their own.
Which suggests the honest posture for anyone who makes things. The feeling of having thought of something is not evidence that you did. It is only evidence that the source tag is missing, and the tag is the part that goes first.
Where it comes from
Modelled on Flournoy's French cryptomnésie. The English word probably enters via the 1900 translation.
Myths & misconceptions
Cryptomnesia works as a legal defence — no intent, no liability.
The landmark case held the opposite. The court accepted that Harrison had not deliberately copied and found infringement ANYWAY. Damages were set at $1,599,987, later reduced to $587,000 in 1981. US copyright law treats subconscious copying identically to deliberate copying; intent is not an element of the offence.
It's a rare, exotic phenomenon.
Laboratory studies in 1989 found that across the generation and recall tasks, roughly 3 to 9 per cent of what people produced had already been produced by someone else — and that the slips came less in the group round itself than afterwards, when people tried to recall which ideas had been theirs.
Compare & contrast
Cryptomnesia vs déjà vu
Mirror images. Déjà vu labels the new as familiar; cryptomnesia labels the familiar as new. Both are failures of the source tag rather than of the memory itself — in cryptomnesia the content survives while its origin is lost; in déjà vu the familiarity survives while the content stays out of reach.
| // | Cryptomnesia | Déjà vu |
|---|---|---|
| Error | Familiar read as new | New read as familiar |
| You notice | Rarely | Immediately |
| Consequence | Can be legal | None |
| Named | 1900 | 1876 |
How it connects
- Deja Vuthe exact inverse failure, and far better known.
- Hindsight Biasthe other memory error that rewrites your relationship to something you already had.
Tell it apart
Questions people ask
- What's the standard example?
- George Harrison's 'My Sweet Lord' (1970) against the Chiffons' 'He's So Fine', decided in 1976. The judge accepted the copying was unconscious and found infringement regardless.
- Does the law care that it was unconscious?
- No. US copyright law treats subconscious copying the same as deliberate copying. Intent is not an element — which makes cryptomnesia an explanation rather than a defence.
- Who coined it and why?
- Théodore Flournoy, in 1900, studying a Geneva medium. He needed a name for 'memories profoundly buried beneath the normal waking state' resurfacing as apparent revelation.