Cryptomnesia is, literally, hidden memory. The term was coined by psychology professor Theodore ThÃ©odore (flournoy-1854) 1921 and is used to explain the origin of experiences that people believe to be original but which are actually based on memories of events'they ve. forgottenryptomnesia may also explain how the apparent plagiarism of such people as Helen Keller or George Harrison of the Beatles might actually be cases of hidden memory.