In 1927, Alois Benjamin Saliger invented the "Psycho-Phone" or "Psychophone", a specialized version of Thomas Edison's phonograph, for sleep learning, stating: "It has been proven that natural sleep is identical with hypnotic sleep and that during natural sleep the unconscious mind is most receptive to suggestions."2 Saliger patented the device in 1932 as the "automatic time-controlled suggestion machine".34
Since the electroencephalography studies by Charles W. Simon and William H. Emmons in 1956, learning by sleep has not been taken seriously. The researchers concluded that learning during sleep was "impractical and probably impossible". They reported that stimulus material presented during sleep was not recalled later when the subject awoke, unless alpha wave activity occurred at the same time the stimulus material was given.56
Sleep-learning is found in influential science fiction and other literature.7 The following examples are listed chronologically by publication or original air date, when known.
Diekelmann, Susanne; Born, Jan (2010). "The memory function of sleep". Nature Reviews Neuroscience. 11 (2): 114–126. doi:10.1038/nrn2762. PMID 20046194. S2CID 1851910. /wiki/Doi_(identifier) ↩
"Psycho-Phone". The New Yorker. 1933. Retrieved 2010-11-18. Well, sir, since 1927, Mr. Saliger has sold more than 2500 Psycho-phones ... https://books.google.com/books?id=DlUQAAAAIAAJ&q=Saliger+psycho-phone ↩
Wright, Gwen. "PsychoPhone". History Detectives: Special Investigations. Public Broadcasting Service (PBS). Retrieved 12 February 2025. https://www.pbs.org/opb/historydetectives/investigation/psychophone/index.html ↩
Benjamin, Ludy T. (23 February 2017). "The Psycho-Phone". Cummings Center Blog. University of Akron. Center for the History of Psychology. Retrieved 12 February 2025. https://centerhistorypsychology.wordpress.com/2017/02/23/the-psycho-phone/ ↩
Fromm, Erika; Ronald E. Shor (1972). Hypnosis. Aldine/Atherton. ISBN 978-0-202-30856-2. 020230856. p. 78 Referring to Charles W. Simon and William H. Emmons EEG, Consciousness, and Sleep Archived 2016-04-17 at the Wayback Machine, Science, 1956, 124, 1066–1069. 978-0-202-30856-2 ↩
Kleitman, Nathaniel (1987). Sleep and Wakefulness. University of Chicago Press. ISBN 0-226-44073-7. p. 125. 0-226-44073-7 ↩
"Hypnopaedia – sleep learning". sleepdex.org. http://www.sleepdex.org/hypnopaedia.htm ↩
"The One with the Hypnosis Tape". March 13, 1997 – via IMDb. https://www.imdb.com/title/tt0583615/ ↩