There is no RationalWiki without you. We are a small non-profit with no staff – we are hundreds of volunteers who document pseudoscience and crankery around the world every day. We will never allow ads because we must remain independent. We cannot rely on big donors with corresponding big agendas. We are not the largest website around, but we believe we play an important role in defending truth and objectivity.
If everyone who saw this today donated $5, we would meet our goal for 2019.
| Fighting pseudoscience isn't free.|
We are 100% user-supported! Help and donate $5, $20 or whatever you can today with !
| Putting the psycho in|
|Men who stare at goats|
|By the powers of tinfoil|
what millions of college students do every day the attempt to impart information to somebody by speaking to them or playing recorded messages while they are asleep. There seem to be two main purposes intended for sleep-learning products. The first is to condition behaviour, to prevent nail-biting, cause weight loss, enhance confidence, etc. The second is to impart information such as foreign language vocabulary or lists of facts. Evidence as to their effectiveness can be classified as "inconclusive".
There is no evidence from well-conducted scientific studies that you can learn new facts while asleep, although some experiments have shown stimulation while asleep can aid with learning when awake. Some studies also show that classical (Pavlovian) conditioning can be performed on sleeping or comatose subjects, suggesting it might be possible to use sleep techniques to combat phobias or otherwise influence behavior; but there are few studies in this area, and nothing to indicate you can lose weight while you sleep.
Alois Benjamin Saliger's Psycho-Phone was one of the first attempts at marketing the idea, in 1927; he claimed the effect would be the same as during hypnosis. Saliger sold scripts for various purposes: to "inspire prosperity, inspiration, normal weight, even life extension".
Be Psychic Sleep Hypnosis
The site "sleeplearning.com" offers a
bullshit audiobook "hypnosis CD" that will grant you psychic powers after having listened to it for just an hour! Whoever wrote the product summary would likely benefit from a sleep-learning CD on "How not to overpromise during the sales process":
You can tap in to your natural psychic abilities by simply listening to this hypnosis CD. Erase the negative energies that cause your conscious brain to not believe. You will be astounded by the clarity of the universe and how clear your intuition becomes.
There will be no doubts in your future, you will know the outcome. You will have the ability to control your life with your own mental strength. There will be no road blocks in your way, no noises drowning out what your mind is telling you, everything will be crisp and crystal clear. You only have to follow yourself to the destiny you have chosen!
Early experiments in learning Chinese and preventing nail-biting seemed to show some positive effect, but one weakness of these experiments was that the test subjects may have been awake and listening. This problem was avoided by the classic experiments conducted by Charles W. Simon and William H. Emmons of the Rand Corporation in the 1950s. They used EEGs to test if the subject was awake or asleep, and sleeping subjects were read lists of questions and answers and then tested on the results. They deduced "learning during actual sleep did not seem possible". Following criticism that these experiments did not take into account the beneficial effect of repeating information, they conducted additional tests, with repeated lists of nouns, but still found "material presented a number of times during sleep (using an EEG criterion) cannot subsequently be recalled."
For a long time, the Simon and Emmons studies were considered conclusive. Recently, a few experiments have shown that experimenters can have some influence on sleepers, though they do not match the earlier, discredited experiments. In 2012, research by Anat Arzi at the Weizmann Institute of Science in Israel indicated that classical conditioning could be used during sleep to get people to associate sounds with smells. This corresponded with earlier research showing that patients who were in a vegetative state or minimally conscious could be conditioned to respond to puffs of air blown into their eyes. This research shows that it may be possible to alter behavior in sleep to treat phobias.
Some experiments have shown that spraying smells or playing sounds or music to sleeping people can enhance the retention of facts they learnt during the day. The experiments were firstly by Susan Diekelmann in Germany in 2010, with subjects remembering the layout of objects in a grid; and a 2012 American study where students performed better in a musical memory game if they had previously been played the music in their sleep. A 2015 study at the University of Zurich found that playing words to sleeping people can aid with vocabulary learning, if they have already been exposed to the same vocabulary. This may be connected to results of Jan Born of Lübeck University who found in 2010 that a continuous 0.75 hertz current fed via electrodes into sleeping brains improved recall of the day's memories by 8%. Evidence suggests that some forms of stimulation can improve memory, but beyond that little is known.
- See the Wikipedia article on Sleep-learning.
- I Tried to Cure My Insomnia by Listening to My Own Voice in My Sleep, Vice, May 25, 2016
- Hypnopaedia: Sleep-Learning, Shannon McKanna, Encyclopedia of Educational Technology
- The Non-Recall of Material Presented during Sleep, William H. Emmons and Charles W. Simon, The American Journal of Psychology, Vol. 69, No. 1 (Mar., 1956), pp. 76-81
- How to learn in your sleep, Nature News, 26 August 2012
- Can You Learn In Your Sleep?, BBC Future, David Robson, 22 July 2014
- How much can you really learn while you're asleep?, The Guardian, 6 October 2015
- We can learn new languages while we sleep, Wired, 30 Jun 2014
- Boosting Vocabulary Learning by Verbal Cueing During Sleep. Schreiner T, Rasch B. Cereb Cortex. 2015 Nov;25(11):4169-79. doi: 10.1093/cercor/bhu139. Epub 2014 Jun 23.
- The Sleep-Memory Connection And All The Ways We Can Learn In Our Sleep, Medical Daily, Aug 21, 2015
- Sleep learning: Learn a language a week – you must be dreaming!, The Telegraph, 25 Feb 2010