Sleep-learning and the Upanishads

Centuries ago, Yajnavalkya used the analogy of “the great fish which travels along both banks, the nearer and the farther” while referring to the human consciousness which oscillates between the waking and the deep sleep state (Brihadaranyaka Upanishad 4.3.17).  He wrote that when the Atman “rests in the intermediate state (of dream)”, it sees both states – waking and deep sleep (Brihad. Up. 4.3.9)[1].   In the state of dreamless sleep, the Advaita Vedantins saw evidence of the existence of Brahman; they reasoned that if a person feels refreshed after sleep, it must be because the Atman had temporarily united with Brahman [2].

There are hopeful signs that the lumbering caravan of modern science, with its constellation of professors (tenured and untenured) commanding a phalanx of caffeinated, unwashed and overworked graduate students, all plodding methodically through the unmapped terrain of human consciousness with their peer-reviewed and statistically significant scientific experiments, might someday serendipitously confirm Yajnavalkya’s insight that it is the same Atman that persists across the three states of waking, dream and deep sleep.  In order to demonstrate continuity, one would have to show that some kind of learning or a unique memory persists between these states.

In the 1950s, after brain waves were first discovered, Simon and Emmons reported an experiment in which they played a tape of answers to questions in a room of sleeping volunteers.  After waking up, the volunteers could not recall anything, indicating that learning in sleep was not possible[3].   The volunteers could recall nothing because when most people fall asleep, they enter the subconscious.  It would take considerable yogic development to become conscious of the outer physical world during sleep.  Recent experiments which test an elementary form of learning known as “Pavlovian conditioning” might provide a flicker of hope though.

A while ago, sleeping newborn babies were subjected to what is known as the Pavlovian conditioning test.  William Fifer and his colleagues subjected sleeping newborn babies to a musical tone followed by a puff of air directed at the eyes.  After repeated trials, the sleeping babies began to scrunch their eyes immediately after hearing the musical tone, indicating that they were anticipating the forthcoming puff of air[4].  In another study, Sullivan subjected one-day old babies who were awake to a citrus odour and lightly stroked their head to produce a head-turn.  The following day, the babies would instinctively turn their head after smelling the citrus odour.  This response was observed irrespective of whether the babies were awake or asleep[5].

A recently-published study (August 26, 2012) conducted by scientists at Weizmann Institute in Israel now demonstrates that adults are also capable of the same type of sleep learning[6].  Sobel and colleagues “repeatedly exposed the sleeping participants to pleasant odours, such as deodorant and shampoo, and unpleasant odours such as rotting fish and meat, and played a specific sound to accompany each scent”.  It was found that “sleep conditioning persists even after they wake up, causing them to sniff strongly or weakly on hearing the relevant tone — even if there was no odour.   The participants were completely unaware that they had learned the relationship between smells and sounds” in their sleep.  The “sniffing responses were slightly more pronounced in those participants who learned the association during the rapid eye movement (REM) stage, which typically occurs during the second half of a night’s sleep”[7]. This may be the first incontrovertible demonstration of sleep learning in human adult brains[8].

One has to wait to see if Sobel’s results can be replicated by other scientists, as is standard scientific practice, but for the purposes of a topical (and presumptuous) blog post, we can assume that will happen over time.  A successful replication of Pavlovian learning may still not validate the Upanishadic assertions.  Since science currently assumes that consciousness arises as an epiphenomenon of brain activity, Pavlovian learning during sleep can be easily attributed to the nugatory brain activity that persists during sleep.  One has to come up with a test which is more compelling to prove that is the same Atman which persists across three states.  Such a test might also require more spiritually evolved human beings who can meet the test criteria !

For the time being, “sleep learning” is an exciting field of science which needs to be monitored for further developments.  I had appended this topic to the end of a previous article “Mental awareness in coma patients” but it deserves to be discussed independently so I fleshed it out separately here.

We turn now to some remarks that Sri Aurobindo made on the subject of dreams.  While discussing the experience of “Samadhi” in The Synthesis of Yoga, he wrote:

It is quite possible indeed to be aware in the dream-trance of the outer physical world through the subtle senses which belong to the subtle body; one may be aware of them just so far as one chooses and on a much wider scale than in the waking condition: for the subtle senses have a far more powerful range than the gross physical organs, a range which may be made practically unlimited. But this awareness of the physical world through the subtle senses is something quite different from our normal awareness of it through the physical organs; the latter is incompatible with the settled state of trance, for the pressure of the physical senses breaks the Samadhi and calls back the mind to live in their normal field where alone they have power. But the subtle senses have power both upon their own planes and upon the physical world, though this is to them more remote than their own world of being [9]

And in this passage from The Letters on Yoga, he elucidates on the manner in which the human consciousness navigates the recondite “dream worlds”:

Ordinarily when one sleeps a complex phenomenon happens. The waking consciousness is no longer there, for all has been withdrawn within into the inner realms of which we are not aware when we are awake, though they exist; for then all that is put behind a veil by the waking mind and nothing remains except the surface self and the outward world – much as the veil of the sunlight hides from us the vast worlds of the stars that are behind it. Sleep is a going inward in which the surface self and the outside world are put away from our sense and vision. But in ordinary sleep we do not become aware of the worlds within; the being seems submerged in a deep subconscience. On the surface of this subconscience floats an obscure layer in which dreams take place, as it seems to us, but, more correctly it may be said, are recorded. When we go very deeply asleep, we have what appears to us as a dreamless slumber; but, in fact, dreams are going on, but they are either too deep down to reach the recording surface or are forgotten, all recollection of their having existed even is wiped out in the transition to the waking consciousness. Ordinary dreams are for the most part or seem to be incoherent, because they are either woven by the subconscient out of deep-lying impressions left in it by our past inner and outer life, woven in a fantastic way which does not easily yield any clue of meaning to the waking mind’s remembrance, or are fragmentary records, mostly distorted, of experiences which are going on behind the veil of sleep – very largely indeed these two elements get mixed up together. For, in fact, a large part of our consciousness in sleep does not get sunk into this subconscious state; it passes beyond the veil into other planes of being which are connected with our own inner planes, planes of supraphysical existence, worlds of a larger life, mind or psyche which are there behind and whose influences come to us without our knowledge. Occasionally we get a dream from these planes, something more than a dream, – a dream experience which is a record direct or symbolic of what happens to us or around us there. As the inner consciousness grows by sadhana(yoga), these dream experiences increase in number, clearness, coherence, accuracy and after some growth of experience and consciousness, we can, if we observe, come to understand them and their significance to our inner life. Even we can by training become so conscious as to follow our own passage, usually veiled to our awareness and memory, through many realms and the process of the return to the waking state. At a certain pitch of this inner wakefulness this kind of sleep, a sleep of experiences, can replace the ordinary subconscious slumber [10].

As when one walks in sleep through luminous dreams
And, conscious, knows the truth their figures mean,
There where reality was its own dream,
He knew things by their soul and not their shape

(Savitri, Book 2, Canto 14)


  1. Roebuck, Valerie J. (ed).  The Upaniṣads.   London ; New York : Penguin Books, 2003, 63-65.
  2. Sharma, Arvind.  Sleep as a state of consciousness in Advaita Vedānta, Albany : State University of New York Press, 2004.
  3. Simon, Charles and Emmons, William.  EEG, Consciousness and Sleep Science 30 November 1956: vol. 124 no. 3231 pp. 1066-1069; cited in Makin, Simon.  “Sleep on it”, Scientific American blog, Nov 20, 2012.
  4. Fifer, William P., et al (2010). “Newborn infants learn during sleep”. Proceedings of the National Academy of Sciences,  107(22):10320-10323; DOI: 10.1073/pnas.1005061107
  5. Sullivan, R. M., Taborsky-Barba, S., Mendoza, R., Itano, A., Leon, M., Cotman, C. W., et al. (1991).  “Olfactory classical conditioning in neonates”. Pediatrics, 87, 511–518.
  6. Weizmann Institute of Science. “Sleep learning is possible: Associations formed when asleep remained intact when awake.” ScienceDaily, 26 Aug. 2012. Web. 27 Aug. 2012.
  7. Costandi, Mo.  “How to learn in your sleep”.  Nature News, 26 August 2012.
  8. While you were sleeping.  26 August 2012.  Science blogs.
  9. Sri Aurobindo. Synthesis of Yoga, CWSA vol 23-24, p 522
  10. Sri Aurobindo. Letters on Yoga, SABCL vol. 23, p 1024

Related Posts

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  13. Vidyas in the Upanishads – part 2
  14. Links between Vedas, Upanishads, Tantra and Puranas
  15. Meditation techniques from the Yoga Upanishads
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  18. Progress reports of Sri Aurobindo
  19. Reconciling Samkhya, Vedanta and Tantra
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  21. Four epistemic methods of consciousness

19 thoughts on “Sleep-learning and the Upanishads

  1. gopal


    i remember Aurobindo saying the subconscient is like a camera over your head recording everything, whether you know or not, so will that not explain these instances of sleep learning, the role of the subconscient mind. Also the instances you have cited seem more like hypnosis. Babies naturally with less interference from the “organizations of MIND” pick up the cues beautifully, to react without “fear response” from the mind, unlike Adults .

    i know the case of Ramanujan and his sleep inspirations has already been discussed in this blog somewhere, there is one more, i wanted to share named “Otto Loewi”. He discovered the very important neurotransmitter chemical ” Acetylcholine “. He did the whole process in his dreams.

    Acetylcholine by the way is used in a lot of medical drugs for therapy. For regulating heart beats, cataract eye surgery, and also for improving the efficiency of digestion tract.

    I think these are instances of mind in the intuitive plane managing to receive the inspirations from the superconscient or supra physical as aurobindo mentions above in the “letters on yoga”.

    1. Sandeep Post author

      i remember Aurobindo saying the subconscient is like a camera over your head recording everything, whether you know or not, so will that not explain these instances of sleep learning, the role of the subconscient mind.

      Yes, Pavlovian learning during sleep can be attributed to to subconscient mind. Most of the volunteers are not developed yogically to have any other recording mechanism.

      I don’t recall reading the “camera over the head” phrase anywhere. Can you post the quote ?

      The Mother did say the subconscient records everything but that’s only during waking state – not at night.

      Mother: The subconscient records everything, and if you have the impression that an ordinary book leaves no effect, it means that you are not conscious of what goes on within you. Each time you read a book in which the consciousness is very low, it strengthens your subconscient and inconscient – it prevents your consciousness from rising upward. It is as if you threw buckets of dirty water on the efforts you had made to purify your subconscient. (Collected Works of the Mother 4:152)

  2. gopal

    tried my best to look for that reference quote , but left only with the sound of the words ringing in my head 😀 . so may be wrong to bring that analogy here. But any way thanks for all these posts on sleep it is one of the toughest parts of sadhana. But as an unchartered territory it is a tremendous field for insights , guidances and sometimes even fun .

      1. amsha

        He obviously invented it, Sri Aurobindo has better means of expression,
        “like a camera over your head” – sounds like person trying to impress stupid

  3. gopal

    ONe question to Sandeep is it not posible to engage in a decent dialectic [The art of investigating or discussing the truth of opinions] without me having to worry about finding the quotes. You must know the works of Aurobindo and Mother is huge and voluminous and you cant expect readers to always quote when they want to engage in a dialectic. i saw this forum as a dialectic which according to one other defenition is ” a dialogue between two or more people who may hold differing views, yet wish to pursue truth by seeking agreement with one another” Am not trying to impress anyone here. may be am working on expression skills to externalize what i understand, that is a better of putting it. sorry had to come up with defence.

    1. Sandeep Post author

      Generally speaking, it is a good habit to remember and provide citations. There are two reasons I can think of:
      1) It helps to make the mind precise instead of remaining vague and nebulous. I keep a record of my favourite quotations and deploy them when required.
      2) It helps others who are also learning the material and want to investigate the information you provided.

      On the topic at hand, it would make a huge difference whether Sri Aurobindo said that subconscient records like a camera during the day only or also at night.

      Lastly, on a public forum, one has to become immune to misunderstandings and occasional abuse, so don’t worry about any allegations against you 🙂

      1. Gopal

        as i put it earlier time indeed answers or is it consciousness? this quote found me in one of the meditation centres here, while i was reading it.. sorry that i attributed the quote to aurobindo when in fact it is Mother herself,and the camera being over or top makes no difference to me.

        November 25, 1913 Prayers and Meditations

        THE greatest enemy of a silent contemplation turned
        towards Thee is surely this constant subconscient registering
        of the multitude of phenomena with which we
        come into contact. So long as we are mentally active, our
        conscious thought veils for us this overactivity of our subconscious
        receptivity; an entire part of our sensibility, and
        perhaps not the smallest, acts like a cine-camera without
        our knowledge and indeed to our detriment. It is only
        when we silence our active thought, which is relatively
        easy, that we see this multitude of little subconscious notations
        surging up from every side and often drowning
        us under their overwhelming flood. So it happens that,
        as soon as we attempt to enter the silence of deep contemplation,
        we are assailed by countless thoughts—if
        thoughts they could be called—which do not interest us
        in the least, do not represent for us any active desire, any
        conscious attachment, but only prove to us our inability
        to control what may be described as the mechanical
        receptivity of our subconscient. A considerable labour
        is needed to silence all these useless noises, to stop this
        wearisome train of images and to purify one’s mind of
        these thousand little nothings, so obstructing and worthless.
        And it is so much time uselessly lost; it is a terrible
        And the remedy? In an over-simple way, certain ascetic
        disciplines recommend solitude and inaction: sheltering
        one’s subconscient from all possible registration;
        that seems tome a childish remedy, for it leaves the ascetic at the mercy of the first surprise-attack; and if one day,
        confident of being perfectly master of himself, he wants to
        come back among his fellowmen in order to help them, his
        subconscient, so long deprived of its activity of reception,
        will surely indulge it more intensively than ever before,
        as soon as the least opportunity offers.
        There is certainly another remedy. What is it? Undoubtedly,
        one must learn to control one’s subconscient
        just as one controls one’s conscious thought. There must
        be many ways of achieving this. Regular introspection in
        the Buddhist manner and a methodical analysis of one’s
        dreams—formed almost always from this subconscious
        registration—are part of the method to be found. But
        there is surely something more rapidly effective. . . .
        O Lord, Eternal Master, Thou shalt be the Teacher,
        the Inspirer; Thou wilt teach me what should be done, so
        that after an indispensable application of it to myself, I
        maymake others also benefit from what Thou hast taught
        With a loving and trustful devotion, I bow to Thee.

        – Mother.

      2. amsha

        Over your head is a proper place of intuition and superconsciousness so your own statement is a clear mistake.

  4. Dreamer

    “…….commanding a phalanx of caffeinated, unwashed and overworked graduate students, all plodding methodically through the unmapped terrain of human consciousness with their peer-reviewed and statistically significant scientific experiments…..” got me smiling for it sounded familiar!!
    I always love to read your posts and this one in particular is awesomely awesome.

  5. Sandeep Post author

    Scientists are recognizing that dreams and waking state are similar:

    Similarities between dreaming and waking
    from a research paper by Yuval Nir and Giulio Tononi

    1) Phenomenology : Dreams are similar to waking state in their audio-visual content. Dreamer might be uncertain whether they are awake or asleep.

    2) Neurophysiology : EEG looks similar in active waking and REM sleep. PET scans have shown that global brain metabolism is comparable in waking and REM Sleep. There is strong activation of high-order occipitotemporal visual cortex in REM sleep, consistent with the vivid visual imagery seen during dreams (and similar to waking state).

    3) There is consistency between a subject’s cognitive and neural organization in dreaming and waking. Studies of children demonstrate that dream features show a gradual development that parallels their cognitive development when awake. Patients with brain lesions that impair their waking cognition also show corresponding deficits in dreams. For example, subjects with impaired facial agnosia also do not have dream of faces.

    4) Dreams also reflect one’s interests and personality, just like mental activity during wakefulness.

    (Nir and Tononi, Dreaming and the brain: from phenomenology to neurophysiology, Trends in Cognitive Sciences, 2010 Feb;14(2):88-100)

    Paper available online@

  6. Pingback: Sleep-learning and the Upanishads | Integral Yoga of Sri Aurobindo … | Neuro Physiology Blog

  7. Chetan

    Very interesting article. Thanks for posting. Sleep learning has been documented elsewhere as well. See the following from Swami Satyananda of Bihar School of Yoga:

    In daily life, most people are not very receptive. This state occurs only when the mind is withdrawn and brought to a point of innocence. There is a scientific definition of innocence which describes it as a state of mind free from the association of logic and mathematics. Innocence is a state of the brain also. There is a time when our brain is completely without inhibitions, and if you plant a seed it will definitely germinate.

    During my earlier years, I often experimented with this state of mind. One of the most interesting experiments was with a little boy who presented himself at my ashram for sannyasa. I wanted to send him to school, but he flatly refused. He was a very naughty boy, an absolute monkey. All day long he broke things, harassed the visitors, and caused accidents. Finally, he became such a liability for the ashram that I decided to try yoga nidra on him.

    Every night I put him to bed in my room and as he was falling asleep, I taught him Gita, Upanishads, Bible, Koran, English, Hindi, Sanskrit, all that I knew. It took me nearly two years.

    When the boy was ten years old I sent him off to Belfast to teach yoga. When he was thirteen I sent him to South America, at sixteen to Australia, at eighteen to Europe. Now he is twenty and I have sent him to USA. He speaks eleven languages fluently, writes in English better than I do, yet he has never been to school. All of his studies and learning took place within that two year period when I gave him yoga nidra, and he doesn’t even remember it now.

    The full article can be found here:


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