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Scientific American

The Sensed-Presence Effect

published April 2010 | comments (10)
How the brain produces the sense of someone present when no one is there
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In the 1922 poem The Waste Land, T. S. Eliot writes, cryptically: Who is the third who always walks beside you? / When I count, there are only you and I together / But when I look ahead up the white road / There is always another one walking beside you.

In his footnotes to this verse, Eliot explained that the lines “were stimulated by the account of one of the Antarctic expeditions [Ernest Shackleton’s] … that the party of explorers, at the extremity of their strength, had the constant delusion that there was one more member than could actually be counted.”

Third man, angel, alien or deity — all are sensed presences, so I call this the sensed-presence effect. In his gripping book, The Third Man Factor (Penguin, 2009), John Geiger documents the effect in mountain climbers, solo sailors and ultraendurance athletes. He lists conditions associated with it: monotony, darkness, barren landscapes, isolation, cold, injury, dehydration, hunger, fatigue and fear. I would add sleep deprivation; I have repeatedly experienced its effects and witnessed it in others during the 3,000-mile nonstop transcontinental bicycle Race Across America. Four-time winner Jure Robic, a Slovenian soldier, recounted to the New York Times that during one race he engaged in combat a gaggle of mailboxes he was convinced were enemy troops; another year he found himself being chased by a “howling band” of black-bearded horsemen: “Mujahedeen, shooting at me. So I ride faster.”

Sleep deprivation also accounts for Charles A. Lindbergh’s sensed presence during his transatlantic flight to Paris: “The fuselage behind me becomes filled with ghostly presences — vaguely outlined forms, transparent, moving, riding weightless with me in the plane … conversing and advising on my flight, discussing problems of my navigation, reassuring me, giving me messages of importance unattainable in ordinary life.”

Whatever the immediate cause of the sensed-presence effect, the deeper cause is to be found in the brain. I suggest four explanations:

  1. The hallucination may be an extension of the normal sensed presence we experience of real people around us, perhaps triggered by isolation.
  2. During oxygen deprivation, sleep deprivation or exhaustion, the rational cortical control over emotions shuts down, as in the fight-or-flight response, enabling inner voices and imaginary companions to arise.
  3. The body schema, or our physical sense of self — believed to be located primarily in the temporal lobe of the left hemisphere — is the image of the body that the brain has constructed. If for any reason your brain is tricked into thinking that there is another you, it constructs a plausible explanation that this other you is actually another person — a sensed presence — nearby.
  4. The mind schema, or our psychological sense of self, coordinates the many independent neural networks that simultaneously work away at problems in daily living so that we feel like a single mind.

Neuroscientist Michael S. Gazzaniga of the University of California, Santa Barbara, calls this the left-hemisphere interpreter — the brain’s storyteller that pulls together countless inputs into a meaningful narrative story. In an experiment with a “split-brain” patient (whose brain hemispheres were surgically disconnected), Gazzaniga presented the word “walk” only to the right hemisphere. The patient got up and began walking. When he was asked why, his left-hemisphere interpreter made up a story to explain this behavior: “I wanted to go get a Coke.”

My brother-in-law Fred Ziel, who has twice climbed Mount Everest, tells me that both times he experienced a sensed presence: first when he was frostbitten and without oxygen at the limit of physical effort above the Hillary Step, and second on Everest’s north ridge after he collapsed from dehydration and hypoxia at 26,000 feet. Both times he was alone and feeling desirous of company. Tellingly, when I asked his opinion as a medical doctor on possible hemispheric differences to account for such phenomena, Fred noted, “Both times the sense was on my right side, perhaps related to my being left-handed.” The sensed presence may be the left-hemisphere interpreter’s explanation for right-hemisphere anomalies.

Whatever its cause, the fact that it happens under so many different conditions tells us that the presence is inside the head and not outside the body.

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10 Comments to “The Sensed-Presence Effect”

  1. alishabet Says:

    My comment is from experience: It’s not necessary to be under stress, or in an isolated place. The feeling of being watched can happen anywhere, for prolonged periods of time, in every day life. It’s usually diagnosed as paranoia, a word that may be the flip side of metanoia, the same thing turned around the other way, a form of self observation, at least that’s what it seems to be to me. I’m not a troller I got interested in the ‘discussion’ about whether there is a god or not. That seems to link to this post about the invisible presence.

    I posted this already but it’s relevant to this idea so here it is again: from Oedipus authored by Patrick Mullahy Footnote, page 507
    “Often in explaining his ideas Freud resorts to analogies or conceptions from the physical world. Another conception of his is “that among the psychic functions there is something which should be differentiated (an amount of affect, a sum of excitation), something having all the attributes of a quantity—although we possess no means of measuring it—a something which is capable of increase, displacement and discharge and which extends itself over the memory traces of an idea like an electric charge over the surface of the body…for the present it is justified by it’s utility in correcting and explaining diverse psychical conditions. Collected papers, Vol I, p.75″

    Freud did not (to my knowledge) name this function as the ‘transcendental function’ which Jung did describe as being a function similar to a mathematical function. I believe this is an accurate description of the transcendental function: “capable of increase, displacement and discharge and which extends itself over the memory traces of an idea ‘like’ an electric charge over the surface of the body…that’s an encyclopedia of implication. That function sorts out, creates significance, importance and relationship in the process of self observation, and life re-view. He wrote that every life has a ‘story’ built up and I have reason to accept that the ‘function’ brought my central idea to my attention over a span of decades, sorting it out from millions of books, trillions of words.
    Any author of a large non-fictional book very likely cannot notice the ‘function’ at work independently of his will, it’s presumed to be his own production. The ‘synchronicities’ that have happened were not emphasized by the ‘function’, which seems to operate very selectively for reasons and purposes that are difficult to put into words, less than an encyclopedia anyway.

  2. alishabet Says:

    p.s.Richard Tarnas makes a remark in his Cosmos and Psyche: ”Accompanying the more profound occurrences of synchronicity was a dawning intuition — that the individual was herself or himself not only embedded in a larger ground of meaning and purpose but also in some sense (is) a focus of it.” That translates to mean ‘a sense that one is observed’, then of being ‘talked to’ by a very strange ‘voice’. The psychiatric term is ‘centrality’ , feeling at the center of everything that happens. Where’s the book about how a ‘sense of being observed’ is produced?

    Theodore Reik experienced it as his internalized parent, admonishing him at times, counseling or sharing his greif.

  3. alishabet Says:

    PPS: I think the example of the man that wanted a drink is very good, an example of how an impulse can be camoflagued and directed, don’t you think? The separate functioning of the right brain and the left brain has been somewhat established already, doesn’t it seem likely that if 24 other men were in the experiment, they all might have wanted a drink too? or there would have been 25 completely different results.

    I went to a class that was supposed to develop the ‘sixth sense’ about 20 years ago. There were students who saw ‘spirits’ standing near other students, there were others who saw ‘auras’ around everyone, there were those who went firewalking, they had no burns and could not understand that! Personally I’ve never seen a spirit, an aura or experienced ‘voices’ other than thought, quite a variety of it. But there is obviously some presence, invisible but it’s there.

    It makes life interesting enough to feel there’s a meaning to it all, there’s a reason for even what I don’t like. This is not original but it works for me: The modern man does not think, but something thinks for him ; he does not act, but something acts through him ; he does not create, but something is created through him ; he does not achieve, but something is achieved through him.

    Good luck with explaining away that presence scientifically. Smile now, I am.

  4. sittingbytheriver Says:

    After staying up all night, I noticed I was seeing people that were not there. A large rock would appear at first glance to be a crouching person. Anything that remotely resembled the shape of a human being was initially identified as one. Very interesting : )

  5. Kenneth Polit Says:

    There is a phenomena that is experienced during a hallucinogenic drug “trip” known as “the watcher”. It manifests as an outside presence. This occurs even if the “tripper is alone. This leads me to believe that this is a construct of the mind.

  6. Gerry Foster Says:

    i really saw you in a debate with depak chopra and other guests. i really was disappointed in some of your statements, and your stance toward him, period. if you think everything can eventually be explained by science, i think you are wrong. yet, throughout history, we have attributed to god what we could not not understand, in acient times, in more recent times. however, i think for once, we may be getting some scientific evidence for things that we did attribute to a god, in string theory, time theory, and theories regarding space and other dimensions. those may be the most plausible reasons for why people search for god. there is too much evidence of a sixth sense to deny it now, the military ceratainly finds enough merit in it to study it now. depak sees these new findings as maybe leading toward the ultimate meaning in believers. you shot him down for equating the two and using that as further proof of what we do not understand and why we believe. suppose when those theories are fully understood, we will understood why we have always sought the presence of a god, and these sciences will satisfy that result in satisfying those quests in us. but to dismiss him as you did, almost shaming him for his opinion, i thought was terrible. i’ve been a sort of follower of yours for many years. i am not a follower of chopra. but there is absolutely reason for us to still believe in the mystical, even if one day it will all be explained by science. but we are not there! we are also not all scholars! i really hung on your every word in that discussion, and, i felt depressed for about 3 weeks afterwards. looking back i could only attribute it to that conference and what you said. if there are other dimensions of existence, how do you know they are not the eternity we all wish for? the knowledge that comes to us may not be in the form of any traditional religion’s explanation of heaven and hell and afterlife. i do believe other dimensions of existence are possible, and even probable. we are childish in our beliefs about these other dimensions, and even in our religious beliefs. but that does not mean is there not more to this universe, and much more to gained from understanding it. you can’t put science in a box by itself, traditionally i feel religion and science have fed off of each other. religion grows to new heights thanks to scientific revelation, and science often moves forward as a result of old religious myths. therefore, i wouldn’t be so dismissive of chopra’s or anyone’s thoughts along those lines. we learn from each other. i think there are a lot of things that proof of other dimensions could explain when it comes to religion, but religious, or spiritual beliefs in themselves shouls not be dismissed, even if you don’t adhere to them. i don’t, but i would love to believe that somehow the oldest religions hold some truths that we have yet to explore and understand.

  7. JoyMars Says:

    There are “spiritual” experiences that can never be, and will never be, explained by science.

    We are at the tail end of the Age of Pisces. The religions of the era — full of mysticism and the belief in sin, suffering, redemption and in the impurity of sex (a first for the human race) — is coming to an end. Whether it is science that takes it down, or it falls from its own exhaustion, it really doesn’t matter. I’m really sick of the incessant bickering.

    Science is outraged that religion encroaches on its territory with a-scientific claptrap like Creationism. But Science then encroaches on the territory of the Psyche, aggressively so — that is when it’s not guffawing over details like not ever being able to settle on a definition of what consciousness is.

    I say both camps keep to your own turf. Play fair. This isn’t kindergarten anymore.

  8. Edward W. Stanley Says:

    RE: Mr. Shermer’s article:

    Fascinating. Compelling. A very reasonable explanation for the phenomena.

    Thank you.

    RE: JoyMars

    I’m not sure how the contrivance regarding science and religion being opposed got its start, but I’m fairly certain, a friar, Roger Bacon, started the formal western scientific method practices used for proving things. I.E. religion started science and therefore could be considered an ‘extension’ of it.

  9. steve estvanik Says:

    Just read this piece in SciAm and the descriptions brought to mind my favorite Samuel Beckett piece – Company – in which a disembodied presence searches or yearns for ‘company’ in its isolation. Beckett must have been tapping into those same brain constructs for self and mind…

  10. Momstrrr Says:

    A very similar effect to what goes on in the brain of a schizophrenic. The brain recognizes two selves. I have little doubt these are related phenomena.