Comment FB :
Julio Cardenas Out of body experiences are not hallucinations! Only people who never experienced one can say that. Science cannot explain something out of its context.
Paula M K Clarke We are much more than a "body".
Noe Jimenez I experienced this when I was a teenager and is real the only thing is that you feel with no power when you come back into your body. But I did it with no knowledge or training is just happens in my life but I was in control with my emotions and I know that I was out of my body.
Sus Anne I had one out-of-body experience when I was 18 and it was so scary/weird/unexpected that I could not enjoy it to the fullest. Would love to try it now and totally embrace it smile emotikon
Powerful, unnerving hallucinations show there’s something malleable about the way our brains construct our sense of self
Modern neuroscientists call the doppelgänger effect an autoscopic phenomenon, in which a person may hallucinate that they are seeing and even interacting with another ‘me’—a visual double. Illustration: Byron Eggenschwiler
About two months after his younger brother died of complications
from HIV, Chris—a friend of mine in his 50s living in California—woke up
early one morning. He got off the bed, stood up, stretched, turned
around and got the fright of his life.
“The shock was electric,”
Chris told me last year. “Because I was still lying in the bed sleeping,
and it was very clearly me lying there sleeping, my first thought was
that I had died.”
Of course, Chris hadn’t died. He was having
what neuropsychologists call a doppelgänger experience: He found himself
inhabiting an illusory body while his real, physical body was lying in
bed. He says he’s not clear how long the feeling lasted. Eventually,
“there was this enormous sucking sensation,” said Chris, making a long,
drawn-out slurping sound. “I felt like I was dragged, almost thrown,
back into the bed, smack into myself.” He woke up screaming.
Doppelgängers are the stuff of literature, found in unsettling stories by authors from Edgar Allan Poe to Guy de Maupassant. Modern neuroscientists call the doppelgänger effect an autoscopic phenomenon (from “autoscopy”; in Greek, autos means “self,” and skopeo means
“looking at”), in which a person may hallucinate that they are seeing
and even interacting with another “me”—a visual double.
Probably
the most widely experienced and best-known form of these autoscopic
phenomena is the out-of-body experience, in which people often report
leaving their physical body and looking down at it from above.
Unnerving
as they can be, out-of-body experiences, doppelgänger phenomena and
other autoscopic hallucinations are probably our best window onto the
way our brain constructs our sense of self, starting with the bodily
self. Having a bodily self means several things. At its most
fundamental, it anchors you in a body that feels like it is yours. You
also feel that your body occupies a certain volume in physical space and
that you are within that volume looking out with a perspective that
feels like your own.
But as Chris’s experience shows, there are
times—albeit rare—when we aren’t anchored in our physical body,
suggesting that there is something malleable about the way our brains
construct our bodily selves.
Over the years, scientists have found other examples of such malleability. Take the rubber-hand illusion—written up in the journal Nature in 1998 by Matthew Botvinick and Jonathan Cohen—in
which an experimenter strokes a subject’s real hand with a brush while
simultaneously stroking a rubber hand. The subject can see only the
rubber hand, not the real hand, which is obscured by a screen.
In
most people, something crazy happens within a couple of minutes:
Instead of feeling the touch of the brush on the real hand, you begin to
feel the touch at the location of the rubber hand. It is as if your
brain takes ownership of the rubber hand.
So what is happening
here? The brain has to make sense of conflicting information: sensations
of brush strokes on the real hand and the sight of a rubber hand being
stroked. So the brain, in effect, decides that the eyes don’t lie: The
rubber hand must be the source of the sensations, and so the brain
proceeds to embody the inanimate hand.
To create a sense of
embodiment, the brain relies on incoming sensations—both from the
outside and from inside the body—to construct maps of the body and body
parts. We perceive these maps as our bodily selves.
Over the past decade, two teams—one led by Olaf Blanke at the Ecole Polytechnique Fédérale in Lausanne, Switzerland, and the other by Henrik Ehrsson
at the Karolinska Institute in Stockholm, Sweden—have demonstrated
full-body versions of the rubber-hand illusion. Just as our brain can
take “ownership” of a rubber hand, it can also be fooled—using more
elaborate experimental setups—into taking ownership of a mannequin’s
body or even a virtual body.
These experiments show us that, to create the bodily self, the brain
has to integrate various sensations—such as touch, vision and many other
types of internal and external information. There is no one place in
the brain where this integration happens. Rather, researchers have
identified a whole host of regions that are involved. The various
illusions arise when the brain is fed conflicting information and tries
to make the sense of it.
One can even fool the brain into
embodying empty space. For example, in the rubber-hand illusion, if the
experimenter takes the rubber hand away and instead moves the brush in
the air in a manner suggestive of having a hand there while
simultaneously stroking the hidden real hand, some people will soon
start feeling touch in empty space. I can attest to this: I was taken
aback by the weirdness of this illusion when I experienced it in Dr.
Ehrsson’s lab.
The brain’s process of sensory integration can be
fooled not just in the lab but in real life too—leading to, for example,
the doppelgänger experience. If the brain’s processes are working
correctly, there should be just one representation of the body in the
brain. But sometimes the process goes awry, leading to two
representations, and the brain has to choose the representation in which
to anchor the self—and sometimes it chooses one, sometimes the other.
This is what neuroscientists now think leads to the doppelgänger effect.
Such hallucinations can make people feel that they have a “soul” or something incorporeal that can leave the physical body. This leads to a kind of dualism—the view that the stuff of the body and the stuff of the mind are distinct and different.
But what these lab experiments
and studies are showing us is that nothing is really leaving the body
during an out-of-body experience. When the brain is operating on sensory
information that is congruent (meaning that the sensations of touch
match what the eyes are seeing, for example), the brain situates the
self in the body and provides a sense of perspective and body ownership.
But when the sensations aren’t congruent, because someone is
being tricked by the rubber-hand illusion or suffering from some
neurological aberration, the brain does its best to make sense of all
the misleading data. The brain can miscalculate the coordinates for the
self, positioning it outside the body or in another illusory body.
So
modern studies of out-of-body experiences and full-body illusions
aren’t making a case for dualism. Rather, they’re showing us that the
sense of bodily self is something that is constructed by the brain
moment by moment. The bodily self turns out to be the basis for our
greater sense of self, which involves more complex aspects including the
narrative self (that is, the stories we tell others and ourselves about
who we are) and the social, cultural self.
Our sense of self
arises from a complex interaction among brain, body, mind and
culture—and in the full-blown selves we are, all aspects of the self
interact with and influence one another. But it all begins with the
body.
—Mr. Ananthaswamy is a consultant for New Scientist magazine and the author of “The Man Who Wasn’t There: Investigations into the Strange New Science of the Self,” recently published by Dutton.
