grumble briefly. Now I forced myself to lie in bed motionless.
For a while, I dozed, then felt the need to move my hands, which were lying on the blanket, into a more comfortable position. In
the same instant, I realized that . . . my body was lying there in
some kind of paralysis. Simultaneously, I found I could pull my
hands out of my physical hands, as if the latter were just a stiff
pair of gloves. The process of detachment started at the fingertips,
in a way that could be felt clearly, with a perceptible sound,
a kind of crackling. This was precisely the movement I had intended
to carry out with my physical hands. With this, I detached
from my body and floated out of it head first, attaining
an upright position, as if I were almost weightless. Nevertheless,
I had a body, consisting of real limbs. You have certainly seen
how elegantly a jellyfish moves through the water. I could now
move around with the same ease.
I lay down horizontally in the air and floated across the bed,
like a swimmer who has pushed himself off the edge of a swimming
pool. A delightful feeling of liberation arose within me.
But soon I was seized by the ancient fear common to all living
creatures—the fear of losing my physical body. It sufficed to
drive me back into my body As noted, the sleep paralysis Waelti describes is not a necessary condition
for OBEs. They frequently occur following accidents, in combat
situations, or during extreme sports—for instance in high-altitude
climbers or marathon runners:
A Scottish woman wrote that, when she was 32 years old, she had
an OBE while training for a marathon. “After running approximately
12–13 miles . . . I started to feel as if I wasn’t looking
through my eyes but from somewhere else. . . . I felt as if something
was leaving my body, and although I was still running
along looking at the scenery, I was looking at myself running as
well. My ‘soul’ or whatever, was floating somewhere above my
body high enough up to see the tops of the trees and the small
hills.”Various studies show that between 8 and 15 percent of people in the
general population have had at least one OBE. There are much higher
incidences in certain groups of people, such as students (25 percent),
paranormal believers (49 percent), and schizophrenics (42 percent);
there are also OBEs of neurological origin, as in epileptics.
A 29-year-old woman has had absence seizures since the age of
12 years. The seizures occur five times a week without warning.
They consist of a blank stare and brief interruption of ongoing
behavior, sometimes with blinking. She had an autoscopic experience
at age 19 years during the only generalized tonoclonic
seizure she has ever had. While working in a department store
she suddenly fell, and she said, “The next thing I knew I was
floating just below the ceiling. I could see myself lying there. I
wasn’t scared; it was too interesting. I saw myself jerking and
overheard my boss telling someone to ‘punch the timecard out’
and that she was going with me to the hospital. Next thing, I was
in space and could see Earth. I felt a hand on my left shoulder,
and when I went to turn around, I couldn’t. Then I looked down
and I had no legs; I just saw stars. I stayed there for a while until
some inner voice told me to go back to the body. I didn’t want to go because it was gorgeous up there, it was warm—not like
heat, but security. Next thing, I woke up in the emergency
room.” No abnormalities were found on the neurological examination.
Skull CT scan was normal. The EEG demonstrated generalized
bursts of 3/s spike-and-wave discharges. At first, the realistic quality of these OBEs seems to argue against
their hallucinatory nature. More interesting, though, is how veridical elements
and hallucination are integrated into a single whole. Often, the
appearance/reality distinction is available: There is insight, but this insight
is only partial. One epileptic patient noted that his body, perceived
from an external perspective, was dressed in the clothes he was really
wearing, but, curiously, his hair was combed, though he knew it had
been uncombed before the onset of the episode. Some epileptic patients
report that their hovering body casts a shadow; others do not report
seeing the shadow. For some, the double is slightly smaller than life-size.
We can also see the insight component in the first report by Ernst
Waelti previously quoted: “Had my normal body fallen like that, my
head would have collided with the edge of my bedside table.”
Another reason the OBE is interesting from a philosophical perspective
is that it is the best known state of consciousness in which two selfmodels
are active at the same time. To be sure, only one of them is the
“locus of identity,” the place where the agent (in philosophy, an entity
that acts) resides. The other self-model—that of the physical body lying,
say, on the bed below—is not, strictly speaking, a self-model, because it
does not function as the origin of the first-person perspective. This second
self-model is not a subject model. It is not the place from which you
direct your attention. On the other hand, it is still your own body that
you are looking at. You recognize it as your own, but now it is not the
body as subject, as the locus of knowledge, agency, and conscious experience.
That is exactly what the Ego is. These observations are interesting
because they allow us to distinguish different functional layers in the
conscious human self.
Interestingly, there is a range of phenomena of autoscopy (that is, the
experience of viewing your body from a distance) that are probably
functionally related to OBEs, and they are of great conceptual interest. The four main types are autoscopic hallucination, heautoscopy, out-ofbody
experience, and the “feeling of a presence.” In autoscopic hallucinations
and heautoscopy, patients see their own body outside, but they
do not identify with it and don’t have the feeling that they are “in” this illusory
body. However, in heautoscopy, things may sometimes go back
and forth, and the patient doesn’t know which body he is in right now.
The shift in the visuospatial first-person perspective, localization, and
identification of the self with an illusory body at an extracorporeal position
are complete in out-of-body experiences. Here the self and the
visuospatial first-person perspective are localized outside one’s body,
and people see their physical body from this disembodied location. The
“feeling of a presence”—which has also been caused by directly stimulating
the brain with an electrode—is particularly interesting: It is not a visual
own-body illusion but an illusion during which a second illusory
body is only felt (but not seen) What about personality correlates? Differential psychology has
shown that significant personality traits of people who frequently experience
OBEs include openness to new experience, neuroticism, a tendency
toward depersonalization (an emotional disorder in which there
is loss of contact with one’s own personal reality, accompanied by feelings
of unreality and strangeness; often people feel that their body is unreal,
changing, or dissolving), schizotypy (sufferers experience distorted
thinking, behave strangely, typically have few, if any, close friends, and
feel nervous around strangers), borderline personality disorder, and
histrionics. Another recent study links OBEs to a capacity for strong absorption—
that is, experiencing the phenomenal world, in all its aspects
and with all one’s senses, in a manner that totally engages one’s attention
and interest—and somatoform dissociation (in part, a tendency to cut
one’s attention off from bodily and motion stimuli), and points out that
such experiences should not automatically be construed as pathological. It is also interesting to take a closer look at the phenomenology of
OBEs. For example, the “head exit” depicted in figure 6a is found in only
12.5 percent of cases. The act of leaving your body is abrupt in 46.9 percent
of cases but can also vary from slow (21.9 percent) to gradual and
very slow (15.6 percent). Many OBEs are short, and one recent study
found a duration of less than five minutes in nearly 40 percent of cases
and less than half a minute in almost 10 percent. In a little more than
half the cases, the subjects “see” their body from an external perspective,
and 62 percent do so from a short distance only. Many OBEs involve
only a passive sense of floating in a body image, though the sense of selfhood
is robust. In a recent study more than half the subjects reported
being unable to control their movements, whereas nearly a third could.
Others experienced no motion at all. Depending on the study, 31 to 84
percent of subjects find themselves located in a second body (but this
may also be an indefinite spatial volume), and about 31 percent of OBEs
are actually “asomatic”—they are experienced as bodiless and include an
externalized visuospatial perspective only. Vision is the dominant sensory
modality in 68.8 percent, hearing in 15.5 percent. An older study
found the content of the visual scene to be realistic (i.e., not supernatural)
in more than 80 percent of cases. I have always believed that OBEs are important for any solid, empirically
grounded theory of self-consciousness. But I had given up on them
long ago; there was just too little substantial research, not enough
progress over decades, and most of the books on OBEs merely seemed
to push metaphysical agendas and ideologies. This changed in 2002,
when Olaf Blanke and his colleagues, while doing clinical work at the
Laboratory of Presurgical Epilepsy Evaluation of the University Hospital
of Geneva, repeatedly induced OBEs and similar experiences by electrically
stimulating the brain of a patient with drug-resistant epilepsy, a
forty-three-year-old woman who had been suffering from seizures for
eleven years. Because it was not possible to find any lesions using neuroimaging
methods, invasive monitoring had to be undertaken to locate
the seizure focus precisely. During the stimulation of the brain’s right
angular gyrus, the patient suddenly reported something strongly resembling
an OBE. The epileptic focus was located more than 5 cm from the
stimulation site in the medial temporal lobe. Electrical stimulation of
this site did not induce OBEs, and OBEs were also not part of the patient’s
habitual seizures.
Initial stimulations induced feelings that
the patient described as “sinking into the bed”
or “falling from a height.” Increasing the current
amplitude to 3.5 milliamperes led her to
report, “I see myself lying in bed, from above,
but I see only my legs and lower trunk.” Further
stimulations also induced an instantaneous
feeling of “lightness” and of “floating”
about six feet above the bed. Often she felt as
though she were just below the ceiling and
legless.
Meanwhile, not only OBEs but also the
“feeling of a presence” have been caused by direct
electrical brain stimulation (see figure 9).
Blanke’s first tentative hypothesis was that
out-of-body experiences, at least in these cases,
resulted from a failure to integrate complex somatosensory and vestibular information. In more recent studies, he
and his colleagues localized the relevant brain lesion or dysfunction at
the temporo-parietal junction (TPJ). They argue that two separate
pathological conditions may have to come together to cause an OBE.
The first is disintegration on the level of the self-model, brought about
by a failure to bind proprioceptive, tactile, and visual information about
one’s body. The second is conflict between external, visual space and the
internal frame of reference created by vestibular information, i.e., our
sense of balance. We all move within an internal frame of reference created
by our vestibular organs. In vertigo or dizziness, for example, we
have problems with vestibular information while experiencing the dominant
external, visual space. If the spatial frame of reference created by
our sense of balance and the one created by vision come apart, the result
could well be the conscious experience of seeing one’s body in a position
that does not coincide with its felt position.
It is now conceivable that some OBEs could be caused by a cerebral
dysfunction at the TPJ. In epileptic patients who report experiencing
OBEs, a significant activation at the TPJ can be observed when electrodes are implanted in the left hemisphere. Interestingly, when
healthy subjects are asked to imagine their bodies being in a certain position,
as if they were seeing themselves from a characteristic perspective
of the OBE, the same brain region is activated in less than half a
second. If this brain region is inhibited by a procedure called transcranial
magnetic stimulation, this transformation of the mental model of
one’s body is impaired. Finally, when an epileptic patient whose OBEs
were caused by damage to the temporo-parietal junction was asked to
simulate mentally an OBE self-model, this led to a partial activation of
the seizure focus. Taken together, these observations point to an
anatomical link among three different but highly similar types of conscious
experiences: real, seizure-caused OBEs; intended mental simulations
of OBEs in healthy subjects; and intended mental simulations of
OBEs in epileptic patients.
Recent findings show that the phenomenal experience of disembodiment
depends not just on the right half of the temporo-parietal junction
but also on an area in the left half, called the extrastriate body-area. A
number of different brain regions may actually contribute to the experience.
Indeed, the OBE may turn out not to be one single and unified target
phenomenon. For example, the phenomenology of exiting the body
varies greatly across different types of reports: The initial seconds clearly
seem to differ between spontaneous OBEs in healthy subjects and those
experienced by the clinical population, such as epileptic patients. The onset may also be different in followers of certain spiritual practices.
Moreover, there could be a considerable neurophenomenological overlap
between lucid dreams (see chapter 5) and OBEs as well as body illusions
in general.
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