Can you summarize what EhrssonLabs is doing to stiumulate OOBEs
EhrssonLabs, run by Henrik Ehrsson at the Karolinska Institute, studies out-of-body
experiences by inducing them experimentally rather than waiting for spontaneous cases.
Their core method is the full-body illusion. A participant wears a head-mounted display
connected to cameras mounted on a mannequin or on another person standing a couple of
meters in front. When the experimenter strokes the participant's real body and simultaneously
strokes the corresponding spot on the mannequin, the brain integrates the visual and tactile
signals and the participant begins to feel the touch as coming from the fake body and to sense
that the fake body is their own. With cameras placed behind the participant, the same setup
makes people feel they are viewing their own body from a position outside it, a laboratory
OOBE.
They have also used an "own-body transformation" setup where a camera films a person's
back and feeds the image to goggles while synchronous touch is applied, producing a strong
sensation of being located behind oneself and even of drifting toward the observed body. A
related line of work uses virtual reality, motion capture, and robotic touch to let people
experience being embodied in a virtual avatar or in a mannequin, and they have combined
these illusions with heart-rate and threat responses to show the body ownership is
physiologically real, not just verbal report. More recent work extends this to multisensory
conflicts, out-of-body-like self-location in VR, and using the illusions to probe how the brain
builds a first-person perspective, with potential clinical spin-offs for pain and body-image
disorders.
UPDATE I don't quite understand. Is the real person supposed to be getting feedback from an
avatar?
Yes, but "feedback" is a bit ambiguous, so let me be precise. In the classic Ehrsson setup the
real person is not controlling the avatar or getting feedback from their own movements.
Instead, the avatar (mannequin, dummy, or another person seen in the head-mounted display)
is what they see, and the experimenter touches both the real body and the corresponding
spot on the avatar at the same time. So the visual feedback comes from watching the avatar
being touched, synchronized with touch on the real body. The brain resolves the conflict by
attributing the felt touch to the avatar, and the person starts to feel the avatar's body as
their own.
In the OOBE version specifically, the cameras are placed behind the participant, so what they
see in the display is their own real back from a point behind them. The experimenter strokes
the real chest/body while the participant watches the back view, sometimes with the camera
on a person behind them mimicking the stroking. Synchronous visual and tactile input again
produces the illusion that they are located outside their body, looking at themselves.
The avatar/VR extensions are related but distinct: there, motion capture and sometimes
robotic touch deliver synchronous visual-tactile or visual-motor signals so the person can
feel embodied in a virtual body that moves with them or is touched in sync. So the
feedback in those cases can include the avatar moving in correspondence with the real
person's movements, which strengthens the sense of owning the virtual body. But the core
trick across all of it is synchronous multisensory stimulation, not the real person piloting an
avatar and receiving feedback from it in the ordinary sense.
. UPDATE so is there anything anomalous going on here that was unexected or at least
interesting?
Yes, several findings from this line of work are genuinely striking, and some were
unexpected.
First, the illusions are strong and fast. People can feel ownership of a rubber hand or a
mannequin within a minute or two of synchronous stroking, and in the full-body version
they report actually being located behind themselves, looking at their own back. That a few
seconds of matched visual and tactile input can override a lifetime of bodily self-
evidence is surprising.
Second, the effects are not just verbal. Ehrsson's group showed that when the fake or virtual
body is threatened, participants sweat more, measured by skin conductance, which is an
autonomic response people cannot easily fake. They have also found that the illusion can
shift body temperature regulation and heart-rate responses. This established that body
ownership is a real, measurable physiological process rather than a story people tell.
Third, the out-of-body illusion is tied to a specific location. The felt self can be moved to
where the cameras are, so the sense of where "I" am is a computed, updatable variable,
not a fixed property of the skull. That is conceptually important and was not obvious before
these experiments.
Fourth, the illusions reveal how closely body ownership is coupled to the first-person
perspective. When self-location shifts, the perceived direction of touch and even the sense of
which body is "mine" can shift with it, which suggests these are not separate modules but a
combined multisensory construction.
Fifth, and perhaps most interesting, the work suggests the brain treats "my body" as a
hypothesis updated by correlated sensory signals. The surprise is how weakly it is
anchored, given how strongly we normally feel it is anchored. There is also the clinical
implication, that manipulating these signals might someday help with phantom limb pain,
chronic pain, or body-image disorders, though that remains largely prospective.
The main thing that would count as anomalous in the strict sense, a result defying
explanation, is not really present. What is surprising is the extent to which a simple
synchronous-touch trick reliably produces experiences that subjects describe as out-of-
body, and the degree to which those experiences carry real physiological consequences.