When the eyes leave the body, is the Self going with them? With this question – which seems to be peculiar at first sight - the Swedish psychologist Henrik Ehrsson is engaged in research with since his scholastics. Of course this game of mind is unrealistic. But again and again people tell of the feeling to be outside of their own body: patients with neurological diseases or apoplectic strokes. Also persons who have been clinically dead for a short period of time tell sometimes of so-called near-death experiences and their out-of-body experiences. Up to ten percent of the population experience at least one time in their life an “out-of-body experience” (OBE), how this misperception is called by experts.
Now researchers report in even two articles for the science magazine “Science” (Bd.317), how they caused similar illusions with people being in good health – without any mystical tomtom. Video cameras and 3D-glasses were enough.

Ehrsson, who is researching at the University College in London and at the well-known Karolinska-Institut in Stockholm, was filming his test persons from a distance of approximately two meters behind their back. He transmitted the pictures in real-time on video-glasses in front of the eyes of the test persons. While doing so, the right and the left eye received slightly different views, which created the spatial impression that the person would watch the own body from behind.

Then the scientist touched the chest of the test person with two plastic pins – out of the view of the camera – and at the same time that spot in the room where the chest of the virtual body was located. That was enough: The test persons believed that they really were sitting behind their own body watching it from there. “Many of them giggled and said ‘Wow, how crazy!’ Ehrsson reports.

A hammer hitting the virtual body – real stress

In a second experiment Ehrsson used more rustic methods. With a hammer he was beating on the virtual bodies of the test persons – and immediately the electrodes were recording stress on their real skin. “We feel that our I is located where our eyes are” says Ehrsson. The illusion would not be limited to sitting or standing, Ehrsson explains to SPIELGEL ONLINE.

The London experiment, a teaching of perfect illusion?

That is not the point, is the opinion of a German-Swiss researchers group, who carried out similar experiments at the École Polytechnique Fédérale de Lausanne. In the experimental set up of the neuro-scientist Olaf Blanke and the philosopher Thomas Metzinger, Mainz, the test persons also were given abstract views by camera and video-glasses (see video). Also these test persons believed to see themselves from outside – even when it was actually a dummy. It is rather the question of studying the consciousness of the own body than out-of-body experiences, Bigna Lenggenhager of the researchers team said to SPIEGEL ONLINE.

Philosopher Metzinger: “A classical OBE surely includes moving all modalities of the senses into the second body”. That is why he wants to call both experiments only “Teleportations-OBEs”, and he considers Ehrsson’s statement for ‘laid it on a little thick’.

After all, the I-feeling can be selectively manipulated – that is fact. “This way video games could reach a totally new level” Ehrsson is speculating. Also tele-operations could profit from making the surgeons believe they would directly be at the operating table.

The rubber hand, the I and Descartes

A fascinating vision. But it is for a totally different reason why psychologists, brain researchers and philosophers are interested in out-of-body experiences - and for that the most primitive experiments seem to be the most suitable ones. ”Here we have shown the simplest form of the I-feeling.” Metzinger says. Already three years ago Ehrsson presented: The brain compounds information in the pre-motor cortex in order to decide whether a limb belongs to the own body or not. Even only with a rubber dummy of the right hand his test persons could be fooled (more…).

In both new experiments visual stimuli alone were enough to confuse the entire body perception. Metzinger interprets this as follows: Here the simplest form of the I-feeling had been manipulated. This would have far reaching consequences for the image of the human being. Beginning with Descartes, philosophers had started from a rational ego, they had even metaphysically enhanced the I.

This idea still persists today: One could not explain the nature of the Self – but it had to do something with reflexion and self-realization, and it also would make the human being unique.

Is all of this only a comfortable fallacy? Metzinger says: “This experiment also could be done the same way with apes. Maybe they could not fill out the questionnaire all that good, but everything else would function as well.”

The unity of body and I-feeling belongs to the basis of self-consciousness – and obviously the brain constantly is busy with connecting different sensations with consistent body percepts.

Though, it can be fudged into the experiment – but the human being cannot consciously control it.

“That goes much deeper” Metzinger says. He sees the chance that psychologists and brain researchers now can take apart the I-consciousness piece by piece and reduce it to its physical basis.

If they are successful with this they probably will also find out that there is no I at all that superordinates everything.

Already the title of their research work sounds like a challenge for ego-philosopher René Descartes: “Video Ergo Sum” – I see, so I am.

From Stefan Schmitt
Source: www.spiegel.de