Friday, August 24, 2007

Out of Body Experience Explained"

Source: "Out-of-body experience recreated", BBC News, August 23, 2007.

This long excerpt explains in part how the experiment worked:
In the Swiss experiments, the researchers asked volunteers to stand in front of a camera while wearing video-display goggles.

Through these goggles, the volunteers could see a camera view of their own back - a three-dimensional "virtual own body" that appeared to be standing in front of them.

When the researchers stroked the back of the volunteer with a pen, the volunteer could see their virtual back being stroked either simultaneously or with a time lag.

The volunteers reported that the sensation seemed to be caused by the pen on their virtual back, rather than their real back, making them feel as if the virtual body was their own rather than a hologram.


Even when the camera was switched to film the back of a mannequin being stroked rather than their own back, the volunteers still reported feeling as if the virtual mannequin body was their own.

And when the researchers switched off the goggles, guided the volunteers back a few paces, and then asked them to walk back to where they had been standing, the volunteers overshot the target, returning nearer to the position of their "virtual self".

Dr Henrik Ehrsson, who led the UCL research, used a similar set-up in his tests and found volunteers had a physiological response - increased skin sweating - when they felt their virtual self was being threatened - appearing to be hit with a hammer.

Dr Ehrsson said: "This experiment suggests that the first-person visual perspective is critically important for the in-body experience. In other words, we feel that our self is located where the eyes are."
Comment: This is a nice example of the the fact that what we perceive is not necessarily what is happening.

Out of body experiences have been seen by some as religious or quasi-religious experiences. Certainly there is nothing unnatural about those in this experiment. Just an indication that our brain works in ways that are unintuitive. I see it as analogous to the images used to illustrate the ideas of gestalt psychology. JAD
Boring women
Old woman front view
young woman back view

Rubin face / Figure-ground vase

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