Out-of-Body Experiences Enter the Lab

Here's a juicy one from the Aug 24 Science.

Labs in Switzerland and the UK have independently used visual tricks to induce "out-of-body" experiences in healthy lab volunteers. At the UK lab -- the ever-productive Wellcome Trust Centre for Neuroimaging in London -- they seem to have combined some visuo-sensory illusions of the sort pioneered by V.S. Ramachandran with some fancy head-mounted display goggles to fool the person into seeing his or her own body elsewhere -- and then feel it when the phantom body gets tapped.

As Greg Miller's news story in Science puts it

Out-of-body experiences are associated more with tabloid newspapers, New Age Web sites, and large doses of hallucinogenic drugs than serious scientific discussion. Yet they're often reported by reputable people who suffer from migraine headaches, epilepsy, and other neurological conditions. Intrigued by such accounts, some researchers are trying to figure out how the brain creates an aspect of human consciousness so fundamental that we take it for granted: the perception that the 'self' conforms to the borders of the physical body.

Now, two teams of cognitive neuroscientists independently report on pages 1048 and 1096 methods for inducing elements of an out-of-body experience in healthy volunteers. Both groups used head-mounted video displays to give people a different perspective on their own bodies. Each team also drew upon the sense of touch to enhance the illusion. Although details of the experience differed, the people in both experiments reported feelings of dissociation from their bodies. The researchers say their findings will pave the way to new brain-imaging studies of body perception and could have practical applications, such as helping virtual-reality programmers design environments that make users feel as if they are really there.

'It's striking because when you hear about out-of-body experiences, it sounds so deeply weird,' says Chris Frith, a cognitive neuroscientist at University College London who did not participate in the new research. 'These studies show you can actually manipulate it experimentally.' The illusions add to evidence that the brain's representation of the physical body is malleable and can be modified by information from the senses, Frith says.

A 2005 paper from the Swiss lab had speculated that out-of-body experiences, or "OBEs,"

are related to a failure to integrate multisensory information from one’s own body at the temporo-parietal junction (TPJ). It is argued that this multisensory disintegration at the TPJ leads to the disruption of several phenomenological and cognitive aspects of self-processing, causing illusory reduplication, illusory self-location, illusory perspective, and illusory agency that are experienced as an OBE.

H. Henrik Ehrsson's brief UCL report doesn't speculate about the anatomical/functional roots of this illusion; Olaf Blanke's paper does.

This is interesting for many reasons. Among them is that such out-of-body experiences support the idea that we have an identity or "soul" independent of our bodies, which in turn supports the dualist notion that mind and brain are two separate things. Modern neuroscience increasingly insists otherwise. These papers hardly settle the argument. But they do seem to erode one type of anecdotal evidence that a soul or mind or identity arises separately from the body.

Is this a neuroscientific parlor game? Well, no. As earlier essays and papers by Frith and Blanke make clear (e.g., Frith's essay about Blanke's paper on several strange neurological cases , the mechanisms being manipulated here may, when they go awry, contribute to disorders involving everything from face recogntion to movement. Great stuff.

For more, see pieces by Blanke here. And Sandra Blakeslee has a story on the two Science papers in today's New York Times.

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medicine, neuroscience, illusions, out-of-body experiences