New Scientist has a special report on out of body and other illusions. Under normal circumstances, your sense of self is firmly anchored inside your body. Sometimes, though, something goes awry, the connection between body and self breaks down and you have an out-of- body experience. Such moments occur when brain function is disturbed, such as after a stroke or epileptic seizure, or while on drugs (no doubt we have our own drugged-up, epileptic stroke experimenters in here). In 2007, however, two research teams independently reported ways of inducing an out-of-body experience in the lab in normal healthy people. The techniques differ slightly, but both involve feeding volunteers video images of themselves from an unusual perspective while applying tactile stimulation, somewhat like the rubber hand illusion. Get volunteers to stand about 2 metres in front of a video camera while wearing goggles displaying video images, converted into a holographic-like 3D projection - the volunteers see a version of their own backs. When they stoked the volunteers' backs, many reported a weird feeling that they were somehow inside the virtual body in front of them (Science, vol 317, p 1096).
The volunteers also experienced "proprioceptive drift" towards the virtual body: they felt as if they were standing in the position of their virtual self. When the researchers turned off the display, moved their volunteers backwards and asked them to return to their original position, many overshot towards where they felt their virtual body had stood. A feeling of out-of-body levitation by repeating the experiment with volunteers who were lying down (Consciousness and Cognition, DOI: 10.1016/j.concog.2008.11.003) has not yet recreated the entire out-of-body experience: It remains an 'as-if' feeling, but they are trying to refine it to the full Flying Harrington. Ehrsson's team have done something similar, with seated volunteers filmed from behind while a researcher stands to the side of them stroking the volunteer's chest and a space just in front of the camera (see illustration). The volunteers see their own backs, feel the stroking but also see somebody stroking a position just behind them. This strongly creates the illusion that they are outside their own bodies, says Ehrsson (Science, vol 317, p 1048). What's more, when Ehrsson tried swinging a hammer at the previously stroked airspace, it elicited a strong stress response in the volunteer. I don't know how many realise this, but the relativity experiments were substantially connected to far cruder versions of these recent ones. Who knows what we might be able to 'see for real' if we experienced more illusions? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups ""Minds Eye"" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/Minds-Eye?hl=en -~----------~----~----~----~------~----~------~--~---
