Something I find interesting as it relates to the idea of creating a fully immersive environment within second life. Granted this is well into the future and not the type of technology to be used, but the idea is there. Bringing one fully into an environment to the extent that they suspend their disbelief.
Swedish researchers create body-swap illusion
Wednesday, Dec 03, 2008 4:4PM UTC
WASHINGTON (Reuters) - Researchers using closed-circuit televisions to
create an illusion have made volunteers virtually swap bodies, even
making women believe they were in a man's body and vice-versa.
The experiment, reported in the Public Library of Science journal PLoS
ONE on Tuesday, shows it is possible to manipulate the human mind to
create the perception of having another body, the Swedish researchers
It helps explain how humans understand the limits of their own bodies,
Valeria Petkova and Henrik Ehrsson of the Karolinska Institute in
They set up a series of experiments aimed at fooling their volunteers,
each an extension of a common illusion in which people can be fooled
into thinking a rubber hand is their own.
For the illusion, the volunteer's real hand is concealed and stroked
at the same time the visible rubber hand is. The brain will often
trick the volunteer into truly feeling as if the rubber hand is his or
her own hand.
Petkova and Ehrsson went further, using a closed-circuit camera to
fool their volunteers into believing a rubber mannequin was in fact
their own body -- and eventually, that another human being was.
"This effect is so robust that, while experiencing being in another
person's body, a participant can face his or her biological body and
shake hands with it without breaking the illusion," they wrote.
They started with a life-sized mannequin.
"Two closed-circuit television cameras were positioned on a male
mannequin such that each recorded events from the position
corresponding to one of the mannequin's eyes," they wrote.
"A set of head-mounted displays connected to the cameras was worn by
the participants, and connected in such a way that the images from the
left and right video cameras were presented on the left and right eye
displays, respectively, providing a true stereoscopic image," they
"Participants were asked to tilt their heads downwards as if looking
down at their bodies. Thus, the participants saw the mannequin's body
where they expected to see their own."
As in the rubber hand illusion, the experimenters touched the
volunteers' bodies at the same time as they touched the mannequin.
"...it was evident that the participants had felt the mannequin's body
to be their own body," they wrote.
Finally, they tried a full body swap between two volunteers and it worked.
The illusion only goes so far. The researchers said they could not
fool their volunteers into thinking they were a box, for example.
(Reporting by Maggie Fox; Editing by Julie Steenhuysen)