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Changing Self Perspective with VR

Residual self image was a concept popularised by the Matrix films, which entered popular culture. The idea that you are always the same person when interacting in ego-space. That is to say, even without your own physical body being in your vision, your mind conjures a new duplicate up that still looks like, talks like, feels and moves like you.

The theory it seems, was half-right, but it was also very, very wrong. You conjure up a replacement body alright, but its not necessarily the same you as you started with. Put into another's form, you react and integrate with that body, treating it, as you.

Experiments at the end of 2008 at the Swedish medical university Karolinska Institutet (KI) by cognitive neuroscientists have opened up quite a can of worms with regard to the meaning of identity. Specifically relating to simstim and to virtual reality experiences. Several experiments conducted by Valeria Petkova, and Henrik Ehrsson have been very successful at making subjects perceive the bodies of mannequins and other people as their own body, and identifying with it as such.

?Joe opens the sauna-cabinet like a big clamshell standing on end with a lot of funny business inside. Our girl shucks her shift and walks into it bare, totally unembarrassed. eager.

She settles in face-forward, butting jacks into sockets. Joe closes it carefully onto her humpback. Clunk. She can?t see in there, or hear, or move. She hates this minute. But she loves what comes next!

Joe?s at his console and the lights on the other side of the glass wall come up. A room is on the other side, all fluff and kicky bits, a girly bedroom. In the bed is a small mound of silk with a rope of yellow hair hanging out. The sheet stirs and gets whammed back flat.

Sitting up in the bed is the darlingest girl you?ve EVER seen. She quivers ? porno for angels. She sticks both her little arms straight up, flips her hair, looks around full of sleepy pazazz. Then she can?t resist rubbing her hands down over her minibreasts and belly. Because, you see, it?s the godawful P. Burke who is sitting there hugging her perfect girl-body, looking at you out of delighted eyes.?

Source: The Girl Who Was Plugged In

They achieved this through perspective manipulation, placing sensory hardware designed for augmented reality, on the being of the other person, and re-routing volunteer's senses throuth it. They saw with the other person's eyes, as far as their brains could tell. Likewise, heard with their ears, and felt with their muscles, at least as far as their brains could tell. This was enough to make the brain believe they were that other person. The perspective shift was strong enough, that they could shake hands with their actual body, and not break the illusion even whilst looking it in the eye.

The strength of the illusion was confirmed when the subjects' bodies showed signs of extreme stress when a knife was held to the body they perceived to be theirs, and threatening gestures made - even when that body was most definitely not the victim's own. The stressful reaction was more in kin with a personal survival reaction than an empathic reaction.

The fundamental importance of these experiments could not possibly be overstated.

It seems the experience of 'being' a particular body, is adaptive, even throughout adulthood, and appears to stem from the point of self-focus - the localisation of self within a given environment.

In other words, you can adapt to being in any body, and treat it as if it always was you, within a short space of time.

The Experiments


The experiments used, have much in common with the Rubber Hand Illusion technique which has been observed before.

Rubber hand studies were first developed for use in VR by the non-profit science society American Association for the Advancement of Science, (or AAAS for short,) in 2007. It had been noted earlier, in the case of prosthetic hands.

The illusion occurs when a person's unseen hand is stroked synchronously with a visible fake hand, and then the person is asked to point to her or his own hand. Subjects invariably err in the direction of the fake hand, attributing it to their own bodies.

Top: Subject dons immersive HMD that subsumes their visual and auditory senses, replacing the natural input with cameras and microphones on the dummy.

Bottom: The dummy is touched with a pen within the subject's altered self view, at the same time and place as their physical body is also touched.

Image credit: PLoS ONE

This time, the experiments were much more involved than just a hand. An entire false body was used. In the first set of experiments, two fake, fake bodies were used as housing for the subject's sense of self. A synchronous one, which corresponded roughly to the form of the human body, and an asynchronous one which did not.

The synchronous form was a plastic display mannequin, whilst the asynchronous was a green plastic crate.

In both cases, the subjects donned a HMD (head mounted display unit) intended to completely block out their natural sense of sight, and of hearing. Everything they saw and heard was directed through the LCD screens of the HMD or heard through its speakers.

The HMD was paired with cameras affixed to the dummy, over the position of the dummy eyes, whilst the speakers were paired with microphones over the dummy ears. Each camera and microphone talked to the appropriate one of the HMD's screens or speakers, such that the individual gained a sense of perspective of seeing and hearing through the dummy eyes and ears.

To complete the illusion, the subject and mannequin stood in the same position, both looking down. A researcher then pressed the dummy's abdomen with a pen, within the camera's field of view. At the exact same time, she pressed the subject's abdomen with another pen, out of camera view.

The net result was the subject saw the pen press against 'their' body, and at the same time, felt it in that location with their muscles. As with rubber hand illusion before it, this new rubber body illusion worked, and in all cases, the subjects found themselves thinking of the mannequin body as theirs.

The effect was much less pronounced although still evident to a degree when the box was used instead of a mannequin, perhaps due to the total alienness of such a body-form.

The pen-stimulation continued for two minutes with each subject, and a variety of positions and strokes utilised, each time exactly the same area, pressure and pattern on the faux and actual body. At the end of the session, the subjects each completed a questionnaire on their experiences, the results of which are shown below:

The Questionnaire Results: Source: PLoS ONE

An interesting thing to note immediately is that there is no sensation of actually being the false body when it is just too different from a recognisable human form. Echoes of the uncanny valley in visualisation, if its not nearly realistic enough to approach what your brain understands as human-like, no synthesis is achieved. However, if the form looks at least vaguely human, with hands, feet, torso, all in the right places relatively, that is enough for a powerful effect of presence.

Likewise the feeling of the pen against the avatar being pen against self, is nearly overwhelming when it looks like an actual body.

No-one felt naked, because of course they could still feel their clothes against their actual body, and it is the sensory data the body recieves which drives this.

Swapping body with another person


Being poked with a pen is all very well, but for a full SimStim or VR immersion experience, rather more sensation is necessary. What happens if the body moves. Does the perception of it still being you hold up, when it is moving about?

The hope was to find that perception of being localised in another human's body during the performance of various tasks would hold up, but there was no way without experimentation of knowing if it would.

Like with the mannequin, a researcher wore the camera/microphone rig, whilst each subject wore the linked HMD. The subjects could see their own body from the perspective of the researcher, standing opposite. They extended their right arm, took hold of the researcher's hand and shook it. Their own physical body providing the motion, and the sensation of hand shaking, which they visually saw from the perspective of the owner of the hand being shook.

Shaking Hands: Source: PLoS ONE

The arrangement allowed the subjects to view and recognise their own physical body from a distance. Yet, as before, the visual, and auditory centre of self, along with the feeling of having an arm shook, wit the visual imagery putting that hand exactly where it should be, conspired to engender a feeling of shaking a familiar friend's hand, as opposed to their own body's.

In addition, the effect worked regardless of differences in skin colour, gender, height and age between researcher and subject. Gender and racial identification factors were found to be unimportant when perceiving a body as one's own.


The sheer scope of this discovery, like the similar work done before it, slowly edging up in totality of sensation, is one of those times when even a VR vety is stunned at the implications.

Yes, we now have empirical proof that when enough sensory modality is applied to a faux body, the person's sense of self shifts to being in that body, in much the same way as the cyberpunk films and movies have predicted.

It is also immensely interesting that there is indeed a similar line of acceptance to potential physical bodies, as there is for visual memes. The uncanny valley has a counterpart - the less familiar a body is, the less likely the mind is to naturally bond with it. A completely different human body will work, as will a display feature to a markedly lesser extent. However, a table, a box, a chair. These things will not.

When VR sensory modality advances enough to be able to place this research into public worlds, we will experience interesting parallels that could not be monitored here. A centaur is not like a table or box, yet it is not like a human form either. At least not entirely. Will the part that is like the human form be enough to counteract that which is not? It is this researcher's considered opinion that it will fall somewhere in the valley. Accepted, but not, and perhaps, just perhaps, taking time to become accustomed to.

Likewise, new hope is breathed into SimStim, that concept of taking a piggy-back ride through the senses of another person. If they are ever developed, something with is fairly likely, a neural-feedback recording device such as that used in novels such as Necromancer or films such as Strange Days, will in actuality, work as advertised, with the viewer's brain automatically bonding a sense of self with the sensory data supplied.

In fact, when shownm the research, Kynan Eng, a researcher in neuroinformatics at the University of Zurich, Switzerland, stated in professional opinion that after a stimulus of an appropriate kind and duration, people could "produce measurable ownership responses to any virtual or real object, such as an often-used tool".

The Race Card

More profoundly perhaps for the general populace, is the interesting tack this opens up on race relations. As experiments to date have shown, the brain adapts regardless of the skin colour of the body it perceives as its own. If you were for example, take someone who is not African-American but who has an unreasoning bigotry towards African-Americans, and with the aid of a self-perception relocation system such as this, you can have them look into a mirror, move choreographed about a room, perhaps look at others, through what their brain is continually subconsciously telling them, is their own African-American physical body.

The effect would require a greater degree of mimicry, born out of increased kinaesthetic sensory feedback most likely - ability of volunteer to move their body in mimicry to how the subject moved theirs. Alternatives include robotic substitute bodies and highly realistic mocap avatars of course.

Profound Disability goes Bye bye

At the start of this report, we had a quote from the story "The girl who was plugged in" the 1974 book by by James Tiptree, Jr, a pen name for psychologist Alice Sheldon.

In it, P Burke, a severely disfigured young lady for whom normal function in society was all but impossible, was plugged into life support, and her brainstem attached to a computer which mediated two way communication for a stunningly beautiful waldo body, a body with no mind of its own, but which became P Burke in every way that mattered.

The technology level demonstrated in that story is far beyond what we have currently, but, combined with the research outlined here, the exact same setup could be used with a robot body, and a sense of self shifted into it, no differently than with the mannequin. Able to see and hear, talk, move via the robot, individuals too badly disfigured or disabled to achieve all their hopes and dreams due to the visual prejudices of others, could be granted a level of normal life above what is currently available.

?Now let?s get one thing clear. P. Burke does not feel her brain is in the next room, she feels it?s in that sweet little body. When you wash your hands, do you feel the water is running on your brain? Of course not. You feel the water on your hand, although the ?feeling? is actually a potential-pattern flickering over the electrochemical jelly between your ears. And it?s delivered there via the long circuits from your hands. Just so, P. Burke?s brain in the cabinet feels the water on her hands in the bathroom. The fact that the signals have jumped across space on the way in makes no difference at all. If you want the jargon, it?s known as eccentric projection or sensory reference and you?ve done it all your life. Clear??

Source: The Girl Who Was Plugged In

Telepresence with full Presence

In the same way as it works for disability, telepresence takes on a whole new meaning when you can guarantee that the interface you are using to put yourself in a remote location, will feel like it is you there. It opens up the possibility for teams of robot waldoes used by educational institutes, to enable students who cannot physically attend, to gain the classroom presence that being in a classroom allows. Lecturers from across the globe to feel like they are standing before the class. Doctors, on-scene disaster experts, commanders who gain first hand perspectives of the battlefields. Robots soldiers whose operators see and hear like it's their own body.

We know now, that the technology works, that the brain processes data by perceived location, not by physical. In a very real sense, one of the greatest psychological humps, is behind us, and we know the technology will function as we hoped. Now, we 'just' have to bring the actual interaction and synchronisation technologies to be.

Final Notes

This work was supported by grants from the Swedish Medical Research Council, the Swedish Foundation for Strategic Research, the Human Frontier Science Programme, and the European Research Council.

None of these bodies None of these bodies had a role in study design, data collection and analysis, decision to publish, or preparation of the original paper, available below.


If I Were You: Perceptual Illusion of Body Swapping - PLoS One original paper

Scientists produce illusion of body-swapping

Swapping your body becomes a virtual reality


Concept of Self - Exposed? (AAAS Rubber Hand Studies)

Virtual Dictionary: Rubber Hand Illusion


Wikipedia: The Girl Who Was Plugged In

The Girl Who Was Plugged In: Selected Quotes:

1, 2, 3, 4, 5, 6

Staff Comments


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