John F. Kennedy Top Minds: Professor David Peterzell, PhD

The Psychology of Virtual Reality 2.0

Professor David Peterzell teaches in the College of Psychology and Clinical Psychology at JFKU. In this video, Professor David discusses the concept of identifying the difference between virtual reality and a person’s internal representation that is mentally constructed. Visit to today to learn more about our programs.


If you’re interested in virtual reality in the self I think one of the things that’s really important is that we, most people walk around with this idea that this is, it’s na??ve realism. We think that, well, I see that table. I’m seeing it physically as it is. I’m seeing the physical world as it is. But if you think about it, if I look at you, what’s happening? Light’s coming down. It’s hitting you. Some of it it’s being absorbed into your skin. And some of it’s being spit out in all directions. And some of that light hits my eye and goes to the back of the eye and forms an image of you. So am I seeing you or am I seeing the image of you on the back of my eye?

At that point most people can realize that I’m not actually seeing you. I’m getting the image on the back of my eye, and I have to infer something about you based on what’s on the back of my eye, and I have to disentangle that from all sorts of other things, like the lights in the room, sounds in the room, everything else and somehow make inferences about you based on this thing that’s proximal. Not you distally. And so everything about you is lost and all I have is a pattern of light on my eyes that I have to reconstruct.

At that point most people can realize that this na??ve realism idea is wrong. We live in a virtual world that’s constructed and it’s informed by what’s coming in from the outside world. But it’s not the physical world. It’s an internal representation or an interface, and that’s what we’re operating on.

There are certain types of people in this world who really get a personal dose of it. If you lose your arm for instance, you lose your arm and you still feel the phantom. You still feel the limb. I’ve dealt with a lot of patients who are really surprised by this. This was Ramachandran’s great insight, was that, or one of them, is that he started to study phantom limb pain and he started realizing that you can actually play games on this internal representation. Because what happens is you lose your limb and you still feel it. You still feel your hand out in space even though it’s gone.

One of the things that means is that well, okay, the way we represent ourselves, our bodies is its own construction. Even though the physical thing is gone, we still have our constructed hand and that’s what we feel. In fact, that’s what we’ve been feeling all along. We’ve projected this hand into space based on something in us.

Right. The thing is you realize that you’re living in a virtual world and that what we construct as ourselves, this physical, mental, and emotional body is itself a construction. Of course if you lose your limb and you still feel something that’s no longer there physically, then you can realize this at a really personal level.

What you can do, and this is Ramachandran’s great insight and I’ve done a lot of research on it, is that you can actually trick the body into thinking that that arm is still there and play with it. A lot of people who lose limbs for instance, they still have this internal virtual representation of the limb that they still feel.

What you do with a simple mirror, I’m going to get the mirror. This is the great notion of Ramachandran’s mirror. The idea is that, okay, an amputee for instance has one arm intact but the other arm is missing. But you can create a simple illusion in virtual reality using a simple mirror. What you do is you, I have my hand in here. Now imagine my other arm is missing. But if I look into the mirror, all of a sudden I can see it. There it is. It’s actually shown up as a reflection. So it’s as if I’m moving both arms. It’s like I’m conducting the orchestra with my intact arm and my missing arm at the same time.

What happens to some people, some amputees is the arm gets animated as if never before, the missing arm. They look down and they see their missing arm moving. And what happens to some people is that all the sudden this painful limb that’s been sitting there, that’s been clenching, or it’s been burning, or it won’t budge an inch, all the sudden is liberated because you can see it move. You’re telling it to move, and it’s all the sudden, it’s doing what you’re telling it to do. The phantom moves out of the painful position and for some people the pain is gone for ever.

This is something that people have been researching for the last 20 years and I’ve been fortunate to be involved in it. It’s this almost amazing finding that if you put somebody in a virtual environment, it can be as simple as a $5 mirror, they can liberate themselves from this frozen phantom because all of a sudden once again the physical body aligns with this internal virtual body that we’ve created and you can move it out of the painful position.

The explanation seems to be related to something happening in the brain, where we have body maps, we have maps of the hand that actually are on the other side of the brain, on the ipsilateral side in the motion and somatic cortices. These things literally change when you lose a limb. That real estate that was controlled by the hand is taken over by other parts of the brain. When you do something like this with the mirror, with modern brain imaging we know that what happens is that the hand basically says, “I’m back,” and it goes and it takes back over that part of the brain, or it unmasks it as it where.

It’s a remarkable fact of this virtual representation of self that it’s actually malleable. It’s not set in stone. It’s these sorts of experiments that are not only useful in terms of treating things like pain and paralysis from things like stroke, but they’re also really interested in understanding that the constructed body and the constructed self are just that, they’re constructions. We treat them as if they’re just set in stone and real, but there’s something illusory about them.

John F. Kennedy University’s Top Minds Video Series

The Top Minds series features video interviews of JFK University professors who are preeminent thinkers in cutting edge fields. From virtual reality to gender identity, housing policy to somatic psychology, these interviews feature experts speaking candidly about the work they’re best known for and make knowledge accessible and available to the public. Each installment is geared toward offering unique insight into some of the most important questions facing human society today.