[MUSIC] Why do we need presence or feeling of immersion in VR at all? Why is this useful? >> Well, the answer is you don't, it just depends on what it is you're trying to do. So for example, I watch a lot of movies, and movies are really good, and they arouse your emotions, and they present something in a different way. They give you ways to think about something that you haven't experienced in any other way, and they're fantastic form, or I read books, and they have again a different way of giving you information about something, or manipulating your emotions, and so on. But something they don't give you, which virtual reality does give you, is I'm part of this. I'm here, I'm in it. So let's an example, one of the biggest uses of virtual reality in the past 25 years is been in the area of clinical psychology. So for example, let's take a relatively straightforward anxiety that many people have, which is fear of heights. So, how clinical psychologists typically deal with people with fear of heights is that they gradually expose them to the thing they fear. So they might start off showing you a picture of a height, and then put you on a little height, and then a bit more height, and a bit more height, and ultimately over many, many sessions, gradually you learn to control your anxiety in greater and greater heights, and this method works as other methods, but they all involve this kind of exposure aspect. Now suppose instead of taking you to real heights you show someone a movie of heights. It is not going to work, because though by projection onto somebody else you might get some kind of level of anxiety. It's not anxiety about you personally. It's not you are on the height. Now if you put someone in virtual reality on a height, because of this illusion of being in the place, you do have a strong sense, yourself, of being on the height. So you can generate very similar levels of anxiety to being in a virtual height as being on a real height, and therefore, the clinical psychologists, instead of taking people, or asking them to go to real heights as part of their exposure therapy, they can take them in virtual reality, in their office, to virtual heights. So the immersion, which leads to this illusion of presence, this illusion of being in the place is really important, because it involves you in the sense of I am here, this is happening to me, therefore, I get the appropriate anxiety and therefore, it can be used in a therapeutic context. This is one example. >> Very interesting, because I have a bit of vertigo myself, and I remember being in one of the VR applications, or experience, with Oculus, and I really had a difficult time actually keeping my body up straight, because I really was like, where is actually up straight I can't actually find it. I think that's really is an overwhelming experience that I was exposing myself to, and if I kind of really do it, with the help of a therapist, maybe one day I'll become less fear of heights. >> But let's put this back in the context. So, the sensory motor contingencies, are like in reality you look down, you see the height, you look down you see in stereo, and so on. You've moved your head down, like you would in reality, and the vision that you've seen shows you vision of a height. Now the next thing is the brain has to decide what's going on here, where am I? Well I've looked down, there's a height there, I'm on a height, my God, and then people will typically step back from that height because, even though they know, this is really important, even though they know it's not true it doesn't matter because there's some parts of the brain that doesn't know about virtual reality. The brain, at any moment of time, has to make a very fast decision. What's going on here and what should I do? And all the evidence is saying I'm on a height, get out the way. Afterwards you say to yourself, yeah I know, but I'm not really there. But it's too late, you've already done it. You already have the anxiety. >> Yeah it just shows how much we're not actually in charge of our own actions, and reactions, and feelings. >> Yeah. [MUSIC]
