Additional information is available at the end of the chapter http://dx.doi.org/10.5772/46411
IntroductionVirtual Reality (VR) has been usually described as a collection of technological devices: a computer capable of interactive 3D visualization, a head-mounted display and data gloves equipped with one or more position trackers [1]. The trackers sense the position and orientation of the user and report that information to the computer which updates the images for display in real time.However, in the behavioral sciences, VR is usually described as [2] "an advanced form of human-computer interface that allows the user to interact with and become immersed in a computer-generated environment in a naturalistic fashion" (p. 82).This feature transforms VR in an "empowering environment", a special, sheltered setting where patients can start to explore and act without feeling of being threatened [3]. Nothing the patients fear can "really" happen to them in VR. With such assurance, they can freely explore, experiment, and experience feelings and/or thoughts. VR thus becomes a very useful intermediate step between the therapist's office and the real world [4; 5]. In other words, the key feature of VR for clinical goals is that it offers an effective support to the activity of the subject by activating the feeling of "presence", the feeling of being inside the virtual world.But what is presence? In this chapter we will use the following three research outcomes emerging from the recent work of cognitive sciences to build a cognitive theory of presence:1. Cognitive processes can be either rational or intuitive: we will argue that presence is an intuitive feeling that is the outcome of an experience-based metacognitive judgment; 2. Skills become intuitive when our brain is able to simulate their outcome: we will show argue that presence monitors intuitively our activity processes using embodied simulations;Virtual Reality in Psychological, Medical and Pedagogical Applications 4 3. Space is perceived in terms of the actions we could take towards them: we will argue that the feeling of Presence in a real or virtual space is directly correlated to the outcome of the actions the subject can enact in it;In sum, the feeling of presence can be described as the product of an intuitive experiencebased metacognitive judgment related to the enaction of our intentions: We are present in an environment -real and/or synthetic -when we are able, inside it, to intuitively transform our intentions in actions. The consequences of this claim for the development of clinical virtual environments are presented and discussed.
Virtual reality: From technology to experienceSince 1986, when Jaron Lamier used the term for the first time, VR has been usually described as a collection of technological devices. In general, a VR system is the combination of the hardware and software that enables developers to create VR applications [6]. The hardware components receive input from user-controlled devices and convey multi-sensory output to create the illusion...