The “mediated sense of presence” is a technology-induced illusion of being present in one (simulated) place when one is actually present in another (physical) place. Typically experienced in virtual worlds, mediated presence is generated by different technological, cognitive, and emotional factors. The aim of this study was to test how to optimise the virtual experience by manipulating some of these factors. Specifically, we tested if an immersive technology and/or a meaningful narrative context influence the users' sense of presence, providing a more compelling experience than a non-immersive and non-contextualized virtual space. Eighty-four students, randomly divided into four groups, were asked to find a blood container inside a virtual hospital in an immersive or non-immersive condition and with or without an emotionally related narrative. Two presence questionnaires and heart-rate variations were used to measure the effects of the four conditions on the users' sense of presence. Results showed a significant effect of narrative, F(8, 73) = 30.346, p < 0.001, and level of immersion, F (8, 73) = 10.913, p < 0.001, and a significant interaction between narrative and immersion, F(8, 73) = 2.062, p = 0.05, both on the presence questionnaires and on the heart-rate variations. Moreover, considering the factors immersion (I) and narrative (N) together, we found that the I–N condition generated the highest level of presence. We argue that both immersion and narrative are important in creating an effective virtual reality experience because they contribute differently to increasing the sense of presence. Immersion increases the place illusion, while the narrative contributes to generating an emotional response and strengthening the subjects' sense of inner presence.

A Second Life for eHealth: Prospects for the Use of 3-D Virtual Worlds in Clinical Psychology

Many researchers and clinicians have proposed using virtual reality (VR) in adjunct to in vivo exposure therapy to provide an innovative form of exposure to patients suffering from different psychological disorders. The rationale behind the 'virtual approach' is that real and virtual exposures elicit a comparable emotional reaction in subjects, even if, to date, there are no experimental data that directly compare these two conditions. To test whether virtual stimuli are as effective as real stimuli, and more effective than photographs in the anxiety induction process, we tested the emotional reactions to real food (RF), virtual reality (VR) food and photographs (PH) of food in two samples of patients affected, respectively, by anorexia (AN) and bulimia nervosa (BN) compared to a group of healthy subjects. The two main hypotheses were the following: (a) the virtual exposure elicits emotional responses comparable to those produced by the real exposure; (b) the sense of presence induced by the VR immersion makes the virtual experience more ecological, and consequently more effective than static pictures in producing emotional responses in humans.

One of the most effective treatments of anxiety is exposure therapy: a person is exposed to specific feared situations or objects that trigger anxiety. This exposure process may be done through actual exposure, with visualization, by imagination or using virtual reality (VR), that provides users with computer simulated environments with and within which they can interact. VR is made possible by the capability of computers to synthesize a 3D graphical environment from numerical data. Furthermore, because input devices sense the subject's reactions and motions, the computer can modify the synthetic environment accordingly, creating the illusion of interacting with, and thus being immersed within the environment. Starting from 1995, different experimental studies have been conducted in order to investigate the effect of VR exposure in the treatment of subclinical fears and anxiety disorders. This review will discuss their outcome and provide guidelines for the use of VR exposure for the treatment of anxious patients.