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Chapter 6. Experimental Validations - Social Phobia 6.3.2 Experimental Protocol All subjects first started with a pre-treatment, individual, eye-tracking session. We first explained them how the system worked and that we were going to analyze the way they used their eyes in a public speaking situation. The phobic subjects were neither told which behaviors were typical of social phobia nor that their results would be compared to those of subjects from a control group. Similarly, the control group subjects were not aware that their results would be compared to those of phobic subjects. Once the session was over, we informed them all that they would be coming back for a second session, twelve weeks later. This corresponded to the end of the therapy for the phobic subjects. The five people from the social phobic group then underwent a 10 week group therapy following the Boston group protocol. Three out of the five subjects then came back for the second eye-tracking session. One of the two others started an individual therapy after two sessions with the group and the other stopped the therapy after seven sessions. We therefore decided to exclude them from the second eye-tracking session. Likewise, we only included the second set of results of the three first subjects from the control group into the study in order for their number to correspond to the phobic subjects’. 6.3.2.1 Pre-treatment Eye-tracking We first equipped the subjects with the eye-tracker and seated them in front of the large back-projection screen. They then went through the calibration process and a phase of accommodation to the equipment. This accommodation phase was a kind of game, during which we asked them to write their name on the screen with their tracked eye. This was done also in order to make them feel more at ease and relaxed. We then asked them to do a public speaking exercise in front of two different VR scenes, during which their eye movements were recorded. The conditions and discussion topics were kept the same for each subject. The first of these VEs, depicted on the middle left of Figure 3.1, was a single person in a bar. The second, shown on the bottom left of Figure 3.1, reproduced an auditorium environment with approximately <strong>20</strong> characters. As for the previous experiment, in order to avoid breaks in presence and to enhance interaction, the discussions were not lead by the therapist. Instead, they were lead by the main character in each of the two scenes. We did this by triggering pre-recorded sentences and thus simulating the virtual character’s speech. For each of these scenes, we asked the subjects to talk for a couple of minutes on a given theme. We tracked the subjects’ eyes during these exercises in order to analyze their visual behaviors. In this first phase, we analyzed the collected data in order to see if there was a noticeable difference in behavior between the phobic subjects and the subjects from the control group. 6.3.2.2 Group Therapy The phobic subjects then went through ten sessions of weekly therapy. These sessions were based on the Boston group protocol [Stern et al., 1999]. The subjects were asked to do presentations on given themes in front of the other members of the group. These sessions were filmed and then analyzed by each patient with the psychiatrist. Each presentation comprised a subject more personal and difficult to talk about than the previous. As an example, for the 86
6.3. Eye-tracking as Assessment and Diagnosis Tool first session, they were asked to talk about their hobbies, and for the last, about a dramatic and difficult situation they had experienced. They were then asked to repeat the exercises in their everyday life and report on the difficulties they encountered and how they dealt with them. All five subjects were asked to evaluate their progress by filling out various scales specific to social anxiety disorders, before and after treatment. These were the Liebowitz social anxiety questionnaire [Liebowitz, 1987], the SISST [Yaoetal., 1998], the BDI [Beck et al., 1961], and the Rathus Assertive Behavior Schedule (RABS) [Rathus, 1973]. This latter was used to measure assertiveness and self-esteem. 6.3.2.3 Post-treatment Eye-tracking Once the phobic subjects finished their ten weeks therapy, we asked all participants to come back for a second eye-tracking session. Three subjects from the phobic group and three from the control group went through this second session. They were exposed to the same two scenes as for the pre-treatment phase and were asked to talk about two different given themes. These differed slightly from the ones in the pre-treatment session in order to avoid repeating a previously done exercise. The goals, in this phase of the study, were the following: analyze the differences in gaze behavior between phobic subjects and non phobic ones. analyze the improvements in the phobic subjects versus control group ones. determine whether there was a habituation to the equipment. This would have been the case if we had noted visible differences in the visual behaviors of the control group subjects as well as the social phobic subjects. 6.3.3 Results First, and as expected, we have noticed an important difference in eye-contact behavior between phobic patients and non phobic subjects in the pre-treatment phase. Phobic patients demonstrated different types of visual avoidance: shutting the eyes for long lapses of time, hyperscanning, hypervigilance, and avoidance of salient facial features. Non phobic subjects, however, did not demonstrate those types of behaviors. The values used in the results are the raw data given by the eye-tracking system. However, what is interesting to us is to compare these values between phobic and non-phobic subjects as well as between pre-treatment and post-treatment phases for a same subject. 6.3.3.1 Salient Facial Feature Avoidance In the case of the auditorium scene, non phobic subjects mostly looked at the central character (the one with the white sweatshirt) but also looked at the other characters when speaking, because they were addressing the whole audience. A phobic subject prone to visual avoidance demonstrates one of two behaviors. He/she either eludes the characters or demonstrates hypervigilance [Horley et al., <strong>20</strong>03]. In the case of this first scene, there was no obvious avoidance of salient facial features from any of the subjects. However, some phobic subjects 87
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Simulating Interactions with Virtua
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3.2.4 Scripts . . . . . . . . . . .
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7.3 Experimental Protocol . . . . .
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Résumé La Réalité Virtuelle (RV
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CHAPTER 1 Introduction 1.1 Context
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1.3. Contributions in areas of dail
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1.5. Organization of this Document
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CHAPTER 2 State of the Art 2.1 Virt
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2.1. Virtual Reality Exposure Thera
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2.2. Models of Visual Attention Fig
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2.3. Motion Editing Peters and O’
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2.3. Motion Editing Figure 2.10: Bi
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Page 135 and 136: APPENDIX D Glossary Acrophobia: acr
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List of Figures LIST OF FIGURES 2.1
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List of Figures 6.3 Results to the
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Bibliography BIBLIOGRAPHY American
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Bibliography Dassault Systèmes. ht
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Bibliography Iscan. http://www.isca
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Bibliography A. Mühlberger, M.J. W
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Bibliography B.O. Rothbaum, L.F. Ho
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WHO. The ICD-10 Classification Of M
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