Larry F. Hodges

Virtual reality exposure in the treatment of social anxiety

Virtual reality as a medium for exposure therapy in the treatment of social anxiety was utilized in a private-practice setting for two different courses of individual treatment: weekly psychotherapy and a 3-day intensive course of therapy. Participants met diagnostic criteria for social phobia with prominent public speaking fears, and completed self-report questionnaires at pretreatment and posttreatment. During exposure therapy, participants were presented with a virtual audience, consisting of video of actual people embedded within a virtual classroom environment. Results indicated that treatment was successful as measured by completion of a behavioral avoidance test at the end of treatment, decreases in self-reported measures of public speaking anxiety comparable to controlled clinical outcome trials for social phobia, and qualitative feedback. Follow-up data, obtained from 1 participant, showed continued improvement after therapy was completed. These preliminary findings suggest that virtual reality may be a useful tool for exposure therapy within a comprehensive treatment of social anxiety.

Social responses to virtual humans: implications for future interface design

Do human-human social interactions carry over to human-virtual human social interactions? How does this affect future interface designers? We replicated classical tests of social influence known as the social facilitation and inhibition effects. Social facilitation/inhibition theory states that when in the presence of others, people perform simple tasks better and complex tasks worse. Participants were randomly assigned to perform both simple and complex tasks alone and in the presence of either a real human, a projected virtual human, or a virtual human in a head-mounted display. Our results showed participants were inhibited by the presence of others, whether real or virtual. That is, participants performed worse on the complex task, both in terms of percent correct and reaction times, when in the presence of others than when alone. Social facilitation did not occur with the real or virtual human. We discuss these results and their implications for future interface designers.

Can a virtual cat persuade you?: the role of gender and realism in speaker persuasiveness

This study examines the roles of gender and visual realism in the persuasiveness of speakers. Participants were presented with a persuasive passage delivered by a male or female person, virtual human, or virtual character. They were then assessed on attitude change and their ratings of the argument, message, and speaker. The results indicated that the virtual speakers were as effective at changing attitudes as real people. Male participants were more persuaded when the speaker was female than when the speaker was male, whereas female participants were more persuaded when the speaker was male than when the speaker was female. Cross gender interactions occurred across all conditions, suggesting that some of the gender stereotypes that occur with people may carry over to interaction with virtual characters. Ratings of the perceptions of the speaker were more favorable for virtual speakers than for human speakers. We discuss the application of these findings in the design of persuasive human computer interfaces.

Evaluation of the Cognitive Effects of Travel Technique in Complex Real and Virtual Environments

We report a series of experiments conducted to investigate the effects of travel technique on information gathering and cognition in complex virtual environments. In the first experiment, participants completed a non-branching multilevel 3D maze at their own pace using either real walking or one of two virtual travel techniques. In the second experiment, we constructed a real-world maze with branching pathways and modeled an identical virtual environment. Participants explored either the real or virtual maze for a predetermined amount of time using real walking or a virtual travel technique. Our results across experiments suggest that for complex environments requiring a large number of turns, virtual travel is an acceptable substitute for real walking if the goal of the application involves learning or reasoning based on information presented in the virtual world. However, for applications that require fast, efficient navigation or travel that closely resembles real-world behavior, real walking has advantages over common joystick-based virtual travel techniques.

Can Immersive Virtual Humans Teach Social Conversational Protocols

We investigated the effects of using immersive virtual humans to teach users social conversational verbal and non-verbal protocols in south Indian culture. The study was conducted using a between-subjects experimental design, and compared instruction and interactive feedback from immersive virtual humans against instruction based on a written study guide with illustrations of the social protocols. Participants were then tested on how well they learned the social conversational protocols by exercising the social conventions in front of videos of real people. The results of our study suggest that participants who trained with the virtual humans performed significantly better than the participants who studied from literature.

Exploring individual differences in raybased selection: strategies and traits

User-centered design is often performed without regard to individual user differences in aptitude and experience. The methodology of this study is an anthropological and observational approach observing users performing a selection task using common virtual environment raybased techniques and analyzes the interaction through psychology aptitude tests, questionnaires and observation. The results of this study show the approach yields useful information about users even in a simple task. The study indicates correlations between performance and aptitude test and user behavior performed to overcome difficulties in the task.

Balance NAVE: a virtual reality facility for research and rehabilitation of balance disorders

We are currently developing an immersive virtual environment display for research into the rehabilitation of balance disorders, called the Balance NAVE (BNAVE). Using this system, the therapist can create varying degrees of sensory conflict and congruence in persons with balance disorders. With the capability of changing visual scenes based on the needs of the therapist, the BNAVE is a promising tool for rehabilitation. The system uses four PCs, three stereoscopic projectors, and three rear-projected screens, which surround the patients entire horizontal field of view. The BNAVE can accommodate many types of sensors and actuators for a wide range of experiments.

Simulator sickness when performing gaze shifts within a wide field of view optic flow environment: preliminary evidence for using virtual reality in vestibular rehabilitation.

BackgroundWide field of view virtual environments offer some unique features that may be beneficial for use in vestibular rehabilitation. For one, optic flow information extracted from the periphery may be critical for recalibrating the sensory processes used by people with vestibular disorders. However, wide FOV devices also have been found to result in greater simulator sickness. Before a wide FOV device can be used in a clinical setting, its safety must be demonstrated.MethodsSymptoms of simulator sickness were recorded by 9 healthy adult subjects after they performed gaze shifting tasks to locate targets superimposed on an optic flow background. Subjects performed 8 trials of gaze shifting on each of the six separate visits.ResultsThe incidence of symptoms of simulator sickness while subjects performed gaze shifts in an optic flow environment was lower than the average reported incidence for flight simulators. The incidence was greater during the first visit compared with subsequent visits. Furthermore, the incidence showed an increasing trend over the 8 trials.ConclusionThe performance of head unrestrained gaze shifts in a wide FOV optic flow environment is tolerated well by healthy subjects. This finding provides rationale for testing these environments in people with vestibular disorders, and supports the concept of using wide FOV virtual reality for vestibular rehabilitation.

Two Handed Selection Techniques for Volumetric Data

We developed three distinct two-handed selection techniques for volumetric data visualizations that use splat-based rendering. Two techniques are bimanual asymmetric, where each hand has a different task. One technique is bimanual symmetric, where each hand has the same task. These techniques were then evaluated based on accuracy, completion times, TLX workload assessment, overall comfort and fatigue, ease of use, and ease of learning. Our results suggest that the bimanual asymmetric selection techniques are best used when performing gross selection for potentially long periods of time and for cognitively demanding tasks. However when optimum accuracy is needed, the bimanual symmetric technique was best for selection

Comparison of Travel Techniques in a Complex, Multi-Level 3D Environment

This paper reports on a study that compares three different methods of travel in a complex, multi-level virtual environment using a between-subjects design. A real walking travel technique was compared to two common virtual travel techniques. Participants explored a two-story 3D maze at their own pace and completed four post-tests requiring them to remember different aspects of the environment. Testing tasks included recall of objects from the environment, recognition of objects present and not present, sketching of maps, and placing objects on a map. We also analyzed task completion time and collision data captured during the experiment session. Participants that utilized the real walking technique were able to place more objects correctly on a map, completed the maze faster, and experienced fewer collisions with the environment. While none of the conditions outperformed each other on any other tests, our results indicate that for tasks involving the naive exploration of a complex, multi-level 3D environment, the real walking technique supports a more efficient exploration than common virtual travel techniques. While there was a consistent trend of better performance on our measures for the real walking technique, it is not clear from our data that the benefits of real walking in these types of environments always justify the cost and space trade-offs of maintaining a wide-area tracking system