The Influence of Virtual Agent Visibility in Virtual Reality Cognitive Training

For avatars - virtual bodys controlled by a human - an established visualization is to display incomplete visualizations, e.g. only head and torso. However, the preference for the body visibility of intelligent virtual agents (IVAs) - fully computer generated virtual humans - may differ. Additionally, the presence of IVAs can have a psychological effect on users that are similar to that of a real human, e.g. facilitation or inhibition of cognitive performance. To investigate the connection between these two topics, we examine the effects of an IVA's level of body visibility on the users' sense of social presence and task performance in virtual reality. In a within-subject user study, 30 participants solved anagram tasks in the presence of five different levels of visibility of our IVA: voice-only, mouth-only, head-only, upper body and full body. While we could not find any differences in the task performance of the users, lower levels of visibility led to a decreased feeling of social presence. Furthermore, by using eye tracking, we found that visually rich representations were looked at for a longer amount of time, but only during the explanation of the task. Afterwards, the users did not pay much visual attention to the agent anymore. Finally, preferences of the users show that the chosen representation is dependent on some factors; most importantly, it should support the users, but not distract them from their task.