A virtual environment (VE) user's avatar may penetrate virtual objects. Some VE designers prevent visual interpenetration, assuming that prevention improves user experience. However, preventing visual avatar interpenetration causes a discrepancy between visual and proprioceptive cues. We investigated users' detection thresh-olds for visual interpenetration and visual-proprioceptive discrepancy and found that users are much less sensitive to visual-proprioceptive discrepancy than to visual interpenetration. We propose using this result to better deal with user penetration of virtual objects.

This paper presents an experiment investigating the impact of behavior and responsiveness on social responses to virtual humans in an immersive virtual environment (IVE). A number of responses are investigated, including presence, copresence, and two physiological responses—heart rate and electrodermal activity (EDA). Our findings suggest that increasing agents' responsiveness even on a simple level can have a significant impact on certain aspects of people's social responses to human-oid agents. Despite being aware that the agents were computer-generated, participants with higher levels of social anxiety were significantly more likely to avoid “disturbing” them. This suggests that on some level people can respond to virtual humans as social actors even in the absence of complex interaction. Responses appear to be shaped both by the agents' behaviors and by people's expectations of the technology. Participants experienced a significantly higher sense of personal contact when the agents were visually responsive to them, as opposed to static or simply moving. However, this effect diminished with experienced computer users. Our preliminary analysis of objective heart-rate data reveals an identical pattern of responses.