The Effect of Crowds on Peripersonal Space and Interpersonal Distance in Immersive Virtual Environments.

Maintaining physical distance is a crucial aspect of social interactions in the real world. This paper investigates how people embodied in self-avatars, manage such spacing in immersive virtual environments. Specifically, we measured how interpersonal distance (IPD) and peripersonal space (PPS) were affected by a surrounding virtual crowd. We designed three crowd density conditions - no crowd, a medium crowd, and a dense crowd - where participants interacted with a virtual human. Additionally, based on the results of a questionnaire, participants were grouped into one of three groups depending on their self-reported comfort level with crowds: some found crowds relaxing, some were indifferent, and some found crowds stressful. Our findings revealed that IPD decreased as crowd density increased, regardless of the participants' groupings. However, PPS exhibited a more nuanced response, with those stressed by a crowd showing heightened sensitivity to crowd density, reflected by larger PPS boundaries, faster reaction times, and less confidence when estimating their PPS boundary. The study also identified significant interactions between crowd density and participants' comfort levels, particularly among the group stressed by a crowd, where heightened stress led to expanded personal space. These results show the critical role of social and environmental factors in shaping spatial perception and behavior in virtual environments.