Humans experience social interactions partly through nonverbal communication, including proxemic behaviors and haptic sensations. Body language, facial expressions, personal spaces, and social touch are multiple factors influencing how a stranger's approach is experienced. Furthermore, the rise of virtual social platforms raises concerns about virtual harassment and the perception of personal space in VR: harassment is felt much more strongly in virtual spaces, and the psychological effects can be just as severe. While most virtual platforms have a 'personal bubble' feature that keeps strangers at a distance, it does not seem to suffice: personal space violations seem influenced by more than simply distance. With this paper, we aim to further clarify the variability of personal spaces. We focus on haptic stimulation, elaborating our hypotheses on the relationship between social touch and the perception of personal spaces. Users wore a haptic compression belt and were immersed in a virtual dark alley. Virtual agents approached them while exhibiting either neutral or threatening body language. In half of all trials, as the agent advanced, the compression belt tightened around the users' torsos with three different pressures. Participants could press a response button when uncomfortable with the agent's proximity. Peripersonal space violations occurred 31% earlier on average when the agent was visibly angry and the compression belt activated. A greater tightening pressure also slightly increased the personal sphere radius by up to 13%. Overall, our results are consistent with previous works on peripersonal spaces. They help further define our relationship to personal space boundaries and encourage using haptic devices during simulated social interactions in VR.

In this paper, we study how thermal haptic feedback can influence social interactions in virtual environments, with an emphasis on persuasion, focus, co-presence, and friendliness. Physical and social warmth have been repeatedly linked in psychological literature, which allows for speculations on the effect of thermal haptics on virtual social interactions. To that effect, we conducted a study on thermal feedback during simulated social interactions with a virtual agent. We tested three conditions: warm, cool, and neutral. Results showed that warm feedback positively influenced users’ perception of the agent and significantly enhanced persuasion and thermal comfort. Multiple users reported the agent feeling less ‘robotic’ and more ‘human’ during the warm condition. Moreover, multiple studies have previously shown the potential of vibrotactile feedback for social interactions. A second study thus evaluated the combination of warmth and vibrations for social interactions. The study included the same protocol and three similar conditions: warmth, vibrations, and warm vibrations. Warmth was perceived as more friendly, while warm vibrations heightened the agent’s virtual presence and persuasion. These results encourage the study of thermal haptics to support positive social interactions. Moreover, they suggest that some haptic feedback are more suited to certain types of social interactions and communication than others.