The influence of body expression, group affiliation and threat proximity on interactions in virtual reality

Social threat requires fast adaptive reactions. One prominent threat-coping behavior present in both humans and other species is freezing, of which heart rate deceleration and reduced postural mobility are two key components. Previous studies mostly focused on freezing reactions in rodents, but now virtual reality offers unique possibilities for controlled and ecologically valid lab-based experiments in humans. This immersive virtual reality study examined how several understudied aspects of social threat, i.e., emotional body expressions, group affiliation, and physical distance from the potential threat, affect freezing behavior in humans. We hypothesized that freezing would be observed for approaching aggressive-looking virtual characters and for virtual characters situated in close proximity. Furthermore, we predicted an enhanced freezing response for approaching, aggressive outgroup members. As expected, reduced heart rate and postural mobility were observed in participants when they faced aggressive-looking and proximal virtual characters. Freezing was also observed for ingroup aggression, specifically when participants were embodied in a black-skinned virtual body and faced black-skinned aggressive and proximal virtual characters. Our results provide novel evidence on the social factors that elicit freezing behavior in humans. Importantly, this evidence is based on a highly ecological virtual reality paradigm that enables people to experience a threatening scenario “as if” it was actually happening to them.