Let's Face It: Influence of Facial Expressions on Social Presence in Collaborative Virtual Reality

As the world becomes more interconnected, physical separation between people increases. Existing collaborative Virtual Reality (VR) applications, designed to bridge this distance, are not yet sufficient in providing a sense of social connection comparable to face-to-face interactions. Possible reasons are the limited multimodality of VR systems and the lack of non-verbal cues in VR avatars. We systematically investigated how facial expressions influence Social Presence in two collaborative VR tasks. We explored four types of facial expressions: eyes and mouth movements, their combination, and no expressions, for two types of explanations: verbal and graphical. To examine how these expressions influence Social Presence, we conducted a controlled VR experiment (N = 48), in which participants had to explain a specific term to their counterpart. Our results demonstrate that eye and mouth movements positively influence Social Presence in VR. Particularly, combining verbal explanations and eye movements induces the highest feeling of co-presence.