In recent times, social interactions are often conducted online in the form of social media, multi-player video games and virtual realities (VRs). In these digital environments, traditional social cues such as facial expression, hand gesture, body smell and physical contact are often absent. What are the sensory cues that support a sustained social interaction in VRs? We aim to identify the property of these sensory cues, characterize the underlying brain circuits, and understand how pathological conditions such as video game addition may arise.