POSTECH’s (Pohang University of Science and Technology) Professor Inseok Hwang’s team has developed ArithMotion, a mobile virtual reality (VR) system that enables anyone to express a wide range of avatar motions with ease. Using simple arithmetic-like controls, users can scale an avatar’s motion up or down and reverse it into an opposite response, allowing more natural nonverbal communication without expensive equipment.
On social VR platforms such as VRChat, people communicate through their avatars’ movements, facial expressions, and gestures. In particular, bodily motions are a key channel for building emotional connections between users and enhancing immersion and a sense of agency. However, because most users do not have access to expensive full-body tracking equipment, they are often limited to repeating preset motions—making natural, spontaneous communication difficult.
In this study, the team focused on a natural form of social behavior known as “peer relativity”—the way people instinctively mirror others’ actions or respond in the opposite direction. They brought this phenomenon directly into VR avatars: when another player celebrates a win with an excited gesture, your avatar can respond in the same way, while threatening behavior from others can trigger a more defensive, protective reaction—preserving a more lifelike sense of social realism.





