Hug Synchronization Enhances Social Presence and Prosociality in Computer-Mediated Communication

There is growing interest in communication artifacts that allow users to connect with others while supporting the emotional well-being that often arises from social interactions. Social presence is central in digital interactions, as it fosters a sense of “being together,” which is essential for affective communication, collaboration, and relationship-building in computer-mediated environments. This study explores the impact of behavioral synchronization through HugBits, a cushion -shaped device designed for remote hug-based interaction, on both perceived social presence and users' prosociality. We conducted two experiments: (1) testing whether hug synchronization increased perceived social presence, and (2) assessing whether synchronization influenced cooperative decision-making in a Prisoner's Dilemma game. In both experiments, the occurrence of behavioral synchronization (i.e., hugging) was controlled by having participants interact with a virtual agent that was designed to probabilistically promote or avoid synchronized hugs. Results show that more synchronized interactions significantly enhanced perceived social presence and promoted cooperative behavior. These findings highlight behavioral synchronization as a promising design strategy for affective communication technologies and provide concrete implications for integrating emotional and behavioral outcomes in computer-mediated communication research.