Implementing multi-person interactions in Virtual Reality (VR) poses two interrelated challenges: (1) accurately capturing and rendering the kinematics of social interactions, and (2) fostering social connectedness, a key component of effective group communication. In physical settings, social connectedness is closely linked to interpersonal motor coordination. Whether similar mechanisms operate in VR, and how best to render them remains an open question. This study investigated group synchronization in VR by manipulating two key factors: visual coupling and joint commitment to synchronize, both known to influence group synchrony and social connectedness. Data from this VR experiment were compared with a previous study conducted in a real-world setting. In both contexts, visual coupling and joint commitment enhanced group synchrony and the feeling of social connectedness. However, their effects on individual kinematic features (e.g., movement frequency and amplitude) diverged between real and virtual environments, suggesting different coordination strategies were employed. These findings demonstrate that while multi-user VR can support the emergence of collective movement and foster social bonds, technical constraints, such as limited motion fidelity and restricted field of view, can shape how users adapt their movements to achieve joint action. This has important theoretical and practical implications for the design and modeling of collective motion in VR.

This poster presents an art-inspired iterative design approach applied to the definition of two experimental scenarios for movement data collection. Scenarios are inspired by warm-up exercises dancers perform to broaden group consciousness. Research focuses on the influence an expert dancer exerts on novice dancers by propagating her own movement patterns (individual motor signatures), for stimulating the emergence of a group movement pattern (group motor signature).

Research in joint action focuses on the psychological, neurological, and physical mechanisms by which humans collabo-rate with other agents, and overlaps with several domains related to human-robot interaction. The development of artificial systems that can support or emulate the requisite aspects of joint action could lead to improved human-robot team performance as well as improvements in subjective metrics (e.g., trust). This workshop highlights theoretical and technical considerations about human-robot joint action and real-time adaptation, with a particular focus on socio-motor entrainment, showing how the emulation of psychological mechanisms (e.g., emotion, intention signaling, mirroring) can lead to improved performance. We will invite speakers with backgrounds in robotics, neuroscience and psychol-ogy, as well as speakers with a focus in adjacent works, such as in human-robot coordinated dance, alignment, or synchronization. We will call for papers that utilize the theory of joint-action in an interactive human-robot context. We will also call for position papers on the application of the theory of joint action to robotics, with a heavy focus on psychological mechanisms that could potentially be emulated or adapted to a human-robot context. Participants will have the opportunity to brainstorm considerations and techniques that would be applicable to joint action inspired works through breakout sessions with the aim to lead to new and improved collaborations across fields.

Multimodal interfaces pose the challenge of dealing with the multi-ple interactive time-scales characterizing human behavior. To dothis, innovative models and time-adaptive technologies are needed,operating at multiple time-scales and adopting a multi-layered ap-proach. The first International Workshop on Multi-Scale MovementTechnologies, hosted virtually during the 22nd ACM InternationalConference on Multimodal Interaction, is aimed at providing re-searchers from different areas with the opportunity to discuss thistopic. This paper summarizes the activities of the workshop andthe accepted papers

Schizophrenia, autism, or social phobia are typically accompanied by social interaction deficits. The objective of the AlterEgo European project is the creation of an interactive cognitive architecture, implementable in various artificial agents, allowing a continuous interaction with patients suffering from social disorders by virtue of changes in behavioral (robot-based) as well as morphological (avatar-based) properties of that agent. Here we present the scientific foundations of the project and its four main experimental steps. The results of the first similarity experiments are reported, which show that healthy participants functionally adapt their social motor interaction when they interact with agents (real or artificial) morphologically and behaviorally similar to, or different from, them. These results obtained with healthy participants have consequences for the rehabilitation of socially deficient patients.

This paper models recent data in the field of postural coordination showing the existence of self-organized postural states, and transition between them, underlying suprapostural tracking movements. The proposed closed-loop controller captures the complex postural behaviors observed in humans and can be used to implement efficient and simple balance control principles in humanoids.

This paper reports on a study on the perception and rendering of distance in multimodal virtual environments. A model for binaural sound synthesis is discussed, and its integration in a real-time system with motion tracking and visual rendering is presented. Results from a validation experiment show that the model effectively simulates relevant auditory cues for distance perception in dynamic conditions. The model is then used in a subsequent experiment on the perception of egocentric distance. The design and preliminary result from this experiment are discussed.