This study advances the design of timing-sensitive, full-body interactive experiences supporting both collaboration and individual agency in children’s group play. We investigate how temporal structuring within an improved version of a full-body interactive system influences behavioral and perceived synchrony among children aged 9–10. Prior research has often focused on dyads, required human facilitation, or neglected relationship between perceived and actual synchrony. Addressing these gaps, we conducted a multi-user study comparing synchronous and asynchronous interaction modes using system-logged behavioral data and self-reports. Results demonstrate the synchronous condition fosters higher user performance, tighter temporal coordination, and stronger perceptions of shared movement. In contrast, the asynchronous mode effectively disrupts unintended coordination, showing how timing design shapes interaction dynamics. Notably, identical movements are perceived as less uniform without temporal alignment. These findings highlight the potential of embodied systems to scaffold or inhibit synchrony through intentional design, supporting richer social engagement and inclusive group play.

As Mixed Reality (MR) systems evolve toward richer, full-body interactive experiences, understanding how spatial configurations shape user behavior becomes essential for designing usable, engaging, and cognitively coherent environments. This paper presents the design and evaluation of three MR mini-games developed to investigate key embodied interaction properties: (1) territoriality and social distance, (2) proprioception and kinaesthesia, and (3) navigation and wayfinding. Implemented across four differently scaled MR footprints, the games were tested with participants from three age groups, children, adolescents, and young adults, to assess how interaction space size influences bodily coordination, spatial negotiation, and social behavior. Using a multimodal analysis approach, we analyze behavioral patterns that emerge at different scales, revealing how users' interaction strategies change based on space. Our findings contribute to the human-centered design of MR systems by offering a behavioral lens on how scale influences user experience, embodiment, and interaction quality. The study informs future applications in education, social interaction, and rehabilitation, where adaptive MR design is critical for inclusive and effective engagement.

This study investigates how interpersonal synchrony (IPS) in full-body interactive Mixed Reality (MR) environments can shape children's prosocial behavior. We introduce DragonIce 2.0, a two-part MR game designed to induce synchronous or asynchronous group activity and assess their impact on prosocial behavior. To examine changes in affiliation (team belonging and peer liking) and collaboration (overt joint actions), we conducted a comparative study with children aged 9-10, using both system logs and self-report measures. The results highlight the importance of context, task structure, and perceived coordination in shaping social outcomes, offering insights into how interaction dynamics shape social engagement in immersive settings. This work contributes a novel approach for studying prosociality in ecologically valid, technology-mediated settings by combining playful, immersive interaction with controlled manipulation of group synchrony. Our findings inform the design of inclusive MR experiences that support social connection, collaboration, and group engagement among children.

Interpersonal Synchrony (IPS), the temporal coordination of actions between individuals, plays a crucial role in fostering social interactions, emotion regulation, and communication.While previous research has explored IPS in dyadic settings, little is known about how it can be supported in multi-user full-body interactive environments, especially for neurodivergent populations.This study presents an iterative design investigation of DragonIce, a full-body interactive experience aimed at promoting IPS among children on the Autism Spectrum (AS).Building on findings from a prior study involving 12 male students with autism, we implemented and tested two targeted interaction design modifications: (1) enhanced visual feedback and (2) the introduction of a hand-held object.The results revealed a significant improvement in behavioral synchrony following refinements and a positive trend in perceived synchrony and user experience, highlighting how specific interaction design elements shape user experience and perceived synchrony in groupbased settings.This work contributes to creating knowledge on how interaction design can be strategically employed to foster IPS, offering new directions for inclusive and socially supportive full-body experiences for neurodivergent children.

This paper investigates how the physical size of a large-scale floor projected full-body interactive environment influences user behavior, focusing on territoriality and social distance across different age groups. Through an interactive game, we examined the interactions of school-age children, adolescents, and young adults in environments of varying sizes$\mathbf{3. 6} \times \mathbf{3. 6}$,$4.5 \times 4.5,5.3 \times 5.3$, and$6 \times 6$meters). Results revealed that schoolage children adapted their spatial behavior to the environment size, maintaining closer distances in smaller spaces and adjusting their play accordingly. Adolescents and young adults, however, exhibited consistent interpersonal distances across all scales, suggesting a preference for fixed personal space. These findings underscore the importance of age-related adaptability in designing interactive spaces, particularly for large-scale environments. This study provides insights into creating intuitive and effective game-based systems that support diverse user needs, offering practical guidelines for scalable, user-centered designs.

This study is part of a broader project exploring the integration of Mixed Reality (MR) in fostering prosocial behaviors among children, particularly focusing on interpersonal synchrony (IPS) and its impact on collaboration. IPS, the coordination of rhythmic movements among individuals, has been associated with improved group cohesion and prosocial behaviors, such as collaboration. Traditional assessments of prosociality typically involve structured play activities for dyads, making them difficult to adapt to other settings. To address these limitations, this research aims to design a flexible embodied MR experience that allows children to choose between collaborative or individual engagement, reflecting the natural dynamics of children's play interactions. For this purpose, we conducted an embodied participatory design (PD) and usability study with 50 children aged 8-10 years. We provide a detailed account on how the PD process was orchestrated and an evaluation of user-system interaction, children's perceptions of play modes, and experience satisfaction. The results show how the MR experience, codesigned with children, supports a free play environment, allowing children to choose their preferred play mode. This study highlights the potential of MR in psychological research and child development, providing a new avenue for assessing individual and collaborative behaviors in larger groups of children.