This paper investigates multi-selection in XR interfaces based on eye and hand interaction. We propose enabling multi-selection using different variations of techniques that combine gaze with a semi-pinch gesture, allowing users to select multiple objects, while on the way to a full-pinch. While our exploration is based on the semi-pinch mode for activating a quasi-mode, we explore four methods for confirming subselections in multi-selection mode, varying in effort and complexity: dwell-time (SemiDwell), swipe (SemiSwipe), tilt (SemiTilt), and non-dominant hand input (SemiNDH), and compare them to a baseline technique. In the user study, we evaluate their effectiveness in reducing task completion time, errors, and effort. The results indicate the strengths and weaknesses of each technique, with SemiSwipe and SemiDwell as the most preferred methods by participants. We also demonstrate their utility in file managing and RTS gaming application scenarios. This study provides valuable insights to advance 3D input systems in XR.

Empathy is central to social interaction, yet how it is externally expressed in virtual reality (VR) communication remains underexplored. In this study, we examined how directionality-aware cues of empathy, such as mimicry, eye contact, and body proximity, relate to cognitive and emotional empathy. We designed high- and low-empathy scenarios and recruited participants with acting experience to ensure clear emotional expressions. Our findings indicate that facial mimicry patterns differ by empathy type: cognitive empathy involves subtle, speech-related muscle movements, whereas emotional empathy is associated with more intense affective expressions. Interestingly, we also found that while facial expressions and lower-body mimicry tend to emerge unconsciously, upper-body mimicry occurs more consciously, suggesting distinct pathways of empathic embodiment. We also observed that vocal intensity mimicry and pitch variability serve as important indicators of empathy, and a consistent hand approach is closely linked to empathy. Additionally, emotional empathy fosters longer eye contact, whereas cognitive empathy stabilizes gaze and head movements. Finally, we constructed machine learning models to predict empathy from these external expressions. Our best classifier achieved an accuracy of 0.756 for cognitive empathy and 0.704 for emotional empathy, indicating the feasibility of objective assessment. These findings provide a deeper understanding of how empathy is manifested in VR communication and support the development of empathy-aware virtual agents and training systems.

Many individuals experience everyday stress. Effective stress management in daily life is crucial before this stress accumulates. Music has been extensively studied as a method for reducing stress. In particular, music therapy is widely used to reduce stress and enhance the well-being of various clinical groups. However, traditional music therapy has physical constraints that require patients to visit a therapeutic location. VR music therapy has been studied to address these issues, but most research focuses on receptive music therapy, failing to utilize VR’s interactive potential fully. Additionally, the potential of applying gamification to VR active music therapy to enhance user engagement and encourage long-term use of the therapy application has not been explored. This paper proposes VR active music therapy based on conventional rhythm-following music therapy methods and VR gamified active music therapy by adding game elements based on Self-Determination Theory (SDT). Our between-subject comparative study (n=33) revealed the stress reduction effects of VR receptive music therapy, VR active music therapy, and VR gamified active music therapy. Importantly, participant interviews provided valuable insights into the user experiences with each VR content, confirming the potential for long-term use of VR gamified active music therapy. Moreover, this research delves into the effect of gamification on stress reduction. Through pilot test and experiments, we identify game elements that could potentially increase stress and provide guidelines for applying gamification to mitigate these factors, thereby enhancing the effectiveness of VR gamified active music therapy.

For social interaction on streaming platforms, chat feedback is a primary means for real-time engagement and expression of opinions. Given that social media is prone to stress by promoting social comparison, this study investigated how the valence and evaluation type of chat feedback influences streamers’ emotions, attention, and performance. In an online game-streaming context, participants engaged in a shooting game while receiving real-time chat feedback of different valence (negative, positive) and evaluation types (comparative, general). The results revealed that receiving negative feedback led to experiencing higher anxiety and lower self-efficacy and social support. Furthermore, comparative feedback negatively affected game performance and attracted more attention to the feedback. Interestingly, the tendency of comparative feedback to capture more attention was stronger when the valence was negative. These findings contribute to understanding the influence of social feedback on emotions and behavior and provide valuable insights for improving the user experience and performance.

Recent studies utilized virtual reality (VR) as an "empathy machine" to mitigate bias towards various social groups. However, studies addressing bias against physical disabilities remain scarce, with inconsistent results based on VR experience design. Moreover, most studies assumed the universal effects of VR simulation on bias reduction, ignoring the potential moderating effects of individual characteristics. This study investigated how experience design components and individual characteristics moderate VR simulation's effect on changes in bias towards physical disabilities. We designed a VR wheelchair experience, manipulating the situational context (negative, neutral) and whole-body avatar visualization (visible, invisible). Participants' implicit and explicit bias levels were assessed to examine the changes according to VR design components and individual characteristics (gender, preexisting bias level). Results indicated that following the VR intervention, implicit bias was reduced in the group with higher preexisting bias but rather increased in the group with lower preexisting bias. In addition, gender interacted with avatar visualization such that male participants' implicit bias was reduced with invisible avatars but increased with visible avatars. Explicit bias, in contrast, was reduced regardless of conditions, suggesting the potential response bias in self-report measures. These findings underscore the importance of considering the complex interplay between experience design and individual characteristics in understanding VR's efficacy as an empathy-inducing tool. This study provides insights and guidelines for developing more effective VR interventions to alleviate implicit bias towards physical disabilities.

Virtual museums are increasingly used to present cultural and educational content, often relying on textual descriptions to convey essential information. However, when users interact with text objects in virtual environments, the optimal text segment quantity for readability and comprehension remains unclear, especially when social distractions such as other visitors are present. This study investigated the effects of text segment quantity and the presence of other visitors on text readability and comprehension in the context of virtual museums. Participants read exhibit descriptions under four text-segment length conditions (1, 2, 4, and 8 lines) with or without simulated visitor agents. The results indicated that readability and comprehension were maximized when text was presented in intermediate segmentation lengths (2 and 4 Lines), while both excessively short (1 line) and long (8 lines) text segments hindered reading performance. Additionally, a significant interaction between text length and the presence of visitors was observed. Specifically, the presence of visitors led to increased comprehension task completion times only in the intermediate segmentation conditions, suggesting that social presence imposes an additional cognitive demand as social distractions in optimal text segment conditions. These findings provide empirical guidelines for designing effective text-based information systems in virtual museums, optimizing both user engagement and learning outcomes in immersive cultural environments.

As Extended Reality (XR) environments increasingly involve large amounts of data and content, designing effective exploration techniques has become critical. Depth-based object exploration is a common but underexplored task in XR environments, especially in settings without physical devices. Prior studies have largely focused on horizontal or planar interactions, leaving depthoriented exploration relatively overlooked. To bridge this gap, we propose three linearly aligned layer transition techniques (Continuous Push, Push&Return, and Tilt&Return) specifically designed to support efficient, precise, and continuous object exploration along the depth axis within depth-based UIs. In a user study with 30 participants, we compared their performance, usability, and user preference across two different layer configurations (8-layer vs. 16-layer). The results highlight that Continuous Push enables faster exploration with lower effort, while Push&Return provides the highest accuracy and is most preferred by users. Based on these findings, we discuss design implications for depth-based interaction techniques in controller-free XR environments.

In virtual reality, avatars represent ourselves and serve as a means to interact with others and the environment. Thus, understanding the self-recognition process in VR and designing self-avatars that have strong connections with the self is critical in enhancing immersion and efficiency of interaction in VR. In this paper, we investigated the characteristics of the self-recognition process in VR and the crucial factors that enhance the bond between the self and the avatar. In Study 1, we tested whether the advantage in cognitive processing of self-related information, often observed in reality, is also replicated for briefly embodied self-avatars in VR and how it is modulated by way of avatar selection and the degree of embodiment. The results showed that the self-avatar was processed more efficiently than other avatars, despite the constant changes in the appearance and a brief embodiment period. Moreover, the self-advantage effect was more pronounced for personally selected avatars, rather than those assigned by the experimenter. In Study 2, we compared the relative importance of motion and visual congruence in the process of identifying an entity as the self-avatar. The results indicated that motion synchrony between the user and the avatar is relatively more emphasized than the match in visual appearance when identifying oneself in VR. These findings highlight the underlying mechanisms and crucial factors for self-recognition in VR, and provide valuable insights for designing more immersive virtual experiences in various social VR applications.

As the utilization of VR is expanding across diverse fields, research on devising attentional cues that could optimize users' task performance in VR has become crucial. Since the cognitive load imposed by the context and the individual's cognitive capacity are representative factors that are known to determine task performance, we aimed to examine how the effects of multisensory attentional cues on task performance are modulated by the two factors. For this purpose, we designed a new experimental paradigm in which participants engaged in dual (N-back, visual search) tasks under different levels of cognitive load while an attentional cue (visual, tactile, or visuotactile) was presented to facilitate search performance. The results showed that multi-sensory attentional cues are generally more effective than uni-sensory cues in enhancing task performance, but the benefit of multi-sensory cues changes according to the level of cognitive load and the individual's cognitive capacity; the amount of benefit increases as the cognitive load is higher and the cognitive capacity is lower. The findings of this study provide practical implications for designing attentional cues to enhance VR task performance, considering both the complexity of the VR context and users' internal characteristics.

Although recent developments in VR tracking technology have enabled VR to become more portable and convenient, VR must overcome limited traversable space to be used for more general purposes. Since future VR HMDs aim to embed bio-sensors, such as eye-tracking and electroencephalography (EEG), the present study investigates how bio-sensors could be integrated into VR locomotion and how usability could be improved. In this paper, teleportation methods were developed by combining eye-tracking, EEG, and hand-tracking for location targeting and teleport triggering processes. In a static teleportation task, we compared the efficiency, accuracy, and usability of each method as well as the interactions between different combinations of methods. The experimental results verified that these locomotion methods were overall suitable for hands-free VR contents, and revealed relative superiority of eye-tracking for location targeting and hand-tracking for teleport triggering. Importantly, we identified specific combinations of locomotion methods appropriate for context by showing the interactions between experimental factors, and components that require improvement for future application. The results of this study contribute to development and understanding of novel VR locomotion methods utilizing bio-signal data, for more efficient and natural VR locomotion experience.

Joint agency, a group-level sense of agency, has been studied as an essential social cognitive element while engaging in collaborative tasks. The joint agency has been actively investigated in diverse contexts (e.g., performance, reward schedules, and predictability), yet the studies were mostly conducted in traditional 2D computer environments. Since virtual reality (VR) is an emerging technology for remote collaboration, we aimed to probe the effects of traditional reward schedule factors along with novel VR features (i.e., avatar visibility) on joint agency during remote collaboration. In this study, we implemented an experiment based on a card-matching game to test the effects of the reward schedule (fair or equal) and the counterpart's avatar hand visibility (absent or present) on the sense of joint agency. The results showed that participants felt a higher sense of joint agency when the reward was distributed equally regardless of the individual performance and when the counterpart's avatar hand was present. Moreover, the effects of reward schedule and avatar hand visibility interacted, with a bigger amount of deficit for the absent avatar hand when the reward was distributed differentially according to performance. Interestingly, the sense of joint agency was strongly correlated to the level of collaborative performance, as well as to perceptions of other social cognitive factors, including cooperativeness, reward fairness, and social presence. These results contribute to the understanding of joint agency perceptions during VR collaboration and provide design guidelines for remote collaborative tasks and environments for users' optimal social experience and performance.

This paper investigates how the size of virtual space and objects within it affect the threshold range of relative translation gains, a Redirected Walking (RDW) technique that scales the user’s movement in virtual space in different ratios for the width and depth. While previous studies assert that a virtual room’s size affects relative translation gain thresholds on account of the virtual horizon’s location, additional research is needed to explore this assumption through a structured approach to visual perception in Virtual Reality (VR). We estimate the relative translation gain thresholds in six spatial conditions configured by three room sizes and the presence of virtual objects (3 × 2), which were set according to differing Angles of Declination (AoDs) between eye-gaze and the forward-gaze. Results show that both size and virtual objects significantly affect the threshold range, it being greater in the large-sized condition and furnished condition. This indicates that the effect of relative translation gains can be further increased by constructing a perceived virtual movable space that is even larger than the adjusted virtual movable space and placing objects in it. Our study can be applied to adjust virtual spaces in synchronizing heterogeneous spaces without coordinate distortion where real and virtual objects can be leveraged to create realistic mutual spaces.

Attention is known to be shifted reflexively by subliminal cues in static environments, but their effect when applied in dynamic environments remains unclear. This study examines the effect of subliminal cues in both static and dynamic environments and presents a novel technique of applying subliminal cues within videos. Experiment 1 confirmed the effect of subliminal cues in guiding covert spatial attention in a static environment. Experiment 2 investigated the effect of subliminal cues in guiding overall gaze distribution in video context by manipulating the frequency of subliminal cues to bias the viewer’s gaze towards a specific side. There was no main effect of cue frequency, but additional findings showed the possibility that the effect of subliminal cues occurred differently between gender, and other factors such as gaze orientation bias influenced the viewer’s gaze distribution. These results provide insights on application of subliminal cues in video contexts and render the directions for future studies.

We propose the concept of relative translation gains, a novel Redirected Walking (RDW) method to create a mutual movable space between the Augmented Reality (AR) host's reference space and the Virtual Reality (VR) client's space. Previous RDW methods have focused on maximizing the movable space at the expense of aligning the coordinates between the AR and VR side, and could only be applied to collaborative scenarios involving sequential tasks. Our method solves these problems by adjusting the remote client's walking speed for each axis of a VR space to modify the movable area without coordinate distortion. We estimate the relative translation gain threshold, defined as the extent to which the walking speed can be altered without creating a perceived difference in distance. In order to reflect features of the reference space in generating the mutual space, we then examine how changing its size affects the threshold value. Our study showed that for remote clients connected to the larger reference space, relative translation gains can be increased to utilize a VR space bigger than their real space. Our method can be applied to create optimal mutual spaces for a wider variety of asymmetric Mixed Reality (MR) remote collaboration systems.

Telepresence avatars enable users in different environments to interact with each other. In order to increase the effectiveness of these interactions, however, the movements of avatars must be adjusted accordingly to account for differences between user environments. For instance, if a user moves from one point to another in one environment, the avatar’s locomotion speed must be adjusted to move to the corresponding target point in another environment at the same time. Several locomotion styles can be used to achieve this speed change. This paper investigates how different avatar locomotion styles (speed, stride, and glide), body visibility levels (full body and head-to-knee), and views (front views and side views) influence human perceptions of the naturalness of motion, similarity to the user’s locomotion, and the degree of preserving the user’s intention. Our results indicate that 1) speed and stride styles are perceived as more natural than the glide style, while the glide style is more intention-preserving than the others, 2) a greater locomotion speed of the avatar is perceived as more natural, similar, and intention-preserving than slower motion, 3) the perception of naturalness has the greatest impact on people’s preferences for locomotion styles, and that 4) head-to-knee body visibility may enhance the perception of naturalness for the glide style.