In everyday interactions with others, we often affect each other’s space through shared physical objects. Despite the commonality of such bidirectional interactions in real life, few have explored this form of interaction in virtual reality. This paper explores bidirectional embodied tangible interaction between a human and a virtual human through shared objects that span the real-virtual boundary in world-fixed virtual reality. The shared objects extend from the real world into the virtual world (and vice versa). We discuss the novel interaction concept and implementation details and present the results of a between-subjects user study with 40 participants where we compared the developed novel real-virtual shared object interaction with a control version where the shared objects were separated as completely physical and virtual. In summary, the results showed that presence and co-presence were increased with the real-virtual object interaction, along with affective attraction to the virtual human and enjoyment of interaction.

Head-mounted displays (HMDs) in virtual reality (VR) occlude the upper face of the wearing users, leading to decreased nonverbal communication cues toward outside users. In this paper, we discuss Googly Eyes, a high-fidelity prototype that displays an illustration of the HMD-wearing user’s eyes in real-time in front of an HMD. We explored the effects of the Googly Eyes on the user experience of non-HMD users. For this, we designed and developed a collaborative asymmetrical co-located task performed by an HMD-wearing user and a non-HMD (tablet) user, and we conducted a between-subjects user study where we compared the Googly Eyes with a baseline HMD experience without any external eye depiction. In this paper, we discuss the system, task, user study details, and results along with implications for future studies.

Virtual reality (VR) is a high-fidelity medium that can offer experiences that are close to real-life. Spatial ability plays an important role in human life, including academic achievement and advancement in work settings. Spatial ability is known to be improved by practicing relevant tasks. Mental rotation and spatial perception are among such tasks that improve spatial skills. In this research, we investigated a "mirror-reversed" interaction technique in a cup stacking task in VR and looked into its effects on spatial ability, brain activity regarding spatial processing and attention (measured with EEG), performance, and user experience in male participants. Participants stacked cups according to given patterns using direct manipulation with horizontally flipped controls, similar to looking in a mirror while performing object manipulation in real life. In a between-subjects user study, we compared this novel interaction with a baseline where the participants completed the same task with regular controls. Although there was no significant main effect of group on the mental rotation and perspective taking/spatial orientation tests scores, within-group analysis indicated a trend toward an improvement in the mirror-reversed group in spatial orientation, while both groups showed a trend toward improvement in mental rotation. Participants in both groups got better at the task over time (their task completion durations decreased). EEG data revealed significant theta band power increase in the mirror-reversed group whereas there was no difference in the alpha band power between the two groups. Our results are encouraging for exploring spatially challenging interactions in VR for spatial skills training. We share the implementation and user study results, and discuss the implications.

Interaction with tangible user interfaces (TUIs) in virtual reality (VR) is known to offer several benefits in terms of user experience. Incorporating identical-formed tangible objects for foot-enabled embodied interaction in VR is not a well-researched area. To address this gap, in this study, we explored foot-enabled embodied interaction in VR through a room-scale tangible soccer game (Tangiball). Users interacted with a physical ball with their feet in real time by seeing its virtual counterpart inside a VR head mounted display (HMD). Tangiball included a custom-built transparent physical ball, inside which motion trackers were secured using custom 3D-printed attachments. A between-subjects user study was performed with 40 participants, in which Tangiball was compared with the control condition of foot-enabled embodied interaction with a purely virtual ball. The results revealed that tangible interaction improved user performance and presence significantly, while no difference in terms of motion sickness was detected between the tangible and virtual versions. This paper discusses the development and evaluation of Tangiball along with implications of the user study results.

Tangible user interfaces (TUIs) have been widely studied in computer, virtual reality and augmented reality systems and are known to improve user experience in these mediums. However, there have been few evaluations of TUIs in wearable mixed reality (MR). In this study, we present the results from a comparative study evaluating three object manipulation techniques in wearable MR: (1) Space-multiplexed identical-formed TUI (i.e., a physical cube that acted as a dynamic tangible proxy with identical real and virtual forms); (2) Time-multiplexed TUI (i.e., a tangible controller that was used to manipulate virtual content); (3) Hand gesture (i.e., reaching, pinching and moving the hand to manipulate virtual content). The interaction techniques were compared with a user study with 42 participants. Results revealed that the tangible cube and the controller interaction methods were comparative to each other while both being superior to the hand gesture interaction method in terms of user experience, performance, and presence. We also present suggestions for interaction design for MR based on our findings.