Virtual reality training systems require the careful design of content presentation, user embodiment, and overall user experience. We explore the impact of different perspectives (first-person and third-person) and virtual self-visualization techniques (VSVTs: mirrors and external avatars) on user embodiment, performance and experience. In a study with 28 participants learning karate movements, we tested four combinations of these factors. Results indicate that perspective influences visual focus and embodiment, while VSVTs affect movement execution, particularly in the third-person avatar condition. Measurements of physiological activity, workload, presence, and enjoyment found no significant overall advantages for any of the conditions. Interviews revealed that most participants preferred the familiar first-person mirror combination, although participants in third-person perspective focused more on their own body and noted the helpfulness of this viewpoint. The study demonstrates that alternative perspectives and visualization techniques offer valuable training options, as these conditions did not produce significant differences in measured cognitive load when compared with each other. Future VR training systems should incorporate interactive feedback and customization options to accommodate individual preferences and optimize learning experiences.

Effective self-reflection is crucial for motor skill acquisition, yet it is challenging to facilitate in single-user VR training environments. We investigate this through a method where users are embodied as a virtual trainer and prompted to actively evaluate a recorded performance. In an empirical study, we systematically varied the trainee’s appearance and their movements. Our mixed-methods analysis reveals that confronting one’s own performance triggers a fundamental role conflict between the user’s identity as the performer and their new role as the evaluator. Most importantly, this conflict challenges a binary view of embodiment. Participants experienced a multi-faceted sense of self, oscillating between identifying with the trainee and detaching as the trainer. Our work contributes a novel characterization of embodied self-evaluation, revealing a psychological duality at its core and offering clear design implications for VR systems that foster self-insight in training and therapy.

Physical training in virtual environments, such as VR, has gained popularity, especially due to the coronavirus pandemic. VR training offers new opportunities compared to traditional methods, including the use of different perspectives, mirrors, and avatars to enhance the understanding of personal movements. However, the interaction of these elements has been less studied. To address this, we developed VReflect, a VR environment that uses mirrors and avatars as virtual self-visualization techniques (VSVT) to improve self-awareness during movement training. In a preliminary study on learning beginner karate movements, we tested four combinations of perspectives and VSVTs. The results indicate that neither first-person nor third-person perspectives can be universally recommended, which is in alignment with previous work. Interviews revealed a preference for the traditional combination of mirrors and first-person perspective.

Human-AI interaction in text production increases complexity in authorship. In two empirical studies (n1 = 30 & n2 = 96), we investigate authorship and ownership in human-AI collaboration for personalized language generation. We show an AI Ghostwriter Effect : Users do not consider themselves the owners and authors of AI-generated text but refrain from publicly declaring AI authorship. Personalization of AI-generated texts did not impact the AI Ghostwriter Effect , and higher levels of participants’ influence on texts increased their sense of ownership. Participants were more likely to attribute ownership to supposedly human ghostwriters than AI ghostwriters, resulting in a higher ownership-authorship discrepancy for human ghostwriters. Rationalizations for authorship in AI ghostwriters and human ghostwriters were similar. We discuss how our findings relate to psychological ownership and human-AI interaction to lay the foundations for adapting authorship frameworks and user interfaces in AI in text-generation tasks.

Exploring the great outdoors offers physical and mental health benefits. Hiking is healthy, provides a sense of accomplishment, and offers an opportunity to relax. However, a nature trip is not always possible, and there is a lack of evidence showing how these beneficial experiences can be replicated in Virtual Reality (VR). In response, we recruited (N=24) participants to explore a virtual mountain landscape in a within-subjects study with different levels of exertion: walking, using a chairlift, and teleporting. We found that physical exertion when walking produced significantly more positive emotions and mindfulness than other conditions. Our research shows that physically demanding outdoor activities in VR can be beneficial for the user and that the achievement of hiking up a virtual mountain on a treadmill positively impacts wellbeing. We demonstrate how physical exertion can be used to add mindfulness and positive affect to VR experiences and discuss consequences for VR designers.

Modern games make creative use of First- and Third-person perspectives (FPP and TPP) to allow the player to explore virtual worlds. Traditionally, FPP and TPP perspectives are seen as distinct concepts. Yet, Virtual Reality (VR) allows for flexibility in choosing perspectives. We introduce the notion of a perspective continuum in VR, which is technically related to the camera position and conceptually to how users perceive their environment in VR. A perspective continuum enables adapting and manipulating the sense of agency and involvement in the virtual world. This flexibility of perspectives broadens the design space of VR experiences through deliberately manipulating perception. In a study, we explore users’ attitudes, experiences and perceptions while controlling a virtual character from the two known perspectives. Statistical analysis of the empirical results shows the existence of a perspective continuum in VR. Our findings can be used to design experiences based on shifts of perception.

Virtual Reality (VR) experiences have massively improved in the mediation of feedback. However, the simulation of forces is still limited. This paper presents Odin's Helmet, a head-worn device to simulate g-forces that act on the human head in real-life situations. Odin's Helmet uses four head-mounted propellers as actuators to simulate g-forces through pushing and pulling the user's head while being immersed in VR. Odin's Helmet's goal is to increase presence and manipulate the user's perception of the otolith organ in the vestibular system. The user's perception will be tricked to experience a sensation of self-movement in VR. A technical evaluation shows Odin's Helmet's applicability to apply perceivable g-forces to the user's head. We conclude with future use cases of Odin's Helmet, such as redirected walking by controlling the user's head orientation, attention guidance, and wind simulations through Odin's Helmet.

We investigate opportunities and challenges of running virtual reality (VR) studies remotely. Today, many consumers own head-mounted displays (HMDs), allowing them to participate in scientific studies from their homes using their own equipment. Researchers can benefit from this approach by being able to recruit study populations normally out of their reach, and to conduct research at times when it is difficult to get people into the lab (cf. the COVID pandemic). In an initial online survey ( N = 227), we assessed HMD owners’ demographics, their VR setups and their attitudes toward remote participation. We then identified different approaches to running remote studies and conducted two case studies for an in-depth understanding. We synthesize our findings into a framework for remote VR studies, discuss strengths and weaknesses of the different approaches, and derive best practices. Our work is valuable for Human-Computer Interaction (HCI) researchers conducting VR studies outside labs.

Virtual Reality experiences and games present believable virtual environments based on graphical quality, spatial audio, and interactivity. The interaction with in-game characters, controlled by computers (agents) or humans (avatars), is an important part of VR experiences. Pre-captured motion sequences increase the visual humanoid resemblance. However, this still precludes realistic social interactions (eye contact, imitation of body language), particularly for agents. We aim to make social interaction more realistic via social touch. Social touch is non-verbal, conveys feelings and signals (coexistence, closure, intimacy). In our research, we created an artificial hand to apply social touch in a repeatable and controlled fashion to investigate its effect on the perceived human-likeness of avatars and agents. Our results show that social touch is effective to further blur the boundary between computer- and human-controlled virtual characters and contributes to experiences that closely resemble human-to-human interactions.

While Virtual Reality continues to increase in fidelity, it remains an open question how to effectively reflect the user's movements and provide congruent feedback in virtual environments. We present VRsneaky, a system for producing auditory movement feedback, which helps participants orient themselves in a virtual environment by providing footstep sounds. The system reacts to the user's specific gait features and adjusts the audio accordingly. In a user study with 28 participants, we found that VRsneaky increases users' sense of presence as well as awareness of their own posture and gait. Additionally, we find that increasing auditory realism significantly influences certain characteristics of participants' gait. Our work shows that gait-aware audio feedback is a means to increase presence in virtual environments. We discuss opportunities and design requirements for future scenarios where users walk through immersive virtual worlds.

We present DronOS, a rapid prototyping framework that can track, control, and automate drone routines. Previous research in the domain of Human-Drone Interaction relied on hardware or proprietary vendor-dependent libraries that had to be exclusively programmed for specific use cases. This forces users to stick with a drone manufacturer or model as well as limiting users in transferring their drone control logic to other drones. To overcome the aforementioned issues, our framework uses low-cost off-the-shelf hardware and applies to a variety of already available or self-crafted drones. To assess the usability of DronOS, we evaluate three drone programming modes: Unity Scripting, Vive Scripting, and Vive Realtime. We find that Vive Scripting required the least subjective workload in programming drone routines while Unity Scripting yielded the highest accuracy and Vive Realtime the least task completion time. We anticipate requirements for drone prototyping frameworks that target novice and expert users as operators.

We present LYRA, a modular in-flight system that enhances service and assists flight attendants during their work. LYRA enables passengers to browse and order services from their smartphones. Smart glasses and a smart shoe-clip with RFID reader module provides flight attendants with situated information. We gained first insights into how flight attendants and passengers use of the system during a long distance flight from Frankfurt to Houston.

We present VRHapticDrones, a system utilizing quadcopters as levitating haptic feedback proxy. A touchable surface is attached to the side of the quadcopters to provide unintrusive, flexible, and programmable haptic feedback in virtual reality. Since the users' sense of presence in virtual reality is a crucial factor for the overall user experience, our system simulates haptic feedback of virtual objects. Quadcopters are dynamically positioned to provide haptic feedback relative to the physical interaction space of the user. In a first user study, we demonstrate that haptic feedback provided by VRHapticDrones significantly increases users' sense of presence compared to vibrotactile controllers and interactions without additional haptic feedback. In a second user study, we explored the quality of induced feedback regarding the expected feeling of different objects. Results show that VRHapticDrones is best suited to simulate objects that are expected to feel either light-weight or have yielding surfaces. With VRHapticDrones we contribute a solution to provide unintrusive and flexible feedback as well as insights for future VR haptic feedback systems.

Although a large number of navigation support systems for visually impaired people have been proposed in the past, navigating through unknown environments is still a major challenge for visually impaired travelers. Existing systems provide navigation information through headphones, speakers or tactile actuators. In this paper, we propose to use small lightweight quadcopters instead to provide navigation information for people with visual impairments. Using a leashed or free-floating quadcopter, the user is navigated by the distinct sound that the quadcopter emits and a haptic stimulus provided by the leash. In a user with 14 visually impaired participants, we compared leashed quadcopter navigation, free-floating quadcopter navigation, and traditional audio navigation. The results show that compared to audio navigation, participants navigate significantly faster with a free-floating quadcopter and make fewer navigation errors using the quadcopter navigation methods.

Visual exploration of large image data sets is a common and widely performed task. With the ubiquity of cameras, personal image collections are growing. Even when working with large high-resolution displays, collections are typically too large to display all images. In this work, we present two full-body, hands-free zooming interaction techniques for image exploration on large high-resolution displays that allow users to freely move in front of the display. We compare these techniques with state-of-the-art image browsing, where a large number of images is presented in a static grid. The first technique selects and enlarges whole columns by full-body-tracking of the user. The second technique additionally uses the height of the users head to select a single picture as a focus point. The results show that novel interaction techniques and visualizations for image sets on large high-resolution displays are required and can enhance the advantages of such displays.