Large Language Model (LLM) -based conversational agents have become increasingly popular in recent years due to their novel capacity for natural, human-like dialogue interactions. However, mistrust in LLMs persists due to concerns about privacy, the potential for incorrect responses (often referred to as “hallucinations”), and issues related to social bias. Previous AI research shows that anthropomorphic form positively influences users’ perceptions. However, this aspect remains under-explored in LLM-based conversational agent research. Our research features two anthropomorphic forms: embodied and behavioral. Embodied Anthropomorphic Form (EA) encompasses chatbot, chatbot with Text-to-Speech (TTS) , and Embodied Conversational Agent (ECA) interface designs. Behavioral Anthropomorphic (BA) Form involves LLMs instructed with and without Theory of Mind (ToM) principles. In an empirical evaluation, we explored how interplay between BA form and EA form, and vice-versa, affects users’ perceptions of LLM-based conversational agents on trust, anthropomorphism, presence, usability, and user experience. Our findings provide evidence of such effects, offering novel insight into the influence of both anthropomorphic forms on perceived anthropomorphism, presence, usability, user experience, and their positive impact on user trust in LLM-based conversational agents. However, the combined highest (i.e., ECA with ToM behaviors ) and lowest (i.e., Chatbot without ToM behaviors ) levels of both forms result in lower user trust, suggesting a complex relationship between embodiment and ToM behaviors that warrants further investigation.

Effective collaboration in Virtual Reality depends on users' ability to accurately perceive the affordances of others within a shared space. This paper presents the first empirical investigation of how people judge others' reaching capabilities in Immersive Virtual Environments (IVEs). We examined whether observers can reliably estimate the maximum horizontal reach distance of virtual actors, how different actor representations influence these perceptual judgments, and whether calibration feedback can improve estimation accuracy. Participants (N=35) judged the reachability of objects for virtual actors across three visual fidelity conditions: high-fidelity, low-fidelity, and end-effector-only representations. Results demonstrate that users can successfully estimate others' horizontal reachability in IVEs, though with overestimation. Calibration through action feedback significantly improved estimation accuracy, with overestimation decreasing across trials. Visual fidelity showed no main effect on initial reachability judgments but significantly affected postcalibration performance, with low-fidelity representations demonstrating significantly better calibration outcomes compared to high-fidelity avatars, while end-effector-only representations showed no significant difference from either condition. The findings contribute to the social perception literature in Virtual Reality (VR) and to provide design guidelines for avatar systems in collaborative virtual environments, where spatial coordination and shared action planning are critical.

Immersive Virtual Environments (IVEs) incorporating tangible graspable objects are becoming more accessible for training and other applications. Visual and proprioceptive information has been shown to be important for accurate distance and size perception. However, previous research has shown that users overestimate the size of tangible objects in IVEs. To address this issue, researchers have demonstrated the use of calibration to alter users' perceptions. In this study, we examined the carryover effects of calibration on the perceived size of graspable dials in IVEs. Participants wore head-mounted displays and experienced two calibration perturbations: Divergent Plus (physical dials 10% larger than virtual) and Divergent Minus (physical dials smaller than virtual). These were compared to the baseline Convergent condition (equal diameters). The results showed significant effects of the calibration on the accuracy of diameter estimates. Overall, a higher overestimation of dial sizes for the haptics-only condition was observed as compared to the vision-only condition. Additionally, participants' estimations worsened when haptic information was added to the vision during calibration but improved when vision information was added to the haptics-only condition during calibration. These findings highlight the importance of calibration in improving the accuracy of size perception in IVEs and contribute to our understanding of how tangible graspable objects are perceived in immersive virtual environments.

Direct perception, as part of the ecological approach to perception, defines a relationship between an organism and their environment that is specified by lawful information.Researchers can apply the ecological approach to eXtended Reality (XR) work to obtain a richer understanding of users' perception-action coordination in novel virtual settings.To encourage widespread adoption of this theoretical framework, this methodological paper introduces four major concepts from the ecological approach that are highly relevant to XR applications.We also provide an overview of existing literature to illustrate how those concepts may be used to inform and test their designs.These elements include the study of calibration and attunement, affordances, action based responses, and intrinsic scaling for measurements.The goal of this work is to increase awareness of the value of the ecological approach, and to provide a practical, evidence-based reference for researchers interested in applying these techniques in XR research.

Understanding visual attention in users during stressful situations with emotional crowds is crucial for the improvement of emergency response, safety, and efficiency. To explore this, we conducted a study examining how the organizational structure and reaction behavior of a virtual emotional crowd affected subjects' visual attention. Participants completed a task in a virtual reality simulation featuring a fire threat. The experiment employed two between-subjects factors (Crowd Type and Reaction Type) and one within-subjects factor (Simulation Phase). The simulation consisted of a normal phase, where participants interacted with virtual human (VHs) pedestrians and vendors in a virtual marketplace, followed by a stressful phase featuring a fire threat within the same setting. The Crowd Type varied between individuals walking alone (Individual Condition) and small groups of 3-4 members (Group Condition). The Reaction Type determined whether the virtual crowd ignored the threat or moved faster to escape. We analyzed subjects' fixation gaze across conditions, revealing that visual attention behavior was significantly influenced by Crowd Type, Reaction Type, and Simulation Phase.

This empirical evaluation aimed to investigate how size perception differs between OST AR and the real world, focusing on two judgment methods: verbal reports and physical judgments. Using a within-subjects experimental design, participants viewed target objects in different sizes in both AR and real-world conditions and estimated their sizes using verbal and physical judgment methods across multiple trials. The study addressed two key hypotheses: (H1) that size perception in AR would differ from the Real World, potentially due to rendering limitations in OST-HMDs, and (H2) that verbal reports and physical judgments would yield different levels of accuracy due to distinct cognitive and perceptual processes involved in each method. Our findings supported these hypotheses, revealing key differences in size perception between the two judgment methods and viewing conditions. Participants consistently underestimated object sizes when using verbal reports in both AR and real-world conditions, with more pronounced errors in AR. In contrast, physical judgments yielded more accurate size estimates under both viewing conditions. Notably, the accuracy of verbal reports decreased as target sizes increased, a trend that was particularly evident in AR. These results underscore the perceptual challenges associated with verbal size judgments in AR and their potential limitations in applications requiring precise size estimations. By highlighting the differences in accuracy and consistency between verbal and physical judgment methods, this study contributes to a deeper understanding of size perception in OST AR and real-world contexts.

Maps have long been a favored tool for navigation in both physical and virtual environments. As a navigation aid in virtual reality, map content and appearance can differ significantly. In this paper, three mini-maps are addressed: the WiM-3DMap, which provides a standard World-in-Miniature of the city model; the novel UC-3DMap, featuring important landmarks alongside ordinary buildings within the user’s vicinity; and the LM-3DMap, presenting only important landmarks. These mini-maps offer varying levels of building detail, potentially affecting spatial knowledge acquisition performance in diverse ways. A comparative study was conducted to evaluate the effectiveness of WiM-3DMap, UC-3DMap, LM-3DMap, and a baseline condition without a mini-map in spatial tasks such as spatial updating, landmark recall, landmark placement, and route recall. The findings demonstrated that LM-3DMap and UC-3DMap outperform WiM-3DMap in the tasks of spatial updating, landmark placement and route recall. However, the absence of detailed local context around the user may impede the effectiveness of LM-3DMap, as evidenced by UC-3DMap’s superior performance in the landmark placement task. These findings underscore the differences in effectiveness among various mini-maps that present distinct levels of building detail. A key conclusion is that including ordinary building information in the user’s immediate surroundings can significantly enhance the performance of a mini-map relying solely on landmarks.

As virtual reality (VR) technology continues to gain traction as a powerful tool for persuasion and marketing, its application in immersive sales environments has become increasingly relevant. VR’s ability to simulate realistic interactions allows for novel approaches to influencing consumer behavior, particularly through the use of interactive Virtual Humans (VHs). In this study, we investigate the effects of user and virtual human age and gender on persuasion and social influence, via various social psychological factors such as brand attitude, interpersonal attraction, source credibility, and presence. In the process, we conducted a 3 (virtual agent age) × 2 (virtual agent gender) × 3 (module topic) multi-factorial design (N=45). The study included two agent gender conditions, namely gender-matched and gender-mismatched with the user, assigned in a between-subjects manner, and three agent age conditions, namely (1) young adult (20-39), (2) middle-aged adult (40-59), and (3) older adult (60-79). Our findings indicate that the age and gender of virtual humans significantly influence their persuasiveness and social impact, which varies based on the user’s own age and gender. Specifically, virtual humans of a different gender from the user may exhibit higher levels of persuasion and social influence. Furthermore, female and older users appear to be more susceptible to influence compared to male and younger users. Our findings provide novel, critical insights for designing more effective virtual sales strategies and tailoring persuasive technologies to diverse user profiles, thus filling a vital gap in understanding the interaction between user and agent characteristics in virtual environments.1

Interpupillary distance (IPD) is the most important parameter for creating a user-specific stereo parallax, which in turn is crucial for correct depth perception. This is why contemporary Head-Mounted Displays (HMDs) offer adjustable lenses to adapt to users’ individual IPDs. However, today’s Video See-Through Augmented Reality (VST AR) HMDs use fixed camera placements to reconstruct the stereoscopic view of a user’s environment. This leads to a potential mismatch between individual IPD settings and the fixed Inter-Camera Distances (ICD), which can lead to perceptual incongruencies, limiting the usability and, potentially, the applicability of VST AR in depth-sensitive use cases. To investigate this incongruency between IPD and ICD, we conducted a 2 × 3 mixed-factor design user study using a near-field, open-loop reaching task comparing distance judgments of Virtual Reality (VR) and VST AR. We also investigated changes in reaching performance via perceptual calibration by incorporating a feedback phase between pre- and post-phase conditions, with a particular focus on the influence of IPD-ICD differences. Our Linear Mixed Model (LMM) analysis showed a significant difference between VR and VST AR, an effect of IPD-ICD mismatch, and a combined effect of both factors. However, subjective measures showed no effect underlining the subconscious nature of the perception of VST AR. This novel insight and its consequences are discussed specifically for depth perception tasks in AR, eXtended Reality (XR), and potential use cases.

This special issue of ACM Transactions on Applied Perception (TAP) features four articles from the 2025 Symposium on Applied Perception (SAP), held in Vancouver, BC, Canada, on August 9-10, 2025. ACM SAP provides an intimate forum for researchers who combine knowledge, methods, and insights from perception research and computer science. This year, SAP received 22 complete submissions, reviewed under a double-blind process. Seventeen were accepted for publication, and four of these were selected for inclusion in this special issue based on their exceptional quality. Each underwent an additional round of reviews consistent with the journal's editorial standards. The four contributions in this issue examine how perceptual and affective factors influence engagement, learning, health, and motivation across a variety of interactive contexts.

In immersive virtual environments (IVEs), accurate size perception is critical, especially in training simulations designed to mimic real-world tasks, such as, nuclear power plant control room or medical procedures. These simulations have dials or instruments of varying sizes. Visual information of the objects alone, often fails to capture subtle size differences in virtual reality (VR). However, integrating haptic and hand-avatars may potentially improve accuracy and performance. This improvement could be especially beneficial for real-world scenarios where hand(s) are intermittently visible or obscured. To investigate how this intermittent presence or absence of body-scaled hand-avatars affects size perception when integrated with haptic information, we conducted 2x2 mixed-factorial experiment design using a near-field, size-estimation task in VR. The experiment conditions compared size estimations with or without virtual hand visibility in the perception and reporting phases. The task involved 16 graspable objects of varying sizes and randomly repeated 3 times across 48 trials per participant (total 80 participants). We employed Linear Mixed Models (LMMs) analysis to objective measures: perceived size, residual error and proportional errors. Results revealed that as the tangible-graspable size increases, overestimation reduces if the hand-avatars are visible in the reporting phase. Also, overestimation reduces as the number of trials increases, if the hand-avatars are visible in the reporting phase. Thus, the presence of hand-avatars facilitated perceptual calibration. This novel study, with different combinations of hand-avatar visibility, taking perception and reporting of size as two separate phases, could open future research directions in more complex scenarios for refined integration of sensory modalities and consequently enhance real-world application performance.

Evidence from the behavioral psychology literature suggests that in unexpected stressful situations, crowd behavior can have a direct impact on people’s emotions and behaviors. This paper investigates whether this effect is elicited in immersive virtual reality by a crowd of virtual humans (VHs) in an external stressful situation induced by a fire. We conducted a mixed-design study in an experimental scenario where users were asked to collect 10 items from a virtual market. The between-subjects factors were reaction type and agent type, while the within-subjects factor was the simulation phase, which included the normal and stressful situations. There were two reaction types where the VHs showed either active (agitated) or passive (calm) behavior towards the external threat situation. For the agent type, the VHs exhibited either individualistic or group (3-4 member group) behaviors. In a mixed factorial 2(crowd type)x 2(reaction type) x 2(simulation phase) design, we examined the influences of these factors on participants’ emotional and behavioral responses. The results showed that the participants’ task performance and social interaction were affected by the simulated stressor. Negative emotions were elicited when they encountered active VHs and small groups of VHs. Furthermore, a greater change in their interpersonal closeness was experienced when interacting with small groups of VHs, than when interacting with individual VHs.

Many AR applications require users to perceive, estimate and calibrate to the size of objects presented in the scene. Distortions in size perception in AR could potentially influence the effectiveness of skills transferred from the AR to the real world. We investigated the after-effects or carry-over effects of calibration of size perception in AR to the real world (RW), by providing feedback and an opportunity for participants to correct their judgments in AR. In an empirical evaluation, we employed a three-phase experiment design. In the pretest phase, participants made size estimations to target objects concurrently using both verbal reports and physical judgment in RW as a baseline. Then, they estimated the size of targets, and then were provided with feedback and subsequently corrected their judgments in a calibration phase. Followed by which, participants made size estimates to target objects in the real world. Our findings revealed that the carryover effects of calibration successfully transferred from AR to RW in both verbal reports and physical judgment methods.

Spatial perception in virtual reality (VR) has been a hot research topic for years. Most of the studies on this topic have focused on visual perception and distance perception. Fewer have examined auditory perception and room size perception, although these aspects are important for improving VR experiences. Recently, a number of studies have shown that perception can be calibrated to information that is relevant to the successful completion of everyday tasks in VR (such as distance estimation and spatial perception). Also, some recent studies have examined calibration of auditory perception as a way to compensate for the classic distance compression problem in VR. In this paper, we present a calibration method for both visual and auditory room size perception. We conducted experiments to investigate how people perceive the size of a virtual room and how the accuracy of their size perception can be calibrated by manipulating perceptible auditory and visual information in VR. The results show that people were more accurate in perceiving room size by means of vision than in audition, but that they could still use audition to perceive room size. The results also show that during calibration, auditory room size perception exhibits learning effects and its accuracy was greatly improved after calibration.

Various experiments have led to a better understanding of how the surrounding environment influences long-term memory and spatial cognition, including those indicating how environmental context is encoded. However, specific external environment characteristics that may impact cognitive memory and performance remain unclear. Using an immersive Virtual Reality (VR) environment, we investigated the effects of color congruency on object placement accuracy, recall speed, and recognition.

In this contribution, we propose to enhance two distant object manipulation techniques, BMSR (Bimanual Near-Field Metaphor with Scaled Replica) and the classic Scaled HOMER (Scaled Hand-Centered Object Manipulation Extending Ray Casting), via nearfield scaled replica manipulation and viewing. In the proposed Direct BMSR, context replicas are displayed so that the target replica can be manipulated relative to its context, allowing the user to directly manipulate the target replica in their arm’s reach space. Some additional features were implemented to make Direct BMSR an effective interface for manipulating objects from a distance. We proposed Scaled HOMER+NFSRV, which augments Scaled HOMER with a near-field scaled replica view (NFSRV) of the target object and its context, enabling the user to observe how the target replica is manipulated in relation to its context in their arm’s reach space while manipulating it from a distance. We conducted a between-subjects empirical evaluation of BMSR, Direct BMSR, Scaled HOMER, and Scaled HOMER+NFSRV. Our findings revealed that Direct BMSR and Scaled HOMER+NFSRV significantly outperformed BMSR and Scaled HOMER, respectively, in terms of accuracy. This finding highlights the advantages of adding near-field scaled replica viewing and manipulation with respect to distant object manipulation.

The perception of distance is a complex process that often involves sensory information beyond that of just vision. In this work, we investigated if depth perception based on auditory information can be calibrated, a process by which perceptual accuracy of depth judgments can be improved by providing feedback and then performing corrective actions. We further investigated if perceptual learning through carryover effects of calibration occurs in different levels of a virtual environment’s visibility based on different levels of virtual lighting. Users performed an auditory depth judgment task over several trials in which they walked where they perceived an aural sound to be, yielding absolute estimates of perceived distance. This task was performed in three sequential phases: pretest, calibration, posttest. Feedback on the perceptual accuracy of distance estimates was only provided in the calibration phase, allowing to study the calibration of auditory depth perception. We employed a 2 (Visibility of virtual environment) $\times 3$ (Phase) $\times 5$ (Target Distance) multi-factorial design, manipulating the phase and target distance as within-subjects factors, and the visibility of the virtual environment as a between-subjects factor. Our results revealed that users generally tend to underestimate aurally perceived distances in VR similar to the distance compression effects that commonly occur in visual distance perception in VR. We found that auditory depth estimates, obtained using an absolute measure, can be calibrated to become more accurate through feedback and corrective action. In terms of environment visibility, we find that environments visible enough to reveal their extent may contain visual information that users attune to in scaling aurally perceived depth.

This study investigated the extent that the non-verbal behaviors of virtual humans (VHs) and their socio-demographic attributes altered users' collision avoidance behaviors in Virtual Reality (VR). Users interacted with VHs representing different levels of ethnicities and gender, exhibiting different conditions of physical movement, and gaze behaviors. The VHs were depicted in three major ethnic conditions namely Asian, Caucasian, and Black. The physical movement states of the VHs were either static in the path of the user or walking toward the user in the opposite direction. The non-verbal gaze behavior of the VHs was either direct gaze or averted gaze. We used an HTC Vive tracking system to track users' performing real walking while we collected objective measures (i,e., continuous gaze, fixation gaze, clearance distance, and travel length), and subjective variables (i.e., game experiences and social presence). The results showed that the ethnicity of the VHs significantly impacted the gaze behavior of the users, and the gender of the VHs affected the user avoidance movement and their reciprocal gaze behavior. Our results revealed that users' physical movement, gaze behaviors, and collision avoidance were moderated by the VHs' perceived ethnicity, gender, and gaze behaviors. Understanding the impact of the socio-demographics attributes of VHs and their gaze behavior on users' collision avoidance is critical for applications in which users are navigating through virtual traffic, crowd, and other inter-personal simulations.

Mixed reality (MR) interactions feature users interacting with a combination of virtual and physical components. Inspired by research investigating aspects associated with near-field interactions in augmented and virtual reality (AR & VR), we investigated how avatarization, the physicality of the interacting components, and the interaction technique used to manipulate a virtual object affected performance and perceptions of user experience in a mixed reality fundamentals of laparoscopic peg-transfer task wherein users had to transfer a virtual ring from one peg to another for a number of trials. We employed a 3 (Physicality of pegs) X 3 (Augmented Avatar Representation) X 2 (Interaction Technique) multi-factorial design, manipulating the physicality of the pegs as a between-subjects factor, the type of augmented self-avatar representation, and the type of interaction technique used for object-manipulation as within-subjects factors. Results indicated that users were significantly more accurate when the pegs were virtual rather than physical because of the increased salience of the task-relevant visual information. From an avatar perspective, providing users with a reach envelope-extending representation, though useful, was found to worsen performance, while co-located avatarization significantly improved performance. Choosing an interaction technique to manipulate objects depends on whether accuracy or efficiency is a priority. Finally, the relationship between the avatar representation and interaction technique dictates just how usable mixed reality interactions are deemed to be.

Active exploration in virtual reality (VR) involves users navigating immersive virtual environments, going from one place to another. While navigating, users often engage in secondary tasks that require attentional resources, as in the case of distracted driving. Inspired by research generally studying the effects of task demands on cybersickness (CS), we investigated how the attentional demands specifically associated with secondary tasks performed during exploration affect CS. Downstream of this, we studied how increased attentional demands from secondary tasks affect spatial memory and navigational performance. We discuss the results of a multi-factorial between-subjects study, manipulating a secondary task's demand across two levels and studying its effects on CS in two different sickness-inducing levels of an exploration experience. The secondary task's demand was manipulated by parametrically varying $n$ in an aural $n$-back working memory task and the provocativeness of the experience was manipulated by varying how frequently users experienced a yaw-rotational reorientation effect during the exploration. Results revealed that increases in the secondary task's demand increased sickness levels, also resulting in a higher temporal onset rate, especially when the experience was not already highly sickening. Increased attentional demand from the secondary task also vitiated navigational performance and spatial memory. Overall, increased demands from secondary tasks performed during navigation produce deleterious effects on the VR experience.

Cybersickness (CS) is one of the challenges that has hindered the widespread adoption of Virtual Reality (VR). Consequently, researchers continue to explore novel means to mitigate the undesirable effects associated with this affliction, one that may require a combination of remedies as opposed to a solitary stratagem. Inspired by research probing into the use of distractions as a means to control pain, we investigated the efficacy of this countermeasure against CS, studying how the introduction of temporally time-gated distractions affects this malady during a virtual experience featuring active exploration. Downstream of this, we studied how other aspects of the VR experience are affected by this intervention. We discuss the results of a between-subjects study manipulating the presence, sensory modality, and nature of periodic and short-lived (5-12 seconds) distractor stimuli across four experimental conditions: 1) no-distractors (ND); 2) auditory distractors (AD); 3) visual distractors (VD); 4) cognitive distractors (CD). Two of these conditions (VD and AD) formed a yoked control design wherein every matched pair of 'seers' and 'hearers' was periodically exposed to distractors that were identical in terms of content, temporality, duration, and sequence. In the CD condition, each participant had to periodically perform a 2-back working memory task, the duration and temporality of which was matched to distractors presented in each matched pair of the yoked conditions. These three conditions were compared to a baseline control group featuring no distractions. Results indicated that the reported sickness levels were lower in all three distraction groups in comparison to the control group. The intervention also increased the amount of time users were able to endure the VR simulation and avoided causing detriments to spatial memory and virtual travel efficiency. Overall, it appears that it may be possible to make users less consciously aware and bothered by the symptoms of CS, thereby reducing its perceived severity.

As virtual reality (VR) technology sees more use in various fields, there is a greater need to understand how to effectively design dynamic virtual environments. As of now, there is still uncertainty in how well users of a VR system are capable of tracking moving targets in a virtual space. In this work, we examined the influence of sensory modality and visual feedback on the accuracy of head-gaze moving target tracking. To this end, a between subjects study was conducted wherein participants would receive targets that were visual, auditory, or audiovisual. Each participant performed two blocks of experimental trials, with a calibration block in between. Results indicate that audiovisual targets promoted greater improvement in tracking performance over single-modality targets, and that audio-only targets are more difficult to track than those of other modalities.

Over the past two decades self-avatars have been shown to affect the perception of both oneself and of environmental properties including the sizes and distances of elements in immersive virtual environments. However, virtual avatars that accurately match the body proportions of their users remain inaccessible to the general public. As such, most virtual experiences that represent the user have a generic avatar that does not fit the proportions of the users' body. This can negatively affect judgments involving affordances, such as passability and maneuverability, which pertain to the relationship between the properties of environmental elements relative to the properties of the user providing information about actions that can be enacted. This is especially true when the task requires the user to maneuver around moving objects like in games. Therefore, it is necessary to understand how different sized self-avatars affect the perception of affordances in dynamic virtual environments. To better understand this, we conducted an experiment investigating how a self-avatar that is either the same size, 20% shorter, or 20% taller, than the user's own body affects passability judgments in a dynamic virtual environment. Our results suggest that the presence of self-avatars results in better regulatory and safer road crossing behavior, and helps participants synchronize self-motion to external stimuli quicker than in the absence of self-avatars.

This paper presents a within-subject study to investigate the effects of leading and following behaviors on user visual attention behaviors when collaborating with a virtual agent (VA) during performing transportation tasks in immersive virtual environments. The task was to carry a target object from a location to a predefined location. There were two conditions, namely leader VA (LVA) and follower VA (FVA). The leader gave instructions to the follower to perform actions. In the FVA condition, users played the leader role, while they played the follower role in the LVA condition. The users and the VA communicated via spoken language. During the experiment, participants wore a head-mounted display and performed real walking in a room. In each condition, each participant performed 20 trials of object transportation for different types of objects. Our preliminary results revealed significant differences in the user visual attention behaviors between the follower and leader VA conditions during the transportation tasks.

With the popularity of Virtual Reality (VR) on the rise, creators from a variety of fields are building increasingly complex experiences that allow users to express themselves more naturally. Self-avatars and object interaction in virtual worlds are at the heart of these experiences. However, these give rise to several perception based challenges that have been the focus of research in recent years. One area that garners most interest is understanding the effects of self-avatars and object interaction on action capabilities or affordances in VR. Affordances have been shown to be influenced by the anthropometric and anthropomorphic properties of the self-avatar embodied. However, self-avatars cannot fully represent real world interaction and fail to provide information about the dynamic properties of surfaces in the environment. For example, pressing against a board to feel its rigidity. This lack of accurate dynamic information can be further amplified when interacting with virtual handheld objects as the weight and inertial feedback associated with them is often mismatched. To investigate this phenomenon, we looked at how the absence of dynamic surface properties affect lateral passability judgments when carrying virtual handheld objects in the presence or absence of gender matched body-scaled self-avatars. Results suggest that participants can calibrate to the missing dynamic information in the presence of self-avatars to make lateral passability judgments, but rely on their internal body schema of a compressed physical body depth in the absence of self-avatars.

We present an empirical evaluation of immersion and self-avatars as compared to desktop viewing in Virtual Reality (VR) for learning computer programming and computational thinking in middle school education using an educational VR simulation. Students were asked to programmatically choreograph dance performances for virtual characters within an educational desktop application we built earlier called Virtual Environment Interactions (VEnvI). As part of a middle school science class, 90 students from the 6th and 7th grades participated in our study. All students first visually programmed dance choreography for a virtual character they created in VEnvI on a laptop. Then, they viewed and interacted with the resulting dance performance in a between-subjects design in one of the three conditions. We compared and contrasted the benefits of embodied immersive virtual reality (EVR) viewing utilizing a head-mounted display with a body-scaled and gender-matched self-avatar, immersive virtual reality only (IVR) viewing, and desktop VR (NVR) viewing with VEnvI on pedagogical outcomes, programming performance, presence, and attitudes towards STEM and computational thinking. Results from a cognition questionnaire showed that, in the learning dimensions of Knowledge and Understanding (Bloom's taxonomy) as well as Multistructural (SOLO taxonomy), participants in EVR and IVR scored significantly higher than NVR. Also, participants in EVR scored significantly higher than IVR. We also discovered similar results in objective programming performance and presence scores in VEnvI. Furthermore, students' attitudes towards computer science, programming confidence, and impressions significantly improved to be the highest in EVR and then IVR as compared to NVR condition. Our work suggests that educators and developers of educational VR simulations, who want to enhance knowledge and understanding as well as simultaneous acquisition of multiple abstract concepts, can do so by employing immersion and self-avatars in VR learning experiences.

User representations are critical to the virtual experience, and involve both the input device used to support interactions as well as how the user is virtually represented in the scene. Inspired by previous work that has shown effects of user representations on the perceptions of relatively static affordances, we attempt to investigate how end-effector representations affect the perceptions of affordances that dynamically change over time. Towards this end, we empirically evaluated how different virtual hand representations affect users' perceptions of dynamic affordances in an object retrieval task wherein users were tasked with retrieving a target from a box for a number of trials while avoiding collisions with its moving doors. We employed a 3 (virtual end-effector representation) X 13 (frequency of moving doors) X 2 (target object size) multi-factorial design, manipulating the input modality and its concomitant virtual end-effector representation as a between-subjects factor across three experimental conditions: (1) Controller (using a controller represented as a virtual controller); (2) Controller-hand (using a controller represented as a virtual hand); (3) Glove (using a hand tracked hi-fidelity glove represented as a virtual hand). Results indicated that the controller-hand condition produced lower levels of performance than both the other conditions. Furthermore, users in this condition exhibited a diminished ability to calibrate their performance over trials. Overall, we find that representing the end-effector as a hand tends to increase embodiment but can also come at the cost of performance, or an increased workload due to a discordant mapping between the virtual representation and the input modality used. It follows that VR system designers should carefully consider the priorities and target requirements of the application being developed when choosing the type of end-effector representation for users to embody in immersive virtual experiences.

Inspired by previous works showing promise for AR self-avatarization - providing users with an augmented self avatar, we investigated whether avatarizing users' end-effectors (hands) improved their interaction performance on a near-field, obstacle avoidance, object retrieval task wherein users were tasked with retrieving a target object from a field of non-target obstacles for a number of trials. We employed a 3 (Augmented hand representation) X 2 (density of obstacles) X 2 (size of obstacles) X 2 (virtual light intensity) multi-factorial design, manipulating the presence/absence and anthropomorphic fidelity of augmented self-avatars overlaid on the user's real hands, as a between subjects factor across three experimental conditions: (1) No-Augmented Avatar (using only real hands); (2) Iconic-Augmented Avatar; (3) Realistic Augmented Avatar. Results indicated that self-avatarization improved interaction performance and was perceived as more usable regardless of the anthropomorphic fidelity of avatar. We also found that the virtual light intensity used in illuminating holograms affects how visible one's real hands are. Overall, our findings seem to indicate that interaction performance may improve when users are provided with a visual representation of the AR system's interacting layer in the form of an augmented self-avatar.

Virtual Reality (VR) is well-known for its use in interdisciplinary applications and research. The visual representation of these applications could vary depending in their purpose and hardware limitation, and in those situations could require an accurate perception of size for task performance. However, the relationship between size perception and visual realism in VR has not yet been explored. In this contribution, we conducted an empirical evaluation using a between-subject design over four conditions of visual realism, namely Realistic, Local Lighting, Cartoon, and Sketch on size perception of target objects in the same virtual environment. Additionally, we gathered participants' size estimates in the real world via a within-subject session. We measured size perception using concurrent verbal reports and physical judgments. Our result showed that although participants' size perception was accurate in the realistic condition, surprisingly they could still tune into the invariant but meaningful information in the environment to accurately estimate the size of targets in the non-photorealistic conditions as well. We additionally found that size estimates in verbal and physical responses were generally different in real world and VR viewing and were moderated by trial presentation over time and target object widths.

Redirected walking allows users to naturally locomote within virtual environments that are larger than or different in layout from the physically tracked space. In this paper, we proposed novel optimization-driven alignment-based and Artificial Potential Field (APF) redirected walking controllers, as well as an integrated version of the two. The first two controllers employ objective functions of one variable, which is the included angle between the user's heading vector and the target vector originating from the user's physical position. The optimized angle represents the physical cell that is best aligned with the virtual cell or the target vector on which the designated point has the minimum APF value. The derived optimized angle is used to finely set RDW gains. The two objective functions can be optimized simultaneously, leading to an integrated controller that is potentially able to take advantage of the alignment-based controller and APF-based controller. Through extensive simulation-based studies, we found that the proposed alignment-based and integrated controllers significantly outperform the state-of-the-art controllers and the proposed APF based controller in terms of the number of resets. Furthermore, the proposed alignment controller and integrated controller provide a more uniform likelihood distribution across distance between resets, as compared to the other controllers.

The goal of this research is to provide much needed empirical data on how the fidelity of popular hand gesture tracked based pointing metaphors versus commodity controller based input affects the efficiency and speed-accuracy tradeoff in users’ spatial selection in personal space interactions in VR. We conduct two experiments in which participants select spherical targets arranged in a circle in personal space, or near-field within their maximum arms reach distance, in VR. Both experiments required participants to select the targets with either a VR controller or with their dominant hand’s index finger, which was tracked with one of two popular contemporary tracking methods. In the first experiment, the targets are arranged in a flat circle in accordance with the ISO 9241-9 Fitts’ law standard, and the simulation selected random combinations of 3 target amplitudes and 3 target widths. Targets were placed centered around the users’ eye level, and the arrangement was placed at either 60%, 75%, or 90% depth plane of the users’ maximum arm’s reach. In experiment 2, the targets varied in depth randomly from one depth plane to another within the same configuration of 13 targets within a trial set, which resembled button selection task in hierarchical menus in differing depth planes in the near-field. The study was conducted using the HTC Vive head-mounted display, and used either a VR controller (HTC Vive), low-fidelity virtual pointing (Leap Motion), or a high-fidelity virtual pointing (tracked VR glove) conditions. Our results revealed that low-fidelity pointing performed worse than both high-fidelity pointing and the VR controller. Overall, target selection performance was found to be worse in depth planes closer to the maximum arms reach, as compared to middle and nearer distances.

Walking through immersive virtual environments is one of the important parts of Virtual Reality (VR) applications. Prior research has established that users’ gait in virtual and real environments differs; however, little research has evaluated how users’ gait differs as users gain more experience with VR. We conducted experiments measuring novice and experienced subjects’ gait parameters in VR and real environments. Results showed that subjects’ performance in VR and Real World was more similar in the last trials than in the first trials; their walking dissimilarity in the start trials diminished by walking more trials. We found trial as a significant variable affecting the walking speed, step length, and trunk angle for both groups of users. While the main effect of expertise was not observed, an interaction effect between expertise and the trial number was shown. Trunk angle increased over time for novices but decreased for experts.

Distance compression, which refers to the underestimation of ego-centric distance to objects, is a common problem in immersive virtual environments. Besides visually compensating the compressed distance, several studies have shown that auditory information can be an alternative solution for this problem. In particular, reverberation time (RT) has been proven to be an effective method to compensate distance compression. To further explore the feasibility of applying audio information to improve distance perception, we investigate whether users’ egocentric distance perception can be calibrated, and whether the calibrated effect can be carried over and even sustain for a longer duration. We conducted a study to understand the perceptual learning and carryover effects by using RT as stimuli for users to perceive distance in IVEs. The results show that the carryover effect exists after calibration, which indicates people can learn to perceive distances by attuning reverberation time, and the accuracy even remains a constant level after 6 months. Our findings could potentially be utilized to improve the distance perception in VR systems as the calibration of auditory distance perception in VR could sustain for several months. This could eventually avoid the burden of frequent training regimens.

We examined the effects on users during collaboration with two types of virtual human (VH) agents in object transportation in an immersive virtual environment or virtual reality (VR). The two types of virtual humans we examined are leader and follower agents. The goal of the users is to interact with the agents using natural language and carry objects from initial locations to destinations. In each trial, the follower agent follows a user’s instructions to perform actions to manipulate the object. The leader agent determines the appropriate actions that the agent and the user should perform. We developed a system which enabled users and virtual agents to carry objects in an intuitive manner. We conducted a within-subjects study to evaluate the user behaviors under two conditions: (LVH) interaction with a leader virtual human and (FVH) interaction with a follower virtual human. We found that the participants in LVH required a higher workload than that in FVH. However, the users’ experiences, game experiences, and users’ impressions between the two conditions were not significantly different.

This investigation compared the impact on the users’ non-verbal behaviors elicited by interacting with a crowd of emotional virtual humans (VHs) in native and non-native language settings. In a between-subject experiment, we collected objective metrics regarding the users’ behaviors during interaction with a crowd of VHs who expressed verbal and non-verbal communicative behaviors in response to users’ speech-based interaction. The study presented four VH crowd conditions based on their emotional disposition, namely Positive, Negative, Neutral, and Mixed, in accordance with which VHs exhibited the appropriate behaviors. Participants were tasked with collecting items in a virtual flea market, and they interacted using natural speech-based dialogue with the VHs. The language conditions were collected in the USA and under two different conditions in Taiwan. The participants in the USA group interacted with the VHs in English (a native language for the USA setting); and two different groups in Taiwan interacted with the VHs in either a foreign (English) or native (Mandarin) language, respectively. Results reveal that in the (TMA, TEN) and (UEN, TEN) conditions, native versus non-native language communication can alter social behaviors (e.g., interaction time) of participants towards virtual interlocutors. Our results also revealed strong effects of cultural differences on participants’ non-verbal social behaviors with VHs in the UEN and TMA conditions.

Humans communicate by writing, often taking notes that assist thinking. With the growing popularity of collaborative Virtual Reality (VR) applications, it is imperative that we better understand aspects that affect writing in these virtual experiences. On-air writing in VR is a popular writing paradigm due to its simplicity in implementation without any explicit needs for specialized hardware. A host of factors can affect the efficacy of this writing paradigm and in this work, we delved into investigating the same. Along these lines, we investigated the effects of a combination of factors on users’ on-air writing performance, aiming to understand the circumstances under which users can both effectively and efficiently write in VR. We were interested in studying the effects of the following factors: (1) input modality: brush vs. near-field raycast vs. pointing gesture, (2) inking trigger method: haptic feedback vs. button based trigger, and (3) canvas geometry: plane vs. hemisphere. To evaluate the writing performance, we conducted an empirical evaluation with thirty participants, requiring them to write the words we indicated under different combinations of these factors. Dependent measures including the writing speed, accuracy rates, perceived workloads, and so on, were analyzed. Results revealed that the brush based input modality produced the best results in writing performance, that haptic feedback was not always effective over button based triggering, and that there are trade-offs associated with the different types of canvas geometries used. This work attempts at laying a foundation for future investigations that seek to understand and further improve the on-air writing experience in immersive virtual environments.

The availability of new and improved display, tracking and input devices for Virtual Reality experiences has facilitated the use of partial and full body self-avatars in interaction with virtual objects in the environment. However, scaling the avatar to match the user's body dimensions remains to be a cumbersome process. Moreover, the effect of body-scaled self-avatars on size perception of virtual handheld objects and related action capabilities has been relatively unexplored. To this end, we present an empirical evaluation investigating the effect of the presence or absence of body-scaled self-avatars and visuo-motor calibration on frontal passability affordance judgments when interacting with virtual handheld objects. The self-avatar's dimensions were scaled to match the participant's eyeheight, arms length, shoulder width and body depth along the mid section. The results indicate that the presence of body-scaled self-avatars produce more realistic judgments of passability and aid the calibration process when interacting with virtual objects. Also, participants rely on the visual size of virtual objects to make judgments even though the kinesthetic and proprioceptive feedback of the object is missing or mismatched.

In this contribution, we empirically investigated the effect of small talk on the users' non-verbal behaviors and emotions when users interacted with a crowd of virtual humans (VHs) with positive behavioral dispositions. Users were tasked with collecting items in a virtual marketplace via natural speech-based dialogue with a crowd of virtual pedestrians and vendors. The users were able to engage in natural speech-based conversation in a predefined corpus of small talk content that covered various commonplace small talk topics such as conversations about the weather, general concerns, and entertainment based on similar real-life situations. For instance, the VHs with the small talk ability would ask the users some simple questions to make small talk or remind the users of their belongings. We conducted a between-subjects empirical evaluation to investigate whether the user behaviors and emotions were different between a small talk condition and a non-small talk condition, and examined gender effects of the participants. We collected objective and subjective measures of the users to analyze users' emotions and social interaction behaviors, when in conversation with VHs that either possessed small-talk capability or not, besides task or goal oriented dialogue capabilities. Our result revealed that the VHs with small talk capability could alter the emotions and non-verbal behaviors of the users. Furthermore, the non-verbal behaviors between female and male participants differed greatly in the presence or absence of small talk.

Prior research in depth perception and perceptuo-motor calibration have primarily focused on participants completing experiments in single sessions and therefore do not empirically evaluate changes over time. Further, these studies do not typically take into account the amount of experience that the participants have in virtual reality (VR) prior to participation, the role of experience during participation, or calibration that may occur throughout the experiment session. In this contribution, we conducted a novel empirical evaluation of how calibration affects perception-action coordination over time. We recruited novice VR users and they completed eight sessions of a depth perception reaching experiment over the course of 12 weeks. During these experiments, we examined how participants' ability to estimate depth in a virtual environment changed as they gradually gained experience. While previous literature has shown that participants tend to underestimate distances, we found that this underestimation diminished over time as they gained experience in the virtual environment. Our study highlights the need for carrying out VR studies over time and the influence that longitudinal calibration can have on spatial perception in long-term VR experiences.

Virtual Reality (VR) technologies are increasingly being applied to various contexts like those gaming, therapy, training, and education. Several of these applications require high degrees of accuracy in spatial and depth perception. Contemporary VR experiences continue to be confronted by the issue of distance compression wherein people systematically underestimate distances in the virtual world, leading to impoverished experiences. Consequently, a number of studies have focused on extensively understanding and exploring factors that influence this phenomenon to address the challenges it poses. Inspired by previous work that has sought to compensate distance compression effects in VR, we examined the potential of manipulating an auditory stimulus’ reverberation time (RT) to alter how users perceive depth. To this end, we conducted a two action forced choice study in which participants repeatedly made relative depth judgements between a pair of scenes featuring a virtual character placed at different distances with varying RTs. Results revealed that RT influences how users perceive depth with this influence being more pronounced in the near field. We found that users tend to associate longer RTs with farther distances and vice versa, indicating the potential to alter RT towards compensating distance underestimation in VR. However, it must be noted that excessively increasing RT (especially in the near field) could come at the cost of sensory segregation, wherein users are unable to unify visual and auditory sensory stimuli in their perceptions of depth. Researchers must hence strive to find the optimal amount of RT to add to a stimulus to ensure seamless virtual experiences.

Virtual reality (VR) experiences currently tend to focus on full body interactions. However, fine motor control in actions such as writing and drawing are seldom studied. Challenges include the inability to perceive fine details due to the low resolution of head mounted displays, the difficulty in simulating fine motor actions in virtual environments, tracking instabilities, latency issues, etc. State of the art VR has managed to address a host of such concerns, supporting a variety of input mechanisms for activities such as writing, sketching, immersive modeling, etc. With VR increasingly being applied in education and medical contexts where writing and note taking is a crucial, it is important to study how well humans can perform these tasks in VR. In a between-subjects empirical evaluation, we studied participants' fine motor coordination with several digital input based writing and artistic tasks performed both in virtual and real world settings, further examining the effects of providing a virtual self avatar on task performance. We integrated multiple tracking systems and applied inverse kinematics to animate the virtual body and simulate hand motions. We went on to compare how different the outputs of these digital input metaphors are to a real world pen and paper approach in an effort to ascertain where we currently stand in being able to support writing and note taking in virtual world contexts. Overall, it seems to be the case that while writing and artistic activities can be successfully supported in VR applications using specialized input devices, the accuracy with which users perform such tasks is significantly higher in the real world, highlighting the need for developments that support such fine motor tasks in VR.

Immersive Virtual Environments (IVEs) incorporating tangibles are becoming more accessible. The success of applications combining 3D printed tangibles and VR often depends on how accurately size is perceived. Research has shown that visuo-haptic perceptual information is important in the perception of size. However, it is unclear how these sensory-perceptual channels are affected by immersive virtual environments that incorporate tangible objects. Towards understanding the effects of different sensory information channels in the near field size perception of tangibles of graspable sizes in IVEs, we conducted a between-subjects study evaluating the accuracy of size perception across three experimental conditions (Vision-only, Haptics-only, Vision and Haptics). We found that overall, participants consistently over-estimated the size of the dials regardless of the type of perceptual information that was presented. Participants in the haptics only condition overestimated diameters to a larger degree as compared to other conditions. Participants were most accurate in the vision only condition and least accurate in the haptics only condition. Our results also revealed that increased efficiency in reporting size over time was most pronounced in the visuo- haptic condition.

This investigation compared the emotional impact caused by a crowd of affective virtual humans (VHs) that communicated in the users' native or foreign language. We evaluated the users' affective reactions to a crowd of VHs that exhibited distinct emotional expressions. A total of four emotions were presented, which were Positive, Negative, Neutral, and Mixed. The VHs performed verbal and non-behaviors accordingly. Under the Mixed condition, the VHs were divided into three groups equally and each group was uniquely assigned one of the three emotions (i.e., positive, negative, and neutral). Users collected ten items from a virtual reality market. To complete the tasks, they interacted using natural speech with the emotional VHs. Three language conditions were investigated: one condition in USA and another two conditions in Taiwan. The group of participants in USA interacted with the VHs in English; and the two groups of participants in Taiwan interacted with the VHs using a foreign (English) language and a native (Mandarin) language respectively. We discovered that the medium of communication or language familiarity had a strong influence on participants' emotional reactions. When participants interacted in a foreign language with VHs with a positive emotional disposition, we found their positive emotional reactions were subdued and negative reactions were elevated. However, this was not the case when participants interacted with VHs in their native language, as their emotional reactions were contingent on the emotional disposition of the VHs.

Virtual reality ( VR ) displays have factors such as vergence-accommodation conflicts that negatively impact depth perception and cause users to misjudge distances to select objects. In addition, popular large-screen immersive displays present the depth of any target rendered through screen parallax information of points, which are encapsulated within stereoscopic voxels that are a distinct unit of space dictating how far an object is placed in front of or behind the screen. As they emanate from the viewers’ eyes (left and right center of projection), the density of voxels is higher in front of the screen (in regions of negative screen parallax) than it is behind the screen (in regions of positive screen parallax), implying a higher spatial resolution of depth in front of the screen than behind the screen. Our experiment implements a near-field fine-motor pick-and-place task in which users pick up a ring and place it around a targeted peg. The targets are arranged in a linear configuration of 3, 5, and 7 pegs along the front-and-back axis with the center peg placed in the same depth as the screen. We use this to evaluate how users manipulate objects in positive versus negative screen parallax space by the metrics of efficiency, accuracy, and economy of movement. In addition, we evaluate how users’ performance is moderated by haptic feedback and mismatch between visual and proprioceptive information. Our results reveal that users perform more efficiently in negative screen parallax space and that haptic feedback and visuo-proprioceptive mismatch have effects on placement efficiency. The implications of these findings are described in the later sections of the article.

We detail the results of two experiments that empirically evaluate the efficiency of spatial selection performance of popular pointing and controller based direct 3D interaction within the participants’ maximum arms reach or personal space in an immersive virtual environment. In the first experiment, targets were presented in a circular configuration of 13 targets in accordance with the ISO 9241-9 Fitts’ Law standard, with a target distance of 5, 9 or 18 cm and target width of 0.65, 0.85, or 1.05cm, and with each circular configuration presented in a random distance of 60%, 75% or 90% of maximum arms length of the participant. The targets were centered at eye level, and in a within-subjects protocol participants selected the targets using a pointer at the tip of the controller or at the tip of their index finger on the dominant hand in the pointing based condition. The second experiment presented each target in a similar width and distance configuration as the previous experiment, but each target also varied in depth from one trial to the next between 60%, 75% or 90% of maximum arms reach. The selections were performed in an HTC Vive head mounted display VR world, using the popular Leap Motion gesture tracking device or the Vive controller. The results of both our experiment taken together revealed that with commodity 3D input devices, participants were more efficient in spatial selection performance in the popular controller based condition, as compared to the pointing based condition. Implications for VR developers and consumers are discussed in the latter sections.

As Virtual Reality (VR) devices become more accessible, a multitude of VR applications engage users in highly immersive virtual environments that feature realistic graphics, real-life scenarios, and self-avatars. Many of these simulations require users to make spontaneous affordance judgments such as stepping over obstacles, passing through gaps, etc. which are shown to be affected by the nature of our self-representation in the virtual world. As the technology for creating self-avatars becomes more widely available, it is important to explore how various affordance judgments are affected by the presence of self-avatars. In this work, we investigate the effects of body-scaled self-avatars on the affordance of passability in a natural setting. We implemented a gender-matched body-scaled self-avatar using HTC Vive trackers and evaluated how passability judgments for a sliding doorway in VR, with and without an avatar, compared to the real world judgments. The results suggest that passability judgments are more conservative in VR as compared to the real world. However, the presence of a self-avatar does not significantly affect passability judgments made in VR. This does not align with previous findings which show that having a self-avatar improves judgments and estimates.

Design discussion is a very important course in architecture education. In this paper, we developed a VR based architecture design discussion system that allows members to visualize and discuss the architectural models and to modify the models during discussion. Since the system is designed to work on top of Rhinoceros and Grasshopper, the object database is updated right after the object modification. Members communicate via voice, object manipulations, and mid-air sketching as well as on-surface sketching in the virtual environment. Several tools have been designed to enhance the sense of presence and to make the discussion more effective. We also developed a rollback mechanism to help users intuitively and quickly revert to a previous state of discussion to make some changes or to start a new direction of discussion. To evaluate the system, we conducted an initial user study with 14 participants to assess the user experience, user impression and effectiveness of the system. The feedback from participants were positive and suggested that the system could be effective and useful for supporting architecture design discussion.

The commercialization and lowering costs of consumer grade Virtual Reality (VR) devices has made the technology increasingly accessible to users around the world. The usage of VR technology is often accompanied by an undesirable side effect called cybersickness. Cyber-sickness is the feeling of discomfort that occurs during VR experiences, producing symptoms similar to those of motion sickness. It continues to remain one of the biggest hurdles to the widespread adoption of VR, making it increasingly important to explore and understand the factors that influence its onset. In this work, we investigated the influence of the presence/absence of motion control on the onset and severity of cybersickness in an HMD based VR driving simulation employing steering as a travel metaphor. Towards this end, we conducted a between subjects study manipulating the presence of control between three experimental conditions, two of which (Driving condition and Yoked Pair condition) formed a yoked control design where every pair of drivers and their yoked pairs were exposed to identical vehicular motion stimuli created by participants in the driving condition. In the other condition (Autonomous Car condition), participants experienced a program driven autonomous vehicle simulation. Results indicated that participants in the Driving condition experienced higher levels of cybersickness than participants in the Yoked Pair condition. While these results don’t conform to findings from previous research which suggests that having control over motion reduces cybersickness, it seems to point towards the importance of the fidelity of the control metaphor’s feedback response in alleviating cybersickness. Simply allowing one control their motion may not readily alleviate cybersickness but could instead increase it in such HMD based VR driving simulations. It may hence be important to consider how well the control metaphor and its feedback matches users’ expectations if we want to successfully mitigate cybersickness.

The commercialization of Virtual Reality (VR) devices is making the technology increasingly accessible to users around the world. Despite the success that VR is starting to see with its growing popularity, it has yet to become widely adopted and achieve its ultimate goal- convincingly simulate real life like experiences. The inability to generate adequate levels of presence and to prevent the manifestation of cybersickness are the two prominent barriers that have hindered VR from achieving its ultimate goal. While traditional research has examined factors that influence (correlate with) the onset and severity cybersickness, there is still a gap in our knowledge about the consequences of having motion control on cybersickness in immersive virtual environments (IVE’s) achieved using tracked Head Mounted Displays (HMD’s). Furthermore, outside of a correlational capacity, it is still unclear as to what causes cybersickness to affect presence in immersive virtual environments. The success of immersive virtual reality as a technology will hence largely come down to our ability to understand the interrelationship between these variables and then address the challenges they pose. Towards this end, we investigated how the affordance of motion control affects cybersickness and presence in an HMD based VR driving simulation by conducting a between subjects study where we manipulated the affordance of control between three experimental conditions. We leverage structural equation modeling in an attempt to build a framework that explains the relationship between virtual motion control, workload, cybersickness, time spent in the simulation, perceived time and presence. Our structural model helps explain why motion control could be an important factor to consider in addressing VR’s challenges and realizing its ultimate aim to simulate reality.

In this contribution we examined the effects on users during interaction with a virtual human crowd in an immersive virtual reality environment. We developed an agent-based crowd model with rich properties including eye gaze, facial expression, body motion, and verbal and non-verbal behaviors. The scenario was a virtual market in which the users needed to gather specific items. In a betweensubjects design, users interacted with a virtual human crowd that showed opposite valenced emotional expressions. There are four conditions in the between-subjects design. These includes different affective virtual crowds namely, Positive, Negative, Neutral, and a Mix condition. The Mix group is defined by a combination of Positive, Negative and Neutral emotional expressive characters. Depending on the specific condition, the virtual humans showed specific verbal and non-verbal behaviors. During the experiment we collected objective measures such as skin electrodermal activity, total time in the simulation, the number of interactions with the agents and performance measures. The subjective measures were the differential emotional survey (DES), and a user experience survey. We reported our findings with an in-depth analysis.

The trade-off between speed and accuracy in precision tasks is important to evaluate during user interaction with input devices. When different sensory cues are added or altered in such interactions, those cues have an effect on this trade-off, and thus, they affect overall user performance. For instance, adding cues like haptic feedback and stereoscopic viewing will result in more realistic user interaction, thus improving performance in these tasks. Also, adding a noticeable disparity between physical and virtual movements creates a mismatch between visual and proprioceptive systems, which generally has a negative effect on performance. In this study, we investigate the effects of haptic feedback, stereoscopic viewing, and visuo-proprioceptive mismatch on how quickly and accurately users complete a virtual pick-and-place task using the PHANToM OMNI. Through this experiment, we find that in the movement phase of a ring transfer, movement time and user performance are affected by haptic feedback and visuo-proprioceptive mismatch, and the main effects of stereoscopic viewing appears to be limited to the more precise step when the ring is around the target peg.

Cybersickness (CS) is one of the challenges that has hindered the widespread adoption of Virtual Reality and its applications. Consequently, a number of studies have focused on extensively understanding and reducing CS. Inspired by previous work that has sought to reduce CS using foveated rendering and Field of View (FOV) restrictions, we investigated how the presence and size of a static central window in peripheral FOV blurring affects CS. To facilitate this peripheral FOV blur, we applied a Gaussian blur effect in the display peripheral region, provisioning a full-resolution central window. Thirty participants took part in a three-session, within-subjects experiment, performing search and spatial updating tasks in a first-person, slow-walking, maze-traveling scenario. Two different central window sizes (small and large) were tested against a baseline condition that didn’t feature display peripheral blurring. Results revealed that the baseline condition produced higher levels of CS than both conditions with a central window. While there were no significant differences between the small and large windows, we observed interaction effects suggesting an influence of window size on “adaptation to CS.” When the central window is small, adaptation to CS seems to take more time but is more pronounced. The interventions had no effect on spatial updating and presence, but were detectable when the blurred area was larger (small central window). Lower sickness levels observed in both window conditions supports the use of peripheral FOV blurring to reduce CS, reducing our dependence on eye tracking. This being said, researchers must strive to find the right balance between window size and detectability to ensure seamless virtual experiences.

We examined the effect of rendering style and the interplay between attention and emotion in users during interaction with a virtual patient in a medical training simulator. The virtual simulation was rendered representing a sample from the photo-realistic to the non-photorealistic continuum, namely Near-Realistic, Cartoon or Pencil-Shader. In a mixed design study, we collected 45 participants’ emotional responses and gaze behavior using surveys and an eye tracker while interacting with a virtual patient who was medically deteriorating over time. We used a cross-lagged panel analysis of attention and emotion to understand their reciprocal relationship over time. We also performed a mediation analysis to compare the extent to which the virtual agent’s appearance and his affective behavior impacted users’ emotional and attentional responses. Results showed the interplay between participants’ visual attention and emotion over time and also showed that attention was a stronger variable than emotion during the interaction with the virtual human.

In this contribution we studied how different rendering styles of a virtual human impacted users' visual attention in an interactive medical training simulator. In a mixed design experiment, 78 participants interacted with a virtual human representing a sample from the non-photorealistic (NPR) to the photorealistic (PR) rendering continuity. We presented five rendering style samples scenarios, namely low fidelity all Pencil Shaded (APS), Low to Mid Fidelity Pencil Shader on virtual patient (VP) only (PS), Mid Fidelity All Cartoon Shaded (ACT), Mid to High Fidelity Cartoon Shader on VP only (CT), and relatively High Fidelity Human Like (HL) appearance, and compared how visual attention differed between groups of users. For this study, we employed an eye tracking system for collecting and analyzing users' gaze during interaction with the virtual human in a failure to rescue medical training simulation. Results suggests that users may spend more time in the simulations on the non-realistic fidelity continuum that necessarily do not involve interaction with the virtual human. However, users preferred visually attending to virtual humans in the middle and high fidelity visual appearance conditions when engaging virtual humans in simulated social face-to-face dialogue as compared to the other conditions

We present an empirical evaluation on how stereoscopic viewing and haptic feedback deferentially affects fine motor perception-action coordination in a pick-and-place task in Virtual Reality (VR). The factors considered were stereoscopic viewing, haptic feedback, sensory-motor congruence and mismatch, and calibration on perception-action coordination in near field fine motor task performance in VR. Quantitative measures of placement error, distance, collision, and time to complete trials were recorded and analyzed. Overall, we found that participants' manual dexterous task performance was enhanced in the presence of both stereoscopic viewing and haptic feedback. However, we found that time to complete task was greatly enhanced by the presence of haptic feedback, and economy and efficiency of movement of the end effector as well as the manipulated object was enhanced by the presence of both haptic feedback and stereoscopic viewing. Whereas, number of collisions and placement accuracy were greatly enhanced by the presence of stereoscopic viewing in near-field fine motor perception-action coordination. Our research additionally shows that mismatch in sensory-motor stimuli can detrimentally affect the number of collisions, and efficiency of end effector and object movements in near-field fine motor activities, and can be further negatively affected by the absence of haptic feedback and stereoscopic viewing. In spite of reduced cue situations in VR, and the absence or presence of stereoscopic viewing and haptic feedback, we found that participants tend to calibrate or adapt their perception-action coordination rapidly with a set of at least 5 trials.

In this contribution, we design, implement and evaluate the pedagogical benefits of a novel interactive note taking interface (iVRNote) in VR for the purpose of learning and reflection lectures. In future VR learning environments, students would have challenges in taking notes when they wear a head mounted display (HMD). To solve this problem, we installed a digital tablet on the desk and provided several tools in VR to facilitate the learning experience. Specifically, we track the stylus' position and orientation in the physical world and then render a virtual stylus in VR. In other words, when students see a virtual stylus somewhere on the desk, they can reach out with their hand for the physical stylus. The information provided will also enable them to know where they will draw or write before the stylus touches the tablet. Since the presented iVRNote featuring our note taking system is a digital environment, we also enable students save efforts in taking extensive notes by providing several functions, such as post-editing and picture taking, so that they can pay more attention to lectures in VR. We also record the time of each stroke on the note to help students review a lecture. They can select a part of their note to revisit the corresponding segment in a virtual online lecture. Figures and the accompanying video demonstrate the feasibility of the presented iVRNote system. To evaluate the system, we conducted a user study with 20 participants to assess the preference and pedagogical benefits of the iVRNote interface. The feedback provided by the participants were overall positive and indicated that the iVRNote interface could be potentially effective in VR learning experiences.

The commercialization of Virtual Reality (VR) devices has made it easier for everyday users to experience VR from the comfort of their living rooms. This recent uptake in VR has also increased reported incidents of cybersickness. Cybersickness refers to the discomfort experienced by an individual while experiencing virtual environments. The symptoms are similar to those of motion sickness but are more disorienting in nature resulting in dizziness, blurred vision, etc. Cybersickness is currently one of the biggest hurdles to the widespread adoption of VR, and it is therefore critical to explore the factors that influence its onset. Towards this end, we present a proof of concept simulation to study cybersickness in highly realistic immersive virtual environments.

Abstract This paper studies the user collaboration experience with proactive and reactive agents in transporting boxes in virtual environments. Two main characters, the avatar and the agent, are controlled by a user and a controller, respectively. The user and the agent communicate with each other by voice. The agent can be proactive or reactive. The user follows the instruction issued by the proactive agent, whereas the user instructs the reactive agent to perform actions. The goal is to transport boxes to goal positions with orientation constraints. We conducted a user study to analyze the behaviors of participants in several aspects, including task completion time, path length, control experience, and co‐presence experience. We report our findings and make suggestions for future development.

HTTP-based Adaptive Streaming (HAS) is the dominant Internet video streaming application. One specific HAS approach, Dynamic Adaptive Streaming over HTTP (DASH), is of particular interest, as it is a widely deployed, standardized implementation. Prior academic research has focused on networking and protocol issues, and has contributed an accepted understanding of the performance and possible performance issues in large deployment scenarios. Our work extends the current understanding of HAS by focusing directly on the impacts of choice of the video quality adaptation algorithm on end-user perceived quality. In congested network scenarios, the details of the adaptation algorithm determine the amount of bandwidth consumed by the application as well as the quality of the rendered video stream. HAS will lead to user-perceived changes in video quality due to intentional changes in quality video segments, or unintentional perceived quality impairments caused by video decoder artifacts such as pixelation, stutters, or short or long stalls in the rendered video when the playback buffer becomes empty. The HAS adaptation algorithm attempts to find the optimal solution to mitigate the conflict between avoiding buffer stalls and maximizing video quality. In this article, we present results from a user study that was designed to provide insights into “best practice guidelines” for a HAS adaptation algorithm. Our findings suggest that a buffer-based strategy might provide a better experience under higher network impairment conditions. For the two network scenarios considered, the buffer-based strategy is effective in avoiding stalls but does so at the cost of reduced video quality. However, the buffer-based strategy does yield a lower number of quality switches as a result of infrequent bitrate adaptations. Participants in buffer-based strategy do notice the drop in video quality causing a decrease in perceived QoE, but the perceived levels of video quality, viewer frustration, and opinions of video clarity and distortion are significantly worse due to artifacts such as stalls in capacity-based strategy. The capacity-based strategy tries to provide the highest video quality possible but produces many more artifacts during playback. The results suggest that player video quality has more of an impact on perceived quality when stalls are infrequent. The study methodology also contributes a unique method for gathering continuous quantitative subjective measure of user perceived quality using a Wii remote.

Research has shown that self-avatars (life-size representations of the user in Virtual Reality (VR)) can affect how people perceive virtual environments. In this paper, we investigated whether the visual fidelity of a self-avatar affects reach boundary perception, as assessed through two variables: 1) action taken (or verbal response) and 2) correct judgment. Participants were randomly assigned to one of four conditions: i) high-fidelity self-avatar, ii) low-fidelity self-avatar, iii) no avatar (end-effector), and iv) real-world as reference task group. Results indicate that all three VR viewing conditions were significantly different from real world in regards to correctly judging the reachability of the target. However, based on verbal responses, only the "no avatar" condition had a non-trivial difference with real world condition. Taken together with reachability data, participants in "no avatar" condition were less likely to correctly reach to the reachable targets. Overall, participant performance improved after completing a calibration phase with feedback, such that correct judgments increased and participants reached to fewer unreachable targets.

Every task we perform in our day-to-day lives requires us to make judgements about size, distance, depth, etc. The same is true for tasks in an immersive virtual environments (IVE). Increasingly, Virtual Reality (VR) applications are being developed for training and entertainment, many of which require the user to determining whether s/he can pass through an opening. Typically, people determine their ability to pass through an aperture by comparing the width of their shoulders to the width of the opening. Thus, judgments of size and distance in an IVE are necessary for accurate judgments of passability. In this experiment, we empirically evaluate how passability judgments in an IVE, viewed through a Head-Mounted Display (HMD), compare to judgments made in the real world. An exact to scale virtual replica of the room and apparatus was used for the VR condition. Results indicate that the accuracy of passability judgments seem to be comparable to the real world.

This paper details the results of an initial empirical evaluation conducted to examine how stereoscopic viewing and haptic feedback affects fine motor actions in a pick-and-place task, similar to the peg transfer task in an FLS training curriculum for laproscopic sugical training. In a between subjects experiment, we examined the effect of stereoscopic viewing and simulated tactile feedback during the fine motor actions of a participants' actions in the near field on the number of collisions and time to complete the task. We found that stereo and haptic feedback contributed to the effectiveness of task performance in different ways. Specifically, we found that the mean time to complete the trials was significantly higher in the abcense of tactile feedback as compared to when it was present, and the mean number of collisions was significantly higher in the presence of stereo as compared to when it was absent.

Immersive Virtual Environments (IVEs) are becoming more accessible and more widely utilized for training. Previous research has shown that the matching of visual and proprioceptive information is important for calibration. While research has demonstrated that self-avatars can enhance ones' sense of presence and improve distance perception, the effects of self-avatar fidelity on near field distance estimations has yet to be investigated. This study tested the effect of avatar fidelity on the accuracy of distance estimations in the near-field. Performance with a virtual avatar was also compared to real-world performance. Three levels of fidelity were tested; 1) an immersive self-avatar with realistic limbs, 2) a low-fidelity self-avatar showing only joint locations, and 3) end-effector only. The results suggest that reach estimations become more accurate as the visual fidelity of the avatar increases, with accuracy for high fidelity avatars approaching real-world performance as compared to low-fidelity and end-effector conditions. In all conditions reach estimations became more accurate after receiving feedback during a calibration phase.

We describe a system for experiment standardization and distributing medication in medical trials using a virtual human. In our system, we employed a virtual experimenter that explains the experiment, medication, procedure and risks involved through a large screen display. The participant is able to interact with and ask questions of the virtual experimenter through a touch screen interface on an additional monitor display. During the interaction, the virtual experimenter will present the participant with a pill. The pill is physically distributed by a custom-made Arduino based dispenser. We conducted an initial user evaluation of the system using a placebo response protocol and a perceived pain scale. In the study, participants submerged their hand in a hot water bath before and after interacting with the system and reported their perceived pain response. The system was either a virtual human or text interface that either disseminated a pill stating that it was an analgesic or did not provide a medication. Through this system, we propose the potential use of virtual humans as a method to provide a consistent and standardized interaction between a participant and experimenter, while maintaining the benefits of social interaction in medication trials.

Creating realistic animations of virtual humans remains comparatively complex and expensive. This research explores the degree to which animation fidelity affects users' gaze behavior when interacting in virtual reality training simulations that include virtual humans. Participants were randomly assigned to one of three conditions, wherein the virtual patient either: 1) was not animated; 2) played idle animations; or 3) played idle animations, looked at the participant when speaking, and lip-synced speech and facial gestures when conversing with the participant. Each participant's gaze was recorded in an inter-personal interactive patient surveillance simulation. Results suggest that conversational and passive animations elicited visual attention in a similar manner, as compared to the no animation condition. Results also suggest that when participants face critical situations in inter-personal medical simulations, visual attention towards the virtual human decreases while gaze towards goal directed activities increases.

With costs of head-mounted displays (HMDs) and tracking technology decreasing rapidly, various virtual reality applications are being widely adopted for education and training. Hardware advancements have enabled replication of real-world interactions in virtual environments to a large extent, paving the way for commercial grade applications that provide a safe and risk-free training environment at a fraction of the cost. But this also mandates the need to develop more intrinsic interaction techniques and to empirically evaluate them in a more comprehensive manner. Although there exists a body of previous research that examines the benefits of selected levels of interaction fidelity on performance, few studies have investigated the constituent components of fidelity in a Interaction Fidelity Continuum (IFC) with several system instances and their respective effects on performance and learning in the context of a real-world skills training application. Our work describes a large between-subjects investigation conducted over several years that utilizes bimanual interaction metaphors at six discrete levels of interaction fidelity to teach basic precision metrology concepts in a near-field spatial interaction task in VR. A combined analysis performed on the data compares and contrasts the six different conditions and their overall effects on performance and learning outcomes, eliciting patterns in the results between the discrete application points on the IFC. With respect to some performance variables, results indicate that simpler restrictive interaction metaphors and highest fidelity metaphors perform better than medium fidelity interaction metaphors. In light of these results, a set of general guidelines are created for developers of spatial interaction metaphors in immersive virtual environments for precise fine-motor skills training simulations.

The ability to select or customize characters in educational applications and games has been shown to influence factors related to learning effects such as transfer, self-efficacy, and motivation. Most previous conclusions on the perception of virtual characters and the effect of character assignment in interactive applications have been reached through short, one-task experiments. To investigate more long-term effects of assigning versus customizing characters as well as explore perceptions of personal character appearance, we conduct a study in which sixth and seventh grade students are introduced to programming concepts with the software VEnvI (Virtual Environment Interactions) in seven one-hour sessions over two weeks. In VEnvI, students create performances for virtual characters by assembling blocks. With a between-subjects design, in which some of the students can alter their character and others are not given that possibility, we examine the influence of the presence or absence of character choice options on learning.

No abstract available.

Fifty-four middle school girls were a part of weeklong program geared towards encouraging young women in STEM careers. During a two-day computer science intervention, we introduced students to our VEnvI software where students program virtual characters to perform choreography. During this time, students were introduced programming concepts: sequencing, loops, and variables. They also spent time performing to learn some of the movements in VEnvI and discussed different aspects of the VEnvI software design including motion capture & Unity 3D Development. The latter conversations were couched in relation to being a computer scientist. Data were collected from the students on the first day of the camp as well as at the end of the second day. Each student was given a piece of paper that only contained a code corresponding to her. The instructions were to write, "What do computer scientists do?" on one side of the page, and to draw a picture of a computer scientist on the other side. Our findings suggest that, at least in the short term, this type of intervention can impact students' perceptions of computer science as well as broaden their perspectives of computer scientists. More students drew female computer scientists in the post-test and showed computer scientists working in teams rather than alone. Further, students' ideas of what computer scientists "do" shifted from fixing computers and making websites to creating, designing, and inventing with computers.

It is our great pleasure to welcome you to Greenville, South Carolina, for the IEEE Conference on Virtual Reality (IEEE VR) 2016. This is the 18th year of the premiere conference in virtual reality and 3D interaction in the world, and we are proud to host it here in South Carolina. In recent years, the conference has travelled to Singapore, Orange County, USA, Orlando, USA, Minneapolis, USA, and Arles, France. During these years the conference has grown in many respects, yet the basic format of mostly a single-track technical session has changed little. This year's conference, however, will feature some notable departures from previous years while still keeping with our cherished traditions of the IEEE VR conference.

We detail the design, implementation, and an initial evaluation of a virtual reality education and entertainment (edutainment) application called Virtual Environment Interactions (VEnvI). VEnvI is an application in which students learn computer science concepts through the process of choreographing movement for a virtual character using a fun and intuitive interface. In this exploratory study, 54 participants as part of a summer camp geared towards promoting participation of women in science and engineering programmatically crafted a dance performance for a virtual human. A subset of those students participated in an immersive embodied interaction metaphor in VEnvI. In creating this metaphor that provides first-person, embodied experiences using self-avatars, we seek to facilitate engagement, excitement and interest in computational thinking. We qualitatively and quantitatively evaluated the extent to which the activities of the summer camp, programming the dance moves, and the embodied interaction within VEnvI facilitated students' edutainment, presence, interest, excitement, and engagement in computing, and the potential to alter their perceptions of computing and computer scientists. Results indicate that students enjoyed the experience and successfully engaged the virtual character in the immersive embodied interaction, thus exhibiting high telepresence and social presence. Students also showed increased interest and excitement regarding the computing field at the end of their summer camp experience using VEnvI.

In an initial study, we characterized the properties of human reach motion in the presence or absence of visuo-haptic feedback in real and Immersive Virtual Environments (IVEs) or virtual reality within a participant’s maximum arm reach. Our goal is to understand how physical reaching actions to the perceived location of targets in the presence or absence of visuo-haptic feedback are different between real and virtual viewing conditions. Typically, participants reach to the perceived location of objects in the three-dimensional (3D) environment to perform selection and manipulation actions during 3D interaction in applications such as virtual assembly or rehabilitation. In these tasks, participants typically have distorted perceptual information in the IVE as compared to the real world, in part due to technological limitations such as minimal visual field of view, resolution, latency, and jitter. In an empirical evaluation, we asked the following questions: (i) how do the perceptual differences between virtual and real world affect our ability to accurately reach to the locations of 3D objects, and (ii) how do the motor responses of participants differ between the presence or absence of visual and haptic feedback? We examined factors such as velocity and distance of physical reaching behavior between the real world and IVE, both in the presence or absence of visuo-haptic information. The results suggest that physical reach responses vary systematically between real and virtual environments, especially in situations involving the presence or absence of visuo-haptic feedback. The implications of our study provide a methodological framework for the analysis of reaching motions for selection and manipulation with novel 3D interaction metaphors and to successfully characterize visuo-haptic versus non-visuo-haptic physical reaches in virtual and real-world situations.

Realistic versus stylized depictions of virtual humans in simulated inter-personal situations and their ability to elicit emotional responses in users has been an open question for artists and researchers alike. We empirically evaluated the effects of near visually realistic vs. non-realistic stylized appearance of virtual humans on the emotional response of participants in a medical virtual reality system that was designed to educate users in recognizing the signs and symptoms of patient deterioration. In a between-subjects experiment protocol, participants interacted with one of three different appearances of a virtual patient, namely visually realistic, cartoon-shaded and charcoal-sketch like conditions in a mixed reality simulation. Emotional impact were measured via a combination of quantitative objective measures were gathered using skin Electrodermal Activity (EDA) sensors, and quantitative subjective measures such as the Differential Emotion Survey (DES IV), Positive and Negative Affect Schedule (PANAS), and Social Presence questionnaire. The emotional states of the participants were analyzed across four distinct time steps during which the medical condition of the virtual patient deteriorated (an emotionally stressful interaction), and were contrasted to a baseline affective state. Objective EDA results showed that in all three conditions, male participants exhibited greater levels of arousal as compared to female participants. We found that negative affect levels were significantly lower in the visually realistic condition, as compared to the stylized appearance conditions. Furthermore, in emotional dimensions of interest-excitement, surprise, anger, fear and guilt participants in all conditions responded similarly. However, in social emotional constructs of shyness, presence, perceived personality, and enjoyment-joy, we found that participants responded differently in the visually realistic condition as compared to the cartoon and sketch conditions. Our study suggests that virtual human appearance can affect not only critical emotional reactions in affective inter-personal training scenarios. but also users' perceptions of personality and social characteristic of the virtual interlocutors.

The need for virtual reality applications for education and training involving bimanual dexterous activities has been increasing in recent years. However, it is unclear how the amount of correspondence between a virtual interaction metaphor to the real-world equivalent, otherwise known as dimensional symmetry, affects bimanual pscyhomotor skills training and how skills learned in the virtual simulation transfer to the real world. How does the number of degrees of freedom enhance or hinder the learning process? Does the increase in dimensional symmetry affect cognitive load? In an empirical evaluation, we compare the effectiveness of a natural 6-DOF interaction metaphor to a simplified 3-DOF metaphor. Our simulation interactively educates users in the step-by-step process of taking a precise measurement using calipers and micrometers in a simulated technical workbench environment. We conducted a usability study to evaluate the user experience and pedagogical benefits using measures including a pre and post cognition questionnaire over all levels of Bloom's taxonomy, workload assessment, system usability, and real world psychomotor assessment tasks. Results from the pre and post cognition questionnaires suggest that learning outcomes improved throughout all levels of Bloom's taxonomy for both conditions, and trends in the data suggest that the 6-DOF metaphor was more effective in real-world skill transference compared to the 3-DOF metaphor.

The effectiveness of visual realism of virtual characters in engaging users and eliciting affective responses has been an open question. We empirically evaluated the effects of realistic vs. non-realistic rendering of virtual humans on the emotional response of participants in a medical virtual reality system that was designed to educate users to recognize the signs and symptoms of patient deterioration. In a between-subjects experiment protocol, participants interacted with one of three different appearances of a virtual patient, namely realistic, non-realistic cartoon-shaded and charcoal-sketch like conditions. Emotional impact of the rendering conditions was measured via a combination of subjective and objective metrics.

We report the results of an empirical evaluation to examine the carryover effects of calibrations to one of three perturbations of visual and proprioceptive feedback: i) Minus condition (-20% gain) in which a visual stylus appeared at 80% of the distance of a physical stylus, ii) Neutral condition (0% gain) in which a visual stylus was co-located with a physical stylus, and iii) Plus condition (+20% gain) in which the visual stylus appeared at 120% of the distance of the physical stylus. Feedback was shown to calibrate distance judgments quickly within an IVE, with estimates being farthest after calibrating to visual information appearing nearer (Minus condition), and nearest after calibrating to visual information appearing further (Plus condition).

Research in visuo-motor coupling has shown that the matching of visual and proprioceptive information is important for calibrating movement. Many state-of-the art virtual reality (VR) systems, commonly known as immersive virtual environments (IVE), are created for training users in tasks that require accurate manual dexterity. Unfortunately, these systems can suffer from technical limitations that may force de-coupling of visual and proprioceptive information due to interference, latency, and tracking error. We present an empirical evaluation of how visually distorted movements affects users' reach to near field targets using a closed-loop physical reach task in an IVE. We specifically examined the recalibration of movements when the visually reached distance is scaled differently than the physically reached distance. Subjects were randomly assigned to one of three visual feedback conditions during which they reached to target while holding a tracked stylus: i) Condition 1 (-20% gain condition) in which the visual stylus appeared at 80% of the distance of the physical stylus, ii) Condition 2 (0% or no gain condition) in which the visual stylus was co-located with the physical stylus, and iii) Condition 3 (+20% gain condition) in which the visual stylus appeared at 120% of the distance of the physical stylus. In all conditions, there is evidence of visuo-motor calibration in that users' accuracy in physically reaching to the target locations improved over trials. During closed-loop physical reach responses, participants generally tended to physically reach farther in condition 1 and closer in condition 3 to the perceived location of the targets, as compared to condition 2 in which participants' physical reach was more accurate to the perceived location of the target.

n this paper, we introduce an embodied pedagogical approach for learning computational concepts, utilizing computational practices, and developing computational perspectives. During a five-week pilot, a group of students spent after-school time learning the basic elements of dance and then using them to program three-dimensional characters that could perform. Throughout the pilot, we found students consistently standing up in front of their computers and using their bodies to think through the actuation of their characters. Preliminary results suggest that designing a virtual-physical dance performance is a motivating and engaging social context in which to introduce students, especially girls, to alternative applications in computing.

We empirically examined the impact of virtual human animation on the emotional responses of participants in a medical virtual reality system for education in the signs and symptoms of patient deterioration. Participants were presented with one of two virtual human conditions in a between-subjects experiment, static (non-animated) and dynamic (animated). Our objective measures included the use of psycho-physical Electro Dermal Activity (EDA) sensors, and subjective measures inspired by social psychology research included the Differential Emotions Survey (DES IV) and Positive and Negative Affect Survey (PANAS). We analyzed the quantitative and qualitative measures associated with participants’ emotional state at four distinct time-steps in the simulated interpersonal experience as the virtual patient’s medical condition deteriorated. Results suggest that participants in the dynamic condition with animations exhibited a higher sense of co-presence and greater emotional response as compared to participants in the static condition, corresponding to the deterioration in the medical condition of the virtual patient. Negative affect of participants in the dynamic condition increased at a higher rate than for participants in the static condition. The virtual human animations elicited a stronger response in negative emotions such as anguish, fear, and anger as the virtual patient’s medical condition worsened.

We present a set of demonstrations of current work in the Clemson University Virtual Environments Group involving the development and testing of interactive virtual environments for applications in training, rehabilitation and workforce development. All of these applications are designed to leverage commodity hardware such as HDTVs, game controllers, and the Kinect sensor.

Distances are regularly underestimated in immersive virtual environments (IVEs) [Witmer and Kline 1998; Loomis and Knapp 2003]. Few experiments, however, have examined the ability of calibration to overcome distortions of depth perception in IVEs. This experiment is designed to examine the effect of calibration via haptic and visual feedback on distance estimates in an IVE. Participants provided verbal and physical reach responses to target distances presented during three sessions; a baseline measure without feedback, a calibration session with visual and haptic feedback, and finally a post-calibration session without feedback. Feedback was shown to calibrate distance estimates within an IVE. Discussion focused on the possibility that costly solutions and research endeavors seeking to remedy the compression of distances may become less necessary if users are simply given the opportunity to use manual activity to calibrate to the IVE.

An experiment was conducted to examine the effects of immersion on a spatial updating task in a virtual panoramic environment (VPE). A virtual panorama, such as Google Streetview, is an environment that is comprised of 3D (spherical) images taken at regular intervals in a real world setting. Participants in this experiment navigated the National Mall area of Washington DC in Google Streetview using either a keyboard and mouse or a head-mounted display (HMD) with a head orientation tracker.

Few experiments have been performed to investigate near-field egocentric distance estimation in an Immersive Virtual Environment (IVE) as compared to the Real World (RW). This article investigates near-field distance estimation in IVEs and RW conditions using physical reach and verbal report measures, by using an apparatus similar to that used by Bingham and Pagano [1998]. Analysis of our experiment shows distance compression in both the IVE and RW conditions in participants' perceptual judgments to targets. This is consistent with previous research in both action space in an IVE and reach space with Augmented Reality (AR). Analysis of verbal responses from participants revealed that participants underestimated significantly less in the virtual world as compared to the RW. We also found that verbal reports and reaches provided different results in both IVEs and RW environments.

The goal of our work is to develop a programmatically controlled peer to bicycle with a human subject for the purpose of studying how social interactions influence road-crossing behavior. The peer is controlled through a combination of reactive controllers that determine the gross motion of the virtual bicycle, action-based controllers that animate the virtual bicyclist and generate verbal behaviors, and a keyboard interface that allows an experimenter to initiate the virtual bicyclist's actions during the course of an experiment. The virtual bicyclist's repertoire of behaviors includes road following, riding alongside the human rider, stopping at intersections, and crossing intersections through specified gaps in traffic. The virtual cyclist engages the human subject through gaze, gesture, and verbal interactions. We describe the structure of the behavior code and report the results of a study examining how 10- and 12-year-old children interact with a peer cyclist that makes either risky or safe choices in selecting gaps in traffic. Results of our study revealed that children who rode with a risky peer were more likely to cross intermediate-sized gaps than children who rode with a safe peer. In addition, children were significantly less likely to stop at the last six intersections after the experience of riding with the risky than the safe peer during the first six intersections. The results of the study and children's reactions to the virtual peer indicate that our virtual peer framework is a promising platform for future behavioral studies of peer influences on children's bicycle riding behavior.

We report a series of experiments conducted to investigate the effects of travel technique on information gathering and cognition in complex virtual environments. In the first experiment, participants completed a non-branching multilevel 3D maze at their own pace using either real walking or one of two virtual travel techniques. In the second experiment, we constructed a real-world maze with branching pathways and modeled an identical virtual environment. Participants explored either the real or virtual maze for a predetermined amount of time using real walking or a virtual travel technique. Our results across experiments suggest that for complex environments requiring a large number of turns, virtual travel is an acceptable substitute for real walking if the goal of the application involves learning or reasoning based on information presented in the virtual world. However, for applications that require fast, efficient navigation or travel that closely resembles real-world behavior, real walking has advantages over common joystick-based virtual travel techniques.

The goal of our work is to develop a programmatically controlled peer to ride with a human subject for the purpose of studying how social interactions influence riding behavior. The peer is controlled through a combination of reactive controllers that determine the gross motion of the virtual bicycle, action-based controllers that animate the virtual bicyclist and generate verbal behaviors, and a keyboard interface that allows an experimenter to initiate the virtual bicyclist's actions during the course of an experiment. The virtual bicyclist's repertoire of behaviors includes road following, riding alongside the human rider, stopping at intersections, and crossing intersections through specified gaps. The virtual cyclist engages the human subject through gaze, gesture, and verbal interactions. We describe the structure of the behavior code and report the results of a pilot study examining how 10- and 12-year-old children interact with a peer cyclist. Results of the pilot study showed that the presence of the peer had a significant influence on the size of the gaps taken as well as time left to spare between the participant and the trailing car in the crossed gap.

We investigated the effects of using immersive virtual humans to teach users social conversational verbal and non-verbal protocols in south Indian culture. The study was conducted using a between-subjects experimental design, and compared instruction and interactive feedback from immersive virtual humans against instruction based on a written study guide with illustrations of the social protocols. Participants were then tested on how well they learned the social conversational protocols by exercising the social conventions in front of videos of real people. The results of our study suggest that participants who trained with the virtual humans performed significantly better than the participants who studied from literature.

Traditionally, students study plays by reading from a book. However, reading dialogue on paper does not always communicate the various emotions and actions that help people understand the significance of the person-to-person interactions that are represented.

An analysis of court cases has revealed that the mistaken identification of the wrong person by victims and witnesses of a crime is the single most common error leading to the arrest and conviction of innocent people [Wells et al. 2006]. Recognizing the role of mistaken identification in erroneous conviction, a growing number of states and police departments have reformed their eyewitness identification procedures. In this paper, we investigate a new procedural reform: the use of a virtual officer who does not know the identity of the suspect in the lineup and therefore cannot bias the witness toward false identification.

We describe a between-subjects experiment that compared four different methods of travel and their effect on cognition and paths taken in an immersive virtual environment (IVE). Participants answered a set of questions based on Crook's condensation of Bloom's taxonomy that assessed their cognition of the IVE with respect to knowledge, understanding and application, and higher mental processes. Participants also drew a sketch map of the IVE and the objects within it. The users' sense of presence was measured using the Steed-Usoh-Slater Presence Questionnaire. The participants' position and head orientation were automatically logged during their exposure to the virtual environment. These logs were later used to create visualizations of the paths taken. Path analysis, such as exploring the overlaid path visualizations and dwell data information, revealed further differences among the travel techniques. Our results suggest that, for applications where problem solving and evaluation of information is important or where opportunity to train is minimal, then having a large tracked space so that the participant can walk around the virtual environment provides benefits over common virtual travel techniques.