The use of virtual reality (VR) has become widespread, and ensuring accessibility to VR is critical for the technology to be inclusive. However, most VR technology relies heavily on visual input for navigation, interaction, and feedback, which makes the VR less accessible for individuals with low vision, a prevalent global health condition. In this study, we developed a virtual, gaze-contingent simulation of central vision loss (CVL) and peripheral vision loss (PVL) in a head-mounted display. We examined how these two types of restricted visual input affected people’s perception of an affordance that is highly related to independent mobility, specifically the perceived ability to step over a virtual gap. In two experiments, participants judged whether they could step over virtual gaps under no vision loss and CVL (Exp 1) or PVL (Exp 2) conditions. Across both experiments, the vision loss conditions showed increases in decision-making time and reduced confidence in judgments compared to no vision loss. Results showed no significant difference in affordance judgments for stepping over for the CVL and no vision loss conditions, suggesting that residual peripheral vision may compensate for central deficits. But participants in the PVL condition underestimated their ability to step over gaps relative to no vision loss. This effect may have been due to an inability to integrate multiple views of the gap in order to make judgments. These findings demonstrate that different types of vision loss differentially impact perception-action coupling in virtual reality and underscore the importance of VR systems that consider sensory loss. Our approach offers a framework for understanding visual accessibility in immersive environments and highlights the potential of low vision simulation for future perception-action research.

Designing effective navigation systems in mixed reality (MR) is a critical challenge that requires a nuanced understanding of how virtual cues interact with user characteristics and the physical environment. To address this, we investigated the impact of two fundamental design choices: the frame of reference for displaying cues (world-fixed vs. screen-fixed) and the use of explicit landmark annotations. An urban environment with local and global landmarks was designed to understand how the visibility of environmental features impacts users’ visual attention and interferes with the formation of spatial knowledge. We assessed the navigation behavior, gaze patterns, and spatial knowledge acquisition of 81 participants (40 female, 41 male). We also analyzed the role of individual differences, including spatial ability and gender. Results show that world-fixed cues aligned better with natural gaze patterns and reduced unnecessary saccades, landmark cues improved learning, particularly for participants with lower spatial ability, and the frequency of utilizing global landmarks during navigation enhances spatial memory. We further observed gender-related differences in gaze–head coordination strategies. These findings advance understanding of how MR navigation cues influence real-time behavior and outcomes in spatial tasks. They provide design recommendations for adaptive MR systems that match cue placement to environmental conditions and user characteristics.

Virtual reality (VR) technology offers highly controlled immersive experiences that can be used to conduct spatial cognition research. However, there are VR-specific perceptual biases that reduce its ability to generalize all findings to real-world scenarios. One specific bias causes observers to perceive objects as closer than intended, a phenomenon called distance compression. Although prior research has focused primarily on visual and technological solutions to distance compression, using other senses as a potential remedy (e.g., hearing) for the bias has not been explored. Here, participants completed both a blind-walking task for distance estimation and a cross-modal perceptual-matching task to evaluate audiovisual spatial displacement. The results showed that real-world sounds spatially displaced both in front of and behind a corresponding visual target increased the accuracy of blind walking relative to vision-only cues, albeit with a small effect. Individual differences measures, including performance on the perceptual-matching task and the relative variability of auditory and visual stimuli, did not account for the individual differences in the effectiveness of spatially displaced sounds. Overall, this study demonstrates the potential for adding multisensory information (specifically the addition of non-virtual sounds) to improve the accuracy of distance perception in VR.

Historically, distances are underestimated in virtual environments, and a mismatch between a participant's inter-pupillary distance (IPD) and the inter-axial distance (IAD) of the head-mounted display (HMD) could contribute to underestimation, but prior work has not examined how this interacts with lens type or target location in the visual field. Prior work testing the effects of IPD mismatch on distance perception in immersive virtual environments (IVEs) shows mixed results for distances within 2-10 meters. One limitation is that this work did not consider the variety of optical lenses employed in different HMDs. The lens type could affect distance perception differently depending on IPD and could affect it even more for targets appearing on the sides of the display rather than in front of the user. We examined whether the HMD type and location of targets in the virtual visual field affect perception when IPD is mismatched and matched. Using a blind walking task, participants judged the distance to targets that were either in front or to the side of the participant. One group viewed targets in the Varjo XR-3 and the other viewed them in the HTC Vive Pro. We found that distances were judged to be farther in the periphery than in front of users for both devices. Only in the HTC Vive Pro did an increase in IPD mismatch result in increased distance estimates for targets presented directly in front of the participant. Directional angular error (error observed in orienting to the target) increased as the target angle increased for both devices. However, in the Varjo XR-3, a higher IPD mismatch resulted in greater angular error when viewing targets to the side. Overall, the findings show that a mismatched IPD can affect depth and orientation judgments depending on target position in the display. However, there are differences in both FOV and resolution that could influence distance and orientation perception. A second experiment was conducted to examine whether these factors contributed to perception. To test for this, we down-sampled the Varjo XR-3 to match the horizontal field of view and resolution of the HTC Vive Pro. We found that orientation error was mostly affected by resolution and FOV as the adjusted Varjo XR-3 yielded similar orientation perception as the HTC Vive Pro. With this knowledge, researchers should consider HMDs, IPD, and viewing area in the display as possible influences on distance and orientation perception in order to make VR accessible and accurate to all users.

How children perceive and interact in immersive virtual environments (IVEs) is an important and emerging topic as virtual reality devices proliferate among this age group. How children understand their opportunities for action in an IVE — the perceived affordances of the space — in comparison to adults has, in particular, been rarely studied. This paper addresses this gap by examining children and adults’ reaching affordances in IVEs. We compared how children and adults judge their ability to reach up and out to targets at different distances in an IVE and how feedback from their actions may influence their accuracy. We found that both children and adults tend to overestimate their reaching capabilities, particularly when reaching out. However, by allowing them to actually reach up or out to the targets (action-outcome feedback), both groups significantly re-calibrated their judgments to align their estimates more closely with their actual capabilities. Notably, children exhibited greater initial overestimation than adults but recalibrated at a similar rate. These findings provide novel insights into how children interact with IVEs and suggest that well-designed feedback mechanisms can enhance their accuracy in action-based tasks. This work has implications for the design of IVEs for children, particularly in educational and training contexts, where ensuring accurate perception of capabilities is critical for learning and safety. By investigating both horizontal and vertical reach, this paper contributes to the understanding of affordance perception across age groups in IVEs, marking an essential step in adapting virtual reality technology to younger users.

Virtual reality (VR) has become a popular tool for studying navigation, providing the experimental control of a laboratory setting but also the potential for immersive and natural experiences that resemble the real world. For VR to be an effective tool to study navigation and be used for training or rehabilitation, it is important to establish whether performance is similar across virtual and real environments. Much of the existing navigation research has focused on young adult performance either in a virtual or a real environment, resulting in an open question regarding the validity of VR for studying age-related effects on spatial navigation. In this paper, young (18-30 years old) and older adults (60 years and older) performed the same navigation task in similar real and virtual environments. They completed a homing task, requiring walking along two legs of a triangle and returning to a home location, under three sensory conditions: visual cues (environmental landmarks present), body-based self-motion cues, and the combination of both cues. Our findings reveal that homing performance in VR demonstrates the same age-related differences as those observed in the real-world task. That said, within-age group differences arise when comparing cue use across environment types. In particular, young adults are less accurate and more variable with self-motion cues than visual cues in VR, while older adults show similar deficits with both cues. However, when both age groups can access multiple sensory cues, navigation performance does not differ between environment types. These results demonstrate that VR effectively captures age-related differences, with navigation performance most closely resembling performance in the real world when navigators can rely on an array of sensory information. Such findings have implications for future research on the aging population, highlighting that VR can be a valuable tool, particularly when multisensory cues are available.

Most modern head-mounted displays (HMDs) do not support the full range of adult inter-pupillary distances (IPDs) (i.e., 45 – 80 mm) due to technological limitations. Prior work indicates that the mismatch between a user’s actual IPD and the IPD set in the HMD (“IPD mismatch”) can affect distance and size judgments in near space (0 – 2 m). Therefore, users with IPDs outside of the supported HMD IPD range may not perceive virtual environments (VEs) accurately. Across three experiments, we investigated whether IPD mismatch significantly affects peoples’ distance judgments at longer distances (4 – 7 m). In two of the experiments, we recruited participants with IPDs smaller than the minimum supported IPD of the HTC Vive Pro HMD. They estimated distances in action space using verbal estimation (Experiment 1) and blind walking (Experiment 2) measures in indoor VEs. We found that: (i) distances were underestimated in action space, and (ii) IPD mismatch had minimal to no effect on their distance judgments. In a third experiment, we investigated whether we could generalize our findings to participants with an IPD within the supported HMD IPD range. We were able to replicate our previous findings. Overall, our findings suggest that IPD mismatch in an HMD may not be a major factor in distance underestimation in action space in VEs.

Virtual reality (VR) has become widely accessible through the development of more commercially available head-mounted displays (HMDs). This accessibility has particularly increased the use of VR in children. However, much of the previous research on understanding perception and action in virtual reality has only been conducted on adults, leaving many open questions about how children perceive and interact with virtual environments. In this paper, we examine whether there are age-related differences in judging the ability to step over a gap using immersive VR. Affordances are a useful measure for understanding objective perceptions of the actions that can be performed in an immersive virtual environment. Such measures are particularly well suited for children given they can easily respond yes or no as to whether they perceive that they can step over a gap. Further, manipulations of the size of virtual body parts could allow us to ascertain how much children rely on the perceived size of their bodies to make decisions about actions. In Experiment 1, adults and children saw motion-tracked virtual feet that were either larger or smaller than their actual foot size. They had to respond as to whether they could step over gaps that varied in width. They also gave perceptual estimates of the width of the gap in feet or meters. The results showed that adults who experience the smaller virtual feet underestimated their stepping ability more than adults with the larger feet. However, children had the opposite effect, such that seeing smaller virtual feet led to an overestimation of their stepping ability. To test whether this age-related difference in body scaling was due to misperception of foot size, adults and children matched virtual shoes to their actual feet size in Experiment 2. This matching task showed no perceptual differences between the age groups. Across our two experiments, we showed that children scale gap affordance judgments differently than adults and this difference cannot be explained by difference in perceptions of the size of virtual feet. The results suggest that children can effectively make perception and action judgments in virtual reality, but do not always do so in the same manner as adults. Such a finding has implications for the design of virtual reality games, educational tools, and training systems that are becoming increasingly common for children.

Accurate perception of one’s action capabilities, or affordance perception, is essential for successful interaction with both real and virtual environments. Affordance perception can potentially be improved by receiving feedback. It is unknown what specific types of feedback are needed for improvements in affordance perception to occur, particularly in virtual environments where cues may be impoverished. The current work studied perception of horizontal reachability in virtual and augmented reality (VR and AR), specifically whether it would improve with feedback, and if any improvement transferred to the real world. Multiple types of feedback were studied in VR or AR: exploratory behavior, static outcome, and action outcome feedback. Our results indicate that exploratory behavior is sufficient for improvement in perceived reachability in VR, but in AR, outcome feedback is necessary. In both VR and AR, outcome feedback was required for improvement in perceived reachability to transfer to the real world. These findings have practical implications for training in virtual environments. If virtual environments are used for training actions that ultimately need to be performed in the real world, outcome feedback should be provided.

In this special issue of IEEE Transactions on Visualization and Computer Graphics (TVCG), we are pleased to present the journal papers from the 23rd IEEE International Symposium on Mixed and Augmented Reality (ISMAR 2024), which will be held as a hybrid conference between October 21 and 25, 2024 in the Greater Seattle Area, USA. ISMAR continues the over twenty-year long tradition of IWAR, ISMR, and ISAR, and is the premier conference for Mixed and Augmented Reality in the world.

Although distance perception to Augmented Reality (AR) objects has been studied for decades, little is known about absolute distance perception with the newest available AR displays. One significant distinction in categories of head-worn AR displays is whether they are optical see-through (OST) or video see-through (VST). These two types of devices have different methods of rendering that could affect the cues available for perceiving distance. Specifically, rendering cast shadows can be challenging, especially in OST displays that rely on additive light for rendering, and there may be alternative shadow shading methods that are equally as effective for conveying cues to depth. The current study tests absolute egocentric distance judgments to targets 3-6 meters away from an observer with two types of shadows, in two types of AR displays, the Hololens 2 (OST) and the Varjo XR-3 (VST). Shadows were realistic cast shadows or non-realistic shadows in the form of a stylized ring placed beneath the object. Participants verbally reported perceived distance to spherical virtual targets presented on or above the ground, viewed through the displays in a real world classroom. We found overall distance underestimation in both devices, but that estimations were more accurate with the Hololens 2 compared to the Varjo XR-3. There was little support for a difference in accuracy of estimations between shadow conditions or position on or above the ground (confirmed by a Bayesian analysis), suggesting that non-realistic shadows may be a good option for providing additional shading cues for depth in AR.

As applications for virtual reality (VR) and augmented reality (AR) technology increase, it will be important to understand how users perceive their action capabilities in virtual environments. Feedback about actions may help to calibrate perception for action opportunities (affordances) so that action judgments in VR and AR mirror actors’ real abilities. Previous work indicates that walking through a virtual doorway while wielding an object can calibrate the perception of one’s passability through feedback from collisions. In the current study, we aimed to replicate this calibration through feedback using a different paradigm in VR while also testing whether this calibration transfers to AR. Participants held a pole at 45°and made passability judgments in AR (pretest phase). Then, they made passability judgments in VR and received feedback on those judgments by walking through a virtual doorway while holding the pole (calibration phase). Participants then returned to AR to make posttest passability judgments. Results indicate that feedback calibrated participants’ judgments in VR. Moreover, this calibration transferred to the AR environment. In other words, after experiencing feedback in VR, passability judgments in VR and in AR became closer to an actor’s actual ability, which could make training applications in these technologies more effective.

Daily travel usually demands navigation on foot across a variety of different application domains, including tasks like search and rescue or commuting. Head-mounted augmented reality (AR) displays provide a preview of future navigation systems on foot, but designing them is still an open problem. In this paper, we look at two choices that such AR systems can make for navigation: 1) whether to denote landmarks with AR cues and 2) how to convey navigation instructions. Specifically, instructions can be given via a head-referenced display (screen-fixed frame of reference) or by giving directions fixed to global positions in the world (world-fixed frame of reference). Given limitations with the tracking stability, field of view, and brightness of most currently available head-mounted AR displays for lengthy routes outdoors, we decided to simulate these conditions in virtual reality. In the current study, participants navigated an urban virtual environment and their spatial knowledge acquisition was assessed. We experimented with whether or not landmarks in the environment were cued, as well as how navigation instructions were displayed (i.e., via screen-fixed or world-fixed directions). We found that the world-fixed frame of reference resulted in better spatial learning when there were no landmarks cued; adding AR landmark cues marginally improved spatial learning in the screen-fixed condition. These benefits in learning were also correlated with participants' reported sense of direction. Our findings have implications for the design of future cognition-driven navigation systems.

Although it is commonly accepted that depth perception in augmented reality (AR) displays is distorted, we have yet to isolate which properties of AR affect people’s ability to correctly perceive virtual objects in real spaces. From prior research on depth perception in commercial virtual reality, it is likely that ergonomic properties and graphical limitations impact visual perception in head-mounted displays (HMDs). However, an insufficient amount of research has been conducted in augmented reality HMDs for us to begin isolating pertinent factors in this family of displays. To this end, in the current research, we evaluate absolute measures of distance perception in the Microsoft HoloLens 2, an optical see-through AR display, and the Varjo XR-3, a video see-through AR display. The current work is the first to evaluate either device using absolute distance perception as a measure. For each display, we asked participants to verbally report distance judgments to both grounded and floating targets that were rendered either with or without a cast shadow along the ground. Our findings suggest that currently available video see-through displays may induce more distance underestimation than their optical see-through counterparts. We also find that the vertical position of an object and the presence of a cast shadow influence depth perception.

Virtual objects in augmented reality (AR) often appear to float atop real world surfaces, which makes it difficult to determine where they are positioned in space. This is problematic as many applications for AR require accurate spatial perception. In the current study, we examine how the way we render cast shadows-which act as an important monocular depth cue for creating a sense of contact between an object and the surface beneath it-impacts spatial perception. Over two experiments, we evaluate people's sense of surface contact given both traditional and non-traditional shadow shading methods in optical see-through augmented reality (OST AR), video see-through augmented reality (VST AR), and virtual reality (VR) head-mounted displays. Our results provide evidence that nontraditional shading techniques for rendering shadows in AR displays may enhance the accuracy of one's perception of surface contact. This finding implies a possible tradeoff between photorealism and accuracy of depth perception, especially in OST AR displays. However, it also supports the use of more stylized graphics like non-traditional cast shadows to improve perception and interaction in AR applications.

Today, augmented reality (AR) is most easily experienced through a mobile device such as a modern smartphone. For AR to be useful for applications such as training, it is important to understand how people perceive interactions with virtual objects presented to them via mobile AR. In this paper, we investigated two judgments of action capabilities (affordances) with virtual objects presented through smartphones: passing through an aperture and stepping over a gap. Our goals were to 1) determine if people can reliably scale these judgments to their body dimensions or capabilities and 2) explore whether cues presented in the context of the action could change their judgments. Assessments of perceived action capabilities were made in a pre/post-test design in which observers judged their affordances towards virtual objects prior to seeing an AR cue denoting their body dimension/capability, while viewing the cue, and after seeing the cue. Different patterns of results were found for the two affordances. For passing through, estimates became closer to shoulder width in the post-cue compared to the pre-cue block. For gap stepping, estimates were closer to actual stepping capability while viewing the cue, but did not persist when the cue was no longer present. Overall, our findings show that mobile smartphones can be used to assess perceived action capabilities with virtual targets and that AR cues can influence the perception of action capabilities in these devices. Our work provides a foundation for future studies investigating perception with the use of mobile AR with smartphones.

The perception of the size of indoor rooms is traditionally measured with spaciousness ratings or verbal estimations of width and length, but these measures inherently focus on specific aspects of rooms that may not accurately capture a holistic perception of room size. The current study asked users to re-create the size of virtual rooms with a visual matching task by adjusting the dimensions of comparison virtual rooms to match those of a previously viewed virtual room. In addition to estimating room size with this novel room re-creation measure, participants also provided spaciousness ratings and verbal reports of length and width for each room. The results indicate that users accurately estimate relative room size using room re-creation. Room dimensions set in the room re-creation task were more accurate to the programmed dimensions and less variable than verbal reports. The room re-creation measure was positively correlated with spaciousness ratings, indicating that it also captures holistic perception of room size. Thus, the virtual room re-creation task accurately assesses both holistic and dimensional perception of the size of virtual rooms in an informative, quantitative manner. The room re-creation measure exemplifies the ability to use virtual reality as a unique tool for measuring space perception. The current study demonstrates the implementation of the novel room re-creation task and its ability to accurately capture the perception of virtual rooms, which can serve as a foundation for future studies to assess the ability of virtual room re-creation to capture the perception of real-world rooms. This new measure of room size perception is relevant to theoretical space perception research as well as applied research in architecture and interior design.

Previous research on distance estimation in virtual reality (VR) has well established that even for geometrically accurate virtual objects and environments users tend to systematically mis-estimate distances. This has implications for Social VR, where it introduces variables in personal space and proxemics behavior that change social behaviors compared to the real world. One yet unexplored factor is related to the trend that avatars' embodied cues in Social VR are often scaled, e.g., by making one's head bigger or one's voice louder, to make social cues more pronounced over longer distances. In this paper we investigate how the perception of avatar distance is changed based on two means for scaling embodied social cues: visual head scale and verbal volume scale. We conducted a human-subject study employing a mixed factorial design with two Social VR avatar representations (full-body, head-only) as a between factor as well as three visual head scales and three verbal volume scales (up-scaled, accurate, down-scaled) as within factors. For three distances from social to far-public space, we found that visual head scale had a significant effect on distance judgments and should be tuned for Social VR, while conflicting verbal volume scales did not, indicating that voices can be scaled in Social VR without immediate repercussions on spatial estimates. We discuss the interactions between the factors and implications for Social VR.

Immersive virtual environments (VEs) are most useful for training and education when viewers perceive and act accurately within them. Judgments of action capabilities within a VE provide a good measure of perceptual fidelity - the notion of how closely perception and action in the VE match that in the real world - and can also assess how perception for action may be calibrated with visual feedback based on one's own actions. In the current study we tested judgments of action capabilities within a VE for two different reaching behaviors: reaching out and reaching up. Our goal was to assess whether feedback from actual reaching improves judgments and if any recalibration due to feedback differed across reaching behaviors. We first measured participants' actual reaching out and reaching up capabilities so that feedback trials could be scaled to their actual abilities. Participants then completed blocks of alternating perceptual adjustment and feedback trials. In adjustment trials, they adjusted a virtual target to a distance perceived to be just reachable. In feedback trials, they viewed targets that were farther or closer than their actual reach, decided whether the target was reachable, and then reached out to the target to receive visual feedback from a hand-held controller. The first feedback block manipulated the target distance to be 30% over or under actual reach and subsequent blocks decreased the deviation to 20%,10% and 5% of actual reach. We found that for both reaching behaviors, reach was initially overestimated, and then perceptual estimations decreased to become more accurate over feedback blocks. Accuracy in the feedback trials themselves showed that targets just beyond reach were more difficult to judge correctly. This study establishes a straightforward methodology that can be used for calibration of actions in VEs and has implications for applications that depend on accurate reaching within VEs.

Augmented reality ( AR ) is important for training complex tasks, such as navigation, assembly, and medical procedures. The effectiveness of such training may depend on accurate spatial localization of AR objects in the environment. This article presents two experiments that test egocentric distance perception in augmented reality within and at the boundaries of action space (up to 35 m) in comparison with distance perception in a matched real-world ( RW ) environment. Using the Microsoft HoloLens, in Experiment 1, participants in two different RW settings judged egocentric distances (ranging from 10 to 35 m) to an AR avatar or a real person using a visual matching measure. Distances to augmented targets were underestimated compared to real targets in the two indoor, RW contexts. Experiment 2 aimed to generalize the results to an absolute distance measure using verbal reports in one of the indoor environments. Similar to Experiment 1, distances to augmented targets were underestimated compared to real targets. We discuss these findings with respect to the importance of methodologies that directly compare performance in real and mediated environments, as well as the inherent differences present in mediated environments that are “matched” to the real world.

Mixed reality is increasingly being used for training, especially for tasks that are difficult for humans to perform such as far distance perception. Although there has been much prior work on the perception of distance in mixed reality, the majority of the work has focused on distances ranging up to about 30 meters. The little work that has investigated distance perception beyond 30 meters has been mixed in terms of whether people tend to over- or underestimate distances in this range. In the current study, we investigated the perception of distances ranging from 25-500 meters in a fully mediated outdoor environment using the ZED Mini and HTC Vive Pro. To our knowledge, no work has examined distance perception to this range in mixed reality. Participants in the study verbally estimated the distances to a variety of objects. Distances were overestimated from 25-200 meters but underestimated from 300-500 meters. Overall, far distance perception in mixed reality may be biased in different directions depending on the range of distances, suggesting a need for future research in this area to support training of far distance perception.

The effectiveness of Augmented Reality (AR) for spatial applications is likely influenced by the extent to which users perceive that they can act on virtual objects as if they are real. While there are some promising initial results that action capabilities in AR are perceived similarly to the real world, AR differs from completely real-world viewing both in the visual information available within a restricted field of view (FOV) and in the ways that perceptual-motor feedback can be provided for the outcome of actions. We addressed both of these differences in a study of judgments of passing through an AR aperture defined by two moveable virtual walls presented via the Microsoft HoloLens. First, we investigated the possible effects of viewing distance on affordance judgments, predicting greater error in judgments at a close distance because of the inability to see the entirety of the aperture within the FOV. Second, we explored the effect of feedback on affordance judgments, predicting that verbal feedback about whether a judgment was correct would be sufficient to see improvements in judgments over time. In contrast to our predictions for distance, we found that judgments for passing through were closer to actual shoulder width when viewed at a distance near the aperture (0.85 m) compared to a farther viewing point (3.20 m). Verbal feedback reduced error over trials, but only at the farther distance, possibly because the judgments at the near distance were close to the ceiling of performance. These findings have implications for tasks that require accurate perception of action capabilities in AR, such as training procedures.

The creation of realistic self-avatars that users identify with is important for many virtual reality applications. However, current approaches for creating biometrically plausible avatars that represent a particular individual require expertise and are time-consuming. We investigated the visual perception of an avatar’s body dimensions by asking males and females to estimate their own body weight and shape on a virtual body using a virtual reality avatar creation tool. In a method of adjustment task, the virtual body was presented in an HTC Vive head-mounted display either co-located with (first-person perspective) or facing (third-person perspective) the participants. Participants adjusted the body weight and dimensions of various body parts to match their own body shape and size. Both males and females underestimated their weight by 10-20% in the virtual body, but the estimates of the other body dimensions were relatively accurate and within a range of ± 6%. There was a stronger influence of visual perspective on the estimates for males, but this effect was dependent on the amount of control over the shape of the virtual body, indicating that the results might be caused by where in the body the weight changes expressed themselves. These results suggest that this avatar creation tool could be used to allow participants to make a relatively accurate self-avatar in terms of adjusting body part dimensions, but not weight, and that the influence of visual perspective and amount of control needed over the body shape are likely gender-specific.

Augmented reality (AR) technologies have the potential to provide individuals with unique training and visualizations, but the effectiveness of these applications may be influenced by users' perceptions of the distance to AR objects. Perceived distances to AR objects may be biased if these objects do not appear to make contact with the ground plane. The current work compared distance judgments of AR targets presented on the ground versus off the ground when no additional AR depth cues, such as shadows, were available to denote ground contact. We predicted that without additional information for height off the ground, observers would perceive the off-ground objects as placed on the ground, but at farther distances. Furthermore, this bias should be exaggerated when targets were viewed with one eye rather than two. In our experiment, participants judged the absolute egocentric distance to various cubes presented on or off the ground with an action-based measure, blind walking. We found that observers walked farther for off-ground AR objects and that this effect was exaggerated when participants viewed off-ground objects with monocular vision compared to binocular vision. However, we also found that the restriction of binocular cues influenced participants' distance judgments for on-ground AR objects. Our results suggest that distances to off-ground AR objects are perceived differently than on-ground AR objects and that the elimination of binocular cues further influences how users perceive these distances.

It is an open question as to whether people perceive and act in augmented reality environments in the same way that they do in real environments. The current work investigated participants' judgments of whether or not they could act on an obstacle portrayed with augmented reality. Specifically, we presented gaps of varying widths and depths to participants in augmented reality using the Microsoft HoloLens. We asked users to indicate whether or not they believed that they could step across the virtual gaps given their widths and depths. Averaging across changes in width and depth, users generally underestimated their abilities to cross gaps. However, this underestimation was significantly greater when the gaps were deep. Thus, our findings suggest that users in augmented reality respond with more conservative judgments when presented with risky stimuli-a response that mimics real world behavior. Their altered reactions to deeper gaps may provide early evidence for augmented reality's capacity to evoke a sense of realism or immersion and its use in evaluating perception and action.

The utility of mediated environments increases when environmental scale (size and distance) is perceived accurately. We present the use of perceived affordances---judgments of action capabilities---as an objective way to assess space perception in an augmented reality (AR) environment. The current study extends the previous use of this methodology in virtual reality (VR) to AR. We tested two locomotion-based affordance tasks. In the first experiment, observers judged whether they could pass through a virtual aperture presented at different widths and distances, and also judged the distance to the aperture. In the second experiment, observers judged whether they could step over a virtual gap on the ground. In both experiments, the virtual objects were displayed with the HoloLens in a real laboratory environment. We demonstrate that affordances for passing through and perceived distance to the aperture are similar in AR to those measured in the real world, but that judgments of gap-crossing in AR were underestimated. These differences across two affordances may result from the different spatial characteristics of the virtual objects (on the ground versus extending off the ground).

As virtual reality expands in popularity, an increasingly diverse audience is gaining exposure to immersive virtual environments (IVEs). A significant body of research has demonstrated how perception and action work in such environments, but most of this work has been done studying adults. Less is known about how physical and cognitive development affect perception and action in IVEs, particularly as applied to preteen and teenage children. Accordingly, in the current study we assess how preteens (children aged 8-12 years) and teenagers (children aged 15-18 years) respond to mismatches between their motor behavior and the visual information presented by an IVE. Over two experiments, we evaluate how these individuals recalibrate their actions across functionally distinct systems of movement. The first experiment analyzed forward walking recalibration after exposure to an IVE with either increased or decreased visual flow. Visual flow during normal bipedal locomotion was manipulated to be either twice or half as fast as the physical gait. The second experiment leveraged a prism throwing adaptation paradigm to test the effect of recalibration on throwing movement. In the first experiment, our results show no differences across age groups, although subjects generally experienced a post-exposure effect of shortened distance estimation after experiencing visually faster flow and longer distance estimation after experiencing visually slower flow. In the second experiment, subjects generally showed the typical prism adaptation behavior of a throwing after-effect error. The error lasted longer for preteens than older children. Our results have implications for the design of virtual systems with children as a target audience.

The use of first-person self-avatars in immersive virtual environments (VEs) has grown over recent years. It is unknown, however, how visual feedback from a self-avatar influences a user's online actions and subsequent calibration of actions within an immersive VE. The current paper uses a prism throwing adaptation paradigm to test the role of a self-avatar arm or full body on action calibration in a VE. Participants' throwing accuracy to a target on the ground was measured first in a normal viewing environment, then with the visual field rotated clockwise about their vertical axis by 17° (prism simulation), and then again in the normal viewing environment with the prism distortion removed. Participants experienced either no-avatar, a first-person avatar arm and hand, or a first-person full body avatar during the entire experimental session, in a between-subjects manipulation. Results showed similar throwing error and adaptation during the prism exposure for all conditions, but a reduced aftereffect (displacement with respect to the target in the opposite direction of the prism-exposure) when the avatar arm or full body was present. The results are discussed in the context of how an avatar can provide a visual frame of reference to aid in action calibration.

Perceiving an accurate sense of absolute scale is important for the utility of virtual environments (VEs). Research shows that absolute egocentric distances are underestimated in VEs compared to the same judgments made in the real world, but there are inconsistencies in the amount of underestimation. We examined two possible factors in the variation in the magnitude of distance underestimation. We compared egocentric distance judgments in a high-cost (NVIS SX60) and low-cost (Oculus Rift DK2) HMD using both indoor and outdoor highly-realistic virtual models. Performance more accurately matched the intended distance in the Oculus compared to the NVIS, and regardless of the HMD, distances were underestimated more in the outdoor versus the indoor VE. These results suggest promise in future use of consumer-level wide field-of-view HMDs for space perception research and applications, and the importance of considering the context of the environment as a factor in the perception of absolute scale within VEs.

Many have experienced vastness, the feeling when the visual space seems to extend without limits away from you, making you feel like a small element within the space. For over 200 years, people have been writing about this experience, for example stating that vastness is important to the experience of awe [Mikulak 2015]. Yet vastness has received little attention in empirical research. Specifically, it is unknown which aspects of the visual stimulus contribute to perceived vastness. This may be due to the inherent difficulties in presenting a variety of vast stimuli while varying only specific visual cues. Using virtual reality addresses these difficulties, as this technology provides precise control over the presented visual stimuli. Here we investigate whether the feeling of vastness can be evoked using virtual reality and explore potential objective measures to assess vastness. We used three different measures during this experiment: 1) An avatar height adjustment task where participants had to adjust an avatar to be equivalent to their own height as viewed from a distance, 2) a distance estimation task and 3) a subjective vastness rating task. These tasks were performed in four environments: a plain (used in all subsequent environments for the ground and sky surfaces), a forest, a mountain and the mountain and forest environments combined. Our results indicate that the feeling of vastness can indeed be experienced to various degrees in virtual environments, demonstrating the potential of VR as a tool for exploring the perception of vastness. Yet the results combined suggest that the percept of vastness is a rather complex construct.

Spatial perception research in the real world and in virtual environments suggests that the body (e.g., hands) plays a role in the perception of the scale of the world. However, little research has closely examined how varying the size of virtual body parts may influence judgments of action capabilities and spatial layout. Here, we questioned whether changing the size of virtual feet would affect judgments of stepping over and estimates of the width of a gap. Participants viewed their disembodied virtual feet as small or large and judged both their ability to step over a gap and the size of gaps shown in the virtual world. Foot size affected both affordance judgments and size estimates such that those with enlarged virtual feet estimated they could step over larger gaps and that the extent of the gap was smaller. Shrunken feet led to the perception of a reduced ability to step over a gap and smaller estimates of width. The results suggest that people use their visually perceived foot size to scale virtual spaces. Regardless of foot size, participants felt that they owned the feet rendered in the virtual world. Seeing disembodied, but motion-tracked, virtual feet affected spatial judgments, suggesting that the presentation of a single tracked body part is sufficient to produce similar effects on perception, as has been observed with the presence of fully co-located virtual self-avatars or other body parts in the past.

The use of third-person self-avatars has become common in non-immersive virtual environments, due in part to the advantages of seeing a full body while moving around in space. However, little research has investigated how third-person self-avatars can benefit task performance in immersive virtual environments (IVEs). This paper explores a procedure that may enhance user ability to act in an IVE from the point of view of a self-avatar projected in front of the viewer. Such abilities could be crucial in applications such as remote operator control, when a third person view is necessary or is the only view available. We conducted an experiment to assess the role of dynamic visual-motor and haptic feedback with a third-person avatar on a user's ability to point to remembered targets from the location of the avatar. The dynamic condition was compared within-subjects to a static condition in which the user's movements were not tracked with the avatar but the same task was required. Overall, participants were relatively good at pointing to targets from the location of the avatar. However, participants in the dynamic condition showed pointing performance that corresponded more closely to the avatar's location than was the case in the static condition. Subjective reports of bodily self-perception were also included and showed increased self-identification, presence, and agency in the dynamic compared to the static condition.

The goal of this research was to investigate women's sensitivity to changes in their perceived weight by altering the body mass index (BMI) of the participants' personalized avatars displayed on a large-screen immersive display. We created the personalized avatars with a full-body 3D scanner that records the participants' body geometry and texture. We altered the weight of the personalized avatars to produce changes in BMI while keeping height, arm length, and inseam fixed and exploited the correlation between body geometry and anthropometric measurements encapsulated in a statistical body shape model created from thousands of body scans. In a 2 × 2 psychophysical experiment, we investigated the relative importance of visual cues, namely shape (own shape vs. an average female body shape with equivalent height and BMI to the participant) and texture (own photo-realistic texture or checkerboard pattern texture) on the ability to accurately perceive own current body weight (by asking the participant, “Is it the same weight as you?”). Our results indicate that shape (where height and BMI are fixed) had little effect on the perception of body weight. Interestingly, the participants perceived their body weight veridically when they saw their own photo-realistic texture. As compared to avatars with photo-realistic texture, the avatars with checkerboard texture needed to be significantly thinner in order to represent the participants' current weight. This suggests that in general the avatars with checkerboard texture appeared bigger. The range that the participants accepted as their own current weight was approximately a 0.83% to − 6.05% BMI change tolerance range around their perceived weight. Both the shape and the texture had an effect on the reported similarity of the body parts and the whole avatar to the participant's body. This work has implications for new measures for patients with body image disorders, as well as researchers interested in creating personalized avatars for games, training applications, or virtual reality.

No abstract available.

Gesture-based controllers such as the Microsoft Kinect are low cost devices that allow a user to interact with complex, three-dimensional simulations using an interface argued to be more natural than game controllers, joy sticks, or a mouse and keyboard. This paper presents a controlled experimental evaluation of the use of Microsoft Kinect to support a 3D object manipulation task. Users were asked to match the orientation of objects with a manipulation interface that displayed either a self-avatar hand and arm or a sphere, both corresponding to users' arm gestures and wrist rotation. Our results show that while there was no overall difference in performance between the self-avatar and sphere visual display conditions, there were clear differences in the two visual display conditions as a function of gender and video-game experience.

Accurate perception of the size of 3D objects depicted on 2D desktop displays is important for many applications. Whether users perceive objects depicted on a display to be the same size as comparable real world objects is not well understood. We propose using affordances judgments as a way of measuring the perceived size of objects depicted in desktop virtual environments and the real world. The methodology involves indicating whether or not a particular action can be performed in a given environment, making it a flexible measure that can be used across different display technologies. In two studies, we test users' perceptions of size by asking them to make affordance judgments in both the real world and a geometrically matched desktop virtual environment. In the first study, users judge whether they can grasp an object and in the second study, they judge whether they can fit their hand through an opening. In both experiments we show that users perceive the size of objects in the desktop virtual environment to be smaller than in the real world.