Perception In Virtual Environments Research Articles

Invited Session V: Binocular vision and interactions: Depth perception in virtual environments: The role of experience.

In this presentation I'll review results of stereoacuity, disparity matching and depth magnitude estimation studies in which comparison of so-called naïve and experienced observers shows substantive differences in performance. I will describe our working theory that the critical difference between these groups is their tolerance to conflicts between stereopsis and other sources of depth information. Further, I will review some recent data that suggest there are some conflicts that even experienced 3D participants cannot disregard.

Sound perception in virtual environments

Virtual environments have been developing and changing the understanding of a space by means design, perception and usage. This study aims to contribute to the literature on the improvement of the auditory perception and cognition of virtual spaces used for education, training, and gaming purposes. This study proposes to offer a realistic representation of soundscapes in virtual environments according to spatial qualities instead of misleading synthetic sounds by integrating acoustical simulations with the immersive environment and questioning the experience of a regular user. The study explores the effects of acoustically simulated and immersive virtual soundscape design methods on auditory perception through changing forms and materials by series of cognitive experiments. The results revealed that the participants achieve more accurate results of source-localization, self-localization, and distance guessing in an immersive environment than in the simulated environment. Also, they were more aware of the soundwalk route, spent more time on tasks, and evaluated the experience more positively in an immersive environment compared to simulations. Despite the placement of the auralizations from the simulations as sound sources in immersive environments, there is still a lack of auditory representation of spatial qualities compared to the accurate calculation of acoustical parameters in a simulated environment.

Journey through a virtual tunnel: Simulated motion and its effects on the experience of time

This paper examines the relationship between time and motion perception in virtual environments. Previous work has shown that the perception of motion can affect the perception of time. We developed a virtual environment that simulates motion in a tunnel and measured its effects on the estimation of the duration of time, the speed at which perceived time passes, and the illusion of self-motion, also known as vection. When large areas of the visual field move in the same direction, vection can occur; observers often perceive this as self-motion rather than motion of the environment. To generate different levels of vection and investigate its effects on time perception, we developed an abstract procedural tunnel generator. The generator can simulate different speeds and densities of tunnel sections (visibly distinguishable sections that form the virtual tunnel), as well as the degree of embodiment of the user avatar (with or without virtual hands). We exposed participants to various tunnel simulations with different durations, speeds, and densities in a remote desktop and a virtual reality (VR) laboratory study. Time passed subjectively faster under high-speed and high-density conditions in both studies. The experience of self-motion was also stronger under high-speed and high-density conditions. Both studies revealed a significant correlation between the perceived passage of time and perceived self-motion. Subjects in the virtual reality study reported a stronger self-motion experience, a faster perceived passage of time, and shorter time estimates than subjects in the desktop study. Our results suggest that a virtual tunnel simulation can manipulate time perception in virtual reality. We will explore these results for the development of virtual reality applications for therapeutic approaches in our future work. This could be particularly useful in treating disorders like depression, autism, and schizophrenia, which are known to be associated with distortions in time perception. For example, the tunnel could be therapeutically applied by resetting patients’ time perceptions by exposing them to the tunnel under different conditions, such as increasing or decreasing perceived time.

Perceiving distance in virtual reality: theoretical insights from contemporary technologies.

Decades of research have shown that absolute egocentric distance is underestimated in virtual environments (VEs) when compared with the real world. This finding has implications on the use of VEs for applications that require an accurate sense of absolute scale. Fortunately, this underperception of scale can be attenuated by several factors, making perception more similar to (but still not the same as) that of the real world. Here, we examine these factors as two categories: (i) experience inherent to the observer, and (ii) characteristics inherent to the display technology. We analyse how these factors influence the sources of information for absolute distance perception with the goal of understanding how the scale of virtual spaces is calibrated. We identify six types of cues that change with these approaches, contributing both to a theoretical understanding of depth perception in VEs and a call for future research that can benefit from changing technologies. This article is part of the theme issue 'New approaches to 3D vision'.

Familiar size affects perception differently in virtual reality and the real world.

The promise of virtual reality (VR) as a tool for perceptual and cognitive research rests on the assumption that perception in virtual environments generalizes to the real world. Here, we conducted two experiments to compare size and distance perception between VR and physical reality (Maltz et al. 2021 J. Vis. 21, 1-18). In experiment 1, we used VR to present dice and Rubik's cubes at their typical sizes or reversed sizes at distances that maintained a constant visual angle. After viewing the stimuli binocularly (to provide vergence and disparity information) or monocularly, participants manually estimated perceived size and distance. Unlike physical reality, where participants relied less on familiar size and more on presented size during binocular versus monocular viewing, in VR participants relied heavily on familiar size regardless of the availability of binocular cues. In experiment 2, we demonstrated that the effects in VR generalized to other stimuli and to a higher quality VR headset. These results suggest that the use of binocular cues and familiar size differs substantially between virtual and physical reality. A deeper understanding of perceptual differences is necessary before assuming that research outcomes from VR will generalize to the real world. This article is part of a discussion meeting issue 'New approaches to 3D vision'.

Alice in Wonderland: The effects of body size and movement on children’s size perception and body representation in virtual reality

Previous work shows that in adults, illusory embodiment of a virtual avatar can be induced using congruent visuomotor cues. Furthermore, embodying different-sized avatars influences adults’ perception of their environment’s size. This study (N = 92) investigated whether children are also susceptible to such embodiment and size illusions. Adults and 5-year-old children viewed a first-person perspective of different-sized avatars moving either congruently or incongruently with their own body. Participants rated their feelings of embodiment over the avatar and also estimated the sizes of their body and objects in the environment. Unlike adults, children embodied the avatar regardless of visuomotor congruency. Both adults and children freely embodied different-sized avatars, and this affected their size perception in the surrounding virtual environment; they felt that objects were larger in a small body and vice versa in a large body. In addition, children felt that their body had grown in the large body condition. These findings have important implications for both our theoretical understanding of own-body representation, and our knowledge of perception in virtual environments.

Effects of Roughness and Texture on Surface Material Perception in Virtual Environments: The Psychophysics Approach

Effects of Roughness and Texture on Surface Material Perception in Virtual Environments: The Psychophysics Approach

Visual and postural eye-height information is flexibly coupled in the perception of virtual environments.

We conducted two experiments to investigate how observers integrate postural and visual eye-height information when estimating the layout of interior space. In Experiment 1, we varied postural and visual eye-height information independently of each other in a virtual-reality setup. Observers estimated the width, depth, and height of simulated rooms. All dimensions were perceived as larger when the virtual visual eye-height corresponded to sitting on the floor as compared with standing upright. In contrast, the estimates remained widely unaffected by the observer's physical posture (likewise sitting vs. standing). In Experiment 2, we studied effects of the viewing condition (real vs. virtual rooms) and (in case of the virtual rooms) adaptation to congruence versus incongruence of visual and postural information. Both media yielded comparable results, which indicates that eye-height information is processed similarly in virtual and genuine reality. In addition, observers adapted to the (in)congruence of visual and postural cues. When we presented trials with congruent information first, both visual and postural cues had an effect on the estimates. However, when information was initially incongruent, observers mostly relied on visual cues, presumably relative to an internalized standard, and disregarded postural cues. Taken together, our results show that the integration of visual and postural eye-height information is situation-dependent. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Social priming influences the perception of a virtual audience: Exploratory study

Virtual reality is an effective therapeutic tool in many psychiatric disorders. However, some patients are not very sensitive to these new treatments due to a difficulty in considering these virtual environments as plausible. The aim of this study is to evaluate the influence of conceptual priming on the perception of virtual environments in healthy participants. We primed participants with a pro-social, non-social or anti-social priming. The participants then had to present themselves for 2 min to an audience of avatars in a virtual amphitheater. We used the ITC-SOPI and the Presence scale to assess participants’ perception of the environments. Our results suggest that there are significant differences between the three priming conditions concerning the perception scale (F(2,75) = 4.579; p = 0.013). More specifically, the pro-social condition significantly favours the positive perception of a virtual audience compared to the anti-social condition (respectively: Mean = 33.31 / SD = 8.76; Mean = 25.38 / SD = 9.26; t = 3.249; p = 0.005). This study shows that an experimental priming task can influence the perception of an environment in virtual reality. Experimental priming can become a very interesting tool for maximizing the therapeutic effects of virtual reality in patients who are not very sensitive to digital tools.

Towards estimating affective states in Virtual Reality based on behavioral data

Inferring users’ perceptions of Virtual Environments (VEs) is essential for Virtual Reality (VR) research. Traditionally, this is achieved through assessing users’ affective states before and after being exposed to a VE, based on standardized, self-assessment questionnaires. The main disadvantage of questionnaires is their sequential administration, i.e., a user’s affective state is measured asynchronously to its generation within the VE. A synchronous measurement of users’ affective states would be highly favorable, e.g., in the context of adaptive systems. Drawing from nonverbal behavior research, we argue that behavioral measures could be a powerful approach to assess users’ affective states in VR. In this paper, we contribute by providing methods and measures evaluated in a user study involving 42 participants to assess a users’ affective states by measuring head movements during VR exposure. We show that head yaw significantly correlates with presence, mental and physical demand, perceived performance, and system usability. We also exploit the identified relationships for two practical tasks that are based on head yaw: (1) predicting a user’s affective state, and (2) detecting manipulated questionnaire answers, i.e., answers that are possibly non-truthful. We found that affective states can be predicted significantly better than a naive estimate for mental demand, physical demand, perceived performance, and usability. Further, manipulated or non-truthful answers can also be estimated significantly better than by a naive approach. These findings mark an initial step in the development of novel methods to assess user perception of VEs.

Effects of Visual Cues on Distance Perception in Virtual Environments Based on Object Identification and Visually Guided Action

ABSTRACT In perceiving a virtual environment (VE), distance perception is important in that it affects users’ behaviors and interactions. This study addresses an on-going issue of virtual reality (VR), distance underestimation within a VE. For this purpose, a 2x2x2x5 mixed design was used with two between-subject variables [visual cue for perception (provided and non-provided) and visual cue for action (provided and non-provided)] and two within-subject variables [response measure (verbal estimation and triangulated blind walking) and distance (1 m, 5 m, 10 m, 20 m, and 35 m)]. Sixty-four undergraduate or graduate students participated in the experiment, and a cube was chosen as the target object. The experimental results showed that visual cues for action mitigated distance underestimation and improved the accuracy of perceived distances. In general, distance underestimation was more obvious in the triangulated blind walking than the verbal estimation, and in the action/vista space than personal space, with relatively lower accuracies. Meanwhile, when visual cue for action were provided, the degree of underestimation decreased significantly with higher accuracy particularly in the triangulated blind walking. Although overestimation was found across all the distances in the verbal estimation, overestimation was found only for the personal distance, and underestimation was found for the action/vista distances in the triangulated blind walking. In both response measures, the accuracy of distance perceptions were the worst in the 10 m condition. These findings can be expected to provide insight into the problem of distance underestimation and can help guide design of VEs.

Real-World and Virtual-World Practices for Virtual Reality Games: Effects on Spatial Perception and Game Performance

Researchers have been investigating ways to improve users’ spatial perception in virtual environments. Very limited studies have focused on the context of virtual reality (VR) games. Tutorials with practices, a common element in games, are good opportunities to implement measures that improve players’ spatial perception. Using an experiment, this paper investigates how two types of practices (real-world and virtual-world practices) influence players’ spatial perception, game performance, and immersion in VR games. Given that spatial perception is viewed as an essential aspect of VR applications, the moderating role of spatial perception on the effect of practices in game performance is also explored. The results demonstrate that virtual-world practice is effective in improving players’ spatial perception of the virtual environment of VR games. Real-world practice is suggested to be effective in enhancing spatial perception when it is averaged over multiple sessions. The results also suggest that spatial perception moderates the effects of practices on game performance. The results imply that practices in game tutorial can be a transitional environment for new players to enter a VR game.

Measuring egocentric distance perception in virtual reality: Influence of methodologies, locomotion and translation gains.

Virtual reality has become a popular means to study human behavior in a wide range of settings, including the role of pedestrians in traffic research. To understand distance perception in virtual environments is thereby crucial to the interpretation of results, as reactions to complex and dynamic traffic scenarios depend on perceptual processes allowing for the correct anticipation of future events. A number of approaches have been suggested to quantify perceived distances. While previous studies imply that the selected method influences the estimates’ accuracy, it is unclear how the respective estimates depend on depth information provided by different perceptual modalities. In the present study, six methodological approaches were compared in a virtual city scenery. The respective influence of visual and non-visual cues was investigated by manipulating the ratio between visually perceived and physically walked distances. In a repeated measures design with 30 participants, significant differences between methods were observed, with the smallest error occurring for visually guided walking and verbal estimates. A linear relation emerged between the visual-to-physical ratio and the extent of underestimation, indicating that non-visual cues during walking affected distance estimates. This relationship was mainly evident for methods building on actual or imagined walking movements and verbal estimates.

Pseudo-haptics: leveraging cross-modal perception in virtual environments

ABSTRACT This paper is an introduction to pseudo-haptics; that is, the use of touch-based illusions created by cross-modal perceptual interactions. Many studies have shown that it is possible to use visual or auditory stimuli to simulate the experience of touch, movement, and force. Pseudo-haptics isis useful in many applications, particularly where the user may not have a haptic device available but where the sensation of haptic feedback is useful in providing information or creating a sense of presence. In this paper, we present an overview of the current state of the literature in pseudo-haptics.

Crossmodal perception in virtual reality

With the proliferation of low-cost, consumer level, head-mounted displays (HMDs) we are witnessing a reappearance of virtual reality. However, there are still important stumbling blocks that hinder the achievable visual quality of the results. Knowledge of human perception in virtual environments can help overcome these limitations. In this work, within the much-studied area of perception in virtual environments, we look into the less explored area of crossmodal perception, that is, the interaction of different senses when perceiving the environment. In particular, we look at the influence of sound on visual perception in a virtual reality scenario. First, we assert the existence of a crossmodal visuo-auditory effect in a VR scenario through two experiments, and find that, similar to what has been reported in conventional displays, our visual perception is affected by auditory stimuli in a VR setup. The crossmodal effect in VR is, however, lower than that present in a conventional display counterpart. Having asserted the effect, a third experiment looks at visuo-auditory crossmodality in the context of material appearance perception. We test different rendering qualities, together with the presence of sound, for a series of materials. The goal of the third experiment is twofold: testing whether known interactions in traditional displays hold in VR, and finding insights that can have practical applications in VR content generation (e.g., by reducing rendering costs).

Orientation Perception in Real and Virtual Environments.

Spatial perception in virtual environments has been a topic of intense research. Arguably, the majority of this work has focused on distance perception. However, orientation perception is also an important factor. In this paper, we systematically investigate allocentric orientation judgments in both real and virtual contexts over the course of four experiments. A pattern of sinusoidal judgment errors known to exist in 2D perspective displays is found to persist in immersive virtual environments. This pattern also manifests itself in a real world setting using two differing judgment methods. The findings suggest the presence of a radial anisotropy that persists across viewing contexts. Additionally, there is some evidence to suggest that observers have multiple strategies for processing orientations but further investigation is needed to fully describe this phenomenon. We also offer design suggestions for 3D user interfaces where users may perform orientation judgments.

Evaluation of near field distance perception in virtual environments

Binaural synthesis of spatial audio for virtual and augmented environments is typically performed by convolving an anechoic signal with impulse responses measured at the listener's ears using a source at a fixed distance. This method is accurate for sounds presented at the measured impulse response's distance, and for more distant sources, decreasing intensity provides a reasonable approximation. However, sources nearer than 1 m provide additional distance cues. The head-shadow effect becomes markedly stronger and exponential sound intensity falloff comes into play, exaggerating inter-aural level differences. Also, the angle to each ear diverges, changing the directionally dependent spectral filtering of the pinnae. Changes in inter-aural level differences can be approximated across listeners, but changes in pinna cues with changes in distance are highly individual, and thus less easily approximated. Reproducing some or all of these cues for each individual may be necessary to create a convincing percept of very near objects in virtual and augmented reality environments. The present work aims to determine the importance of each cue for static and dynamic sources. Listening tests have been conducted in a virtual environment using generic and individual head related impulse responses, with and without near-field compensation.

Effects of Detail and Navigability on Size Perception in Virtual Environments

Effects of Detail and Navigability on Size Perception in Virtual Environments

Can walking motions improve visually induced rotational self-motion illusions in virtual reality?

Illusions of self-motion (vection) can provide compelling sensations of moving through virtual environments without the need for complex motion simulators or large tracked physical walking spaces. Here we explore the interaction between biomechanical cues (stepping along a rotating circular treadmill) and visual cues (viewing simulated self-rotation) for providing stationary users a compelling sensation of rotational self-motion (circular vection). When tested individually, biomechanical and visual cues were similarly effective in eliciting self-motion illusions. However, in combination they yielded significantly more intense self-motion illusions. These findings provide the first compelling evidence that walking motions can be used to significantly enhance visually induced rotational self-motion perception in virtual environments (and vice versa) without having to provide for physical self-motion or motion platforms. This is noteworthy, as linear treadmills have been found to actually impair visually induced translational self-motion perception (Ash, Palmisano, Apthorp, & Allison, 2013). Given the predominant focus on linear walking interfaces for virtual-reality locomotion, our findings suggest that investigating circular and curvilinear walking interfaces offers a promising direction for future research and development and can help to enhance self-motion illusions, presence and immersion in virtual-reality systems.

Perceptually salient haptic rendering for enhancing kinesthetic perception in virtual environments

Kinesthetic or dynamic touch involves the use of muscle sensitivity to perceive mechanical properties of objects that are gripped in the hand and wielded in space. Many previous studies with real objects have investigated the mechanical properties that underlie human haptic perception. Few virtual environments, however, have systematically incorporated the relevant mechanical parameters underlying kinesthetic perception. In this study, the ability of a haptic device to render kinesthetic information regarding the inertial properties of virtual objects was tested. Results suggest that users were able to perceive length of rendered virtual objects via the haptic device. Further, users can be trained using the haptic device to increase sensitivity to specific mechanical parameters (like inertia) that are perceptually salient in perceiving properties of rendered objects. The primary implication of this finding is that rendering kinesthetic parameters and employing feedback in a systematic manner may increase the realism of virtual environments and also improve haptic perception.