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While compelling illusions of self-motion (vection) can be induced purely by visual motion, they are rarely experienced immediately. This vection onset latency is thought to represent the time required to resolve sensory conflicts between the stationary observer’s visual and nonvisual information about self-motion. In this study, we investigated whether manipulations designed to increase the weightings assigned to vision (compared to the nonvisual senses) might reduce vection onset latency. We presented two different types of visual priming displays directly before our main vection-inducing displays: (1) ‘random motion’ priming displays — designed to pre-activate general, as opposed to self-motion-specific, visual motion processing systems; and (2) ‘dynamic no-motion’ priming displays — designed to stimulate vision, but not generate conscious motion perceptions. Prior exposure to both types of priming displays was found to significantly shorten vection onset latencies for the main self-motion display. These experiments show that vection onset latencies can be reduced by pre-activating the visual system with both types of priming display. Importantly, these visual priming displays did not need to be capable of inducing vection or conscious motion perception in order to produce such benefits.

This study investigated claims of disrupted equilibrium when listening to the Shepard–Risset glissando (which creates an auditory illusion of perpetually ascending/descending pitch). During each trial, 23 participants stood quietly on a force plate for 90 s with their eyes either open or closed (30 s pre-sound, 30 s of sound and 30 s post-sound). Their centre of foot pressure (CoP) was continuously recorded during the trial and a verbal measure of illusory self-motion (i.e., vection) was obtained directly afterwards. As expected, vection was stronger during Shepard–Risset glissandi than during white noise or phase-scrambled auditory control stimuli. Individual differences in auditorily evoked postural sway (observed during sound) were also found to predict the strength of this vection. Importantly, the patterns of sway induced by Shepard–Risset glissandi differed significantly from those during our auditory control stimuli — but only in terms of their temporal dynamics. Since significant sound type differences were not seen in terms of sway magnitude, this stresses the importance of investigating the temporal dynamics of sound–posture interactions.

While head-mounted display (HMD) based gaming is often limited by cybersickness, research suggests that repeated exposure to virtual reality (VR) can reduce the severity of these symptoms. This study was therefore aimed at: (1) examining the exposure conditions required to reduce cybersickness during HMD VR; and (2) learning whether such reductions generalise from one HMD VR game to another. Our participants played two commercially-available HMD VR video games over two consecutive days. Their first exposure to HMD VR on both days was always to a 15-min virtual rollercoaster ride. On Day 1, half of our participants also played a virtual climbing game for 15-min, while the rest of them finished testing early. Participants in the latter group were only exposed to the climbing game late on Day 2. We found that sickness was significantly reduced for our participants on their second exposure to the virtual rollercoaster. However, sickness to the rollercoaster on Day 2 was unaffected by whether they had played the climbing game on Day 1. Sickness during virtual climbing was also unaffected by group differences in exposure to the virtual rollercoaster. This convergent evidence suggested that the reductions in cybersickness produced by repeated exposure to HMD VR were game-specific. While these benefits did not generalise to the second game, two 15-min exposures to the same HMD VR game was sufficient to significantly reduce cybersickness in this study.

Virtual reality (VR) is widely recognised as a promising technology for training emergency first responders and other safety–critical workers. It is uniquely able to immerse trainees in extreme situations that are too risky or dangerous to be examined in traditional real-world safety training. Most organisations seeking to implement VR safety training often limit their decisions to financial and technological factors. However, in this paper, we argue that a socio-technical systems approach is required to better appreciate the social costs and benefits of VR training, which are important for a successful implementation. The paper also reports our own research on a real-world implementation of VR safety training for the Mine Rescue Brigades in New South Wales, Australia. The training—conducted in both fully immersive (360 VR) and non-immersive (Desktop VR) virtual reality—involved a search and rescue operation which was necessitated by an underground fire at the bottom of the transport drift in a coal mine. Following this training, the 368 trainees not only completed a post-training questionnaire, but also were interviewed, to assess their training experiences in the VR environment. The findings provide a comprehensive account of the social costs and benefits of adopting VR as a safety training tool. Overall, the trainees perceived the benefits to far outweigh the costs, with an overall high inclination to recommend the VR training to other colleagues. Desktop VR was found to be as fit for delivering successful training as the more immersive 360 VR. However, this Desktop VR generated considerably less motion sickness in trainees. These findings should help organisations and training providers decide on: (1) whether or not to invest in VR safety training solutions; (2) which type technology/method of delivery to use.

It is generally believed that the phosphenes induced by transcranial electric current stimulation (tECS) are a product of retinal activation, even when electrode placement is directly over the primary visual cortex. However, the origins of these tECS-induced phosphenes have not yet been conclusively determined. In this study, phosphene detection thresholds using an FPz-Oz montage were compared with those from (i) an Oz-Cz montage to determine whether prefrontal regions, such as the retina, contribute to phosphenes and (ii) an FPz-Cz montage to determine whether the visual cortex in the occipital lobe contributes to phosphenes. Twenty-two participants received transcranial current stimulation with each of these montages (as well as a T3-T4 montage included for exploratory purposes) at 6, 10, 16, 20, 24, 28, and 32 Hz. To estimate differences in current density at the retina and occipital lobe across montages, modeling of current density at phosphene thresholds was measured across 20 head models. Consistent with the proposal that tECS-induced phosphenes are generated in the retina, increasing current density near the retina (FPz-Oz relative to Oz-Cz montage) reduced phosphene thresholds. However, increasing current density near the occipital cortex (FPz-Oz relative to FPz-Cz montage) also reduced phosphene thresholds while also requiring less current density at the retina according to the modeling estimates. This suggests that tECS of this occipital cortex also contributed to phosphene perception. © 2020 Bioelectromagnetics Society.

During head-mounted display (HMD)-based virtual reality (VR), head movements and motion-to-photon-based display lag generate differences in our virtual and physical head pose (referred to as DVP). We propose that large-amplitude, time-varying patterns of DVP serve as the primary trigger for cybersickness under such conditions. We test this hypothesis by measuring the sickness and estimating the DVP experienced under different levels of experimentally imposed display lag (ranging from 0 to 222 ms on top of the VR system's ~ 4 ms baseline lag). On each trial, seated participants made continuous, oscillatory head rotations in yaw, pitch or roll while viewing a large virtual room with an Oculus Rift CV1 HMD (head movements were timed to a computer-generated metronome set at either 1.0 or 0.5 Hz). After the experiment, their head-tracking data were used to objectively estimate the DVP during each trial. The mean, peak, and standard deviation of these DVP data were then compared to the participant's cybersickness ratings for that trial. Irrespective of the axis, or the speed, of the participant's head movements, the severity of their cybersickness was found to increase with each of these three DVP summary measures. In line with our DVP hypothesis, cybersickness consistently increased with the amplitude and the variability of our participants' DVP. DVP similarly predicted their conscious experiences during HMD VR-such as the strength of their feelings of spatial presence and their perception of the virtual scene's stability.

The phenomenon of cybersickness is currently hindering the mass market adoption of head-mounted display (HMD) virtual reality (VR) technologies. This study examined the effects of dynamic field-of-view (FOV) restriction on the cybersickness generated by ecological HMD-based gameplay. Forty participants were exposed to a commercially available HMD game (Marvel Powers United VR) under both unrestricted FOV and dynamic FOV restriction conditions across three sessions. Participants had their spontaneous postural instability measured before entering VR. Then, during/following each of these 10-min exposures to HMD VR, they rated their cybersickness, vection (illusory self-motion), and feelings of presence. Individual differences in spontaneous postural instability were found to predict cybersickness during HMD VR gameplay. Cybersickness severity increased steadily over the course of each VR exposure and was significantly reduced by dynamic FOV restriction. Presence also increased steadily over the course of each VR exposure and was positively correlated with vection. We conclude that: (1) postural instability can identify people who are more susceptible to cybersickness, (2) vection can increase an HMD user’s feelings of presence, and (3) dynamic FOV restriction can serve as a viable countermeasure to cybersickness.

Cybersickness is common during head-mounted display (HMD) based virtual reality. This study examined whether it is possible to: (1) identify people who are more susceptible to this cybersickness; and (2) find general ways to reduce its occurrence and severity. Our participants were exposed to HMD-based virtual reality four times over two different days (using “Freedom Locomotion VR”). During these 10-min trials, participants were either free-standing or posturally restrained as they actively controlled or passively viewed their locomotion through the virtual environment. Cybersickness was found to increase steadily over time during each exposure. While this cybersickness was markedly reduced on day 2 (compared to day 1), it was not significantly altered by either the use of postural restraints or active locomotion control. However, the sick and well participants in our study were found to differ in terms of their spontaneous postural activity (before they entered virtual reality). We found that the participants who experienced stronger vection also tended to report more severe cybersickness in this study. These findings suggest that we should be able to identify people who are more susceptible to cybersickness and help them become more resistant to it (via repeated exposures to HMD-based virtual reality).

The relationship between vection (illusory self-motion) and cybersickness is complex. This pilot study examined whether only unexpected vection provokes sickness during head-mounted display (HMD) based virtual reality (VR). 20 participants ran through the tutorial of Mission: ISS (an HMD VR app) until they experienced notable sickness (maximum exposure was 15 minutes). We found that: 1) cybersickness was positively related to vection strength; and 2) cybersickness appeared to be more likely to occur during unexpected vection. Given the implications of these findings, future studies should attempt to replicate them and confirm the unexpected vection hypothesis with larger sample sizes and rigorous experimental designs.

Head-mounted display (HMD)-based virtual reality (VR) is ideally suited for presence and generating compelling visual experiences of self-motion, but users can suffer from side effects associated with head-to-display lag. We used the Oculus Rift HMD (consumer release – CV1) to simulate forward self-motion in depth. Observers made continuous yaw head movements at approximately 0.5 Hz or 1.0 Hz while viewing these self-motion simulations. We examined the perceptual effects of increasing the display lag, by adding lag to the baseline lag of the system (estimated to be approximately 5.3 ms or 0.5 frames per second). We found that increasing the head-to-display lag up to 212 ms reduced the presence and the strength of vection. In addition, faster (1.0 Hz) head oscillations were found to generate weaker presence and vection in the virtual environment than the slower (0.5 Hz) head oscillations. We also found that a positive correlation between vection and presence (found previously) persists across a wide range of head-to-display lags, and, increasing lag from a very low baseline level still impaired both experiences. Both vection and presence in virtual environments can therefore be impaired by either increasing head-display lag or making more rapid angular head movements.

While head-mounted display-based virtual reality (VR) can produce compelling feelings of presence (or “being there”) in its users, it also often induces motion sickness. This study compared the presence, cybersickness and perceptions of self-motion (or “vection”) induced when using two common methods of virtual locomotion: steering locomotion and teleporting. In four trials, conducted over two separate days, 25 participants repeatedly explored the “Red Fall” virtual environment in the game Nature Treks VR for 16 min at a time. Although steering locomotion was found to be more sickening on average than teleporting, 9 participants reported more severe sickness while teleporting. On checking their spontaneous postural activity before entering VR, these “TELEsick” participants were found to differ from “STEERsick” participants in terms of their positional variability when attempting to stand still. While cybersickness was not altered by having the user stand or sit during gameplay, presence was enhanced by standing during virtual locomotion. Cybersickness was found to increase with time in trial for both methods of virtual locomotion. By contrast, presence only increased with time in trial during steering locomotion (it did not vary over time when teleporting). Steering locomotion was also found to generate greater presence for female, but not male, participants. While there was not a clear advantage for teleporting over steering locomotion in terms of reducing cybersickness, we did find some evidence of the benefits of steering locomotion for presence.

It is well known that applying transcranial alternating current stimulation (tACS) to the scalp can generate artefactual visual perceptions of flashing or shimmering light known as phosphenes. The thresholds for generating these phosphenes have been used by international standards bodies to provide conservative estimates of the field strength required to interfere with human neural functioning and set safety limits accordingly. However, the precise relationship between electric currents and phosphene perception thresholds remains uncertain. The present study used tACS to systematically investigate the effects of the location and the frequency of stimulation on phosphene perception thresholds. These thresholds were obtained from 24 participants using a within-subject design as a function of scalp stimulation sites (FPz-Cz versus Oz-Cz) and stimulation frequency (2-30 Hz in steps of 2 Hz). Phosphene perception thresholds were consistently lower for FPz-Cz stimulation, and regardless of tACS location were lowest for 16 Hz stimulation. Threshold variation between participants was very small, which is meaningful when setting standards based on phosphenes. Bioelectromagnetics. 2019;40:365-374. © 2019 Bioelectromagnetics Society.

Cybersickness is common during virtual reality experiences with head-mounted displays (HMDs). Previously it has been shown that individual differences in postural activity can predict which people are more likely to experience visually-induced motion sickness. This study examined whether such predictions also generalise to the cybersickness experienced during active HMD-based virtual reality. Multisensory stimulation was generated by having participants continuously turn their heads from left to right while viewing the self-motion simulations. Real-time head tracking was then used to create ecological (‘compensated’) and non-ecological (‘inversely compensated’) head-and-display motion conditions. Ten (out of 20) participants reported feeling sick after being exposed to these self-motion simulations. Cybersickness did not differ significantly between the two compensation conditions. However, individual differences in spontaneous postural instability when standing quietly were found to predict the likelihood of subsequently experiencing cybersickness. These findings support recent proposals that postural measures can help diagnose who will benefit the most/least from HMD-based virtual reality.

Changing the speed, size and material properties of optic flow can significantly alter the experience of vection (i.e. visually induced illusions of self-motion). Until now, there has not been a systematic investigation of the effects of luminance contrast, averaged luminance and stimulus spatial frequency on vection. This study examined the vection induced by horizontally oriented gratings that continuously drifted downwards at either 20° or 60°/s. Each of the visual motion stimuli tested had one of: (a) six different levels of luminance contrast; (b) four different levels of averaged luminance; and (c) four different spatial frequencies. Our experiments showed that vection could be significantly altered by manipulating each of these visual properties. Vection strength increased with the grating's luminance contrast (in Experiment 1), its averaged luminance (in Experiment 2), and its spatial frequency (in Experiment 3). Importantly, interactions between these three factors were also found for the vection induced in Experiment 4. While simulations showed that these vection results could have been caused by effects on stimulus motion energy, differences in perceived grating visibility, brightness or speed may have also contributed to our findings.

Humans rely on multiple senses to perceive their self-motion in the real world. For example, a sideways linear head translation can be sensed either by lamellar optic flow of the visual scene projected on the retina of the eye or by stimulation of vestibular hair cell receptors found in the otolith macula of the inner ear. Mismatches in visual and vestibular information can induce cybersickness during head-mounted display (HMD) based virtual reality (VR). In this pilot study, participants were immersed in a virtual environment using two recent consumer-grade HMDs: the Oculus Go (3DOF angular only head tracking) and the Oculus Quest (6DOF angular and linear head tracking). On each trial they generated horizontal linear head oscillations along the interaural axis at a rate of 0.5 Hz. This head movement should generate greater sensory conflict when viewing the virtual environment on the Oculus Go (compared to the Quest) due to the absence of linear tracking. We found that perceived scene instability always increased with the degree of linear visual-vestibular conflict. However, cybersickness was not experienced by 7/14 participants, but was experienced by the remaining participants in at least one of the stereoscopic viewing conditions (six of whom also reported cybersickness in monoscopic viewing conditions). No statistical difference in spatial presence was found across conditions, suggesting that participants could tolerate considerable scene instability while retaining the feeling of being there in the virtual environment. Levels of perceived scene instability, spatial presence and cybersickness were found to be similar between the Oculus Go and the Oculus Quest with linear tracking disabled. The limited effect of linear coupling on cybersickness, compared with its strong effect on perceived scene instability, suggests that perceived scene instability may not always be associated with cybersickness. However, perceived scene instability does appear to provide explanatory power over the cybersickness observed in stereoscopic viewing conditions.

This study investigated the relationships between personality and creativity in the perception of two different ambiguous visual illusions. Previous research has suggested that Industriousness and Openness/Intellect (as measured by the Big Five Aspects Scale) are both associated with individual differences in perceptual switching rates for binocular rivalry stimuli. Here, we examined whether these relationships generalise to the Necker Cube and the Spinning Dancer illusions. In the experimental phase of this study, participants viewed these ambiguous figures under both static and dynamic, as well as free-view and fixation, conditions. As predicted, perceptual switching rates were higher: (a) for the static Necker Cube than the Spinning Dancer, and (b) in free-view compared with fixation conditions. In the second phase of the study, personality type and divergent thinking were measured using the Big Five Aspects Scale and the Alternate Uses Task, respectively. Higher creativity/divergent thinking (as measured by the Alternate Uses Task) was found to predict greater switching rates for the static Necker Cube (but not the Spinning Dancer) under both free-view and fixation conditions. These findings suggest that there are differences in the perceptual processing of creative individuals.

This paper discusses results from two successive rounds of virtual mines rescue training. The first round was conducted in a surround projection environment (360-VR), and the second round was conducted in desktop virtual reality (Desktop-VR). In the 360-VR condition, trainees participated as groups, making collective decisions. In the Desktop-VR condition, trainees could control their avatars individually. Overall, 372 participants took part in this study, including 284 mines rescuers who took part in 360-VR, and 243 in Desktop-VR. (155 rescuers experienced both.) Each rescuer who trained in 360-VR completed a battery of pre- and post-training questionnaires. Those who attended the Desktop-VR session only completed the post-training questionnaire. We performed principal components analysis on the questionnaire data, followed by a multiple regression analysis, the results of which suggest that the chief factor contributing to positive learning outcome was Learning Context, which extracted information about the quality of the learning content, the trainers, and their feedback. Subjective feedback from the Desktop-VR participants indicated that they preferred Desktop-VR to 360-VR for this training activity, which highlights the importance of choosing an appropriate platform for training applications, and links back to the importance of Learning Context. Overall, we conclude the following: 1) it is possible to train effectively using a variety of technologies but technology that is well-suited to the training task is more useful than technology that is “more advanced,” and 2) factors that have always been important in training, such as the quality of human trainers, remain critical for virtual reality training.

Research has shown that consistent stereoscopic information improves the vection (i.e. illusions of self-motion) induced in stationary observers. This study investigates the effects of placing stereoscopic information into direct conflict with monocular motion signals by swapping the observer’s left and right eye views to reverse disparity. Experiments compared the vection induced by stereo-consistent, stereo-reversed and flat-stereo patterns of: (1) same-size optic flow, which contained monocular motion perspective information about self-motion, and (2) changing-size optic flow, which provided additional monocular information about motion-in-depth based on local changes in object image sizes. As expected, consistent stereoscopic information improved the vection-in-depth induced by both changing-size and same-size patterns of optic flow. Unexpectedly, stereo-reversed patterns of same-size optic flow also induced stronger vection-in-depth than flat-stereo patterns of same-size optic flow. The effects of stereo-consistent and stereo-reversed information on vection strength were found to correlate reliably with their effects on perceived motion-in-depth and motion after-effect durations, but not with their effects on perceived scene depth. This suggests that stereo-consistent and stereo-reversed advantages for vection were both due to effects on perceived motion-in-depth. The current findings clearly demonstrate that stereoscopic information does not need to be consistent with monocular motion signals in order to improve vection. When taken together with past findings, they suggest that stereoscopic information only needs to be dynamic (as opposed to static) in order to improve vection-in-depth.

Research has previously shown that adding consistent stereoscopic information to self-motion displays can improve the vection in depth induced in physically stationary observers. In some past studies, the simulated eye-separation was always close to the observer's actual eye-separation, as the aim was to examine vection under ecological viewing conditions that provided consistent binocular and monocular self-motion information. The present study investigated whether large discrepancies between the observer's simulated and physical eye-separations would alter the vection-inducing potential of stereoscopic optic flow (either helping, hindering, or preventing the induction of vection). Our self-motion displays simulated eye-separations of 0 cm (the non-stereoscopic control), 3.25 cm (reduced from normal), 6.5 cm (approximately normal), and 13 cm (exaggerated relative to normal). The rated strength of vection in depth was found to increase systematically with the simulated eye-separation. While vection was the strongest in the 13-cm condition (stronger than even the 6.5-cm condition), the 3.25-cm condition still produced superior vection to the 0-cm control (i.e., it had significantly stronger vection ratings and shorter onset latencies). Perceptions of scene depth and object motion-in-depth speed were also found to increase with the simulated eye-separation. As expected based on the findings of previous studies, correlational analyses suggested that the stereoscopic advantage for vection (found for all of our non-zero eye-separation conditions) was due to the increase in perceived motion-in-depth.

Sounds are thought to contribute to the perceptions of self-motion, often via higher-level, cognitive mechanisms. This study examined whether illusory self-motion (i.e. vection) could be induced by auditory metaphorical motion stimulation (without providing any spatialized or low-level sensory information consistent with self-motion). Five different types of auditory stimuli were presented in mono to our 20 blindfolded, stationary participants (via a loud speaker array): (1) an ascending Shepard-Risset glissando; (2) a descending Shepard-Risset glissando; (3) a combined Shepard-Risset glissando; (4) a combined-adjusted (loudness-controlled) Shepard-Risset glissando; and (5) a white-noise control stimulus. We found that auditory vection was consistently induced by all four Shepard-Risset glissandi compared to the white-noise control. This metaphorical auditory vection appeared similar in strength to the vection induced by the visual reference stimulus simulating vertical self-motion. Replicating past visual vection findings, we also found that individual differences in postural instability appeared to significantly predict auditory vection strength ratings. These findings are consistent with the notion that auditory contributions to self-motion perception may be predominantly due to higher-level cognitive factors.

Behavioural studies have consistently found stronger vection responses for oscillating, compared to smooth/constant, patterns of radial flow (the simulated viewpoint oscillation advantage for vection). Traditional accounts predict that simulated viewpoint oscillation should impair vection by increasing visual–vestibular conflicts in stationary observers (as this visual oscillation simulates self-accelerations that should strongly stimulate the vestibular apparatus). However, support for increased vestibular activity during accelerating vection has been mixed in the brain imaging literature. This fMRI study examined BOLD activity in visual (cingulate sulcus visual area — CSv; medial temporal complex — MT+; V6; precuneus motion area — PcM) and vestibular regions (parieto-insular vestibular cortex — PIVC/posterior insular cortex — PIC; ventral intraparietal region — VIP) when stationary observers were exposed to vection-inducing optic flow (i.e., globally coherent oscillating and smooth self-motion displays) as well as two suitable control displays. In line with earlier studies in which no vection occurred, CSv and PIVC/PIC both showed significantly increased BOLD activity during oscillating global motion compared to the other motion conditions (although this effect was found for fewer subjects in PIVC/PIC). The increase in BOLD activity in PIVC/PIC during prolonged exposure to the oscillating (compared to smooth) patterns of global optical flow appears consistent with vestibular facilitation.

Cybersickness is often experienced when viewing virtual environments through head-mounted displays (HMDs). This study examined whether vection (i.e., illusory self-motion) and mismatches between perceived and physical head motions contribute to such adverse experiences. Observers made oscillatory yaw head rotations while viewing stereoscopic optic flow through an Oculus Rift HMD. Vection and cybersickness were measured under 3 conditions of visual compensation for physical head movements: “compensated”, “uncompensated”, and “inversely compensated”. When a nearer aperture was simulated by the HMD, vection was found to be strongest in the “compensated” condition and weakest in the “inversely compensated” condition. However, vection was similar for all 3 conditions during full-field exposures. Cybersickness was most severe for the “inversely compensated” condition, but was not different for the other two conditions. We conclude that mismatches between perceived and physical head-movements can contribute strongly to cybersickness. The relationship between vection and cybersickness is weaker and appears complex.

We validated an optical method for measuring the display lag of modern head-mounted displays (HMDs). The method used a high-speed digital camera to track landmarks rendered on a display panel of the Oculus Rift CV1 and S models. We used an Nvidia GeForce RTX 2080 graphics adapter and found that the minimum estimated baseline latency of both the Oculus CV1 and S was extremely short (∼2 ms). Variability in lag was low, even when the lag was systematically inflated. Cybersickness was induced with the small baseline lag and increased as this lag was inflated. These findings indicate the Oculus Rift CV1 and S are capable of extremely low baseline display lag latencies for angular head rotation, which appears to account for their low levels of reported cybersickness.

We compared the cybersickness produced when a virtual environment (VE) was viewed binocularly and monocularly through an Oculus Rift CV1 head-mounted display (HMD). During each exposure to the VE participants made continuous yaw head movements in time with a computer-generated metronome. Across trials we also varied their head movement frequency (0.5 or 1.0 Hz) and motion-to-photon delays (from ∼5 - ∼212 ms). We found that: 1) cybersickness severity increased with added display lag; and 2) monocular viewing appeared to protect against these increases in cybersickness. We conclude that active binocular viewing with this HMD introduced artifacts that increased the likelihood of more severe sickness.

We compared two common techniques of controller-based locomotion (teleportation and steering locomotion) in virtual reality (VR) in terms of the cybersickness they produce. Participants had to continuously navigate a commercial VR application for 16 minutes using each technique, while standing and seated. While teleportation produced less cybersickness than steering locomotion on average, a number of participants reported teleportation to be more sickening. These ‘telesick’ participants were found to have greater medio/lateral positional variability in their spontaneous postural sway than ‘steersick’ participants prior to VR exposure. We conclude that different individuals may require unique techniques to comfortably locomote in VR.

This study investigated whether individual differences in postural stability/activity can be used to predict who will become sick when exposed to head-mounted display (HMD) based virtual reality (VR). We found that participants who reported feeling sick after at least one exposure to VR displayed different postural activity than those who remained well. Importantly these differences were present in their sway data before they even donned the HMD. These results are inline with the postural instability theory of motion sickness and suggest that we can identify individuals who are more susceptible HMD-based cybersickness based on their spontaneous postural sway.

This study examined the contributions of low-, mid- and high-level visual motion information to vection. We compared the vection experiences induced by hand-drawn and computer-generated animation clips to those induced by versions of these movies that contained only their pure optic flow. While the original movies were found to induce longer and stronger vection experiences than the pure optic flow, vection onsets were not significantly altered by removing the mid- and high-level information. We conclude that low-level visual motion information appears to be important for vection induction, whereas mid- and higher-level display information appears to be important for sustaining and strengthening this vection after its initial induction.

We recently showed that auditory illusions of self-motion can be induced in the absence of physically accurate spatial cues (Mursic et al., 2017). The current study was aimed at identifying which features of this auditory stimulus (the Shepard–Risset glissando) were responsible for this metaphorical auditory vection, as well as confirming anecdotal reports of motion sickness for this stimulus. Five different types of auditory stimuli were presented to 31 blindfolded, stationary participants through a loudspeaker array: (1) a descending Shepard–Risset glissando; (2) a descending discrete Shepard scale; (3) a descending sweep signal; (4) a phase-scrambled version of (1) (auditory control type 1); and (5) white noise (auditory control type 2). We found that the auditory vection induced by the Shepard–Risset glissando was stronger than both types of auditory control, and the discrete Shepard scale stimulus. However, vection strength was not found to differ between the Shepard–Risset glissando and the sweep signal. This suggests that the continuous, gliding structure of both these auditory stimuli was integral to the induction of vection. Consistent with anecdotal reports that the Shepard–Risset glissando is also capable of generating motion sickness (as measured by the Fast Motion Sickness Scale and the Simulator Sickness Questionnaire), the likelihood and severity of sickness for these stimuli was found to increase with the strength of the auditory vection.

Purpose Leading causes of irreversible blindness such as age-related macular degeneration (AMD) and glaucoma can, respectively, lead to central or peripheral vision loss. The ability of sufferers to process visual motion information can be impacted even during early stages of eye disease. We used head-mounted display virtual reality as a tool to better understand how vision changes caused by eye diseases directly affect the processing of visual information critical for self-motion perception. Methods Participants with intermediate AMD or early manifest glaucoma with near-normal visual acuities and visual fields were recruited for this study. We examined their experiences of self-motion in depth (linear vection), spatial presence, and cybersickness when viewing radially expanding patterns of optic flow simulating different speeds of self-motion in depth. Viewing was performed with the head stationary (passive condition) or while making lateral-sway head movements (active conditions). Results Participants with AMD (i.e., central visual field loss) were found to have greater vection strength and spatial presence, compared to participants with normal visual fields. However, participants with glaucoma (i.e., peripheral visual field loss) were found to have lower vection strength and spatial presence, compared to participants with normal visual fields. Both AMD and glaucoma groups reported reduced severity in cybersickness compared to healthy normals. Conclusions These findings strongly support the view that perceived self-motion is differentially influenced by peripheral versus central vision loss, and that patients with different visual field defects are oppositely biased when processing visual cues to self-motion perception.