Unobtrusive vehicle motion prediction cues reduced simulator sickness during passive travel in a driving simulator

This study investigated cues that permit prediction of turns during passive movement through a virtual environment. Effects on simulator sickness (SS), presence and enjoyment were examined. Subjects were exposed to complex visual motion through a cartoon-like simulated environment in a driving simulator. Forward velocity remained constant and the motion path was the same across all experimental conditions. Using a within-subject design, we examined visual paths that provided different levels of cue salience - detailed, simplified and no cues - for the upcoming simulated vehicle motion. Following each trial, participants completed questionnaires on SS, presence and enjoyment. After all of the trials were completed, a debriefing determined participants' perceptions of vehicle motion attributes and their awareness of the prediction cues. The results showed that SS in the no-cue condition was significantly greater than that in the conditions that provided vehicle motion cues. Presence and enjoyment responses were not different across the conditions. No participants reported differences between prediction cue conditions or recognized that the vehicle motion followed the same path across trials. However, participants tended to report that the motion was smoother for the detailed-cue than the no-cue condition. Participants ranked turn predictability as higher in conditions with prediction cues. The results support the hypothesis that unobtrusive and unreported motion cues may alleviate SS in a virtual environment.     

The effects of simulated fog and motion on simulator sickness in a driving simulator and the duration of after-effects

In the study, we checked: 1) how the simulator test conditions affect the severity of simulator sickness symptoms; 2) how the severity of simulator sickness symptoms changes over time; and 3) whether the conditions of the simulator test affect the severity of these symptoms in different ways, depending on the time that has elapsed since the performance of the task in the simulator.     

Psychophysiological evaluation of simulator sickness evoked by a graphic simulator

The present study investigated the effects of simulator sickness, as an important bias factor on evaluation of emotional changes under the controlled condition of driving a car for 60 min at a constant speed (60 km/h) in a graphic simulator. Simulator sickness was measured and analyzed every 5 min using both subjective evaluation and physiological signals. Results of the subjective evaluation showed there was a significant difference between the rest and the driving conditions 10 min after the main experiment started and that the level of difference increased linearly with time. Analysis of the central and the autonomic nervous systems showed the significant differences in delta, theta, alpha and beta bands of an electroencephalogram (EEG), skin temperature, and the R-R interval between the rest and the driving conditions after about 5 min from the start of driving. In particular, there was the highest correlation between parameter of theta and subjective evaluation, and thus theta was considered an effective physiological parameter for numerically evaluating simulator sickness. The results indicate that physiological changes due to simulator sickness can be a bias factor in evaluation of human sensibility.     

Pleasant music as a countermeasure against visually induced motion sickness

Visually induced motion sickness (VIMS) is a well-known side-effect in virtual environments or simulators. However, effective behavioral countermeasures against VIMS are still sparse. In this study, we tested whether music can reduce the severity of VIMS. Ninety-three volunteers were immersed in an approximately 14-minute-long video taken during a bicycle ride. Participants were randomly assigned to one of four experimental groups, either including relaxing music, neutral music, stressful music, or no music. Sickness scores were collected using the Fast Motion Sickness Scale and the Simulator Sickness Questionnaire. Results showed an overall trend for relaxing music to reduce the severity of VIMS. When factoring in the subjective pleasantness of the music, a significant reduction of VIMS occurred only when the presented music was perceived as pleasant, regardless of the music type. In addition, we found a gender effect with women reporting more sickness than men. We assume that the presentation of pleasant music can be an effective, low-cost, and easy-to-administer method to reduce VIMS.     

Investigation of driving performance, vection, postural sway, and simulator sickness in a fixed-based driving simulator

This paper reports the results of a pilot study conducted to determine whether there is a relationship between simulator sickness and measures of driver inputs, vection, and postural sway, in a fixed base driving simulator. Seven males and four females performed a series of alternating left and right turns (20 each), with straigth-aways inbetween. The task was designed to promote experiences of circular and linear vection, and associated sway. It was hypothesized that greater driver inputs (i.e., steering wheel and braking activity; deviation from the centerline) would correlate: with reports of vection and measures of postural sway. Ten of the eleven subjects reported moderate sickness, which precluded any statistical comparisons between “sick” and “not sick” however, there was a significant tendency for persons who reported vection to also report sickness. There were no gender differences in reported incidence of vection or sickness, however, males tended to exhibit greater lateral velocity. The next phase of investigation will necessitate reducing the strength of the stimulus (i.e., require less turns) to increase variability of sickness scores amongst subjects and permit comparisons between “sick” and “not sick.” Measurement considerations include increasing the sensitivity of vection ratings, and examination of the timecourse for the development of postural sway.     

Research in visually induced motion sickness

While humans have experienced motion sickness symptoms in response to inertial motion from early history through the present day, motion sickness symptoms also occur from exposure to some types of visual displays. Even in the absence of physical motion, symptoms may result from visually perceived motion, which are often classified as effects of visually induced motion sickness (VIMS). This paper provides a brief discussion of general motion sickness and then reviews findings from three lines of recent VIMS investigations that we have conducted.     

The effect of visual motion stimulus characteristics on vection and visually induced motion sickness

Several factors contribute to the likelihood of experiencing illusory sensations of self-motion (i.e., vection) in Virtual Reality (VR) applications. VR users can also experience adverse effects such as disorientation, oculomotor issues, or nausea known as visually induced motion sickness (VIMS). The goal of the present study was to systematically investigate three characteristics of visual motion stimuli—speed, density, and axis of rotation—and how they relate to both vection and VIMS. Two experiments were conducted. In Experiment 1, a stereoscopic stimulus containing a star field of white spheres on a black background was presented to 21 participants. The stimulus contained linear forward motion (expanding optic flow) and was varied with respect to (a) speed (faster, slower) and (b) density (lower, higher). Ratings of vection (onset time, intensity, duration), VIMS (measured via FMS, SSQ), and presence were recorded. In Experiment 1 vection was found to be strongest under faster and higher density conditions. VIMS was overall minimal and not affected by either speed or density. In Experiment 2, rotation along the pitch, yaw, or roll axes were added to the stimulus that created the strongest vection in Experiment 1, resulting in spiral/curvilinear motion profiles. Again, subjective ratings of vection, VIMS, and presence were collected. Results showed that vection intensity was significantly increased when pitch or roll rotation were added to forward motion. Despite overall low VIMS scores, pitch rotation resulted in the highest FMS scores and significantly greater disorientation as measured by the SSQ. No correlations between the vection and VIMS measures were observed. Overall, these results suggest that all three stimulus’ characteristics (density, speed, added rotations) can alter the sensation of vection and can have additive effects, but that this increase in vection is not necessarily associated with increases in VIMS.     

The effects of habituation and adding a rest-frame on experienced simulator sickness in an advanced mobility scooter driving simulator

The aim of this article is to investigate the effect of a physical rest-frame, habituation and age on simulator sickness in an advanced mobility scooter driving simulator. Twenty-six young and 34 older adults completed a total of 12 drives in an advanced mobility scooter driving simulator over two visits. A 2x2 crossover design was used to measure the effect of a rest frame that was added to the driving simulator on either the first or second visit. The Simulator Sickness Questionnaire was used to measure simulator sickness symptoms. A significant decrease in simulator sickness was observed between the first and the second visit. Older adults reported more severe simulator sickness symptoms compared to younger participants. No effect of rest-frame could be found. Habituation appears to be the most effective method to reduce simulator sickness in an advanced mobility scooter driving simulator. More research is needed to investigate simulator sickness in patient groups.

Practitioner summary: Experiencing simulator sickness is a major problem across all types of simulators. The present experiment investigated the effect of a rest-frame, habituation and age on developing simulator sickness symptoms in an advanced mobility scooter driving simulator. Habituation appeared to be the most effective method to reduce simulator sickness.     

Brightness and contrast do not affect visually induced motion sickness in a passively-flown fixed-base flight simulator

BackgroundVisually Induced Motion Sickness (VIMS) or simulator sickness is often elicited by a visual stimulus that lacks the appropriate vestibular or proprioceptive feedback. In this study, we chose to investigate the effects of brightness and contrast of the visual scene on VIMS.HypothesisWe hypothesized that visual environments differing in brightness or contrast would differentially induce VIMS. The symptoms of VIMS should be most severe for the combination of high brightness and high contrast and conversely lowest for the low brightness and low contrast condition.Methods33 healthy subjects were tested in a fixed-base flight simulator. Each subject flew in four consecutive but counterbalanced conditions during one large experimental session. The four conditions consisted of identical recorded flight paths, differing only in brightness and contrast in a fully crossed design. VIMS was assessed with the Simulator Sickness Questionnaire and the Fast Motion Sickness scale administered during and after each condition. Postural Sway (PS) was measured after each condition.ResultsAll four brightness and contrast conditions were found to be effective in that they increased PS and elicited moderate VIMS. However, there were no main or interaction effects for brightness or contrast.ConclusionsOur findings suggest that brightness and contrast do not modulate the induction of VIMS. This conclusion may be limited to moderately provocative stimuli.     

Task performance in a head-mounted display: The impacts of varying latency

The purpose of this study was to determine how latency in a head-mounted display (HMD) affects human performance. Virtual environments (VEs) are used frequently for training. However, VEs can cause simulator sickness. Prior work in our laboratory has examined the role of varying latency in simulator sickness. However, the effect of varying latency on task performance has not been examined. Subjects participated in a repeated measures study where they were exposed to two different latency conditions in an HMD: constant (70 ms) and varying (70–270 ms). During each HMD exposure, subjects used a laser pointer to repeatedly “shoot” at laser targets while accuracy and time-to-hit were recorded. Subjects scored fewer hits and took longer to hit targets in the varying latency condition. These findings indicate that individuals exposed to varying latency perform worse than individuals exposed to a lower constant latency.     

A comparison of guidance cues in desktop virtual environments

Designers of educational and entertainment desktop virtual environments (VEs) have employed a variety of cues for motivating users to perform actions or adopt particular viewpoints. However, there has been little formal study comparing user responses to such cues. This paper reports the results of a preliminary study of five cues (agents, signs, man-made landmarks, environmental landmarks, and trails) for motivating actions in virtual environments. Given a sample task of navigating to a target destination, no significant differences between the cues were observed in terms of overall success or speed. However, significant differences between the cues were found on other measures, including minimization of detours (trails) and awareness of guidance (agents, signs, trails). Frequency of desktop VE usage was also found to influence performance.     

The use of force feedback and auditory cues for performance of an assembly task in an immersive virtual environment

Using an immersive virtual environment, this study investigated whether the inclusion of force feedback or auditory cues improved manipulation performance and subjective reports of usability for an assembly task. Twenty-four volunteers (12 males and 12 females) were required to assemble and then disassemble five interconnecting virtual parts with either auditory, force, or no feedback cues provided. Performance for the assembly task was measured using completion time and number of collisions between parts, while the users preferences across conditions were evaluated using subjective reports of usability. The results indicated that the addition of force feedback slowed completion time and led to more collisions between parts for males. In contrast, females exhibited no change in the mean completion time for the assembly task but did show an increase in collision counts. Despite these negative performance findings when adding force feedback, users did report perceived increases in realism, helpfulness and utility towards the assembly task when force feedback was provided. Unlike force feedback, the results showed that auditory feedback, indicating that parts had collided during the assembly task, had no negative performance effects on the objective measures while still increasing perceived realism and overall user satisfaction. When auditory cues and force feedback were presented together, performance times, number of collisions, and usability were not improved compared to conditions containing just auditory cues or force feedback alone. Based on these results, and given the task and display devices used in the present study, the less costly option of excluding auditory and force feedback cues would produce the best performance when measured by the number of collisions and completion time. However, if increased ratings of usability for an assembly task are desired while maintaining objective performance levels and reduced cost, then the inclusion of auditory feedback cues is best.