Intra-visual conflict in visually induced motion sickness

Motion sickness (MS) can be a debilitating side-effect not just of sea travel, but also when immersed in video games or virtual environments (visually induced MS). To explore the impact of visual display parameters on motion sickness, we presented footage taken on an automobile race track to different groups of observers during three experiments. In Experiment 1, one group watched the movie wearing a head-mounted display (HMD) and a second group looked at a large projection screen with unrestricted view. Resolution and visual angle were equated. In contrast to common assumption, the projection screen produced significantly higher motion sickness scores than the HMD. To understand this rather surprising result, two further groups watched the movie with a limited field of view and reduced display angle, either through a synoptic device or a reduction screen (Experiment 2). Visually induced MS was reduced in both groups to the same extent. In Experiment 3, a fifth group of observers looked at the large screen with a limited field of view, but with unrestricted display angle. Results again showed decreased sickness scores. We conclude that another factor above and beyond display angle is critical to explain visually induced MS, namely the visual surround of the display. If present, the surround increases visually induced MS by causing an additional intra-visual conflict that makes it harder for the visual system to dominate the vestibular information and thus increases the nauseogenic conflict between visual and vestibular information.

► Comparison of visual display parameters regarding visually induced motion sickness.
► Reducing the display angle decreases sickness scores.
► Visual surround of the display causes an intra-visual conflict.
► The intra-visual conflict exacerbates visually induced motion sickness.