Variations in visual sensitivity predict motion sickness in virtual reality

Severity of motion sickness varies across individuals. While some experience immediate symptoms, others seem relatively immune. We explored a potential explanation for such individual variability based on cue conflict theory. According to cue conflict theory, sensory signals that lead to mutually incompatible perceptual interpretations will produce physical discomfort. A direct consequence of such theory is that individuals with greater sensitivity to visual (or vestibular) sensory cues should show greater susceptibility, because they would be more likely to detect a conflict. Using virtual reality (VR), we assessed individual sensitivity to a number of visual cues and subsequently induced moderate levels of motion sickness using stereoscopic movies presented in the VR headset. We found that an observer's sensitivity to motion parallax cues predicted severity of motion sickness symptoms. We also evaluated evidence for another reported source of variability in motion sickness severity in VR, namely sex, but found little support. We speculate that previously reported sex differences might have been due to poor personalization of VR displays, which default to male settings and introduce cue conflicts for the majority of females. Our results identify a sensitivity-based sensory predictor of motion sickness, which can be used to personalize VR experiences and mitigate discomfort.