Sensory conflict theory and postural instability theory were often tested individually to explain cybersickness in VR systems, but they were seldom systematically compared. An earlier study evaluated them on a large screen using 2D videos. This study evaluated sensory conflict and postural instability on the discomfort in VR. Virtual visual locomotion were shown on an head-mounted display. A motion platform vibrated in low-frequency while the participant stood on top. Each factor was manipulated alone or in combination. Results showed that the visual motion only condition led to the highest miserable score, higher than the physical vibration only condition. This suggested that consistent with previous literature, sensory conflict may be a major contributing factor of cybersickness.

Sensory conflict theory attempts to provide the framework of cyber-sickness in virtual reality (VR) systems by the mismatch between visual and vestibular senses. This study examined whether coupling motion sensations to the visual stimulus in a VR setting could reduce the discomfort. A motion-coupled VR system was used. Motion platform provides motion that supplements visual stimulus from the head-mounted display. Participants experience programmed visual and motion yaw rotations while viewing a virtual apartment. Three conditions were tested on how motion and visual stimuli synchronise which each other: purely visual, motion synchronised with visual, and visually-levelled frame of reference. Results showed that providing matching visual-motion stimuli decreased the miserable score (MISC) of cybersickness and increased the joyfulness score (JOSC) of their subjective feeling.

The perceived distance estimation in an immersive virtual reality system is generally underestimated to the actual distance. Approaches had been found to provide users with better dimensional perception. One method used in head-mounted displays is to interact by walking with visual feedback, but it is not suitable for a CAVE-like system, like imseCAVE, with confined spaces for walking. A verbal corrective feedback mechanism is proposed. The result shows that estimation accuracy generally improves after eight feedback trials although some estimations become overestimated. One possible explanation is the need of more verbal feedback trials. Further research on top-down approach for improvement in depth perception is suggested.