Effects of image scale and system time delay on simulator sickness within head-coupled virtual environments

Novel patterns of visual-vestibular intersensory stimulation often result i n symptoms of simulator sickness, raising health and safety concerns regard ing virtual environment exposure. Two experiments investigated the effect o f conflicting visual-vestibular cues on subjective reports of simulator sic kness during and after a 30-min exposure to a head-coupled virtual interfac e. Virtual image scale factors (0.5, 1.0, 2.0 magnification, generated by v arying geometric field of view angle) were investigated in Experiment 1, an d additional system time delays (125, 250 ms) were investigated in Experime nt 2. Simulator sickness metrics included spoken self-reports during exposu re and simulator sickness questionnaires (pre-exposure. immediate postexpos ure, and 20 min postexposure). Head yaw angular position data were also rec orded. Reports of simulator sickness symptoms were significantly greater in the minification (0.5) and magnification (2.0) image scale factor conditio ns than in the neutral condition (1.0). Simulator sickness did not vary wit h changes in time delay, however. Furthermore, a comparison across experime nts suggests no appreciable increase in simulator sickness with increasing time delays above the nominal value (48 ms). Head angular position data exh ibited certain systematic variations across conditions. Actual or potential applications of this research include virtual environment training, simula tion, and entertainment systems.