The Effects of Degrees of Freedom and Field of View on Motion Sickness in a Virtual Reality Context

Abstract

With a growing interest in head-mounted display (HMD)-based virtual reality (VR) environments, there have been lots of studies enhancing user experience (UX) in the context. In particular, the study of motion sickness (MS) symptoms, which are a major barrier to providing a positive UX, is of high importance. This study investigated the effects of degree of freedom (DOF) and field of view (FOV) of HMD on MS symptoms. A user experiment was designed based on a 2 × 2 mixed design with DOF as a between-subject design variable (3-DOF and 6-DOF) and FOV as a within-subject design variable (Narrow and Wide). Participants experienced VR game content in four conditions in random order. MS symptoms were captured using heart rate variability (HRV) and virtual reality sickness questionnaire (VRSQ) at the pre- and post-task moment. The results showed that MS symptoms occurred more in the 3-DOF condition than in the 6-DOF. Further, MS symptoms in DOF conditions were adjusted depending on the FOV. In the Wide condition, we found a significant difference in MS symptoms depending on the DOF, but in the Narrow condition, no significant differences were found. Through this finding, we were able to not only show the effectiveness of HRV as MS measures but also provide meaningful design insights into HMD-based VR practices.