Effects of field of view on task performance with head-mounted displays

Abstract

The field of view (FOV) in most head-mounted displays (HMDs) is no more than 60 degrees wide—far narrower than our normal FOV of about 200° wide. This mismatch arises mostly from the difficulty and expense of building wide-FOV HMDs. Restricting a person's FOV, however, has been shown in real environments to affect people's behavior and degrade task performance. Previous work in virtual reality too has shown that restricting FOV to 50° or less in an HMD can degrade performance. I conducted experiments with a custom, wide-FOV HMD and found that performance is degraded even at the relatively high FOV of 112°, and further at 48°. The experiments used a prototype tiled wide-FOV HMD to measure performance in VR at up to 176° total horizontal FOV, and a custom large-area tracking system to establish new findings on performance while walking about a large virtual environment. FOV was significant in predicting performance of two tasks: searching for and locating a target by turning one's head, and walking through a simple maze-like environment while avoiding walls. Wide FOV (112° or greater) was especially important for the walking task; for it, performance at 112° was 23% less than at 176°. At 48°, performance was 31% less than at 176°. For the search task, performance at 112° was 12% less than at 176°. At 48°, performance was 24% less than at 176°. Additional analyses of the data show trends that suggest future investigation. Restricting FOV appears to decrease the user's sense of presence, as measured by a questionnaire. VR sickness, also measured by questionnaire, increased with successive exposures to our system within an hour-long session, but stayed at relatively low levels. FOV appears to alter the occurrence of some sickness symptoms, but the data are inconclusive on whether FOV predicts total sickness. I performed additional measures and analyses, including tests of postural instability, distance memory, spatial memory, head-movement behavior, and comparisons with other HMDs and with real-world performance.