Effect of the Horizontal Visual Field on Human Sense of Direction in a Curved Passage
Authors: Takahashi Naoki , Yoshioka Yohsuke 
Published: June 2023

In our previous study, we have investigated the relationship between the shape of the curved passages and the sense of direction using a head-mounted display (Oculus Quest/Oculus). However, the horizontal visual field of the head-mounted display used in the study was about 90 degrees, whereas the human horizontal visual field is about 200 degrees. Because of this, the results could be different when passing through a curved passage with a wider horizontal visual field. Therefore, in this study, the effect of the horizontal visual field on the accuracy of the sense of direction in the curved passages was investigated.Ten college students participated in the experiment. The subjects were asked to wear a head-mounted display with a visual field of about 180 degrees (StarVR One/ StarVR Corporation) and hold a controller. The subjects also wore soundproof earmuffs to prevent hearing the surrounding sounds. After that, they were asked to walk through some curved passages constructed in a virtual environment.First, a virtual arrow was displayed and arranged at the beginning point of the passage. The subjects were asked to memorize the direction indicated by the virtual arrow (instructed direction). After memorization was completed, the subjects were asked to walk to the end of the passage. When the subjects reach the end of the passage, the entire passage was removed, and only an arrow indicating the traveling direction at the endpoint of the passage appears. After the arrow appeared, the subjects changed the direction of the arrow with the controller to reproduce the instructed direction (reproduced direction). The difference in angle between the “instructed direction” and the “reproduced direction” was used to extract the change in the sense of direction.The passages used in the experiment consisted of curved and straight parts. The width of the passages was 1500 mm, the height was 2500 mm, and the radius of curvature of the curved part was 3500 mm inside and 5000 mm outside. The turning angle of the curved passage was set at six levels in 15 degrees increments, ranging from 15 to 90 degrees (15, 30, 45, 60, 75, and 90 degrees). Furthermore, the subject’s horizontal visual field was restricted to two levels (90 and 180 degrees). A total of twelve conditions were set by combining these two variables. Each condition was presented twice in a random order for each subject.As a result of the experiment, no significant difference was detected in the difference between the “instructed direction” and “reproduced direction” between the condition with the horizontal visual field of 90 degrees and 180 degrees. This result suggested that the accuracy of the sense of direction is not significantly changed even if the horizontal visual field is restricted to 90 degrees. Therefore, the visual field outside of 90 degrees does not seem to affect the accuracy of direction sense in curved passage. For this reason, it is assumed that our previous study results can be applied even when the visual field is wider than 90 degrees.