The Perceived Naturalness of Virtual Walking Speeds during WIP Locomotion: Summary and Meta-Analyses

It is well established that individuals tend to underestimate visually presented walking speeds when relying on treadmills for virtual walking. However, prior to the present studies this perceptual distortion had not been observed in relation to Walking-in-Place (WIP) locomotion, and a number of the factors contributing to the perceptual distortion have yet to be identified. In this paper we present a summary of seven of our studies investigating what factors that influence self-motion perception during virtual walking and two meta-analyses of the findings of the seven studies. The studies relate to how gait cycle characteristics, visual display properties, and methodological differences affect speed underestimation during treadmill and WIP locomotion. The studies suggested the following: A significant main effect was found for step frequency; both display and geometric field of view were inversely proportional to the degree of underestimation; varying degrees of peripheral occlusion and increased HMD weight did not yield significant main effects; and the choice of method (i.e., how the speeds were presented) had a significant effect on the upper and lower bounds of what speeds were perceived as natural. All seven studies compared treadmill and WIP locomotion and higher speeds were generally preferred during treadmill walking, but only some studies found a significant effect. Meta-analyses of the differences between the two movement types revealed a significant difference and provided pooled estimates of the magnitude of this difference.