Investigating the Perception of Travel Distance Using Visual and Non-Visual Self-Motion Cues

Abstract

Having an accurate perception of travel distance is essential for navigating and moving through the world. In Chapter 2, I show that transforming visual motion into travel distance differs depending on the speed and direction of optic flow being perceived. Motion at the slower speed was associated with people feeling like they had moved further compared to motion at the faster speeds. In Chapter 3, I use a series of 4 experiments to investigate how various characteristics of a virtual environment affects your perception of travel distance through it. The specific parameters I investigated were: (1) the structure of an environment, and presence and texture of a ground surface, (2) the naturalism and scale of an environment, (3) colour, and (4) the density of a starfield. Results show no effect of the structure of an environment, and the presence of a ground surface (Experiment 1), or between the naturalism of an environment (Experiment 2), or whether the environment has colour or not (Experiment 3). However, I did find a small effect of the texture of the ground surface and the scale of an environment. In Experiment 4, I also show that there may be a ceiling effect with the starfield density needed to accurately estimate travel distance. Together these experiments will have implications for the design of real and virtual environments where perceived motion is important and enable us to further predict our perception of moving through these environments. In Chapter 4, I used a large-field edgeless display to either visually “move” participants while they were (i) physically stationary, (ii) performing a blind walking task on a treadmill, or (iii) visually “moving” while walking on a treadmill. Optic flow simulating forward self-motion was presented either full field, in the central field (central ±20°), or in the far periphery (beyond ±90°). I show that the high sensitivity to optic flow in the far periphery is a general feature of perceptual odometry even when integrating non-visual cues with visual cues.