Human action laws in electronic virtual worlds: An empirical study of path steering performance in VR

This paper is concerned with simple human performance "laws of action" for three classes of tasks-pointing, crossing, and steering, as well as their applications in Virtual Reality research. In comparison to Fitts' law of pointing, the "law of steering"- the quantitative relationship between human temporal performance and the movement path's spatial characteristics- has been notably under investigated. After a review of research on the law of steering in different domains and time periods, we examine the applicability of the law of steering in a VR locomotion task. Participants drove a virtual vehicle in a virtual environment on paths whose shape and width were systematically manipulated. Results showed that the law of steering indeed applies to locomotion in Virtual Environments. Participants' mean trial completion times linearly correlated (r(2) between 0.985 and 0.999) with an index of difficulty quantified as path length to width ratio for the straight and circular paths used in this experiment. On average both the mean and the maximum speeds of the participants were linearly proportional to path width. Such human performance regularity provides a quantitative tool for 3D human-machine inter-face design and evaluation. We also propose to use the law-of-steering model in Virtual Reality manipulation tasks such as the "ring and wire" task in the future.