Abstract

Because even the most advanced virtual reality systems can unintentionally synthesize visual display artifacts that resemble common visual illusions, the two visual systems hypothesis may be helpful in guiding the design and evaluation of usable interaction techniques for complex virtual reality applications. The hypothe- sis suggests that inherently cognitive classes of interaction techniques, such as vocal interaction and closed loop (with visual feedback) pointing, are subject to particular execution errors, while inherently motor classes of interaction techniques, such as open loop (no visual feedback) pointing, are not.

This thesis describes an experimental investigation of open loop and closed loop pointing compared to voice-based input in a large-scale interactive display. Experimental results verify that the unintentional illusory errors that are predicted by the two visual systems hypothesis appear with the use of vocal interaction in the presence of a visual illusion known as the Roelofs Effect. Similar response errors were found in closed loop pointing, but there were comparatively fewer illusory errors in open loop pointing. An examination of lag (temporal delay in visual feedback) yielded evidence that lag may also reduce the illusory response errors. These findings support our claim that the two visual systems hypothesis can be influential in improving the usability of virtual reality applications.

@MastersThesis{Po2002,
	author = {Barry Po, M.Sc},
	title = {Open Loop Pointing in Virtual Environments},
	school = {UBC},
	year = {2002},
	supervisor = {Kellogg S. Booth},
}