Abstract
A direct comparison between perceptual judgments in real and virtual environments (VEs) provides a way to evaluate the “perceptual fidelity” of the VE, testing whether the VE allows observers to behave as they do in the real world. We have previously demonstrated that participants underestimate distances to targets on the ground in VEs when compared to their performance in the real world (e.g., Thompson et al. 2004, Presence) and that judgments of the width of perceived passability of an aperture are overestimated relative to shoulder width (Creem-Regehr et al. 2008, VSS). However it is unknown how judgments of perceived affordances directly compare to those made in the real world. The present study allowed for a comparison between distance judgments and perceived affordances across closely matched procedures and settings in a real and virtual environment. Participants viewed two poles in a real classroom or a virtual model of the same classroom. Similar to previous results, participants significantly underestimated the distance to the target in VEs as compared to the real classroom. Affordance judgments of passability between the two poles were analyzed as a percentage of participants' shoulder widths. When in a VE, participants required significantly wider spaces to indicate passage than when in the real classroom. The result of a greater passability width to shoulder width ratio in the VE is consistent with an underestimation of perceived size of the aperture. This may be associated with underestimation of distance or other factors such as uncertainty of scale or judgments made with respect to the observer's unseen body. Future work will assess the generalizability of these results by testing other distance, size and affordance judgments in matched real and virtual spaces. The effectiveness of VEs to accurately portray real world environments and the utility of VEs as perceptual tools will be discussed.
This work was supported by NSF grant 0914488.