Measuring spatial knowledge in a virtual environment: Distances and angles

Spatial knowledge in virtual environments (VE’s) is often evaluated using performance measures acquired in the VE. We show that pointing errors measured in a VE are highly predictive of pointing errors in the real world; however, errors in distance estimations made in a VE are not as predictive of distance errors in the real world. We examine factors that affect bearing and distance estimations made in real vs. virtual environments and find that gender is highly influential. INTRODUCTION In the last decade, there has been considerable interest in using computergenerated environments (virtual environments – or VE’s) for training spatial knowledge. Because VE’s are able to depict threedimensional spaces interactively, they offer a promising medium for training people about the spatial characteristics of places and situations that are rare, remote, or dangerous. For example, VE’s can be used to train firefighters about a building’s layout before they must enter it to put out a fire (see Bliss, Tidwell, & Guest, 1997). Another promising application of VE technology is as a research tool for understanding human spatial cognition. In addition to enabling participants to explore large spaces within the confines of the laboratory, VE’s also allow experimenters more control over stimulus characteristics than they typically have in the real world. Indeed, several recent neurophysiological studies of spatial cognition have used VE’s as stimuli to draw conclusions about real-world spatial cognition (Aguirre & D’Esposito, 1997; Maguire et al., 1998). Training and research applications that use VE’s as substitutes for real-world spaces raise two important questions. First, when spatial knowledge is acquired in a VE, what is the degree to which measurements taken in the VE can substitute for similar ones in the real-world? This question is especially important for training applications in which assessment of the trainee’s capabilities must be made before transfer. Second, before generalizing results found in a VE to real-world cognition, it is important to know the degree to which spatial knowledge acquired in a VE is comparable to that acquired in the real-world. A recent study by Ruddle, Payne, and Jones (1997) focused our attention on these questions. Ruddle et al. (1997) trained people to learn the spatial layout of a virtual office building and later measured their knowledge of it while they were in the VE. They then compared these results directly with those from a widely-cited study of spatial cognition in a similar but real office building (Thorndyke & Hayes-Roth, 1982). Before making such comparisons between measurements acquired in a VE and those acquired in the real-world, we feel that it is necessary to assess the degree to which the understanding of a virtual space predicts that of the real world space on which it was modeled. It is also important to understand the degree to which spatial knowledge acquired in a VE is systematically different than that acquired in the real world. We addressed these issues by exposing people to two maze environments—one virtual, the other real. We then tested participants’ knowledge of distances and directions between objects in these mazes. To examine the transfer of spatial knowledge, participants were also tested in a real-world maze after learning in a virtual one. Paper presented at the 39 annual meeting of the Psychonomics Society, Dallas TX, 21 Nov. 1998 METHOD Participants The participants were 27 students (12 men) enrolled in an introductory Psychology course at the University of Washington. Twenty-one of the participants received extra credit for their participation. The remaining six were paid $10 per hour. Materials The real-world environments were two 4.88 m x 4.88 m mazes constructed from 2.13 m black curtains hanging from an overhead grid of cables. The system of cables and curtains allowed the experimenter to reconfigure the mazes rapidly between conditions of the experiment. Mazes were covered with white fabric to reduce the amount of directed light entering them. Four prominent landmarks (in the real world – three large cardboard letters and a cardboard box; in the VE – a ball, a violin, a sword, and a gun) were placed at fixed locations in either maze. Figure 1 illustrates the configuration of the mazes.