The use of exploratory factor analysis in research on presence is summarized and critically examined. We conclude that, as with research on human intelligence in the first half of the twentieth century, exploratory factor analysis has been extremely limited in its ability to test hypotheses and to advance theory. To illustrate these ideas, we examine a recent analysis by Witmer, Jerome, and Singer (2005, Presence 14 , 298–312). We suggest that analyses based on confirmatory methods are in general better suited to advance our understanding of the concept of presence.

Two experiments collectively explored four factors that may influence people's judgments of exocentric (interobject) distances in virtual environments. Participants freely navigated in a simple virtual environment and repeatedly made magnitude estimations of exocentric distances. Distances were generally overestimated. An exponential model (Stevens' power law) fit the data, and exponent estimates were generally less than unity. Geometric field of view (GFOV) and the presence of error-corrective feedback were found to have the strongest effect on accuracy. In fact, distance perception was nearly veridical when made with an 80 deg. GFOV and when receiving feedback. Display type (head-mounted versus desktop) and the presence of additional perspective cues were less influential.

Many training applications of virtual environments (VEs) require people to be able to transfer spatial knowledge acquired in a VE to a real-world situation. Using the concept of fidelity, we examine the variables that mediate the transfer of spatial knowledge and discuss the form and development of spatial representations in VE training. We report the results of an experiment in which groups were trained in six different environments (no training, real world, map, VE desktop, VE immersive, and VE long immersive) and then were asked to apply route and configurational knowledge in a real-world maze environment. Short periods of VE training were no more effective than map training; however with sufficient exposure to the virtual training environment, VE training eventually surpassed real-world training. Robust gender differences in training effectiveness of VEs were also found.