Document Type


Date of Degree

Fall 2011

Degree Name

PhD (Doctor of Philosophy)

Degree In

Computer Science

First Advisor

James Cremer

First Committee Member

Juan Pablo Hourcade

Second Committee Member

Joseph Kearney

Third Committee Member

Jodie Plumert

Fourth Committee Member

Christopher Wyman


Virtual environments (VEs) have gained widespread use in recent years as a tool for training new skills, particularly in cases where training in the real environment can be risky or dangerous. But while there are many potential applications that could benefit from using VEs, our understanding of several basic perceptual and cognitive tasks in VEs - distance and traveled distance estimation, speed estimation, spatial orientation, and wayfinding - is not yet well developed. This dissertation increases understanding of two of these problems through three experiments on distance estimation and three on traveled distance estimation.

The first experiment directly compared participants' distance estimates across several visual presentation methods and measurement protocols. Results, for instance, showed no significant differences between estimates made when VEs are displayed in a head-mounted or a large-screen immersive display. In the second distance estimation experiment, participants made a series of distance judgments with feedback during an adaptation phase, and then made a series of " test phase" judgments without feedback in an environment that was similar but differently scaled. Under certain scaling conditions, there were significant differences between adaptation accuracy and test accuracy, suggesting that people's perceptual judgment is less well grounded in VEs than in the real world. Finally, our third distance estimation experiment was a pilot that further confirmed underestimation of distances in VEs while providing initial experience with a travel distance task valuable for the second half of our research. The fourth experiment is one of the first to directly compare traveled distance estimates between real and virtual environments. Results, for instance, showed a significant difference between estimates made by people who were passively moved through a real environment and people who experienced simulated self-motion in a virtual environment. The fifth and sixth experiments investigated whether scene density and richness affect people's sense of traveled distanced. In each of these experiments, participants who experienced feature-sparse environments judged traveled distances significantly differently than subject who experienced feature-rich environments. However, traveled distance estimation seems to involve more cognitive factors than distance estimation, and population differences between the two experiments make general conclusions somewhat difficult without further experimentation.


xiii, 169 pages


Includes bibliographical references (pages 162-169).


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Copyright 2011 Tien Dat Nguyen