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Master of Science / Psychological Sciences / Lester C. Loschky / A fundamental issue in visual attention is the relationship between the useful field of view (UFOV), the region of visual space where information is encoded within a single fixation, and eccentricity. A common assumption is that impairing attentional resources reduces the size of the UFOV (i.e. “tunnel vision”). However, most research has not accounted for eccentricity-dependent changes in spatial resolution, potentially conflating fixed visual properties with flexible changes in visual attention. Williams (1988; 1989) argued that foveal loads are necessary to reduce the size of the UFOV, producing "tunnel vision". Without a foveal load, it is argued that the attentional decrement is constant across the visual field (i.e. "general interference"). However, other research asserts that auditory working memory (WM) loads produce tunnel vision. To date, foveal versus auditory WM loads have not been compared to determine if they differentially change the size of the UFOV. In two experiments, we tested the effects of a foveal (rotated L vs. T discrimination) task, and an auditory WM (N-back) task on an extrafoveal (Gabor) discrimination task. Gabor patches were scaled for size and processing time to produce equal performance across the visual field under single task conditions, thus removing the confound of eccentricity-dependent differences in visual sensitivity. The results showed that while both foveal and auditory loads reduced Gabor orientation sensitivity, only the foveal load interacted with retinal eccentricity to produce tunnel vision, clearly demonstrating task-specific changes to the form of the UFOV. This has theoretical implications for understanding the UFOV.

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Graduation date: 1997

The purpose of this thesis is to evaluate the possibilities of using 3D perspective displays in different military settings, and to illustrate the limitations of 3D displays, that is, when 2D displays are to be preferred. More specifically, this thesis explores (a) readability during vibrations, (b) perception aspects on perspective aircraft displays, and (c) the value of spatial cues in 3D air traffic displays in military settings. The results show, for example, that vertical vibrations influence recognition performance negatively. The recognition of 2D and 3D symbols, as well as judgment of relations between symbols on a 3D display, may indeed be an arduous task. Results, further, indicate improved performance for relation judgments between objects in 3D space in dynamic rather than static scenarios in tactical indicators. In situations where perception of a direction nevertheless is problematic, enhancements like, for example, drop-lines may improve performance. From a practical point of view the goal has been to investigate the possibility to develop and use a 3D perspective display in an airplane like JAS 39 Gripen. A general conclusion is that 3D displays indeed can be used in many situations but it is important to seriously consider any possible limitations of 3D displays. The future work should be focused on implementing and testing the tactical display in a real setting with real military pilots.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves [61]-[65]). Also available in electronic version. Access restricted to campus users.

Includes bibliographical references.

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