CCE Theses and Dissertations

Implication of Contrats and Sizze Sensitivities in Information Cueing

Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Graduate School of Computer and Information Sciences


Getrude W. Abramson

Committee Member

Gerorge K. Fornshell

Committee Member

Michael J. Laszlo


Psychometric and photometric studies have shown that psychophysical retinoptical reactions occur when slight changes are made to contrast and size attributes even if those changes are not consciously seen. It was hypothesized that minimum response thresholds for contrast and size exist and that, if these minimum thresholds could be identified, instructional designers and others could subtly encourage computer users to follow optimal yet optional navigation strategies. The goal of this study was to determine the minimum thresholds of contrast and size attributes needed to visually cue computer users. It was hypothesized that variations in contrast (luminance), size, or a combination of contrast and size could attract a viewer's attention and subtly cue them along a particular navigation strategy.

One hundred gratings were developed to examine five conditions of contrast and size both individually and in combination. The five conditions were used to determine the minimum contrast and size observation thresholds. The study results indicated that at levels just below conscious awareness subjects observed a difference in contrast nearly 40% of the time. When contrast attributes were raised to levels slightly above conscious awareness, contrast observations were made nearly 45% of the time. When size attributes were studied the results were lower but more significant than for contrast. Size attributes just below conscious awareness was observed only 25% of the time but when size values were raised slightly above the visual threshold observation rose to nearly 45%. When both contrast and size attributes were studied in combination, the most significant results occurred. At levels just below conscious awareness the combination study results were in the 46% range. When the combination attributes were slightly above the Just-Noticeable-Difference range, observations rose to nearly 60%.

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