Texture fading correlates with stimulus salience

Perceptual fading of texture targets on similarly textured backgrounds was studied in relation to stimulus salience using texture patterns defined by orientation contrast, shape contrast, and order contrast. In two independent experiments, perceptual salience of the targets was determined. In the first, the textural contrast of the stimuli was varied and their salience quantified using magnitude estimation; in the second, reaction time was measured for the same stimulus patterns. In a third experiment, stimulus fading time was determined. Whereas magnitude estimates and fading time increased, reaction time decreased with increasing textural contrast strength, the shape of the curves depending on the kind of texture pattern used. When fading time was plotted against target salience, the slopes of the regression lines for shape and order contrast were similar, while the slope for orientation contrast was steeper, indicating longer fading times at equal stimulus salience. A control experiment using short oriented bars instead of gratings revealed that this difference may be attributed to the abutting contour between the target and its surround. With this contour removed, the fading time was largely the same for all three kinds of texture patterns. In the absence of a border (no cancellation), the unconnected target areas appeared to change gradually in orientation, shape, and spatial arrangement, thereby assuming the properties of the background (substitution).