Abstract
Comparing sensitivities to different cues does not necessarily tell us about their relative saliencies when combined at suprathreshold. Measurements of the relative saliency of combined cues are important as they indicate the relative weightings given by vision to different cues in naturalistic situations, for example in order to highlight warnings. We sought to measure the relative saliencies of combined luminance, colour and texture contrast using a psychophysical task. Stimuli were small circular patches bordered by a thin black line and containing combinations of luminance decrements, purple or red colour contrast, and increments in the contrast of a binary noise texture. The patches were arranged in a diagonal grid on a mid grey background. There were two tasks: 1 ‘Separate’, in which the different cues were presented separately in a two-interval design and participants indicated which interval contained the stronger orientation structure; 2. ‘Combined’, in which different cues were combined within each patch but arranged to produce competing orientation structure, and participants had to indicate which orientation, and therefore cue, was dominant. We varied the contrast ratio between the cues around suprathreshold baseline levels to find the points of subjective equality in both tasks. Participants required significantly more luminance and colour contrast in the Combined compared to Separate conditions (contrast ratios differed by about 0.1 log units). This result shows that suprathreshold texture is more salient than colour or luminance when the different cues are presented in combination.
Meeting abstract presented at VSS 2012