Visual search for size is influenced by a background texture gradient.
Deborah J. Aks, James T. Enns · Journal of Experimental Psychology Human Perception & Performance · 1996
Research on the perception of texture gradients has relied heavily on the subjective reports of observers engaged in free-viewing.We asked whether these findings generalized to speeded performance.Experiment 1 showed that an important aspect of subjective perception-sizeconstancy scaling with perceived distance-also predicted the speed of pop-out visual search for cylinders viewed against a texture gradient.Experiment 2 showed that this finding could not be attributed to the local contrast between search items and the background texture.Experiment 3 assessed the relative contributions of 2 separable dimensions of texture gradients-perspective (radial spreading) and compression (foreshortening)-finding them to be independent in the more rapid search conditions (long target among shorter distractors) but combined in their influence in the slower conditions (short target among longer distractors).When observers view the texture gradient shown in Fig- ure 1A they usually report seeing a flat surface recede into the distance, despite the fact that a two-dimensional (2-D) image alone cannot specify the three-dimensional (3-D) surface that gave rise to the projection.This study asked whether the factors influencing the perceived slant of such texture gradients also influences rapid visual search for objects placed on their surface.Although a large number of previous studies have examined the perception of slant in texture gradients (e.g., Flock,