Visual search for size is influenced by a background texture gradient

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-size-constancy 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 distracters) but combined in their influence in the slower conditions (short target among longer distracters).