Brightness filling-in incorporates information about 3-D structure V Pelekanos, H Ban, A Welchman |
|---|
School of Psychology, University of Birmingham, United Kingdom
|
| A range of illusions demonstrate that edge luminance contrast strongly influences the perceived brightness of an enclosed homogenous region. Such phenomena are compatible with a filling-in process that spreads contrast information from borders to the interior. This process is disrupted by backward masking, where the apparent brightness of a target is reduced by the brief presentation of a mask (Paradiso & Nakayama, 1991, Vision Research, 31, 1221-1236). Here we ask whether filling-in processes occur at early or intermediate stages of visual processing, using disparity-defined slanted surfaces. In two experiments, we manipulated the three-dimensional (3D) properties (slant direction) of the target and mask, and measured the differential disruption that masking causes on brightness judgments. On a given trial, participants (N=7) judged which of two successively presented target surfaces had a brighter centre, with a staircase used to control stimulus luminance. We found that masking was greatest when the target and mask had the same 3D orientation, with opposing slants attenuating the interference in apparent brightness. Control measures ruled out explanations based on monocular image properties. These results suggest that brightness filling-in operates at an intermediate stage of visual processing that involves information about the 3D properties of the scene. |
| Up Home |
|---|