The role of disparity information in alleviating visual crowding A Astle1, D McGovern2, P McGraw1 |
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1Nottingham Visual Neuroscience, The University of Nottingham, United Kingdom |
| Crowding describes a phenomenon where visual targets are more difficult to identify when flanked by nearby distractors. We investigated the effect of flanking Gabors on the orientation discrimination of a parafoveal target Gabor. Orientation discrimination thresholds were measured as a function of flanker spacing when flankers were presented in the same plane as the target and when they were presented at a range of crossed and uncrossed disparities relative to the target. Thresholds were measured for a range of separations in the same plane. A flanker separation was chosen that induced a significant threshold elevation. Flankers were subsequently fixed at this separation for each subject while the disparity between the target and flankers was altered. Thresholds reduced systematically as the disparity of the flankers changed. The resulting tuning function was asymmetric, with flankers presented in uncrossed disparity allowing greater alleviation from crowding. Complete release from crowding was achieved when flankers were presented with sufficient disparity. In a single plane, flankers located further away from fixation have a greater crowding effect than closer flankers. In contrast to this, we show that flankers which are closer, in terms of relative disparity, have a greater crowding effect than those which are further away. |
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