The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, The University of Haifa, Haifa, Israel.
The Department of Learning Disabilities, Faculty of Education, The University of Haifa, Haifa, Israel.
Sci Rep. 2021 Jan 22;11(1):2116. doi: 10.1038/s41598-021-81533-9.
Crowding, the failure to identify a peripheral item in clutter, is an essential bottleneck in visual information processing. A hallmark characteristic of crowding is the inner-outer asymmetry in which the outer flanker (more eccentric) produces stronger interference than the inner one (closer to the fovea). We tested the contribution of the inner-outer asymmetry to the pattern of crowding errors in a typical radial crowding display in which both flankers are presented simultaneously on the horizontal meridian. In two experiments, observers were asked to estimate the orientation of a Gabor target. Instead of the target, observers reported the outer flanker much more frequently than the inner one. When the target was the outer Gabor, crowding was reduced. Furthermore, when there were four flankers, two on each side of the target, observers misreported the outer flanker adjacent to the target, not the outermost flanker. Model comparisons suggested that orientation crowding reflects sampling over a weighted sum of the represented features, in which the outer flanker is more heavily weighted compared to the inner one. Our findings reveal a counterintuitive phenomenon: in a radial arrangement of orientation crowding, within a region of selection, the outer item dominates appearance more than the inner one.
拥挤，即在杂乱中无法识别一个外围项目，是视觉信息处理的一个基本瓶颈。拥挤的一个显著特征是内外不对称，其中外部侧抑制（更偏外侧）比内部侧抑制（更靠近中央凹）产生更强的干扰。我们在典型的放射状拥挤显示中测试了内外不对称对外侧抑制的干扰模式的贡献，其中两个侧抑制同时呈现在水平子午线。在两项实验中，观察者被要求估计一个 Gabor 目标的方向。观察者报告外侧侧抑制的频率远高于内侧侧抑制，而不是目标。当目标是外侧 Gabor 时，拥挤程度降低。此外，当有四个侧抑制时，两个在目标的每一侧，观察者错误报告了与目标相邻的外侧侧抑制，而不是最外侧的侧抑制。模型比较表明，方向拥挤反映了对代表特征的加权和的抽样，其中与内侧相比，外侧侧抑制的权重更大。我们的发现揭示了一个反直觉的现象：在一个方向拥挤的放射状排列中，在一个选择区域内，外部项目比内部项目更能主导外观。
