Feng Chengzhi, Jiang Yi, He Sheng
Department of Psychology, University of Minnesota, Minneapolis, MN 55455, USA.
J Vis. 2007 Jul 17;7(2):13.1-10. doi: 10.1167/7.2.13.
The crowding effect is a ubiquitous phenomenon in spatial perception that has been extensively investigated. A notable property of spatial crowding is the radial and tangential asymmetry in which crowding is much more severe for items arranged on a radial line originating from the fixation point compared with items arranged tangentially with regard to the fixation point. Here, we report another asymmetric property of the crowding effect between horizontally and vertically arranged spatial layouts. In multiple experiments using a number of different stimulus patterns (e.g., letter Cs, letter Ts, and parallel/nonparallel line segments), results consistently showed that the crowding effect was significantly stronger when the target and distractors were horizontally rather than vertically arranged. Such a horizontal versus vertical asymmetry was found in all four quadrants of visual space. Importantly, a further visual acuity test did not reveal a horizontal versus vertical asymmetric effect.
拥挤效应是空间感知中一种普遍存在的现象，已得到广泛研究。空间拥挤的一个显著特性是径向和切向不对称，即与相对于注视点呈切线排列的项目相比，对于沿从注视点出发的径向线排列的项目，拥挤效应要严重得多。在此，我们报告了水平和垂直排列的空间布局之间拥挤效应的另一种不对称特性。在使用多种不同刺激模式（如字母C、字母T以及平行/不平行线段）的多个实验中，结果一致表明，当目标和干扰项水平排列而非垂直排列时，拥挤效应显著更强。在视觉空间的所有四个象限中均发现了这种水平与垂直的不对称。重要的是，进一步的视力测试并未揭示水平与垂直的不对称效应。
