Cleary R, Braddick O J
Department of Experimental Psychology, University of Cambridge, England.
Vision Res. 1990;30(2):317-27. doi: 10.1016/0042-6989(90)90046-n.
When an array of random dots is displaced, the ability to report the direction of apparent motion is subject to an upper spatial limit (dmax). Using spatially low-pass filtered random dot kinematograms we show that dmax is dependent on the upper cut-off frequency of the stimulus (Fh). The extent of this dependence is critically dependent on the size of the stimulus. Our results suggest a process whereby low spatial frequency motion information is masked by the presence of high spatial frequencies in the same region of the field, analogous to phenomena occurring in the perception of static form (e.g. the Abraham Lincoln effect). The effects of stimulus size on dmax, found for broad-band stimuli by ourselves and others, result from a loss of high frequency sensitivity at increased retinal eccentricities; this loss reduces the masking effect of high frequencies, as stimulus size increases.
当一组随机点发生位移时，报告视在运动方向的能力存在一个空间上限（dmax）。使用空间低通滤波的随机点运动图，我们发现dmax取决于刺激的上限截止频率（Fh）。这种依赖程度关键取决于刺激的大小。我们的结果表明了一个过程，即低空间频率运动信息被视野同一区域中高空间频率的存在所掩盖，这类似于在静态形状感知中出现的现象（例如亚伯拉罕·林肯效应）。我们自己和其他人在宽带刺激中发现的刺激大小对dmax的影响，是由于视网膜偏心度增加时高频敏感度的丧失；随着刺激大小增加，这种丧失会降低高频的掩盖效应。
