Bowns L
School of Psychology, University of Nottingham, University Park, NG7 2RD, Nottingham, United Kingdom.
Vision Res. 2001 Mar;41(7):965-72. doi: 10.1016/s0042-6989(00)00289-3.
Bowns (Vision Research, 36(22) (1996), 3685) argued that there are distinct features in two-component moving patterns (plaids) that if tracked move in the same direction as (1) the intersection of constraints direction (IOC) Adelson and Movshon (Nature, 300 (1992), 523); and (2) the vector sum direction (VS) Yo and Wilson (Vision Research, 32(1) (1992), 135). The IOC and VS are hypotheses of how the motion of single components is combined to give pattern motion. This paper shows that there are also features that provide an explanation for a reversed motion described by Derrington, Badcock, and Holroyd (Vision Research, 32(4), (1992), 699), and investigates why reversals only occur under specific conditions. Section 3 replicates the original study by Derrington et al. (1992) and confirms that the reversals are limited to low temporal frequencies. Section 4 varies the spatial displacement of features that also predict reversals and shows that the temporal frequency at which reversals occur varies and is linearly dependent on the displacement of these specified features. Derrington et al. (1992) showed that reversals only occur when components have oblique angles, and suggested an explanation in terms of speed differences. Section 5 was not consistent with this hypothesis. An alternative explanation for why reversals only occur at oblique angles, and at low spatial frequencies is provided in terms of feature properties. Results supporting the IOC, vector sum, and squaring have previously been interpreted in terms of three disparate mechanisms. This may not be necessary.
鲍恩斯（《视觉研究》，第36卷第22期（1996年），第3685页）认为，在双分量运动模式（方格图案）中存在独特特征，若对其进行追踪，这些特征的移动方向与以下两者相同：（1）约束方向交点（IOC），如阿德尔森和莫夫尚（《自然》，第300卷（1992年），第523页）所述；（2）矢量和方向（VS），如约和威尔逊（《视觉研究》，第32卷第1期（1992年），第135页）所述。IOC和VS是关于单个分量的运动如何组合以产生图案运动的假设。本文表明，还存在一些特征可以解释德林顿、巴德科克和霍罗伊德（《视觉研究》，第32卷第4期（1992年），第699页）所描述的反向运动，并探究了为何反向运动仅在特定条件下发生。第3节重复了德林顿等人（1992年）的原始研究，并证实反向运动仅限于低时间频率。第4节改变了同样能预测反向运动的特征的空间位移，结果表明反向运动发生时的时间频率会发生变化，并且与这些特定特征的位移呈线性相关。德林顿等人（1992年）表明，反向运动仅在分量具有倾斜角度时才会发生，并从速度差异的角度提出了解释。第5节与该假设不一致。本文从特征属性的角度提供了另一种解释，说明为何反向运动仅在倾斜角度和低空间频率下发生。此前支持IOC、矢量和及平方运算的结果曾依据三种不同机制进行解释。或许并无此必要。
