Mowafy L, Blake R, Lappin J S
Vanderbilt University, Nashville, Tennessee.
Percept Psychophys. 1990 Dec;48(6):583-92. doi: 10.3758/bf03211604.
When viewing a pair of bars defined by the difference of spatial Gaussian functions (DOGs), human observers can discriminate accurately the relative movements of the bars, even when they differ in spatial frequency. On each trial, observers viewed two brief presentation intervals in which a pair of vertically oriented DOGs moved randomly back and forth within a restricted range. During one interval, both bars moved in the same horizontal direction and by the same magnitude (correlated movements); in the other interval, their movements were uncorrelated. When discrimination accuracy is related to the simultaneous detection of two independent movements, it was found that, if observers can detect the movements of spatially separated bars, they can tell whether their relative movements are correlated. Performance remained remarkably accurate even when the two bars differed in spatial frequency by more than two octaves or were presented separately to the two eyes. Apparently, the accurate discrimination of coherent motion involves an efficient spatial integration of optical motion information over multiple spatial locations and multiple spatial scales.
当观察由空间高斯函数差（DOGs）定义的一对条纹时，即使条纹的空间频率不同，人类观察者也能准确辨别条纹的相对运动。在每次试验中，观察者观看两个短暂的呈现间隔，期间一对垂直定向的DOGs在限定范围内随机来回移动。在一个间隔期间，两条条纹沿相同的水平方向且以相同的幅度移动（相关运动）；在另一个间隔期间，它们的运动是不相关的。当辨别准确性与同时检测两个独立运动相关时，研究发现，如果观察者能够检测到空间上分离的条纹的运动，他们就能判断它们的相对运动是否相关。即使两条条纹的空间频率相差超过两个八度或分别呈现给两只眼睛，表现仍保持非常准确。显然，对连贯运动的准确辨别涉及在多个空间位置和多个空间尺度上对光学运动信息进行有效的空间整合。
