Gilroy Lee A, Hock Howard S
Middle Tennessee State University, Murfreesboro, Tennessee, USA.
Atten Percept Psychophys. 2009 Oct;71(7):1563-75. doi: 10.3758/APP.71.7.1563.
Motion perception usually is accompanied by the phenomenological impression of sequence as objects move through successions of locations. Nonetheless, there is accumulating evidence that sequential information is neither necessary nor sufficient for perceiving motion. It is shown here that apparent motion is specified by counterchange rather than sequence-that is, by co-occurring toward- and away-from-background changes at two spatial locations, regardless of whether the changes are simultaneous or sequential. Motion is perceived from the location of the toward to the location of the away change, even when the changes occur in reverse temporal order. It is not perceived for sequences of away or toward changes, as would be expected if motion were specified by onset or offset asynchronicity. Results previously attributed to onset and offset asynchrony are instead attributable to onsets and offsets occurring in close temporal proximity at the same location. This was consistent with units for detecting away and toward changes that are temporally biphasic; that is, they are excited by changes in one direction and inhibited by immediately preceding or immediately following changes in the opposite direction. These results are accounted for by a model for counterchange-specified motion entailing the biphasic detection of toward and away changes.
当物体在一系列位置间移动时，运动感知通常伴随着序列的现象学印象。然而，越来越多的证据表明，序列信息对于感知运动既非必要条件也非充分条件。本文表明，表观运动是由反向变化而非序列来确定的——也就是说，由在两个空间位置同时出现的朝向和远离背景的变化来确定，无论这些变化是同时发生还是相继发生。即使变化以相反的时间顺序出现，运动也是从朝向变化的位置被感知到远离变化的位置。对于远离或朝向变化的序列，运动并不会被感知到，而如果运动是由起始或结束的异步性来确定的话，情况则会有所不同。之前归因于起始和结束异步性的结果，实际上是由于在同一位置上的起始和结束在时间上紧密相邻而产生的。这与用于检测远离和朝向变化的时间上双相的单元是一致的；也就是说，它们会被一个方向上的变化所激发，并被紧接着的相反方向上的变化所抑制。这些结果可以通过一个用于反向变化确定运动的模型来解释，该模型需要对朝向和远离变化进行双相检测。
