Kramer P, Rudd M
Johns Hopkins University, Baltimore, Maryland, USA.
Percept Psychophys. 1999 Jul;61(5):952-62. doi: 10.3758/bf03206909.
Visual stimuli remain visible for some time after their physical offset (visible persistence). Visible persistence has been hypothesized to play an important role in determining the pattern of correspondence matching in the Ternus apparent-motion display. In this display, one or more elements reappears in overlapping locations at different times, whereas another element appears alternately to the right or the left of these elements. Usually either the elements are perceived to move coherently as a group (group motion), or one element may be perceived to hop over one or more other elements (element motion). According to the visible-persistence account of the perceptual organization of the Ternus display, element motion is seen when the temporal gap between elements in overlapping locations is small enough to be bridged by visible persistence; if it is not, group motion is seen. We conducted four experiments to test this visible-persistence account. In Experiments 1 and 2, a form correspondence cue (line length) was introduced to bias the visual system toward the element-motion interpretation, while visible persistence was either reduced or eliminated. The element-motion percept dominated despite the elimination of visible persistence. In Experiments 3 and 4, we found that Ternus elements presented without interruption, and thus presumably persisting over time, can be perceived in group motion. Together, the results indicate that visible persistence is neither necessary nor sufficient to account for the pattern of correspondence matches in the Ternus display.
视觉刺激在其物理消失后仍会在一段时间内保持可见（可见持续性）。据推测，可见持续性在确定特努斯表观运动显示中的对应匹配模式方面起着重要作用。在这种显示中，一个或多个元素在不同时间出现在重叠位置，而另一个元素则交替出现在这些元素的右侧或左侧。通常，要么这些元素被感知为作为一个整体连贯移动（群组运动），要么一个元素可能被感知为跳过一个或多个其他元素（元素运动）。根据特努斯显示的感知组织的可见持续性解释，当重叠位置的元素之间的时间间隔足够小以至于可以通过可见持续性来弥合时，就会看到元素运动；如果不是这样，就会看到群组运动。我们进行了四项实验来检验这种可见持续性解释。在实验1和实验2中，引入了一种形式对应线索（线长），以使视觉系统偏向于元素运动解释，同时减少或消除可见持续性。尽管消除了可见持续性，元素运动感知仍然占主导。在实验3和实验4中，我们发现不间断呈现的特努斯元素，因此大概是随时间持续存在的，可以被感知为群组运动。总之，结果表明，可见持续性对于解释特努斯显示中的对应匹配模式既不是必要的也不是充分的。
