Au Ricky K C, Watanabe Katsumi
Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan; Japan Society for the Promotion of Science, Tokyo, Japan.
Vision Res. 2013 Nov;92:19-25. doi: 10.1016/j.visres.2013.08.009. Epub 2013 Aug 29.
When a visual object is briefly flashed, it appears to lag behind another moving object (flash-lag effect; FLE). Previous studies showed that a sudden change to the moving object at the time of the flash presentation would eliminate the FLE. We examined whether the FLE would be eliminated when a sudden color change was embedded in a sequence of color alternations on a moving object. Observers viewed a moving disc, the color of which did not change at all, changed only once when another stationary object flashed, or alternated regularly (Experiment 1) or randomly (Experiment 2) between two colors as it was moving before the flash presentation. Although the magnitude was reduced compared with the no-change condition, the FLE observed with the moving object that changed color during motion was significantly stronger than that in the one-change condition. In Experiment 3, the object color alternated between two but unexpectedly changed to a new color when the flash appeared. The elimination of FLE in such condition was comparable to the one-change condition, suggesting that the unexpected change restored the salience of the moving object at the time of flash presentation, which spared the observer from perceiving the FLE. We propose that, without an unexpected event, rapid changes in the surface feature of the moving object partially degrade the maintenance of object file, but this does not preclude the visual system in registering the existence of only one object in the motion stream.
当一个视觉对象短暂闪现时，它似乎会落后于另一个移动对象（闪光滞后效应；FLE）。先前的研究表明，在闪光呈现时对移动对象进行突然改变会消除FLE。我们研究了在移动对象上的颜色交替序列中嵌入突然的颜色变化时，FLE是否会被消除。观察者观看一个移动的圆盘，其颜色根本不变、在另一个静止对象闪现时只改变一次，或者在闪光呈现之前移动时在两种颜色之间有规律地（实验1）或随机地（实验2）交替。尽管与无变化条件相比幅度有所减小，但在运动过程中颜色发生变化的移动对象上观察到的FLE明显强于只改变一次颜色的情况。在实验3中，对象颜色在两种颜色之间交替，但在闪光出现时意外地变为一种新颜色。在这种情况下FLE的消除与只改变一次颜色的情况相当，这表明意外变化恢复了闪光呈现时移动对象的显著性，使观察者不会察觉到FLE。我们提出，在没有意外事件的情况下，移动对象表面特征的快速变化会部分降低对象文件的维持，但这并不妨碍视觉系统在运动流中记录只有一个对象的存在。
