Predictability and the Dynamics of Position Processing in the Flash-Lag Effect

Several models have been proposed to account for the flash-lag effect. One criterion for evaluating alternative models is to consider the separate effects of motion predictability and flash predictability. We first established that flash predictability has an impact on the size of the perceived spatial offset in the flash-lag illusion. We then examined motion predictability by varying the consistency of the motion trajectory. Both manipulations affected the magnitude of the flash-lag illusion. These outcomes suggest that the perception of position is a dynamic process that can be modulated by explicit cues in advance of the flash and by the temporal integration of position information over a consistent motion trajectory. A complete explanation of the flash-lag effect must specify how flash predictability and motion predictability modulate position-processing mechanisms.