Motion signal and the perceived positions of moving objects.

When a flash is presented in spatial alignment with a moving stimulus, the flash appears to lag behind (the flash-lag effect). The motion of the object can influence the position of the flash, but there may also be a reciprocal effect of the flash on the moving object. Here, we demonstrate that this is the case. We show that when a flash is presented near the moving object, the flash-lag effect does not depend greatly on the duration of the preflash trajectory. However, when the flash is presented sufficiently far from the moving object, the flash-lag effect increases with the duration of the preflash trajectory, until it reaches an asymptotic level. We also show that the interaction of the near flash can occur when it is task irrelevant. Finally, using the motion aftereffect, we demonstrate that motion signals are involved in the time evolution of the flash-lag effect.