Perceptual organization of moving stimuli modulates the flash-lag effect

When a visual stimulus is flashed at a given location the moment a second m oving stimulus arrives at the same location, observers report the flashed s timulus as spatially lagging behind the moving stimulus (the flash-lag effe ct). The authors investigated whether the global configuration (perceptual organization) of the moving stimulus influences the magnitude of the flash- lag effect. The results indicate that a flash presented near the leading po rtion of a moving stimulus lags significantly more than a flash presented n ear the trailing portion. This result also holds for objects consisting of several elements that group to form a unitary percept of an object in motio n. The present study demonstrates a novel interaction between the global co nfiguration of moving objects and the representation of their spatial posit ion and may provide a new and useful tool for the study of perceptual organ ization.