Figure 1.

Stimulus and task during the visual and the auditory condition. The ISIs ranged from 0 to 0.2 second in the visual and 0 to 0.1 second in the auditory condition. Subjects had to judge whether or not the two stimuli appeared simultaneously. The ON-time was randomly assigned as 0.4, 0.5, or 0.6 second but was added to the ISI in the visual and not the auditory condition. Stimuli were turned off simultaneously. The intertrial interval (ITI) ranged from 0.5 to 0.6 second and was randomly assigned after the offset of the stimulus.