Example stimuli and electrophysiology results from the three tasks of experiment 1. Auditory stimuli were presented in only task 1 (i.e. not in tasks 2 and 3). The visual background color in all the experiments was black. (A) In task 1, the auditory series consisted of 80% standard tones and 20% deviant tones, and frequencies of deviant and standard tones were counterbalanced across participants. Each tone was presented for 200 ms at 600-ms intervals. Participants were instructed to report when the fixation cross turned red (10% of trials, randomly distributed) and ignore the task-irrelevant auditory stimuli. (B) In task 2, the visual search array consisted of one circle (target) and 11 diamonds. The target was randomly located at 2, 4, 8, or 10 o’clock with equal probability. Participants were instructed to report the position of the target (upper or lower visual field) in each trial. (C) In task 3, the gray circle of the visual search array in task 2 turned red in 10% of trials (randomly distributed). Participants were instructed to detect and report the presence of the red circle. (D) The grand averaged event-related potentials at the frontal electrode FCz for standard and deviant tones in task 1 (top). Subtraction of these waveforms provides the MMN in task 1 (bottom). Shading represents standard error. The topographic scalp map shows the distribution of the MMN at peak. (E) The grand averaged event-related potentials at contralateral and ipsilateral electrode sites (59 and 91, near the PO7/PO8 locations in the international 10/10 system) relative to the target in task 2 (top). The N2pc difference waveform (bottom) was obtained by subtracting the ipsilateral waveform from the contralateral waveform. Shading represents standard error. The topographic scalp map shows the distribution of the N2pc at the peak. (F) The grand averaged event-related potentials at contralateral and ipsilateral electrode sites (59 and 91) relative to the gray circle in task 3 (top). Subtraction of these waveforms provides the N2pc difference waveform (bottom). Shading represents standard error. The topographic scalp map shows the distribution of the N2pc at the peak.