Figure 1.

Sequence of events within a trial: participants focused on a fixation point with two flanking square boxes for a variable delay interval. On 30% of the trials, an auditory tone was played followed by a jittered inter-stimulus interval. On the remaining 70% of the trials, no tone was played during the 100ms and ISI period. A target was then presented in one of the two boxes until response. After the response, the target was removed and the boxes remained for 2000ms. The next trial began following a blank screen with central fixation cross, during which blinking is permitted. Participants completed a practice block of 10 trials and two blocks of 100 trials.