Speed-accuracy trade-offs during the antisaccade task.

<p>A: A schematic depiction of the speed-accuracy trade-off (SATO). As reaction time (RT) increases, the probability of an error decreases. The circle denotes the point where optimal accuracy is achieved with the fastest RT. Beyond this point, making faster responses entails a cost in reduced accuracy. B: The antisaccade paradigm. Schematic and timeline of the three conditions: easy, hard, and fake-hard. Each trial lasted four seconds and began with an instructional cue (300 ms), either a blue or yellow ‘X’ that indicated whether the trial was hard or easy. The mapping of cue color to trial type was counterbalanced across participants. The cue was horizontally flanked by two white squares of 0.4° width that marked the potential locations of stimulus appearance, 10° left and right of center. The squares remained visible for the duration of each run. At 300 ms, the instructional cue was replaced by a white fixation ring of 1.3° diameter at the center of the screen. At 1800 ms, the fixation ring disappeared (200 ms gap). At 2000 ms, the fixation ring reappeared at one of the two stimulus locations, right or left with equal probability. This was the imperative stimulus to which the participant responded by making a saccade in the opposite direction. The ring remained in the peripheral location for 1000 ms and then returned to the center, where participants were instructed to return their gaze for 1000 ms before the start of the next trial. Hard trials were distinguished by a 3 db increase in luminance of the peripheral squares starting during the gap. Except for the hard cue, fake-hard trials were identical to easy trials. Fixation epochs were simply a continuation of the fixation display that constitutes the final second of the previous saccadic trial. C: Mean saccadic RT as a function of trial position in relation to an error (ERR) with standard error bars.