Stimuli. All stimuli were drawn with 3-pixel-thick linesand appeared against a black background. The fixationdisplay consisted of a 0.2° × 0.2° cross in the center of thescreen, surrounded by four 1.7° × 1.7° empty squareplaceholders. These squares appeared at the corners ofan imaginary 3.66° × 3.66° square centered at fixation.The cue and target displays were similar to the fixationdisplay except for the following differences. In the cuedisplay, four filled dots (0.25° in diameter) appeared atcardinal locations around one of the placeholders, withdot-placeholder center-to-center distance set at 1.2°.These dots were either red (RGB values = 255, 0, 0) orwhite (RGB values = 255, 255, 255). In the target display,a letter, “E” or “H,” subtending 1° × 1°, appeared in thecenter of each placeholder. One letter, the target, was red(RGB values = 255, 0, 0), one distractor was pink (RGBvalues = 210, 0, 80), and the other two distractors wereorange (RGB values = 210, 80, 0).

Design. The experiment included 20 practice trials followed by 500 experimental trials divided into 50-trialblocks. Participants were allowed a self-paced rest betweenblocks. Cue-relevance conditions, red (relevant-coloronset) or white (irrelevant-color onset), alternated betweenblocks, with the first-presented condition counterbalancedbetween subjects. The cue and target locations were randomly set on each trial. Therefore, the cue and targetappeared at the same location on 25% of the trials (samelocation trials). Since each display contained exactly two“Es” and two “Hs,” on different-location trials the letter thatappeared at the cued location was the same as the targeton one third of the trials (compatible-distractor condition)and different from the target on two thirds of the trials(incompatible-distractor condition)

Procedure. The sequence of events on each trial is presented in Figure 1. Participants were instructed to report asquickly and as accurately as possible whether the red letterwas an “E” or an “H” by pressing “1” or “3” on the numericalkeypad, respectively. Each trial began with the fixation display, which appeared for a random duration ranging from700 ms to 1,300 ms. Then, the cue display appeared for 100ms. It was followed by the fixation display for 50 ms andthen by the target display, which remained on the screen for100 ms. The response duration was limited to 2,000 ms.Errors were followed by a 500-ms beep. After response, ablank screen appeared for 500 ms, after which a new trialbegan. Participants were instructed to maintain their eyeson the fixation cross. They were informed about the presence of the cues and instructed to ignore them

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