A variant of an Eriksen flanker task was used (Saalmann et al., 2012 ). In each trial, participants were instructed to fixate on a central white square (0.82° visual angle) presented on a gray background at a distance of approximately 84 cm. After a baseline “fixation” period (2 s, Figure 1 a), a spatial cue (100 ms duration; 1.36° visual angle) was presented at one of 16 pseudorandomly chosen locations (Figure 1 a). After a delay interval of 2.5 ± 1 s, during which subjects maintained the location information, a target shape (barrel or bowtie) appeared at the precued location embedded in a circular array of 16 shape stimuli (radius 16.5 cm, visual angle 22.22°). Targets were flanked either by congruent (C) or incongruent (IC) distracters. Targets and distracters had a visual angle of 2.73° × 3.07°. Target type (barrel or bowtie, 50% chance) as well as distractor congruency (congruent and incongruent at 50% chance) were randomly determined on each trial. Participants indicated via button press whether the target was a “barrel” (left index finger) or a “bowtie” (right index finger).
Visual stimuli were back‐projected onto a semitranslucent screen by an Eiki LC‐XL100L projector with a projection resolution of 1,024 × 768 pixels. Eye movements and blinks were continuously recorded using an Eyelink 1000 eye‐tracking device (SR Research, Ontario, Canada).
Visual stimuli were back‐projected onto a semitranslucent screen by an Eiki LC‐XL100L projector with a projection resolution of 1,024 × 768 pixels. Eye movements and blinks were continuously recorded using an Eyelink 1000 eye‐tracking device (SR Research, Ontario, Canada).