Fig. 1.

Design of the experiment. a In this version of the alternating serial reaction time (ASRT) task, an arrow stimulus appears at the center of the screen. The presentation of arrow stimuli follows an eight-element sequence, within which pattern (P) and random (r) elements alternate with one another. The timing of an arrow trial is presented below the trial structure. b In the alternating sequence structure, numbers denote the four spatial directions (1 = left, 2 = up, 3 = down, 4 = right) of the arrows. The alternating sequence makes some runs of three consecutive trials (triplets) more probable than others. High-probability triplets are denoted with gold shading, and low-probability triplets are denoted with coral shading. Among high-probability triplets, pattern (with black font in the lower table) and random (with blue font in the lower table) high-probability triplets are distinguished. In the random triplet category (r–P–r structure, see the green font in the lower table), random low-probability triplets are also distinguished (with coral font in the lower table). (Color figure online)