2.3.2 Flanker task
Two types of trials, congruent (i.e., >>>>> or <<<<<) and incongruent (i.e., >><>> or <<><<), were included in the flanker task. As is typical in flanker-type tasks, participants were instructed to decide whether the central arrow pointed to the left or the right by responding with the ā€œFā€ or ā€œJā€ button on the keyboard. Since we introduced picture-naming trials before flanker trials, the response language and trial type of picture-naming were intermixed with pseudorandom presentations of flanker trials (except for the voluntary switching block).
There were 6 blocks, each of which included 114 cross-task trials (2 warm-up trials followed by 56 congruent trials and 56 incongruent trials). The six blocks were divided into two natural blocks, two forced blocks, and two voluntary blocks, with the ordering of blocks being counterbalanced across participants. Trial sequences were randomized throughout the task so that participants could not anticipate upcoming trial types.
Figure 1. Procedure of the present study. Cross-task trial structure (upper panel) and experimental design (lower panel).