Neural electrophysiological mechanism of joint hierarchical rule shifting: an event-related potential study.

Although previous studies have explored the brain mechanism by which an individual independently accomplishes task switching or rule shifting with different hierarchical structures, electrophysiological evidence indicating that two actors cooperate to complete the hierarchical rule shift remains unclear. This study adopts a modified joint hierarchical rule shifting paradigm in which one actor judged the parity task and the other decided the magnitude task. Results demonstrated that cues in high- and low-shift conditions elicited larger P2 amplitudes and that low-shift had a larger P3 amplitude than high-shift. Results further indicated that participants required more attention resources to ascertain who would make a judgment for the current trial and that low hierarchical features were superior in reconfiguring changed rules. Regarding the target, the high-shift condition evoked smaller P2 and larger N2 amplitudes when compared to low-shift and repeat conditions, whereas when compared to high- and low-shifts, the repeat condition elicited a larger P3 amplitude. The findings revealed that participants required more control resources to process the varied features and that repeat condition required the least cognitive resources to update rules. Thus, participants had different process patterns between cues and targets when cooperating with their co-actors.