Balancing act: Investigating modulators and mechanisms of cognitive stability and flexibility.

Every day, we face the opposing requirements to flexibly shift between goals and to shield them against distractions. Context-dependent adjustments of cognitive stability and flexibility are a prerequisite for adaptive behavior. A current debate centers on whether these two functions of cognitive control involve a trade-off, manifesting in reciprocal performance benefits and costs, or if cognitive stability and flexibility can be regulated independently. This study aimed to test the assumption of a stability-flexibility trade-off and investigate determinants of control regulations. We examined whether cognitive stability and flexibility can be regulated voluntarily and whether these adjustments are modulated by the task relevance of distracting information. In two task-switching paradigms with varying distractor relevance, we assessed task-switch costs and interference costs as inverse indicators of stability and flexibility. We instructed participants to either focus on the current task or switch flexibly between tasks in within-subjects designs, and monetary rewards were contingent on how well participants succeeded in implementing these instructions. Across both experiments, participants adjusted their task-switch costs but not their interference costs according to the instructions. The distractor relevance further did not moderate these adjustments. Multilevel analyses revealed no correlations between changes in task-switch costs and interference costs in both experiments. Taken together, our results provide evidence that adjustments in task-switch costs are partly under voluntary control. However, they did not provide evidence for the expected trade-off between indicators of cognitive stability and flexibility, at least in the task-switching paradigms we used. (PsycInfo Database Record (c) 2026 APA, all rights reserved).