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 tradeoff, 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 tradeoff 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 instructed participants to either focus on the current task or to switch flexibly between tasks in within-subject designs. Monetary rewards were contingent on how well participants succeeded in implementing these instructions. Across both experiments, participants adjusted their cognitive flexibility but not stability according to the instructions. The distractor relevance further did not moderate control adjustments. Multilevel analyses revealed no correlations between changes in task-switch costs and interference costs in both experiments, providing no evidence for the expected tradeoff between cognitive stability and flexibility. Our results provide evidence that adjustments in cognitive flexibility are partly under voluntary control. However, they do not support the notion of an inherent stability-flexibility tradeoff, at least in the task-switching paradigms we used.