The role of the left dorsolateral prefrontal cortex in the interplay between metacontrol and mind-wandering. Evidence from a HD-tDCS study

The metacontrol framework claims that cognitive control operates along a continuum between persistence and flexibility. While spontaneous mind-wandering is often considered a failure of control, emerging evidence suggests that different types of mind-wandering, intentional versus unintentional, may reflect distinct metacontrol dynamics. We examined how high-definition transcranial direct current stimulation (HD-tDCS) over the left dorsolateral prefrontal cortex modulates the interplay between metacontrol strategies and mind-wandering, using a global-local task combined with intermittent thought probes. Ninety-two participants completed a global-local task while receiving either anodal or sham HD-tDCS at 1.5 mA over the left dorsolateral prefrontal cortex. Mind-wandering episodes were assessed using thought probes, distinguishing between intentional and unintentional mind-wandering. Metacontrol tendencies were inferred from global precedence effects observed in response accuracy and latency. HD-tDCS selectively enhanced accuracy in the local condition during the second half of the task, suggesting an increase in persistence-oriented control. Intentional mind-wandering was positively associated with cognitive flexibility (greater global precedence), while unintentional mind-wandering correlated with persistence. However, stimulation did not directly affect mind-wandering rate. Our findings support a double dissociation between types of mind-wandering and metacontrol styles. They provide causal evidence that HD-tDCS over the left dorsolateral prefrontal cortex can promote persistence without altering spontaneous thought frequency, thereby validating and extending the metacontrol framework.