The costs of monitoring: Does self-catching the wandering mind influence task performance and/or residual probe-caught mind-wandering?

We examined whether continuous self-monitoring for mind-wandering episodes impairs primary-task performance and differentially affects residual probe-caught deliberate versus spontaneous mind-wandering. Participants (N = 117) completed the Metronome Response Task, which requires rhythmic keypresses synchronized with auditory tones. The task was intermittently interrupted by thought probes sampling experiences of deliberate and spontaneous mind-wandering. Critically, whereas both groups provided probe-caught responses, one group received additional instructions to self-catch and report mind-wandering episodes as they occurred. Results revealed that self-catching significantly increased rhythmic response time variability (d = 0.46), indicating impaired task performance. This performance cost emerged despite (a) no significant differences in probe-caught mind-wandering reports, and (b) no significant evidence that self-monitoring differentially reduced deliberate versus spontaneous mind-wandering across the groups. These findings suggest that the metacognitive act of monitoring one's attentional state is not cost-free, but rather draws upon limited cognitive resources needed for primary task performance. The observed performance costs align with models proposing that monitoring for mind wandering engages higher-order evaluative processes that compete with task-focused attention.