Intentional mind wandering is objectively linked to low effort and tasks with high predictability

Background: Intentional Mind Wandering (IMW) is proposed to be a low arousal state resulting from boredom, to distinguish it from unintentional mind wandering (UMW), which may be a low executive control state resulting from exhaustion of resources. Aim: To demonstrate that there are objective differences between IMW and UMW reflecting the subjective difference that IMW is a low effort and high predictability strategy. Methods: The metronome response task (MRT) requires participants to predict when the next tone in a regular series will occur. Inter-Trial Interval (ITI) variants of the MRT were presented in blocks of ~90 seconds. Results: The most predictable version of MRT resulted in the percentage of reported IMW doubling, whereas UMW remained similar in all three versions of the MRT. IMW necessitated subjective effort to be low (maximum 5 on a 1-9 scale). IMW in easy and predictable versions of the task resulted in normal performance, whereas IMW during difficult tasks that required sustained attention led to poor performance and occasional errors. IMW during the least predictable MRT led to a significantly higher rate of omission errors (compared to on-task or UMW), and also to a higher maximum-in-block reaction time, as predicted by the worst performance rule. Conscientiousness was linked to reduced IMW (but not reduced UMW), higher on-task probes, increased effort, and improved prediction accuracy. Conclusions: Subjective assessment of low task difficulty predisposes to IMW, evoking increases of both omission errors and slow lapses and decreases in willingness and in compliant allocation of cognitive resources.