Local Use-Dependent Activity Triggers Mind Wandering: Resource Depletion or Executive Dysfunction?

Mind wandering (MW) is a highly prevalent phenomenon despite its negative consequences on behavior. Current views about its origin share the idea that MW occurs due to changes in the executive functions system. Here, we argue that not all instances of MW are necessarily related to changes in that system. Combining results from MW and sleep research, we propose that MW could also be related to the depletion of resources in primary task-related networks. To test this hypothesis, participants performed four sessions of the texture discrimination task (TDT) on a day. The TDT is a perceptual learning task in which performance is negatively related to the local build-up of sleep pressure. During the TDT, MW was recorded in both a subjective (i.e., with thought probes) and an objective (i.e., phasic pupillary response) manner. Results showed that accuracy on the TDT was mirrored in the objective measure of MW. For the subjective measure, the pattern was similar to that of task performance but could not be interpreted as reliable. These results demonstrate that not all MW is necessarily related to changes in the executive system and support the hypothesis that MW could be related to the depletion of local, task-related resources. Public Significance Statement Our study contributes to the ongoing debate about the origin of mind wandering (MW). Departing from current dominant views that implicate the executive functions system in MW, we here provide evidence for the alternative proposition that MW might be locally initiated due to an increase in sleep pressure in neural areas engaged during performance of a task.