It seems like science still has a ways to go before this question can be answered, but scientists have already started the investigation. In a recent study, Mason and colleagues used fMRI and thought sampling to study which areas of the brain show increased activations in one kind of situation where our minds are likely to wander: when we perform tasks that become banal with continual practice. They compared brain activity that was associated with performing blocks of well-practiced tasks with that of non-practiced, but otherwise identical, tasks and observed greater activation for the practiced tasks in following brain areas: bilateral medial prefrontal cortex (BAs 6, 8, 9, and 10); bilateral superior frontal gyri (BAs 8 and 9); anterior cingulate (BA10); bilateral aspects of the posterior cingulate (BAs 29 and 30); precuneus (BAs 7 and 31); left angular gyrus (BA 39); bilateral aspects of the insula (BA 13); left superior temporal (BA 22), the right superior temporal (BA 41) and the left middle temporal gyri (BA 19). They also found a significant positive relation between changes in brain activity in many of the aforementioned regions for blocks in which subjects performed practiced, relative to non-practiced, tasks and the subjects’ frequency of mind-wandering, which was assessed using the daydream frequency scale of the Imaginal Processes Inventory. Following-up with this intriguing study, it would be interesting to examine the brain activity that arises during specific instances, as opposed to blocks, when participants report mind-wandering.
Wandering minds: the default network and stimulus-independent thought.
Mason MF, Norton MI, Van Horn JD, Wegner DM, Grafton ST, Macrae CN
Despite evidence pointing to a ubiquitous tendency of human minds to wander, little is known about the neural operations that support this core component of human cognition. Using both thought sampling and brain imaging, the current investigation demonstrated that mind-wandering is associated with activity in a default network of cortical regions that are active when the brain is “at rest.” In addition, individuals’ reports of the tendency of their minds to wander were correlated with activity in this network.