While the self-reported incidence of mind wandering was unchanged in the case of occipital and sham stimulation, it rose considerably when this stimulation was applied to the frontal lobes.

“Our results go beyond what was achieved in earlier, fMRI-based studies,” Bar states. “They demonstrate that the frontal lobes play a causal role in the production of mind wandering behavior.”

In an unanticipated finding, the present study demonstrated how the increased mind wandering behavior produced by external stimulation not only does not harm subjects’ ability to succeed at an appointed task, it actually helps.

Source: Psych Central News
http://psychcentral.com/news/2015/02/24/daydreams-may-improve-cognition/81