Scientific American: “Researchers at Dartmouth College may have the answer. They found that a default network of regions in the brain’s cortex—a grouping known to be active when the mind is completely unoccupied—is firing away as a person is engaged in routine activities. Malia Mason, now a postdoctoral researcher of neurocognition at Harvard Medical School, trained subjects in verbal and spatial memory tasks that after four days of continual repetition became quite banal—perfect conditions for thinking about something unassociated with the work at hand. In fact, subjects reported more daydreaming when performing the rehearsed sequences rather then when the tasks were tweaked slightly to introduce a novel stimulus requiring a bit more focus.”