http://nautil.us/issue/53/monsters/what-boredom-does-to-you
"Scientifically, daydreaming is an interesting phenomenon because it speaks to the capacity that people have to create thought in a pure way rather than thought happening when it's a response to events in the outside world," said Jonathan Smallwood.
It turns out that in the default mode, we're still tapping about 95 percent of the energy we use when our brains are engaged in hardcore, focused thinking. Despite being in an inattentive state, our brains are still doing a remarkable amount of work.
The areas of the brain that make up the default mode network - the medial temporal lobe, the medial prefrontal cortex, and the posterior cingulate cortex - are turned off when we engage in attention-demanding tasks. But they are very active in autobiographical memory (our personal archive of life experiences); theory of mind (essentially, our ability to imagine what others are thinking and feeling); and - this one's a doozy - self-referential processing (basically, crafting a coherent sense of self.)
Killingsworth and Gibert found that "people are thinking about what is not happening almost as often as they are thinking about what is" and "doing so typically makes them unhappy."
