By most measures, we spend about a third of our time daydreaming, yet our brain is unusually active during these seemingly idle moments. Left to its own devices, our brain activates several areas associated with complex problem solving, which researchers had previously assumed were dormant during daydreams. Moreover, it appears to be the only time these areas work in unison.

Of course, just sitting around doing nothing doesn't mean you'll solve the world's problems. In fact, the exact ingredients of the "Eureka moment" are not yet known, but just as luck favors the prepared, so does insight--and it's not just expertise that matters. Your attitude factors in as well.

Even before we are presented with a problem, our state of mind can affect whether or not we will likely resort to insightful thinking. People in a positive mood were more likely to experience an insight, researchers at Drexel and Northwestern found.

Over the last few weeks I've been waist-high in a new programming project, and after a few hours of intense PHP-wrangling I find it super-helpful to gaze out the window or at the ceiling and daydream about nothing in particular with a notebook and pen nearby. That's the time I'm most likely to come up with that bugfix, data structure design, or logic flow that wasn't clear in the heat of the work.

A Wandering Mind Heads Straight Toward Insight [The Wall Street Journal]