It's a workday, just after lunch. You have a deadline and there's plenty of time left in the day to get the task done. If only you could stop thinking about other things. One thought can lead to your mind just...wandering away. This can't be good, right? You've probably been scolded as a kid for daydreaming in class. But in recent years, neuroscientists and psychologists have found that there are some very redeeming qualities to this mental state - in fact, it could be an essential cognitive skill. Here's an excerpt from an interview conducted with one of those researchers.