From The Big Questions:
But is that really the best way to solve problems and improve your mind? Not necessarily, according to social scientists who have been studying this question in recent years. While researchers have found new support for the old Victorian practices, they’ve also discovered evidence for the benefits of daydreaming. This activity, long dismissed as a waste of time (or worse — psychology textbooks warned it could lead to psychosis), has gained new respect from researchers like Jonathan Schooler, a psychologist at the University of California, Santa Barbara.
“If daydreaming is so problematic, why do we do it so much?” Dr. Schooler asks. “It’s an exemplification of what distinguishes us from other animals: the capacity to leave the here and now to and to engage in future thinking and distant planning about events that aren’t before us right now. It provides us with the opportunity for mental time travel, and it seems to be useful for creativity.”
During a typical day, about 30 percent of your time is given over to mind wandering, which is the type of daydreaming that researchers have been studying. It’s when your mind is taken up with “task-unrelated thoughts,” and it’s most likely to happen when you’re performing a repetitive but undemanding task, like taking a walk, jogging or knitting. It has repeatedly been shown to foster creativity, as in experiment reported last year by Dr. Schooler and several colleagues, including Benjamin Baird and Jonathan Smallwood at U.C. Santa Barbara.