In 2010 psychologists Matthew A. Killingsworth and Daniel T. Gilbert (Harvard University) published a paper in Science magazine called: A Wandering Mind Is an Unhappy Mind
The abstract of the article is: “We developed a smartphone technology to sample people’s ongoing thoughts, feelings, and actions and found (i) that people are thinking about what is not happening almost as often as they are thinking about what is and (ii) found that doing so typically makes them unhappy.” If you’d like to read the full article check it out on ScienceMag.org. You’ll need to register — but it’s free.
Here’s an extract from the article:
“A human mind is a wandering mind, and a wandering mind is an unhappy mind,” Killingsworth and Gilbert write. “The ability to think about what is not happening is a cognitive achievement that comes at an emotional cost.”
“Unlike other animals, humans spend a lot of time thinking about what isn’t going on around them: contemplating events that happened in the past, might happen in the future, or may never happen at all. Indeed, mind-wandering appears to be the human brain’s default mode of operation.”
“Mind-wandering is an excellent predictor of people’s happiness,” Killingsworth says. “In fact, how often our minds leave the present and where they tend to go is a better predictor of our happiness than the activities in which we are engaged.”
As a final thought they added:
“Many philosophical and religious traditions teach that happiness is to be found by living in the moment, and practitioners are trained to resist mind wandering and to ‘be here now,’” Killingsworth and Gilbert note in Science. “These traditions suggest that a wandering mind is an unhappy mind.”