Where was I? Oh yes. Um, apparently people spend around half their waking hours thinking of things other than what's going on around them. And it doesn't even make them happy.
Harvard psychologists Matthew Killingsworth and Daniel Gilbert used an iPhone web app to gather data on subjects' thoughts, feelings, and actions.
They contacted 2,250 volunteers at random intervals to ask how happy they were, what they were currently doing, and whether they were thinking about that or about something else that was pleasant, neutral, or unpleasant.
On average, respondents reported that their minds were wandering 46.9 percent of the time, and at least 30 percent of the time during every activity - except making love.
"Mind-wandering appears ubiquitous across all activities," says Killingsworth, a doctoral student in psychology at Harvard. "This study shows that our mental lives are pervaded, to a remarkable degree, by the non-present."
Killingsworth and Gilbert found that people were happiest when making love, exercising, or engaging in conversation. They were least happy when resting, working, or using a home computer.
Astonishingly, the researchers say, mind-wandering is a better predictor of our happiness than what we're actually doing at any given moment. They estimate that only 4.6 percent of a person's happiness is triggered by what they're actually doing, while a person's mind-wandering status accounts for about 10.8 percent.
Time-lag analyses indicate that mind-wandering is generally the cause, not the consequence, of unhappiness.
"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 a paper in Science. "These traditions suggest that a wandering mind is an unhappy mind."
So how happy are you? Check out the app at www.trackyourhappiness.org - if you don't get side-tracked first.