People spend nearly half their waking hours thinking about what isn't going on around them, and this mind-wandering typically makes them unhappy, says a new research.
The study was conducted using an iPhone web app to gather 250,000 data points on subjects' thoughts, feelings, and actions as they went about their lives. Psychologists Matthew A. Killingsworth and Daniel T. Gilbert of Harvard University did the research.
"A human mind is a wandering mind, and a wandering mind is an unhappy mind," Killingsworth and Gilbert wrote. "The ability to think about what is not happening is a cognitive achievement that comes at an emotional cost."
To track this behavior, Killingsworth developed an iPhone web app that contacted 2,250 volunteers at random intervals to ask how happy they were, what they were currently doing, and whether they were thinking about their current activity or about something else that was pleasant, neutral, or unpleasant.
Subjects could choose from 22 general activities, such as walking, eating, shopping, and watching television. On average, respondents reported that their minds were wandering 46.9 percent of time, and no less than 30 percent of the time during every activity except making love.
"Mind-wandering appears ubiquitous across all activities," said 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, a professor of psychology at Harvard, 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.
"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."
The researchers estimated that only 4.6 percent of a person's happiness in a given moment was attributable to the specific activity he or she was doing, whereas a person's mind-wandering status accounted for about 10.8 percent of his or her happiness.
Time-lag analyses conducted by the researchers suggested that their subjects' mind-wandering was generally the cause, not the consequence, of their 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 noted.
"These traditions suggest that a wandering mind is an unhappy mind."
The research has been published in the journal Science.