Does Mind Wandering Make You Unhappy?

Right now, as you read this sentence, there is a fair chance part of your mind is somewhere else: an email you have not answered, a conversation from yesterday, what to cook tonight. That is not a personal failing. It may be the normal state of a human mind.

In 2010 two Harvard psychologists, Matthew Killingsworth and Daniel Gilbert, set out to measure how often this happens, and whether it matters. Their answer was published in Science under a title that has been quoted ever since: a wandering mind is an unhappy mind.

The experiment in your pocket

Instead of bringing people into a laboratory, the researchers went to where people actually live. They built an iPhone app that contacted volunteers at random moments during the day and asked three quick questions: how are you feeling right now, what are you doing, and are you thinking about something other than what you are doing?

About 2,250 adults, aged 18 to 88, took part, and the project collected roughly a quarter of a million answers. Across all those moments, people reported that their minds were wandering 46.9% of the time. The only activity during which it dropped clearly below 30% was making love.

The second finding was the one that made headlines. People were less happy when their minds were wandering than when they were focused on what they were doing. That held even for pleasant daydreams: according to the authors, drifting to a nice topic made people no happier than staying on task, while drifting to neutral or unpleasant topics made them less happy.

In fact, whether someone's mind was wandering explained more of the variation in their happiness (about 10.8%) than what they were actually doing (about 4.6%). And because each person answered many times, the researchers could look at timing. Mind wandering tended to come before the drop in mood, not after it, which led them to suggest it was generally a cause rather than a consequence of unhappiness.

Why the headline is not the whole story

It is a striking study, and a large one. But three things are worth keeping in mind before concluding that daydreaming is bad for you.

First, the sample. The volunteers were iPhone owners who chose to download a happiness app, and about three quarters were American. That is not a random slice of humanity.

Second, the timing analysis is suggestive, not proof. It is still a correlational design. A bad mood can build slowly before anyone reports it, and people whose lives are more stressful may both wander more and feel worse.

Third, "mind wandering" is not one thing. In 2013 Michael Franklin and colleagues ran a similar experience-sampling study but asked people how interesting their off-task thoughts were. Overall their results matched the original: mind wandering generally went with a lower mood. But when the wandering thoughts were rated as highly interesting, mood was actually more positive than during on-task moments.

Deliberate versus spontaneous

An even more important distinction came from the psychologist Paul Seli and his colleagues. They pointed out that most studies had lumped together two very different experiences: letting your mind drift on purpose, and finding that it has drifted without your permission.

In a 2016 paper in Psychological Science, they showed that the two can behave differently. Changing the conditions of a task affected intentional and unintentional mind wandering in different ways, which is strong evidence that they are not the same process. In a review the same year, they argued that much of the earlier research needed to be reread with this distinction in mind.

The difference matters in everyday life. Choosing to think about your weekend during a boring queue is one thing. Discovering that you have read the same page three times without taking in a word is another. Only the second looks like a lapse of control, and only the second tends to feel frustrating.

The case for a wandering mind

There is also evidence that wandering can be useful. In a 2012 experiment, Benjamin Baird, Jonathan Smallwood and colleagues gave people a creativity task: think of as many unusual uses as possible for an everyday object. Then they took a break. Some did a demanding task, some did an undemanding task that let the mind drift, some rested, and some had no break at all.

When they returned to the same problems, the group that had done the easy, mind-wandering-friendly task improved considerably more than the others. The improvement appeared only for problems they had already seen before the break, which fits the old idea of incubation: leaving a problem alone while part of the mind keeps working on it.

This was one experiment, with a specific creativity measure, and it deserves to be treated as a promising result rather than a law. But it is a useful counterweight. A mind that can leave the present moment is also a mind that can plan, remember, imagine and solve.

What this means for you

Taken together, the research does not say that mind wandering is bad. It says that unnoticed, unwanted wandering, especially towards worries, tends to go with a lower mood, while deliberate, interesting wandering can be neutral or even helpful.

• Notice the direction. Is your mind drifting towards plans and ideas, or circling around the same worry? Repetitive, negative thinking is closer to what psychologists call rumination. Our rumination and reflection test looks at the difference between brooding and more constructive self-reflection.
• Notice the intention. Did you choose to drift, or did you find yourself somewhere else? Our mind wandering test looks at how often and how you wander, and the mindfulness test looks at how much you tend to notice what is happening in the present.
• Use easy tasks on purpose. If you are stuck on a problem, a walk or a simple chore after working on it may give incubation a chance. The evidence is limited, but the cost is low.

If you find that your thoughts keep returning to the same painful themes and it is affecting your mood or sleep, that is worth discussing with a qualified professional.