When Keen Minds Are Quick to Wander

We're all afflicted with wandering minds. Those that are especially prone to gallop away during an easy task may just have more horsepower to begin with.

Working memory is the place where your mind holds and manipulates the things you're currently thinking about. If you can fit more items in there at once, you have a better working memory capacity--and odds are you score better on IQ and other tests. Previous studies have shown that when our working memory is busier, our minds wander less. Does this mean wandering uses resources from working memory, taking valuable brainpower away from other tasks?

Daniel Levinson, a graduate student at the University of Wisconsin, Madison, led a study of working memory and mind wandering. Scientists call wandering "task-unrelated thought" or TUT, as in the chastising sound you might imagine when you catch yourself drifting away from your work.

Levinson used two experiments to study whether people with better working memories are more likely to let their attention drift during a simple assignment. In the first experiment, 74 subjects performed an easy visual task on a screen, pressing keys in response to the letters they saw. In the second, 42 subjects did an even duller task, pressing a key in time with their own breathing. Both experiments were periodically interrupted by a message on the computer screen asking whether subjects had just been thinking about something besides the job at hand.

All subjects also completed a standard test of their working memories. In both experiments, people with higher working memory scores reported more episodes of mind wandering (or TUT).

Levinson thinks that since the tasks used here were simple, using only a minimum of working memory resources, subjects' minds were free to wander. Those who had greater resources to begin with had more left over after clicking the keyboard, and tended to spend it elsewhere--say, planning a grocery list. In previous studies, more challenging tasks had eaten up working memory resources and left little behind for daydreaming.

Of course, a correlation between working memory and mind wandering doesn't prove that one causes the other, as Levinson readily agrees. To show that, he says, you'd have to increase individuals' working memory and see that their ability to mind wander also increased. Alternatively, maybe people with better working memories just find these computer-screen tasks easier to begin with, and that sends some other part of their minds meandering.

But Levinson says the subjects in his study with higher working memory, for the most part, didn't outperform others (as you might expect if they found those tasks easier). When researchers removed the one measure by which those subjects did do better from their analysis, the result stayed the same: Minds with greater working memory resources wandered more.

If mind wandering really does depend on working memory, Levinson says there are various theories about how that relationship might work. One idea is that a fragmentary thought can pop into your consciousness spontaneously, or because your stomach rumbles and reminds you of lunch. Your working memory may grasp that fragment and spin it into a longer yarn of thought: Where should I get lunch today? After lunch do I have time to go to the library? Now you're gathering and elaborating on bits of information that aren't in your immediate environment--a job that requires your working memory.

Levinson thinks this kind of research could lead to training methods that help people keep their minds on task. Until then, maybe we can hack the system on our own.

To keep my own mind on task while I'm writing, I like to be in a mildly distracting environment. A subdued Starbucks works, as does playing classical music at my desk. (TV, music with lyrics, or that horrible guy on his cell phone next to me at Starbucks do not work.) Paradoxically, giving myself a small distraction to handle seems to help me focus. Judging by the scarcity of open outlets at most coffee shops, I'm not the only person who does this.

I asked Levinson whether committing part of my working memory to tuning out a distraction should help tone down my mental chatter. "Yes!" he said. "People with more working memory are better at blocking out visual distractors on a screen. So people think that working memory is used to filter out distractions." Spending some resources on this task should leave me with less free rein to wander. Though, he points out, I'd also have fewer remaining resources for the task at hand.

Levinson suggests a different trick. Working memory is known for helping you keep track of your priorities and override your habits, he says. If you set a goal to rein in your mind when you notice it wandering, the simple act of remembering that goal may claim some of your working memory resources and make you less likely to drift.

Though this tactic may sound like a recipe for frustration (Wandering again? Tut tut!), Levinson considers it empowering. "It's a choice that I'm actually making when I elaborate on my mind wandering, and I'm using my resources when I do it," he says. "I also have a choice to invest those resources somewhere else."

There's also the zen approach. "It's impossible not to mind wander," Levinson says. "On average, people will mind wander for half of their daily lives." We can't help it. But maybe we can take a moment along the way to appreciate what a mobile mind says about our brainpower.

No, really, just a moment. You can go now.


Levinson, D., Smallwood, J., & Davidson, R. (2012). The Persistence of Thought: Evidence for a Role of Working Memory in the Maintenance of Task-Unrelated Thinking Psychological Science DOI: 10.1177/0956797611431465 


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