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Why Do We Zone Out?
Credit: Leonid Ikan | Shutterstock

The level of attention we pay to the outside world naturally waxes and wanes. No matter how hard we might try to stay focused on an everyday task — such as brushing our teeth or queuing for coffee — we simply can't stop our minds from wandering. Half the time we aren't even aware that we've mentally digressed. Fortunately, though, research suggests that those bizarre bouts of cognition sans awareness, commonly known as "zoning out," are actually a good thing.

Jonathan Smallwood, a neuroscientist at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany and Jonathan Schooler, a psychologist at the University of California, Santa Barbara, may be the world's leading experts on zoning out, which they call "the offline mode." By monitoring the brain activity of study participants as they complete random tasks, the researchers have found that our minds spend up to 13 percent of the time offline. Furthermore, they've proven that, when zoned out, we have almost no idea what's happening in the world around us. [Read: Does Hypnosis Work? ]

What benefit do these lapses in attention bestow? Evidence suggests that zoning out may be vital to creativity and imaginative thought. It allows us to float along internal streams of consciousness without being distracted by dull external stimuli. In offline mode, we become free to follow where our minds randomly take us — perhaps arriving at a "eureka!" moment, or at the very least, a spontaneous and interesting idea.

How does zoning out happen? In what Smallwood and Schooler call the "decoupling hypothesis," the brain may actually decouple attention from outward sensation during these times of mental free verse. It decides that nothing too important, difficult or dangerous is happening out there, and cuts the connection between the external and internal worlds . We then literally become unable to perceive what is happening outside of our own wandering minds.

Differences in the way our eyes move while we are and aren't zoned out lends support for the decoupling hypothesis. As detailed in the March issue of the journal PLoS ONE, Smallwood, Schooler and their colleagues found that under normal circumstances, our pupils dilate in response to changes in our surroundings. When we're zoned out, on the other hand, our pupils fail to respond at all to external changes. Instead, they fluctuate in size independently from their surroundings, as if marching to the beat of their own drum — or the mind's drum.

The neuroscientists believe that the brain's locus coeruleus-norepinephrine (LC-NE) system, which controls attention and the response to stress or stimulation, may be the part that reconfigures itself when you zone out. They plan to do more research to find out.

Follow Natalie Wolchover on Twitter @nattyover.