I am going to do my best to hold your attention until the very last word of this column. Actually, I know it’s futile. Along the way, your mind will wander off, then return, then drift away again. But I can console myself with some recent research on the subject of mind wandering. Mind wandering is not necessarily the sign of a boring column. It’s just one of the things that make us human.

Everybody knows what it is like for our minds to wander, and yet, for a long time psychologists shied away from examining the experience. It seemed too elusive and subjective to study scientifically. Only in the past decade have they even measured just how common mind wandering is. The answer is very.

Some of the most striking evidence comes from Jonathan Schooler, a psychologist at the University of California at Santa Barbara who is one of the leading researchers on mind wandering. In 2005 he and his colleagues told a group of undergraduates to read the opening chapters of War and Peace on a computer monitor and then to tap a key whenever they realized they were not thinking about what they were reading. On average, the students reported that their minds wandered 5.4 times in a 45-minute session. Other researchers have gotten similar results with simpler tasks, such as pronouncing words or pressing a button in response to seeing particular letters and numbers. Depending on the experiment, people spend up to half their time not thinking about the task at hand—even when they’ve been told explicitly to pay attention.

Psychologists have also discovered ways to increase and decrease mind wandering. Jonathan Smallwood, a colleague of Schooler’s at UC Santa Barbara, instructed subjects to tap a key every time they saw a new number appear on a computer screen but to hold off tapping if the number was three. The more quickly the numbers came, the less often the subjects’ minds wandered. But as people practiced the task and became more familiar with it, their mind wandering increased. Smallwood has also found that mood affects mind wandering: If he showed people a short video about a sick dog before they performed the task, for example, they spent more time mind wandering than did a separate group that had watched a comedy clip.

Alcohol tweaks mind wandering in a particularly interesting way, as Schooler and his colleagues report in a new paper entitled “Lost in the Sauce,” published in Psychological Science. The psychologists ran the War and Peace experiment again, but this time after serving their subjects some vodka with cranberry juice. Drunk readers actually reported less mind wandering than sober people did. That does not mean that you should swill vodka if you want a laser focus on Tolstoy’s deathless prose, though. Schooler has shown that there are, in fact, two kinds of mind wandering: mind wandering when you are aware that you’re thinking about something else and mind wandering without awareness. He calls this second kind “zoning out.”

To determine which kind of mind wandering people experience, Schooler and his collaborators told the participants in the War and Peace experiment to report their own drifting but also asked them every few minutes if they were thinking of something else. If people responded to those questions with a yes, that meant they weren’t aware enough of their own minds to report their mind wandering on their own. These experiments show that we spend about 13 percent of our time zoning out. But when we are drunk, that figure doubles. In other words, inebriated subjects report less mind wandering only because they are less aware of their own minds.

When our minds wander, we lose touch with the outside world. We don’t actually black out, of course, but we are more likely to make mistakes, fail to encode memories, or miss a connection. Zoning out makes us particularly prone to these errors. Schooler and Smallwood, along with Merrill McSpadden of the University of British Columbia, tested the effect of zoning out by having a test group read a Sherlock Holmes mystery in which a villain used a pseudonym. As people were reading the passages discussing this fact, the researchers checked their state of attentiveness. Just 30 percent of the people who were zoning out at the key moments could give the villain’s pseudonym, while 61 percent of the people who weren’t zoning out at those moments succeeded.

These results are shocking when you stop to think about them. Each of us has a magnificent hive of billions of neurons in our head, joined to each other by trillions of connections. The human brain is arguably the most complex organ in the natural world. And yet studies on mind wandering are showing that we find it difficult to stay focused for more than a few minutes on even the easiest tasks, despite the fact that we make mistakes whenever we drift away.