Companies of one need to become adept at “single-tasking”—doing one thing for an extended period of time without distraction. This capacity helps you focus on the right tasks, do them faster, and do them with less stress. Gloria Mark, a professor in the Department of Informatics at the University of California, found that for every interruption, it takes an average of twenty-three minutes and fifteen seconds to fully get back to the task. Fewer distractions means speedier work.

To combat this, I take several months off from interviews, calls, and meetings each year to create new products or write books without interruption. Being engaged in deep and focused work, because I’ve cut myself off from communication and availability to others, creates efficiency.

In a classic study by Harvard’s Leslie Perlow, she embedded herself in a software company in which engineers met and interrupted one another so much that they felt compelled to work nights and weekends to finish projects. Leslie nudged them to experiment with “quiet time”: two periods each day when interruptions were banned, 8:00 A.M. to 11:00 A.M. and 3:00 P.M. to 5:00 P.M. Leslie found productivity increased 59 percent during the morning quiet time and 65 percent during the afternoon break.

After this had been going on for about one year, I finally asked him, “Why always an hour and a half?” He answered, “That’s easy. I have found out that my attention span is about an hour and a half. If I work on any one topic longer than this, I begin to repeat myself. At the same time, I have learned that nothing of importance can really be tackled in much less time. One does not get to the point where one understands what one is talking about.

This cognitive ability to remember the past and anticipate the future is one reason some of us feel so busy—not because of the number of tasks we have to complete in the day, but because of the sheer number of things competing for our attention. What is commonly called “distraction” is probably better understood as overstimulation.

Recent findings in neuroscience have shown that our conscious minds cannot do more than one thing at a time. It may feel like you are able to multitask and think about two (or more) things at once, but really your mind is switching between them. This is a costly process neurologically speaking. Switching from one task to another takes energy and a measurable amount of time. Then, when we switch back, it takes another period of time to really wrap our minds around the original object of attention. And it’s not only about the time cost; it’s about the quality of our attention. If we are always switching from one thing to another, then we are never able to truly focus and experience the pleasure and effectiveness of a focused mind. Instead we live in a state of constant recalibration, or what the writer Linda Stone perceptively calls “continuous partial attention.”

Human awareness is not the speedy, nimble creature some of us believe it to be. Our brains have evolved to be more like owls than hummingbirds: we notice something, turn our attention to it, and focus in. It is in this state of intense, solitary focus that we are in possession of our most uniquely human and powerful mental faculties. When we focus on one thing, we are at our most thoughtful, creative, and productive.

But in the screen-heavy environment of the twenty-first century, our mind-owls, large and unwieldy, are treated like hummingbirds, and they end up flopping ineffectively from one thing to the next. Doing this day in and day out accommodates us to what is actually an unnatural, anxiety-producing mode in which the mind struggles to find nourishment.

Which owl is going to feel busier, the one focusing on the sound of a mouse in the snow, or the one trying to draw tiny bits of nectar from a thousand flowers? And which owl is going to be, in the end, better nourished?