A waitress takes a nap during her break at a restaurant in Shanghai.Carlos Barria / Reuters

Have you ever decided to take the next hour before you have to go to get something done, and then mysteriously failed to accomplish anything? If so, you're not alone. This phenomenon, when knowing that the available time has a limit keeps you from using it to its fullest, is the subject of a new study in the Journal of Consumer Research. Through a series of eight different experiments, performed not just in labs but also in an airport’s waiting areas, the researchers found that this is a fairly widespread and consistent behavior. On average, even when people know they have a full hour before they have to move onto something else, they’ll use five to 15 minutes less to work on something than if the hour has nothing scheduled after it.  

Gabriela Tonietto, a professor of marketing at Rutgers Business School, began the research while she was working on her Ph.D. “This is the second half of my dissertation,” she says, “which is somewhat inspired by me trying to work on the first half of my dissertation.” Surprised by how unproductive she could sometimes be, she noticed that the situations in which she took the least advantage of her time were when she knew she’d have to leave soon to meet a friend for drinks, for example, or had another activity scheduled. “I tend to do that more when I have something coming up that's concrete in my mind,” she says.

To see if other people acted similarly, she devised studies in the lab where subjects were asked to predict how much time they would be able to spend on an activity in an hour that had something scheduled immediately after it, versus an hour that had no bound. The answers tended to be shorter for bounded hours. She also asked study participants how much time they should be able to spend in theory on a task in a bounded hour, versus how much they felt they actually would. The latter estimate tended to be shorter. “It ranges, but there is about this five to 15 minutes that vanish in people's minds … and that’s enough for us to question what we can actually do with the time,” she says.

In another study, a research assistant was given a plane ticket specifically so that he could go through airport security. He went from waiting area to waiting area explaining that he was a psychology graduate student and asking people if they had time to immediately fill out a 15-minute-long survey. He also asked when their flight was scheduled to board. People whose flight would board in 30 minutes were less likely to do the survey than those who had more time, even though they still would have had time to complete it.

To build on those results, after obtaining separate study subjects’ schedules for the days after they were contacted, the researchers randomly chose an hour that either had a bound or did not, and asked whether the subjects would like to do a 30-minute survey or a 45-minute one. If they chose the 45-minute survey, they would be paid more. Still, those subjects whose time was bounded were less likely to choose the 45-minute one. It seems that there’s just something that makes people uncomfortable about that—a sense of cutting things close, even when there is objectively a small risk of running out of time. No matter what reassurances are given that there will be enough time, and even when subjects accounted for the time it would take to get ready so that they really didn’t have to do anything for a full hour, the results are the same.

Why do people feel this way? It isn’t clear yet, says Tonietto. There are some theories that suggest the thing someone is paying attention to feels physically closer than it really is. Perhaps that meeting with a friend or that work party looming in the distance feels closer, or larger—somehow more in need of time—than it truly is.  

On a practical level, she suggests that scheduling things back to back may actually improve productivity. If you schedule in an hour between meetings, chances are you won’t use that time well. Furthermore, it pays to break big tasks down into smaller ones, so that you can reach a goal even in a shorter period of time. People tend to like the feeling of accomplishment that comes from finishing something, and if you’re afraid you won’t be able to complete it, you might not start at all. You might check your email again, read a good article in The Atlantic—and before you know it, the time has flown.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.