When: The Scientific Secrets of Perfect Timing(14)

The consequences are grave. “The decrease in hand hygiene compliance that we detected during a typical work shift would contribute to approximately 7,500 unnecessary infections per year at an annual cost of approximately $150 million across the 34 hospitals included in this study,” the authors write. Spread this rate across annual hospital admissions in the United States, and the cost of the trough is massive: 600,000 unnecessary infections, $12.5 billion in added costs, and up to 35,000 unnecessary deaths.7

Afternoons can also be deadly beyond the white walls of a hospital. In the United Kingdom, sleep-related vehicle accidents peak twice during every twenty-four-hour period. One is between 2 a.m. and 6 a.m., the middle of the night. The other is between 2 p.m. and 4 p.m., the middle of the afternoon. Researchers have found the same pattern of traffic accidents in the United States, Israel, Finland, France, and other countries.8

One British survey got even more precise when it found that the typical worker reaches the most unproductive moment of the day at 2:55 p.m.9 When we enter this region of the day, we often lose our bearings. In chapter 1, I briefly discussed the “morning morality effect,” which found that people were more likely to be dishonest in the afternoon because most of us are “better able to resist opportunities to lie, cheat, steal and engage in other unethical behavior in the morning than in the afternoon.”10 This phenomenon depended in part on chronotype, with owls displaying a different pattern from larks or third birds. But in that study, evening types proved more ethical between midnight and 1:30 a.m., not during the afternoon. Regardless of our chronotype, the afternoon can impair our professional and ethical judgment.

The good news is that vigilance breaks can loosen the trough’s grip on our behavior. As the doctors at the University of Michigan demonstrate, inserting regular mandatory vigilance breaks into tasks helps us regain the focus needed to proceed with challenging work that must be done in the afternoon. Imagine if Captain Turner, who hadn’t slept the night before his fateful decisions, had taken a brief vigilance break with other crew members to review how fast the Lusitania needed to travel and how best to calculate the ship’s position in order to avoid U-boats.

This simple intervention is backed by heartening evidence. For instance, the largest health care system in the United States is the Veterans Health Administration, which operates about 170 hospitals across the country. In response to the persistence of medical errors (many of which occurred in afternoons), a team of physicians at the VA implemented a comprehensive training system across the hospitals (on which Michigan modeled its own efforts) that was built around the concept of more intentional and more frequent breaks, and featured such tools as “laminated checklist cards, whiteboards, paper forms, and wall mounted posters.” One year after the training began, the surgical mortality rate (how often people died during or shortly after surgery) dropped 18 percent.11

Still, for most people, work doesn’t involve paralyzing others and cutting them open—or other life-on-the-line responsibilities such as flying a twenty-seven-ton jet or guiding troops into battle. For the rest of us, another type of break offers a simple way to steer around the dangers of the trough. Call them “restorative breaks.” And to understand them, let’s leave the American Midwest and head to Scandinavia and the Middle East.


FROM THE SCHOOLHOUSE TO THE COURTHOUSE: THE POWER OF RESTORATIVE BREAKS

In chapter 1 we learned about some curious results on Denmark’s national standardized exams. Danish schoolchildren who take the tests in the afternoon score significantly worse than those who take the exams earlier in the day. To a school principal or education policy maker, the response seems obvious: Whatever it takes, move all the tests to the morning. However, the researchers also discovered another remedy, one with applications beyond schools and tests, that is remarkably easy to explain and implement.

When the Danish students had a twenty-to thirty-minute break “to eat, play, and chat” before a test, their scores did not decline. In fact, they increased. As the researchers note, “A break causes an improvement that is larger than the hourly deterioration.”12 That is, scores go down after noon. But scores go up by a higher amount after breaks.

Taking a test in the afternoon without a break produces scores that are equivalent to spending less time in school each year and having parents with lower incomes and less education. But taking the same test after a twenty-to thirty-minute break leads to scores that are equivalent to students spending three additional weeks in the classroom and having somewhat wealthier and better-educated parents. And the benefits were the greatest for the lowest-performing students.

Unfortunately, Danish schools, like many around the world, offer only two breaks each day. Worse, legions of school systems are cutting back on recess and other restorative pauses for students in the name of rigor and—get ready for the irony—higher test scores. But as Harvard’s Francesca Gino, one of the study’s authors, puts it, “If there were a break after every hour, test scores would actually improve over the course of the day.”13

Many younger students underperform during the trough, which risks both providing teachers with an inaccurate sense of their progress and prompting administrators to attribute to what and how students are learning something that is really an issue of when they’re taking a test. “We believe these results to have two important policy implications,” say the researchers who studied the Danish experience. “[F]irst, cognitive fatigue should be taken into consideration when deciding on the length of the school day and the frequency and duration of breaks. Our results show that longer school days can be justified, if they include an appropriate number of breaks. Second, school accountability systems should control for the influence of external factors on test scores . . . a more straightforward approach would be to plan tests as closely after breaks as possible.”14