• Since de Mairan’s discovery nearly three centuries ago, scientists have established that nearly all living things—from single-cell organisms that lurk in ponds to multicellular organisms that drive minivans—have biological clocks.

• The answer goes back to those sentries guarding our cognitive castle. For most of us, mornings are when those guards are on alert, ready to repel any invaders. Such vigilance—often called “inhibitory control”—helps our brains to solve analytic problems by keeping out distractions.22 But insight problems are different. They require less vigilance and fewer inhibitions. That “flash of illuminance” is more likely to occur when the guards are gone. At those looser moments, a few distractions can help us spot connections we might have missed when our filters were tighter. For analytic problems, lack of inhibitory control is a bug. For insight problems, it’s a feature.

• Benjamin Franklin had it right: Early to bed and early to rise makes a person healthy, wealthy, and wise.

• What ultimately matters, then, is that type, task, and time align—what social scientists call “the synchrony effect.”44 For instance, even though it’s obviously more dangerous to drive at night, owls actually drive worse early in the day because mornings are out of synch with their natural cycle of vigilance and alertness.45 Younger people typically have keener memories than older folks. But many of these age-based cognitive differences weaken, and sometimes disappear, when synchrony is taken into account. In fact, some research has shown that for memory tasks older adults use the same regions of the brain as younger adults do when operating in the morning but different (and less effective) regions later in the day.

• 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.

• 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.

• Short breaks from a task can prevent habituation, help us maintain focus, and reactivate our commitment to a goal.17 And frequent short breaks are more effective than occasional ones.

• High performers, its research concludes, work for fifty-two minutes and then break for seventeen minutes.

• To me, naps are less an element of self-care than a source of self-loathing. They are a sign of personal failure and moral weakness. But I’ve recently changed my mind.

• Naps, research shows, confer two key benefits: They improve cognitive performance and they boost mental and physical health.

• Other researchers have found the same results—that caffeine, usually in the form of coffee, followed by a nap of ten to twenty minutes, is the ideal technique for staving off sleepiness and increasing performance.

• If you’re not a coffee drinker, search online for an alternative drink that provides about two hundred milligrams of caffeine. (If you avoid caffeine, skip this step. Also reconsider your life choices.)

• Anders Ericsson is “the world expert on world experts.”9 A psychologist who studies extraordinary performers, Ericsson found that elite performers have something in common: They’re really good at taking breaks. Most expert musicians and athletes begin practicing in earnest around nine o’clock in the morning, hit their peak during the late morning, break in the afternoon, and then practice for a few more hours in the evening. For example, the practice pattern of the most accomplished violinists looks like this:

• My sleep will remain undisturbed knowing that a swerving stock market steered some elite MBAs to jobs at McKinsey or Bain rather than at Goldman Sachs or Morgan Stanley and thereby left them extremely rich rather than insanely wealthy.

• Let your results do the talking. A new job can be daunting because it requires establishing yourself in the organization’s hierarchy. Many individuals overcompensate for their initial nervousness and assert themselves too quickly and too soon. That can be counterproductive. Research from UCLA’s Corinne Bendersky suggests that over time extroverts lose status in groups.13 So, at the outset, concentrate on accomplishing a few meaningful achievements, and once you’ve gained status by demonstrating excellence, feel free to be more assertive.

• (Francis-Tan and Mialon also found that the more a couple spent on its wedding and any engagement ring, the more likely they were to divorce.)

• In short, for one of life’s ultimate when questions, forget the romantics and listen to the scientists. Prudence beats passion.

• This U-curve of happiness—a mild slump rather than a raging crisis—is an extremely robust finding. A slightly earlier study of more than 500,000 Americans and Europeans by economists David Blanchflower and Andrew Oswald found that well-being consistently slid around the middle of life. “The regularity is intriguing,” they observe. “The U-shape is similar for males and females, and for each side of the Atlantic Ocean.” But it wasn’t merely an Anglo-American phenomenon. Blanchflower and Oswald also analyzed data from around the world and discovered something remarkable. “In total, we document a statistically significant U-shape in happiness or life satisfaction for 72 countries,” they write, from Albania and Argentina through the nation-state alphabet to Uzbekistan and Zimbabwe.

• That raises an intriguing possibility: Could the midpoint slump be more biology than sociology, less a malleable reaction to circumstance than an immutable force of nature?

• One reason the Hemingway technique works is something called the Zeigarnik effect, our tendency to remember unfinished tasks better than finished ones.

• In the 1960s and 1970s, organizational psychologist Bruce Tuckman developed an influential theory of how groups move through time. Tuckman believed that all teams proceeded through four stages: forming, storming, norming, and performing.

• First, he said, write down your top twenty-five goals for the rest of your life. Second, look at the list and circle your top five goals, those that are unquestionably your highest priority. That will give you two lists—one with your top five goals, the other with the next twenty. Third, immediately start planning how to achieve those top five goals. And the other twenty? Get rid of them. Avoid them at all costs. Don’t even look at them until you’ve achieved the top five, which might take a long time. Doing a few important things well is far more likely to propel you out of the slump than a dozen half-assed and half-finished projects are.

• Then, in two paragraphs, write yourself an e-mail expressing compassion or understanding for this element of your life. Imagine what someone who cares about you might say. He would likely be more forgiving than you. Indeed, University of Texas professor Kristin Neff suggests you write your letter “from the perspective of an unconditionally loving imaginary friend.” But mix understanding with action. Add a few sentences on what changes you can make to your life and how you can improve in the future. A self-compassion letter operates like the converse corollary of the Golden Rule: It offers a way to treat yourself as you would others.

• The James Dean effect is another example of how endings alter our perception. They help us encode—that is, to evaluate and record—entire experiences. You might have heard of the “peak-end rule.” Formulated in the early 1990s by Daniel Kahneman and colleagues including Don Redelmeier and Barbara Fredrickson, who studied patient experiences during colonoscopies and other unpleasant experiences, the rule says that when we remember an event we assign the greatest weight to its most intense moment (the peak) and how it culminates (the end).

• This “end of life bias,” as the researchers call it, suggests that we believe people’s true selves are revealed at the end—even if their death is unexpected and the bulk of their lives evinced a far different self.

• The researchers found that at the core of meaningful endings is one of the most complex emotions humans experience: poignancy, a mix of happiness and sadness. For graduates and everyone else, the most powerful endings deliver poignancy because poignancy delivers significance. One reason we overlook poignancy is that it operates by an upside-down form of emotional physics. Adding a small component of sadness to an otherwise happy moment elevates that moment rather than diminishes it. “Poignancy,” the researchers write, “seems to be particular to the experience of endings.” The best endings don’t leave us happy. Instead, they produce something richer—a rush of unexpected insight, a fleeting moment of transcendence, the possibility that by discarding what we wanted we’ve gotten what we need.

• Or what if someone at a store who’s made a major purchase—a computer, an appliance, an expensive item of clothing—departs the establishment past a line of employees saying, “Thank you,” and giving that customer a round of applause?

• Organic rituals, not artificial ones, generate cohesion.

• Like poignancy, nostalgia is a “bittersweet but predominantly positive and fundamentally social emotion.” Thinking in the past tense offers “a window into the intrinsic self,” a portal to who we really are.11 It makes the present meaningful.

• Which leads to the present itself. Two final studies are illuminating. In the first, five Harvard researchers asked people to make small “time capsules” of the present moment (three songs they recently listened to, an inside joke, the last social event they attended, a recent photo, etc.) or write about a recent conversation. Then they asked people to guess how curious they’d be to see what they documented several months later. When the time came to view the time capsules, people were far more curious than they had predicted. They also found the contents of what they’d memorialized far more meaningful than they had expected.

• “By recording ordinary moments today, one can make the present a ‘present’ for the future,” the researchers write.

• Melanie Rudd, Kathleen Vohs, and Jennifer Aaker found that the experience of awe—the sight of the Grand Canyon, the birth of a child, a spectacular thunderstorm—changes our perception of time. When we experience awe, time slows down. It expands. We feel like we have more of it. And that sensation lifts our well-being. “Experiences of awe bring people into the present moment, and being in the present moment underlies awe’s capacity to adjust time perception, influence decisions, and make life feel more satisfying than it would otherwise.”

• Taken together, all of these studies suggest that the path to a life of meaning and significance isn’t to “live in the present” as so many spiritual gurus have advised. It is to integrate our perspectives on time into a coherent whole, one that helps us comprehend who we are and why we’re here.

• I used to believe that lunch breaks, naps, and taking walks were niceties. Now I believe they’re necessities.

• I used to believe in the value of happy endings. Now I believe that the power of endings rests not in their unmitigated sunniness but in their poignancy and meaning.

• I used to believe that synchronizing with others was merely a mechanical process. Now I believe that it requires a sense of belonging, rewards a sense of purpose, and reveals a part of our nature.