How We Learn: The Surprising Truth About When, Where, and Why It Happens

by Benedict Carey

“Spaced interleaving”

after all, is to be able to perform well in any conditions. Changing locations is not the only way to take advantage of the so-called context effect on learning, however. Altering the time of day you study also helps, as does changing how you engage the material, by reading or discussing, typing into a computer or writing by hand, reciting in front of a mirror or studying while listening to music: Each counts as a different learning “environment” in which you store the material in a different way.

studies show that “deep sleep,” which is concentrated in the first half of the night, is most valuable for retaining hard facts—names, dates, formulas, concepts. If you’re preparing for a test that’s heavy on retention (foreign vocabulary, names and dates, chemical structures), it’s better to hit the sack at your usual time, get that full dose of deep sleep, and roll out of bed early for a quick review. But the stages of sleep that help consolidate motor skills and creative thinking—whether in math, science, or writing—occur in the morning hours, before waking. If it’s a music recital or athletic competition you’re preparing for, or a test that demands creative thinking, you might consider staying up a little later than usual and sleeping in. As discussed in chapter 10: If you’re going to burn the candle, it helps to know which end to burn it on.

Q: Is there an optimal amount of time to study or practice? A: More important than how long you study is how you distribute the study time you have. Breaking up study or practice time—dividing it into two or three sessions, instead of one—is far more effective than concentrating it. If you’ve allotted two hours to mastering a German lesson, for example, you’ll remember more if you do an hour today and an hour tomorrow, or—even better—an hour the next day. That split forces you to reengage the material, dig up what you already know, and re-store it—an active mental step that reliably improves memory.

Cramming works fine as a last resort, a way to ramp up fast for an exam if you’re behind and have no choice. It’s a time-tested solution, after all. The downside is that, after the test, you won’t remember a whole lot of what you “learned”—if you remember any at all. The reason is that the brain can sharpen a memory only after some forgetting has occurred. In this way, memory is like a muscle: A little “breakdown” allows it to subsequently build greater strength. Cramming, by definition, prevents this from happening. Spaced rehearsal or study (see previous question) or self-examination (see next question) are far more effective ways to prepare. You’ll remember the material longer and be able to carry it into the next course or semester easily. Studies find that people remember up to twice as much of material that they rehearsed in spaced or tested sessions than during cramming. If you must cram, do so in courses that are not central to your main area of focus.

How much does quizzing oneself, like with flashcards, help? A: A lot, actually. Self-testing is one of the strongest study techniques there is.

No. Distraction is a hazard if you need continuous focus, like when listening to a lecture. But a short study break—five, ten, twenty minutes to check in on Facebook, respond to a few emails, check sports scores—is the most effective technique learning scientists know of to help you solve a problem when you’re stuck. Distracting yourself from the task at hand allows you to let go of mistaken assumptions, reexamine the clues in a new way, and come back fresh.