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

by Benedict Carey

Interleaving. That’s a cognitive science word, and it simply means mixing related but distinct material during study.

The mixing of items, skills, or concepts during practice, over the longer term, seems to help us not only see the distinctions between them but also to achieve a clearer grasp of each one individually. The hardest part is abandoning our primal faith in repetition.

To solve a problem, you first have to identify what kind of problem it is.

His central innovation was a process of “mixed review.”

Mixing problems during study forces us to identify each type of problem and match it to the appropriate kind of solution.

blocked practice can largely reduce the pedagogical value of the word problem.”

interleaving. You have to review the material anyway at some point. You have to learn to distinguish between a holy ton of terms, names, events, concepts, and formulas at exam time, or execute a fantastic number of perfect bow movements at recital. Why not practice the necessary discrimination skills incrementally, every time you sit down, rather than all at once when ramping up for a final test?

their brains came equipped with evolved modules to make important, subtle discriminations, and to put those differing symbols into categories.

The modules are intended to sharpen snap judgments—perceptual skills—so that you “know” what you’re looking at without having to explain why, at least not right away.

PLMs build perceptual intuition—

What about the kid watching the clock in math class, trying to figure out what on earth “slope” means or how to graph 3(x + 1) = y? Here, too, perceptual modules have shown great promise. At a school in Santa Monica, Kellman tested a module that works just like the instrument panel trainer, only with equations and graphs. A graph of a line pops up on the computer screen, and below it are three equations to choose from (or an equation with three choices of graphs beneath; it alternates). Again, students have to work fast: make a choice and move on; make another choice, and another, through dozens of screens. With enough training, the student begins to feel the right answer, “and then they can figure out why it’s right afterwards, if they need to,” as Joe Wise, the high school teacher working with Kellman, told me.

Most important, I’ve used it to show that PLMs are meant for a certain kind of target: discriminating or classifying things that look the same to the untrained eye but are not. To me it’s absolutely worth the extra time if there’s one specific perceptual knot that’s giving you a migraine. The difference between sine, cosine, tangent, cotangent. Intervals and cadences in music. Between types of chemical bonds. Between financing strategies, or annual report numbers. Even between simple things, like whether the sum of two fractions (3/5 and 1/3) is greater or less than 1. Run through a bunch of examples—fast—and let the sensory areas of your brain do the rest.

Sleeping and waking adjust themselves to the demands and risks of our life, not according to what the health manuals say.

“The implication is that if you are preparing for a performance—a music recital, say—it’s better to stay up late than get up early,” Smith told me. “These coaches that have athletes or other performers up at five o’clock in the morning, I think that’s crazy.”

Learning is how we figure out what we want to do, what we’re good at, how we might make a living when the time comes. That’s survival, too.

that unconscious downtime clarifies memory and sharpens skills—that it’s a necessary step to lock in both. In a fundamental sense, that is, sleep is learning.

life for foragers, as the Harvard psychologist Steven Pinker so succinctly puts it, “is a camping trip that never ends.”

Concentration may, in fact, include any number of breaks, diversions, and random thoughts. That’s why many of the techniques described in this book might seem unusual at first, or out of step with what we’re told to expect. We’re still in foraging mode to a larger extent than we know.

I have been a science reporter for twenty-eight years, my entire working life, and for most of that time I had little interest in writing a nonfiction book for adults. It was too close to my day job. When you spend eight or nine hours a day sorting through studies, interviewing scientists, chasing down contrary evidence and arguments, you want to shut down the factory at the end of the day. You don’t want to do more of the same; you don’t want to do more at all.

These are the stitches that hold together our daily existence; they represent life itself, not random deviations from it. Our study and practice time needs to orient itself around them—not the other way around.

I’m continually caught short in topics I’m supposed to know well, and embarrassed by what I don’t know. Yet even that experience smells less of defeat than it once did. Given the dangers of fluency, or misplaced confidence, exposed ignorance seems to me like a cushioned fall.

Let go, and watch how the presumed enemies of learning—ignorance, distraction, interruption, restlessness, even quitting—can work in your favor. Learning is, after all, what you do.

Breaking up study or practice time—dividing it into two or three sessions, instead of one—is far more effective than concentrating

Studying highlighted notes and trying to write them out—without looking—works memory harder and is a much more effective approach to review. There’s an added benefit as well: It also shows you immediately what you don’t know and need to circle back and review.

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.

Fluency illusions form automatically and subconsciously. Beware study “aids” that can reinforce the illusion: highlighting or rewriting notes, working from a teacher’s outline, restudying after you’ve just studied. These are mostly passive exercises, and they enrich learning not at all.

Mixing or “interleaving” multiple skills in a practice session, by contrast, sharpens our grasp of all of them. This principle applies broadly to a range of skills, and can be incorporated into daily homework or practice—by doing a geometry proof from early in the term, for example, or playing arpeggios you learned years ago, or intermingling artistic styles in studying for an art history class.