Last week, we talked about Interleaving in the context of learning and memory. A key aspect of it, as articulated by Robert Bjork, the psychologist we used to introduce the term, is a concept he calls "desirable difficulty." There's something helpfully hard about following up a study session on, say, constitutional law, with a study session on contracts, instead of just doubling up on constitutional law. The cognitive work it takes to switch subjects has been shown to produce much deeper and longer-lasting comprehension. You can think of this process as a form of intellectual cross-training in which your mental muscles become stronger and more flexible, because they are regularly stretched in different ways. A similar idea is called "spacing," which is simply planning out your study sessions so that there are significant breaks between them. That way your brain has to put in a useful amount of effort to remember what you previously covered, a process that helps lay down more powerful and more permanent neural pathways to the information. Here's how Bjork explains the payoff. "When we access things from our memory, we do more than reveal it's there. It's not like a playback. What we retrieve becomes more retrievable in the future. Provided the retrieval succeeds, the more difficult and involved the retrieval, the more beneficial it is." For this reason, Bjork recommends spending less time simply re-reading your notes or highlights and more time quizzing yourself, whether with flash cards or some other tool that will push you beyond just recognizing material and move you toward the more useful task of retrieving it. He even suggests reducing the amount of notes you take in class, instead waiting to take notes after class. Recalling content you've been taught is more effective than thoughtlessly copying down everything the teacher says. You might be surprised by that advice, especially if you're in law school, where many students seem to treat in-class note-taking as if they were applying for a job as a court reporter. But even if you don't follow Bjork's advice completely, at least consider whether your current way of learning new content includes anything resembling the desirable difficulties he describes. Consider also that something like interleaving might not just make your study sessions more productive, it could also make your writing sessions more productive. Jeff Fisher, the co-director of the Supreme Court Litigation Clinic at Stanford Law School and one of the most accomplished appellate lawyers in the US, visited my class once and told the students that he regularly drafts three briefs at once. Switching between cases, he said, really helps him. An article in The Chronicle of Higher Education called The Habits of Highly Productive Writers supports Fisher's approach. Along with observations like, "Highly productive writers leave off at a point where it'll be easy to start again," and "Highly productive writers don't let themselves off the hook," the author, Rachel Toor, offers this suggestion. "Highly productive writers work on more than one thing at once." "Some pieces need time to smolder. Leaving them to turn to something short and manageable makes it easier to go back to the big thing. Fallowing and crop rotation lead to a greater harvest." What I like about this point is the way it ties into something Toor says earlier in the piece: that a lot of writing gets done when you're not actually writing. She uses a passage from the novel, The End of the Affair by Graham Greene, to illustrate what she means. "So much in writing depends on the superficiality of one's days. One may be preoccupied with shopping and income tax returns and chance conversations, but the stream of the unconscious continues to flow, undisturbed, solving problems, planning ahead. One sits down sterile and dispirited at the desk, and suddenly the words come as though from the air. The situations that seem blocked in a hopeless impasse move forward: the work has been done while one slept or shopped or talked with friends." But perhaps an easier, more playful way to remember this idea is through an anecdote that the French writer, Andre Breton, who helped found the movement known as Surrealism, tells about a fellow poet. The poet apparently used to hang a notice on the door of his house every evening before he went to sleep. The notice said, "The poet is working." The implication, "My brain is working on things, even when the rest of me is asleep." Of course, if you don't start projects, the parts of your brain that could help you out while you are sleeping or off doing something else, won't have any material to work with. They'll have less overall time to come up with ideas and solutions. Consider Jeff Fisher three- briefs-at-once approach. Suppose he has 3 briefs to write in the same 30-day month. He could focus entirely on the first brief during the initial 10 days, entirely on second brief during the second 10 days, and entirely on the third brief during the last 10 days. But that stacking strategy would limit the amount of time he gives his subconscious to help with each brief to just 10 days. By instead interleaving and periodically switching between the 3 briefs over the course of the whole month, there's a way in which he triples the help he gets. Now his subconscious has the full 30 days. Plus, he enjoys the added benefit of not getting so wrapped up in one brief that he loses the ability to step back and revise it with some helpful cognitive distance. So we'll add a third benefit to interleaving. It can help you learn. It can help you write. And it can help you edit.
