Want Good Grades? Ditch that Highlighter
This essay, which first appeared on my previous website, was the most popular blog post I ever wrote. I’m re-posting it here since I found that people were still searching for it and recommending it to their students.
A few years ago I had the pleasure of moving into a brand-new academic building on my campus. As I walked through the building each day, I saw students poring over their work in comfy chairs or empty classrooms and conference rooms, and others gathering together in small groups to discuss projects or prepare for classes.
Witnessing all of this informal study made the heart of this teacher glad—except for the fact that I saw so many students engaged in two unhelpful learning activities: highlighting and re-reading. It might surprise you to learn that these two beloved study activities, ones in which students almost universally engage, have very little effect on your long-term learning. Worse still, highlighting course material and then re-reading it later gives you the illusion that you know your stuff, without any of the actual learning.
In 2013, a team of psychologists who study human learning published an overview of ten study techniques in which students commonly engage. They examined the bodies of research behind each of these strategies, and rated them from low utility (or not very useful at all) to high utility (very useful). Their findings, published in the journal Psychological Science in the Public Interest, will likely come as unwelcome news to most students.
Both highlighting (or underlining) and rereading were rated as having very low utility. Summarizing a large body of research on highlighting, the authors conclude: “In most situation that have been examined and with most participants, highlighting does little to boost performance” on quizzes or exams. The findings on re-reading are almost exactly the same. In other words, across a wide range of experiments on learning, in different disciplines and with students of different ages, these two strategies simply did not produce effective, long-term learning.
You might object that you have been highlighting and re-reading course materials for your entire school career, and you’ve done just fine. You probably have this impression for two reasons. First, highlighting and re-reading can be effective for very short-term learning. If your only goal is to survive a test you have on Monday morning at 9:00 pm, and it’s 11:00 pm on Sunday night, re-reading highlighted passages might help you get through that exam. But whatever you “learned” during that re-reading cram session will fade from your mind very quickly. Your learning will be shallow and short-lived.
You also might believe that highlighting and-rereading work because you have no ability to make a scientific comparison between highlighting or re-reading and other, more effective learning strategies. If you could clone yourself and the universe, you could study for your history exam using highlighting, and your clone could study for the exact same exam using a different strategy. Afterward, you could compare your scores, and see who received the better exam score, you or your clone. Without the ability to conduct that kind of experiment, you have no easy way to understand how other strategies might prove even more effective than the ones you are already using.
If you are currently earning all A’s without much effort, you should probably keep doing whatever you are doing, and can stop reading right now. But if you’d like to understand how to study in ways that will increase your long-term learning, three study strategies—all of which have been proven effective by mounds of research—will help you become a much more effective and efficient student.
1) Practice Testing. Memory researchers have learned in recent decades that our brains have enormous storage capacity. The challenge for our memories is not so much cramming stuff in there; it’s being able to retrieve information or ideas from our memories when we need them (i.e., when you’re sitting down in front of a test). It turns out that the more times you practice retrieving something from your memory, the better you get at it. Highlighting and re-reading do not require you to use your memory at all; practice testing does. So if you want your memory to go to work for you in the exam, give it lots of practice when you study. Close your book and test yourself. You can use flashcards; you can take practice quizzes online; or you can even just practice writing and re-writing the key ideas or information that you want to remember.
2) Spaced Study. You probably know this one already, so I won’t belabor it. But the evidence for it is irrefutable. You will have a much greater long-term grasp of your learning if you space out your study over multiple sessions instead of cramming it all into one. In one very simple experiment that demonstrated this, students who studied foreign language vocabulary for ten minutes three days in a row outperformed their peers who studied the same vocabulary words in a single thirty-minute session. Your parents and all of your previous teachers were right: spacing out your study sessions over time beats cramming—by a lot.
3) Making Connections. When we learn something deeply, we relate it to other aspects of our lives and our existing knowledge. We have thick networks of connections between what we know already—or what we experience outside of school—and what we are learning. As you are studying, try to make connections between what you are learning and other things you have learned or experienced. Ask yourself connection-making questions: Have I ever encountered this before? Have I learned anything similar in another course? In what real-world contexts would this concept or skill operate? Why is it significant? This strategy will work best if you write these ideas down; fill out your notebook or your texts with new connections, rather than with highlighting or underlining.
All three of these strategies require more work than highlighting or re-reading. Learning isn’t always easy. In fact, some learning researchers suggest that struggle in learning is beneficial. When we grasp things easily and quickly, we also forget them easily and quickly.
The real problem with highlighting and re-reading arises when they represent your only study strategies. They are easy and comfortable strategies for many students—which also means that they are largely ineffective. They can, however, provide good starting points for your study, if you combine them with these other, more effective strategies.
If you really love it, then, you can hang onto your highlighter, and start your studying with it. Just make sure that eventually you put it down, pick up your pen, and use study strategies that actually work.
For a less academic but equally research-supported overview of effective learning strategies for students, check out the essay Strengthening the Student Toolbox.