In our age of information overload, remembering things can be a daunting task. But as a memory researcher and university professor, I found some hope in that challenge.
In January 2021, like millions of educators and having watched my own daughter struggle with online learning, I became concerned about teaching through a screen. I spent two decades basing grades primarily on midterms and finals, but it's hard to avoid cheating during online exams. So I had to abandon traditional assessment methods for measuring learning. Then I realized I could use a different assessment system to drive learning.
In my lab, we were conducting brain imaging studies based on decades-old research showing that testing people with recently viewed material dramatically increases their retention over time. Modeled after our experiments, I gave my students a three-day period to take an open-book online quiz each week, after which they could see the correct answers and learn from their mistakes or reinforce what they got right.
The goal of these quizzes was not to torture my students, but to prompt them to think critically about the material regularly, with my feedback and support. Student response to this approach exceeded my wildest expectations; 85% strongly agreed that weekly quizzes, with feedback, helped them learn. (If you're not a teacher, let me assure you that students almost never say anything positive about any type of test.)
The tests work as a learning tool because they exploit a simple principle of human brain function. We are programmed to learn from our mistakes and challenges, a phenomenon called error-based learning.
Neuroscience has shown that error-based learning is key to learning new motor skills: we learn to perform skilled movements by observing the difference between what we intend to do and what we actually do. For example, when musicians practice a song they already know quite well, some parts will be relatively simple, but others will be difficult. Instead of recording a new memory of each part of the song every time it is played, the best solution for the brain is to modify existing memories to better handle the challenging parts.
Error-based learning can also explain the benefits of learning actively by doing, rather than passively learning by memorizing. When you drive through a new neighborhood, you will learn much more about the layout of the area than if you pass through the same neighborhood as a passenger in a taxi. Actively navigating a new environment gives you the opportunity to learn in real time from the results of your actions.
A lot of academic studies show something similar. Compare test results For students who read the material over and over again versus those who read it fewer times but test their knowledge repeatedly, it is the latter who retain the greatest amount long-term.
Scientists don't completely agree about why testing has such a powerful effect on memory. The simplest explanation is that tests expose your weaknesses. In general, we tend to be overconfident in our ability to retain information. Those who are tested have the humiliating, but productive experience of sometimes not remembering information they thought they had learned well.
Beyond its ability to open our eyes to our weaknesses, wrestling itself can make us better learners. Computers and artificial intelligence systems learn through trial and error, adjusting the connections between their artificial neurons to get better and better at the right answer. Cognitive psychologists Mark Carrier and Harold Pashler theorized that humans can learn through a similar struggle.
my laboratory evidence found to support this in a functional magnetic resonance imaging study, where we found that the tests increase activity in the hippocampus, a memory center in the brain. In our study, we used our “hippocampus in a box” computer model that simulates how this brain structure supports learning and memory. We saw that the benefits of testing don't come from making mistakes per se, but from challenging yourself to take advantage of what you've learned.
When you test yourself, you try to generate the correct answer, but the result may not be completely perfect. Your brain will come up with a fuzzy approximation, creating a struggle to get it right and providing opportunities to learn more.
Stress testing your memory in this way exposes weaknesses in the connections between neurons so that memory can be updated, strengthening useful connections and removing those that get in the way. Instead of relearning the same thing over and over again, it is much more efficient to fine-tune the correct neural connections and fix only those parts that we have difficulty with. Our brains save space and learn quickly by focusing on what we didn't already know.
Although we usually benefit from error-based learning, there is one important condition: it works if you eventually get close to the correct answer, or at least if you can rule out incorrect answers. You don't benefit from mistakes if you have no idea what you did wrong.
Another influential factor is the moment of their learning. Virtually all students, including my former self, have prepared for the exams. While my late nights worked in the short term, most of what I had learned would be gone a few days after the end of the semester. I am not alone; a mountain of findings in psychology Show that you can generally get much more bang for your buck by leaving gaps between learning sessions rather than spending the same amount of time studying.
To understand why this might be the case, suppose you read my latest article on episodic memory while sitting on the couch in your living room, and then the next day you read it again on the beach. At first, the hippocampus may extract the memory of the last time you read the article, but it will take a while because you are seeing the same information in a different context. As a result, coalitions of neurons in the hippocampus reorganize to place more emphasis on the content of what you read, so information is less tied to where and when you first read it.
Computer modeling helps show how, if you keep returning to the same information periodically, the hippocampus can continually update those memories until they have no discernible context, making them easy to access anywhere, anytime.
Error-based learning tells us that whether you're trying to learn surfing, Spanish, or sociology, if you manage to do it effortlessly, you're not getting the most out of your experience. Even if it's not pleasant, struggling with information can be a good thing. It often means that you are really learning.
Charan Ranganath is a professor of psychology and neuroscience at UC Davis. This essay was adapted from author's next book“Why we remember: Unlocking the power of memory to hold on to what matters.”
