Evidence-based learning methods I use regularly

Learning has been my lifelong interest, and I’ve tried to improve how I learn for almost all of my adult life. Of course, I made mistakes along the way, but I also found things that worked. Over time, I settled on a few methods that I regularly use. I want to share them with you so you can learn more efficiently and effectively.

Why do we have the ability to learn in the first place? We don’t know what kind of world we will be born into and how it will change over time, so we need tools that help us change with it. Learning enables us to adapt to an unpredictable environment in which we will live.

Myths and evidence

Myths have plagued the area of learning. The myths below are not the only ones but those that show up more often.

• Myth 1: A single optimal learning style (visual, auditory, or kinaesthetic) exists for each learner. Some learning styles are better suited for certain lectures or topics, but all learners benefit from each style similarly.
• Myth 2: Multitasking produces good learning results.
• Myth 3: Being “left- or right-brained” affects the ability to learn.
• Myth 4: Brain training games provide transferable benefits to other cognitive tasks.
• Myth 5: We use only 10% of our brain capacity, and we can increase the percentage.

Luckily for us, the scientific community has been hard at work in the last hundred years and demonstrated that a few learning methods consistently outperform the rest when compared on long-term storage and application of acquired knowledge and skills. My trial-and-error experience over many years matches the current scientific evidence (which I referenced at the end of the essay).

• Retrieval: Forcing yourself to retrieve something from memory (recall) makes you remember it better than reviewing it (recognition).
• Variation: Learning different topics or skills in the same learning session and actively learning from two or more examples.
• Spacing effects: A topic or skill is studied and practiced more than once at different times.

Let’s go into more detail about each method.

Method 1: Retrieval (recall over recognition)

Forcing yourself to retrieve something from memory (recall) makes you remember it better than just reviewing it (recognition).

The above finding is somewhat unexpected but well-documented and tested. The biggest barrier to using retrieval as a learning method more frequently is thinking you’re using it even though you aren’t. For example, when you highlight something in a book, you note that this information might be important and where to find it later. When you re-read the same book in subsequent learning sessions, it’s too easy to deceive yourself that the highlighted part is already fully committed to memory and that you can get it back anytime you want. How does the deception happen?

Meet the illusion of understanding, the gap between what you know and what you think you know. It’s been tested and verified in many contexts and always comes down to human overconfidence. One of the scientists exploring the problem explains the source of the illusion:

We think the source of the illusion is that people fail to distinguish what they know from what others know. We’re constantly depending on other people, and the actual processing that goes on is distributed among people in our community. It’s as if the sense of understanding is contagious. When other people understand, you feel like you understand.

Similarly, when something is written down by others and you have easy access to it (like highlighted sections in books), you feel like you can recall it purely from memory anytime you want.

Another example of deceiving yourself during learning is asking a question and choosing from several provided answers. You might deduce the correct answer by eliminating incorrect ones or recognizing it from previous learning sessions, but it’s testing your deduction skills more than your memory.

On the other hand, if you’re asked a question and not given any possible answers, correctly answering the question will reinforce the answer in your memory more than through other methods. If you answer incorrectly, the feedback is clear, and there are no chances to deceive yourself.

With that in mind, always choose recall over recognition as a learning method. Retrieving something from memory will feel harder than recognizing it on a page or a screen, but long-term performance in memory retention will always be better.

Here are some specific ways to benefit from retrieval practice:

• Force yourself to remember from memory. For example, when learning with flashcards, withhold the correct answer instead of showing multiple answers to choose from. Or instead of re-reading your notes, seek someone to ask you questions from the notes.
• Quiz before, during, and after a lesson. Frequent quizzing helps retain knowledge for longer, but you can quiz yourself or others even before the learning session because that will prime and divert the attention to essential parts of the lesson.
• Write notes in your own words. When you read, hear, or watch something you want to remember, write it down in your own words. If you had to take verbatim notes during a lecture or meeting, take a new piece of paper or open a new document, and try to recall what is most important without looking at the first set of notes. In addition to that, immediately write down questions you’ll want to answer in a future study session.
• Teach what you learn. Teaching, explaining, and presenting from memory is a form of retrieval practice. You must deeply understand the material to be ready to explain it to different audiences and field questions on the spot. Most of my talks, workshops, and courses are an application of this tactic.

Method 2: Variation (interleaving and transfer)

Interleaved practice, or interleaving, is learning different topics or skills at the same time as opposed to focusing on one skill or topic at a time, called blocked practice, which entails little-to-no variation.

Interestingly, interleaving works best when topics and skills are similar and likely to interfere with one another. A frequently used example in scientific literature is learning to distinguish styles of paintings from different eras or artists. Instead of focusing on one style or artist at a time, combining them in one session and trying to differentiate when they are similar will be hard but lead to better long-term results in your ability to distinguish them. The same principle applies to learning any motor skill.

Interleaving is more challenging during the initial acquisition because it feels harder to learn several related things at once, and because the observed performance improves slower. However, if you persevere, the long-term retention will be significantly higher than if you had used blocked practice.

Beyond interleaving, there are additional benefits of variation in learning. When you learn something in only one way or location or from only one example, it’s impossible to disentangle the thing to be learned and the context. For instance, a set of experiments demonstrated that when students learn something in one physical location and then take a delayed test in another, the recall of learned material suffers. However, if they switch locations for each learning session, the recall in a new test location remains high.

Another benefit of variation is creating useful abstractions. When you have multiple examples, you can highlight similarities and differences, find the underlying principle, and then apply the abstraction in new domains. This behavior is called transfer learning, one of the main ways we quickly adapt to new situations. In several experiments that explored this phenomenon, people were given a different number of relevant examples. The results were clear:

1. When people were given only one example, they were least likely to create a useful abstraction that could be applied to solve a novel but similar problem.
2. When people were given only one example and a relevant abstraction together, they weren’t much more successful than in the first scenario.
3. When people were given two examples, they were much more likely to create a useful abstraction and apply it to other domains than in the first two scenarios.
4. When people were given two examples and a relevant abstraction together, they were most successful in solving a novel problem.

If you wonder if learning only an abstraction would be the most efficient way, the answer is “no.” Multiple examples serve as real-world applications of the abstraction, and the best results for transfer come only when they are paired together.

Unlike interleaving, where similar training material added additional difficulty and better long-term retention, it seems that dissimilar training examples make it more difficult to extract a useful abstraction but allow it to be used more flexibly once acquired.

The general rule of applying variation in learning for long-term retention is to apply knowledge and skills in two or more contexts or to learn something from two or more examples.

Here are some specific ways to do that:

• Vary your environment. If you’re practicing a movement in sports—and depending on the sport—practice the movement with different players or opponents, on various surfaces, under diverse weather conditions, and with different equipment and clothing.
• Study multiple subjects in parallel. Most schools are already set up in a way where various subjects are taught at the same time. While it feels like juggling too many things at once, it turns out to be beneficial long-term.
• Add variation within the same subject. For example, if you’re learning a foreign language, practicing how to apply multiple tenses (past, present, future) during one learning session should yield better long-term results than focusing on only one. In sports, try to combine learning several different movements in one learning session and over a short period instead of focusing on only one move at a time.
• Seek different points of view. Reading several publications and media about the same or similar topic helps highlight similarities and differences between different authors, where they agree and disagree. Getting to that point of view is impossible from only one source.
• Review your notes. Related to the point above, I take extensive notes about things I read, encounter in the world, or contemplate. I review them later and connect them to something similar I had found before. I can’t do it by relying on memory alone.

Method 3: Spacing effects

Spacing effects or temporally distributed practice is a way of learning where certain information or skills are studied and practiced more than once at different times, as opposed to massed practice, where everything is crammed into a single longer session. In other words, if you want to learn a particular topic, scheduling two one-hour sessions a week apart will produce better results than one two-hour session. The distributed practice has been studied for more than a century. Its effects are undeniable and often underutilized by students and learners.

The biggest challenge in applying the spacing method is knowing the optimal distribution of practice sessions considering many variables, such as:

• Your current knowledge of the topic and adjacent topics.
• How much time you are able to devote to one practice session and for how long you can focus and engage.
• When do you need to know the topic. In other words, are you studying for a test in a month or in a year, or do you want to remember it forever?
• Are you learning a motor or cognitive skill.

In one experiment, researchers wanted to understand the optimal spacing when someone wants to learn not-well-known facts about the world (imagine history and geography facts). The researchers set up a study with an initial learning session, a subsequent repeated learning session, and the final test sometime later. The researchers varied the period between the two study sessions and the period between the initial study session and the test. The experiment results showed that the farther the test is in the future, the closer the second study session should be to the initial one as a ratio to the total duration. For example:

• If your test is in two months, you will perform best if you restudy in about three weeks (~35% of two months).
• If your test is in a year, you will perform best if you restudy in five weeks (~9% of one year).

“Great!” you say, “I can apply that.” But will the findings hold for learning Spanish? What if you already know Italian, which is similar to Spanish? Will the results stay valid for learning how to paint? Or how to play basketball? And what if you can practice twice a week until the test instead of only once? Unfortunately, it’s not clear how the findings for optimal spacing for one specific instance are transferable to different skills, topics, and learners, but future research will likely help.

Still, not everything is lost. Distributed practice is fantastic, and you will perform better by using almost any repeated schedule instead of doing only one massed practice. Here are some specific ways to benefit from spacing effects:

• Use a specialized service. Some specialized services include spaced practice features for a particular skill. For example, Duolingo uses billions of data points to optimize the best time for you to refresh your vocabulary. The service adapts to your needs, starting from good baselines and recommendations that would be impossible to get only from your interactions and data points.
• Use a generic tool that spreads learning material over time, increasing the gaps between learning sessions. The one I often use is Anki flashcards.
• Set reminders. After your learning session (or several related sessions), set a reminder to test yourself at a future time; a recurring calendar entry works just fine. When reminded, evaluate how well you performed. If it was good, do a quick restudy and double the time until the next test reminder; if it was bad, plan for a restudy session soon.
• Plan and prepare. In general, spread learning over a longer period with many shorter learning sessions in-between. Remember 7Ps: Proper Planning and Preparation Prevents Piss Poor Performance.

Caveat: “learning for the test” approach

There is a small caveat to what I wrote in this essay. Blocked (a single topic) and massed (all-at-once) practices usually deliver better test results immediately after the learning session. These methods could lead to the “learning for the test” approach that I too often applied to my early schooling:

• Go through one narrow topic days before the test
• Pass the test
• Never revisit the topic
• Completely forget it

My goal then was to survive school, not learn for the long-term. That being said, many people will find themselves in a situation where they must pass an unnecessary-but-bureaucratic exam, so it’s good to be aware of what outcomes will be driven by different learning tools.

Conclusion

Scientist Robert Bjork talks about the desirable difficulty in his work as a good indicator of the effectiveness of a learning method. The three methods—retrieval, variation, spacing—are unintuitive in a way that learners find them more challenging and feel that they are not progressing as fast as they could, but later test results undeniably demonstrate that they perform better than methods that feel easier.

If you want to learn something long-term, it will be demanding along the way, often so much so that you will question your sanity and competence. However, don’t reach for something easier but understand that the difficulty is the signal that you’re on the right path.

References and additional resources

I have been collecting notes and references about learning methods for many years. I stumbled upon Acquiring an Accurate Mental Model of Human Learning: Towards an Owner’s Manual article in the second half of 2022. It was published just a year earlier and is a fantastic collection and analysis of existing scientific work about learning. It’s so good and extensive that it almost prevented me from writing this essay. The article is 68 pages long. The last 25 pages contain references to studies and scientific literature, which is why I decided not to cite many references here. If learning methods interest you and you want to dig deeper, this is probably the best starting point: [PDF] Pan, Steven & Bjork, Robert. (2021). Acquiring an Accurate Mental Model of Human Learning: Towards an Owner’s Manual

The Biggest Myth In Education is a great video from Veritasium on YouTube in which the myth about individual learning styles is debunked. All relevant research papers are linked in the description of the video.

The quote about the source of our illusion of understanding is by Steven Sloman, professor of cognitive, linguistic, and psychological sciences at Brown University, on Freakonomics Radio episode How to Change Your Mind. One of the early papers on the topic was The Misunderstood Limits of Folk Science: An Illusion of Explanatory Depth. Subsequent papers looking into everyday objects and politics confirmed the initial findings.

The research about creating useful abstractions is Gick, M. L., & Holyoak, K. J. (1983). Schema induction and analogical transfer. Cognitive Psychology, 15(1), 1–38. https://doi.org/10.1016/0010-0285(83)90002-6

The research mentioned in the distributed practice is Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T., & Pashler, H. (2008). Spacing effects in learning: A temporal ridgeline of optimal retention. Psychological Science, 19(11), 1095-1102. https://doi.org/10.1111/j.1467-9280.2008.02209.x

About the student model and forgetting curves from Duolingo blog in How we learn how you learn.