In short
Testing yourself beats rereading because pulling information out of memory strengthens it. In experiments, students who practiced recalling a text remembered much more a week later than students who spent the same time rereading it, even though rereading felt more effective at the time.
Most of us think of a test as the end of learning, the moment you find out how much went in. Memory research points the other way. The act of pulling information out of your head is one of the most effective ways to put it there in the first place, and a few minutes of it can do more than an hour of rereading.
Psychologists call this retrieval practice. In study guides and on social media it usually goes by active recall. This article covers what the evidence shows, why it works, and how to use it when you are learning something for your job.
What the research found
The best-known experiment comes from Henry Roediger and Jeffrey Karpicke at Washington University in St. Louis. Students studied short science passages under two conditions. Some spent their sessions rereading the text. Others read it a few times and spent the rest of the time writing down what they could remember, without looking.
A week later the recall group remembered 61% of the material and the rereading group 40%. The rereaders had gone through the passages about fourteen times on average, against about three for the recall group, and they were also the more confident of the two about how well they would do (APS Observer).
A later study by Karpicke and Janell Blunt compared recall with a technique many teachers recommend: drawing a concept map that shows how the ideas in a text connect. Across two experiments with 200 students, the recall group scored about 50% higher a week later. The advantage held for questions that asked students to link ideas the text never linked directly, so recall was helping understanding as well as memory. Most of the students had predicted the opposite result (Purdue University).
Why recall works
Every time you retrieve something from memory, you make the path to it a little stronger. Reading the same page again does much less, because the answer is in front of you and your memory has nothing to do.
Recall also gives you honest feedback. When you close your notes and try to explain a topic, you find out at once which parts you know and which parts you only recognize. Rereading hides that difference, and it explains how the rereaders in Roediger and Karpicke’s study could be so confident and do so badly.
A recall session in which you struggle and remember only half the material still does more for you than a smooth reread, because the effort of reconstructing what you half remember is part of what strengthens it.
Five ways to test yourself
You do not need a formal quiz. Any activity that makes you produce an answer from memory counts.
The blank page. At the end of a session, close everything and write down the main ideas as a list or a rough diagram. Then open your notes and mark what you missed. This takes five minutes and works for almost any subject.
Questions instead of notes. When you take notes, write each key point as a question with the answer underneath or on the back. Later you cover the answers and work through the questions. This turns your notes into a test you can reuse.
Flashcards, used properly. Flashcards suit facts, terms, shortcuts and commands. Say or write the answer before you flip the card, and keep the cards you get wrong in a separate pile to come back to sooner.
Do the task without the guide. For practical skills, the best test is the task itself. If you are learning a piece of software, try to complete a job in it without the tutorial open, and look things up only when you are truly stuck.
Explain it to someone. Teaching a colleague, or writing a short explanation as if you were, makes you retrieve the ideas and put them in order. We cover this in more depth in Explain It Simply or You Do Not Understand It Yet.
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Mistakes that weaken the effect
Checking the answer too early. If you look at the answer before you have really tried, you are back to recognition. Give yourself a proper attempt first, even if it ends in a guess.
Skipping the check. Recall without feedback can fix mistakes in place. After each attempt, compare your answer with the source and correct it.
Testing only once. One recall session helps, and several spread over days help a lot more. Recall and spacing work best together, which is the subject of What Actually Makes Things Stick in Memory.
Only testing the easy parts. It is tempting to quiz yourself on what you already know because getting it right is pleasant. Spend most of your recall time on the material you get wrong.
How this fits the bigger picture
Active recall is one of the habits in our guide on how to learn a new skill, alongside spacing, explaining in your own words and practicing the hard parts. It is also the habit that gives the quickest return for the least change in routine. If you add one thing to the way you study, add five minutes of recall at the end of every session.
Every lesson in the free courses on Train Your Skills ends with a short test, and the next lesson opens once you pass it. If you get questions wrong, you see which ones and can try again as many times as you need. Browse the free courses to try it on a skill you need.
Frequently asked questions
What is active recall?
Active recall is a study method in which you retrieve information from memory instead of reviewing it on the page. Common forms are self-quizzing, flashcards, writing down what you remember, and explaining a topic without notes.
Is active recall better than making summaries?
Yes, in most of the research. Summarizing was rated as a low-utility technique in a major 2013 review, while practice testing received the highest rating. A summary can still be useful as a resource to test yourself against.
Does active recall work for practical skills as well as facts?
It does. For software, procedures or methods, recall means attempting the task without instructions and checking where you got stuck. It is harder than following a tutorial, and that extra difficulty helps you keep the skill.
How long should a recall session be?
Short sessions work well. Five to fifteen minutes at the end of a lesson, and a similar slot a day or two later, cover most needs. Longer sessions are fine but tend to drift into rereading.
Why does testing myself seem less productive than rereading?
Testing shows you what you have not learned yet, while rereading shows you what you recognize. The first is uncomfortable and the second is reassuring, and in the research the reassuring method produces worse results a week later.
Sources
- APS Observer, “Test-Enhanced Learning”, on Roediger and Karpicke (2006). psychologicalscience.org
- Purdue University, “Research finds practicing retrieval is best tool for learning”, on Karpicke and Blunt (2011), Science. purdue.edu
