Active recall: study by remembering instead of rereading

Active recall means studying by trying to remember the content without looking at the answer, instead of rereading your notebook. You close the material, try to answer or explain, and only then check what was missing. In experiments, remembering actively tends to make memory more durable than rereading. But it takes more work and, in the moment, can feel harder.

What is it, and is it the same as doing practice questions?

Practice questions are one form of active recall, but not the only one. The principle is the same: pulling the information out of memory instead of just looking at it again. You can use exam questions, summaries written without consulting anything, explaining aloud to someone, or a diagram drawn from memory.

The scientific basis comes from Karpicke and Roediger (2008). In experiments with university students learning foreign-language vocabulary, repeating the test on words already answered correctly brought a large gain on a test given after a delay. Restudying after having already learned the words brought no benefit on that delayed test (Karpicke & Roediger, 2008).

In the experiments by Roediger and Karpicke (2006), the tests were free recall, without feedback: students recalled the text freely and that was it. Checking the answer afterwards, as we suggest below, is a common study practice, but it is not what those experiments measured.

It is worth noting that those experiments used simple materials, such as vocabulary lists, and recall tasks. For more complex subjects, active retrieval is still a good foundation, but it calls for adaptation: questions about understanding and application, not only definitions. A question like "why was the National Assembly created?" demands more than repeating a name.

Why rereading does not work as well

Rereading gives a feeling of familiarity. The text looks known, and that makes you think you know it. That feeling misleads. Roediger and Karpicke (2006) compared students who reread a text with others who took repeated tests. With a test after five minutes, the rereaders did better. With tests after two days or a week, those who had taken tests remembered much more, while the rereaders felt more confident (Roediger & Karpicke, 2006).

Dunlosky and colleagues (2013) ranked rereading as low utility and practice testing as high utility for learning.

Rereading is still useful for understanding a topic for the first time. For remembering later, it is weak.

How to do it without looking at your summary

1. Read a short section, about ten minutes of study, and close the material.
2. Write or say aloud what you remember, in two or three minutes.
3. Open the material and check. Mark what was missing or wrong. That is a clue about what to review, not a judgment about you.
4. Redo only what was missing, a few hours or a day later.
5. Repeat at the next review, with a longer gap. This goes well with spaced repetition.

Examples to use today

Biology: after reading about photosynthesis, close the notebook and answer: where does it happen, what goes in and what comes out. If you get stuck, check and try again at the end of the day.

Spanish: after a list of expressions, say aloud "Llevo dos horas estudiando" (I have been studying for two hours) and explain when to use that form. Then make up a new sentence about your routine, without consulting anything.

History: write from memory three consequences of the French Revolution. Check and fill in what was missing.

German: without looking, write three sentences with "sein" in the forms "ich bin", "du bist" and "er ist". Then check against the table.

Ways to practice besides questions

Pick the one that fits the subject. These are practical suggestions, not protocols from a specific study:

• Blank page: close the material and write everything you remember about the topic, in bullet points. Then compare with the notebook and fill in with another color.
• Flashcards: question on one side, answer on the other. Ask questions that call for an explanation ("why does water boil at a lower temperature at the top of a mountain?"), not only names and dates.
• Explain to someone: tell the topic to a classmate, a family member or even the wall. Where you get stuck is the weak point.
• Solve without looking at the example: in math and science, read the solution to an exercise, close it and redo it. Then solve a similar one.

If the topic is new and you remember nothing, that is fine. Trying and not managing yet is still a useful step: when you check, you see exactly what was missing.

How long per day

There is no proven number. A realistic proposal is to set aside 15 to 30 minutes a day just for retrieving what you studied on previous days, and use the rest of the time to learn new content. If time is short, it is worth more to test what matters most for the exam than to reread everything.

How to know if it is working

If you remember the topic without consulting anything at the next review, the method is on track. If you only recognize the answer when you see it in the text, the review needs to be more active: less looking, more trying.

Do you need an app?

No. Paper cards, with the question on one side and the answer on the other, work well. You can also use a blank sheet. Apps help organize dates and questions, and many are free, but the tool is secondary. What makes the difference is trying to remember before checking.

Common mistakes

• Looking at the answer before trying. You lose the effort that fixes the memory.
• Doing everything in one long session. Short rounds tend to be easier to keep up.
• Thinking that getting a question right today guarantees the topic is stored. It is worth checking again after a while.

If your question is what to mix in the same session, see also interleaved practice.

Sources

1. Karpicke, J. D., & Roediger, H. L. (2008). The critical importance of retrieval for learning. Science, 319(5865), 966-968. https://doi.org/10.1126/science.1152408
2. Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249-255. https://doi.org/10.1111/j.1467-9280.2006.01693.x
3. Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving students' learning with effective learning techniques: Promising directions from cognitive and educational psychology. Psychological Science in the Public Interest, 14(1), 4-58. https://doi.org/10.1177/1529100612453266