Forgetting and Actively Recalling

28.08.2018 |

Episode #7 of the course How to improve your memory by David Urbansky


So far, we have focused on how to remember information (what research calls “persistence”). But forgetting (or “transience”) is just as important.



Research has shown that after only one day, 50-80% of learned information is removed from your memory if you haven’t used any memorization techniques or tried to recall it. After 30 days, only about 3% of the original information can be recalled [1].

This sounds bad, especially if your goal is to use that learned information a month later in an exam. However, forgetting is actually an important feature of our brains. Outdated and wrong information needs to be purged to allow for faster decision making [2]. Imagine if you could still remember all your old cell phone numbers. If someone asked you for your number, your brain would be slowed down by sifting through all your old numbers to find the current one. Just like actively recalling information strengthens connections in your brain, not recalling weakens them. The adage “use it or lose it” applies, and that is actually a good thing.

Forgetting also helps our decision making process by generalizing information [1]. For instance, think back to your last vacation. Do you remember every meal you ate and how much it cost? Probably not, but you will remember whether the food on that trip was good and affordable in general.


How to Avoid Forgetting

What about information we want to keep? How can we make sure this information stays in our long-term memory for good? The key is understanding that neural pathways are like roads connecting cities. If they are not maintained, they will eventually crumble and become unusable. Therefore, it is important to refresh the associations you create with your memory techniques using spaced repetition. The memory grandmaster, Dominic O’Brien, suggests the following recall intervals:

• Recall immediately after learning something.

• Recall after one day.

• Recall after three days.

• Recall after one week.

• Recall after one month.

• Recall after three months.

After this cycle, the memorized information should be properly reinforced to stay in your long-term memory.


Active Recall vs. Review

For this to work, you must actively recall, not just review the information. The distinction here is tremendously important. Let me explain in the context of learning new vocabulary in a foreign language. Once you have learned that “luna” means “moon” in Spanish, you have to use spaced repetition as explained above to move this information into long-term memory. Reviewing means that after one day, you simply read again that luna means moon. Active recall, on the other hand, means testing yourself and trying to retrieve this information from memory first. All the techniques in this course rely on active recall, so you already know what to do. Remember the technique we used to memorize that luna means moon? When the image of the lunatic with the moon mask pops into your mind and helps you bridge the gap from “moon” to “luna,” you’ve just used active recall. Boom.

A study on remembering word pairs (just like we did in our example) showed that participants using active recall were able to remember 80% of the learned information, while the review group could only remember 34% [3].

Today, you learned that forgetting is actually important and improves decision making by keeping only the most relevant information in your memory. You also learned that you can use active recall and spaced repetition to avoid forgetting information you want to keep.

Tomorrow, you’ll learn how to fuel your mind with the best memory-enhancing nutrients!


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[1] Curve of Forgetting

[2] The Persistence and Transience of Memory

[3] The Critical Importance of Retrieval


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