Memory’s Two Components: Storage and Retrieval

A photo album with a few photos taken out of it

Imagine you’re at your high school reunion. A man walks up and shakes your hand, saying how good it is to see you. You recognize them, but can’t recall their name. Luckily, someone else in your group rescues you by chiming in, “Charlie! How have you been?”

Oh right, Charlie, you think. I knew that.

And you’re right, you did know that, at least in the sense that his name was stored in your brain. Your inability to remember his name wasn’t a problem with storage but with retrieval. In How We Learn, Benedict Carey explains the difference between these two aspects of memory:

“Any memory has two strengths, a storage strength and a retrieval strength. Storage strength is just that, a measure of how well learned something is. It builds up steadily with studying, and more sharply with use. … Retrieval strength, on the other hand, is a measure of how easily a nugget of information comes to mind. It, too, increases with studying, and with use. Without reinforcement, however, retrieval strength drops off quickly.”1

Learning isn’t just about storage.

The big idea here is that learning isn’t just about getting information into your brain; it’s also about cultivating the ability to pull that information out when you need it. Storage without retrieval is useless because, while you may have the information somewhere in your brain, you can’t put it to use or prove that you know it on a test. And, of course, retrieval without storage is useless too – like having the key to an empty storage unit.

Usually, the problem we have isn’t a lack of storage, but that we have storage without retrieval. The information is in our brain … somewhere. The problem is we can’t access it.

This reminds me of the difference between familiarity and true knowledge. Truly knowing something means having both strong storage and strong retrieval for a piece of information. True knowing is seeing that man at your high school reunion and saying, “Hi Charlie!” without hesitation.

(Note: Read this if you want to get better at remembering names.)

Forgetting, Updated

This distinction gives us a new way to think about forgetting. When we forgot Charlie’s name, it wasn’t so much that his name wasn’t stored in our brains but that we’d lost the ability to retrieve it.

Thus, we should update the “use it or lose it” principle of memory: If you’ve done the work to create a strongly stored memory, you won’t necessarily lose that memory if you stop using it, but you will lose the ability to recall the information with ease. Much of the time, forgetting is just that – not losing the information, but losing the ability to retrieve it.

And this begs the question, why would we store information that we’re unable to retrieve? The answer has to do with human nature, as Carey explains:

“In its nomadic hominid youth, the brain was continually refreshing its mental map to adapt to changing weather, terrain, and predators. Retrieval strength evolved to update information quickly, keeping the most relevant details handy. It lives for the day. Storage strength, on the other hand, evolved so that old tricks could be relearned, and fast, if needed. Seasons pass, but they repeat; so do weather and terrain. Storage strength plans for the future.”1

For a student, “the future” might be a final exam. Let’s use AP US History as an example. Throughout the school year, you learn the history of the United States in chronological order. You work hard to store the information from the first unit in your brain, and you quiz yourself prior to the unit test so that your retrieval strength is strong. But then the class moves on to the next unit, and you stop working on retrieval for the previous unit. It’s still stored though, so when it comes time to review for the AP test, you don’t have to completely relearn all the material; you just have to build back up your retrieval strength. This kind of forgetting is okay, as long as you refresh your ability to recall the information before the final.

“The old dog quickly relearns old tricks.” –Benedict Carey1

Developing Both Storage and Retrieval

Memories are formed via a process called encoding, through which information is taken in and understood. If the encoding is successful, the information will be stored in short-term memory for short-term use. If enough work is done with that information, it will become stored in long-term memory.2

So your first goal in studying something is to get it stored in long-term memory. This almost always involves writing because the effort of putting pen to paper does a great job convincing your brain to care enough about the information to hold onto it. It also helps to verbalize as you study.

Many students falter at this step, only doing enough work to store the information in short-term memory. They “get it” enough to do the homework and pass the quiz, but then they stop there and slip back down the mastery path’s muddy slope. To make it stick in long-term memory, you have to keep working with it beyond the initial encoding.

If you do do the work of building up storage strength for the memory, great, but you’re still not done. You also need to develop retrieval strength, so you can actually access the information when you need it.

So your next goal in studying is to force yourself to recall the information. This means taking practice tests, doing brain dumps, doing mental recall practice, and teaching it to other people. All of these techniques build up the retrieval strength of the memory.

The need for both storage and retrieval helps explain why both massed practice and interleaving are so important. Massed practice builds up the storage strength for whatever it is you’re learning by having you drill a particular type of problem over and over again. But once that’s done, you should switch to interleaving – in which the problem types are mixed up randomly – so you’re forced to practice retrieving the proper techniques for solving each different type of problem.

Spaced repetition has a role to play here too. Revisiting a topic repeatedly over time reinforces both storage and retrieval. And critically, you don’t want to do this immediately after learning something. You need to wait a little while – an hour or two if something is brand new and longer as your memory strengthens – in order to make the recall difficult.

“The harder we have to work to retrieve a memory, the greater the subsequent spike in retrieval and storage strength (learning).” – Benedict Carey1

There’s a sweet spot to aim for, where we’re on the verge of forgetting, but we can still retrieve the information. When you work with the information again at that moment, you’re not only rescuing the memory from being forgotten but also strengthening the memory for future use.

Multiple Choice vs. Short Answer/Essay

Neither storage nor retrieval is all-or-nothing. Most students walk into their exams with a medium-to-high level of storage for the information on the test, but with a low-to-medium level of retrieval for it. Such students will tend to do much better on multiple-choice questions than they will on short-answer or essay questions.

Multiple choice questions provide an aide in retrieval, allowing you to simply recognize the correct answer from a short list of options. Questions that require you to write your own answer are much harder because they don’t give you any cues or clues to make retrieval easier. Developing your retrieval strength for the information is always important, but it’s especially important if you’re going to have to self-generate the answers on your test.

This also applies to situations – both in and out of school – that demand creative problem-solving. Since innovation is all about combinations of ideas, you’ll be far more creative if you have a large bank of ideas to draw upon that you can actually make withdrawals from. Real-world problems don’t present you with a ready-made list of potential answers. Instead, they demand that you draw upon your knowledge to come up with a solution.

And as the high school reunion example demonstrates, life isn’t multiple choice. What we usually need is true knowledge – which means both strong storage and strong retrieval.

1 Carey, Benedict. How We Learn: The Surprising Truth About When, Where, and Why it Happens. Random House, 2014.

2 “How Memory Works.” The Derek Bok Center for Teaching and Learning. Harvard University.

Why You Should Verbalize As You Study

A student studying with closed lips, not verbalizing as they study

Most people study in silence, and if you’re in a library, perhaps that makes sense. But if you’re somewhere where you’re allowed to talk, you should be verbalizing as you study, even if you’re all alone. There are several reasons why verbalizing helps you remember what you’re learning.

More Senses = More Memory

We’ve long known that the more senses you involve in learning, the stronger the memories formed.1 And since learning styles are a myth, there’s no good reason to focus on just visual, auditory, or kinesthetic studying. You should do all of them. (Smell and taste also enhance memory too, but it’s hard to smell history or taste fractions, so we’ll settle for what we can get.)

But if you picture someone studying, you probably picture someone sitting at a desk with either a computer or a textbook open, taking notes … in silence. They’re doing visual learning because they’re looking at information. And hopefully, they’re doing kinesthetic learning, of a sort, by writing things down. But we’re missing the verbal component. True, they might be verbalizing in their head, but that’s not as powerful as actually speaking and hearing.

Talking about what you’re learning as you learn it, even just by verbalizing exactly what you’re writing down, is a powerful way to improve retention.

Explaining = Understanding

One of my favorite things to do as a tutor is asking my students to explain what they’re learning verbally. It’s often quite revealing. A student who seems to be following along and “getting it” might prove to be completely incapable of explaining the concept in their own words. On the other hand, a student who appears confused might surprise me by articulating the concept beautifully.

If you can’t explain it verbally, you probably don’t really understand it.

A teacher helping a student study by having a dialogue

Similarly, I’ll often ask math students to explain the steps they’ve taken in a problem. If they’ve made a mistake, this will tell me what went wrong in their thinking. Or if they’ve gotten it right, I can use this to confirm that they actually know what they’re doing. I’m concerned that they might just be going through the motions robotically, following an algorithm for solving this type of problem, without actually understanding how the math works.

Spoken Recall and Teaching

On a related note, verbalizing what you’ve just learned is a great way to study.

Let’s say you’ve just learned about the causes of the American Revolution. As an informal practice test, go teach it to someone else. I’m not saying you should deliver a 50-minute lecture on the topic, but you should be able to tell the story of how the French and Indian War was very expensive, which caused Britain to tax the colonists, and how they were upset about not having representation in Parliament because they had adopted the ideals of the Enlightenment.

Teaching is a powerful way to learn, and you can even do it when no one’s around. I often talk my way through complicated concepts that I’m studying as a form of mental recall practice – sometimes in my head, but sometimes aloud. (Yes, I’m weird like that.)

Verbalizing For Foreign Languages

Verbalizing is extremely important when you’re studying a foreign language because your ultimate goal is not merely to be able to read and write the language, but also to speak it.

In French, this is important because the words are not spelled the way they sound, and you need to practice navigating that disparity. In Spanish, this is important because words always sound exactly the way they’re spelled, so if you know how to say it, you also know how to spell it. Either way, you should be verbalizing the entire time you’re studying vocabulary, practicing conjugations, or doing worksheets.


Psychologists have studied the effects of verbalizing during learning and problem-solving activities, and their findings confirm this advice:

  • Verbalization helps with problem-solving because it “facilitates both the discovery of general principles and their employment in solving successive problems.”2
  • Students who combine verbalization with visual studying remember more than those who use visual studying alone.3
  • Laboratory studies have shown that verbalization is beneficial in a variety of learning situations.4

So the evidence is clear: When you’re trying to learn something, speak up!

1 Medina, John. Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School. Pear Press, 2008.

2 Gagné, R. M., & Smith, E. C., Jr. (1962). A study of the effects of verbalization on problem solvingJournal of Experimental Psychology, 63(1), 12–18.

3 Kurtz, K. H., & Hovland, C. I. (1953). The effect of verbalization during observation of stimulus objects upon accuracy of recognition and recallJournal of Experimental Psychology, 45(3), 157–164.

4 Weener, P. Note taking and student verbalization as instrumental learning activitiesInstr Sci 3, 51–73 (1974).

What It Really Means When a Student Says “I Don’t Know”

Not knowing is an essential step in the learning process, but that does not always make saying the words “I don’t know” easy. Acknowledging a lack of knowledge is like stepping into the garden of our brain and pulling the tarp off of a brand new patch of dirt. We have to do this in order to ready the soil and begin to sow the seeds of knowledge which, with care and attention, will soon fill the once empty plot with roots and lush green foliage. But it can be embarrassing to see peers with already flourishing gardens where yours is bare. You might peek beneath the plastic at your little patch of earth, your stomach twisting in knots, and vow to never ever take the tarp off. This means, of course, that any knowledge you do accumulate will remain at the surface level. Unable to take root, it will eventually wither, nullifying the time and effort you may have spent.

I often work with students who are nervous about admitting that they don’t know something. Scratch that, I often work with people who are nervous about admitting that they don’t know something. In fact, I myself am often anxious about appearing ignorant. At one point or another, I think we all have been guilty of nodding along to a conversation we only half understand, hoping nobody will notice. But in doing this, we shut down part of our capacity to be open and active learners. This is a shame because really, “I don’t know” moments are anything but shameful; they are enriching opportunities to create solid foundations and invite curiosity. By cultivating a sense of normalcy and encouraging bravery around these moments, we can work together to begin to till that soil.

On the other end of the spectrum, for some students “I don’t know” has become as routine an answer as “fine.” Consider the following conversation:

Coach: “How are you doing?”

Student: “Fine.”

Coach: “Great. How is school going?”

Student: “Fine.”

Coach: “Cool. So, what are we working on today?”

Student: “I don’t know.”

Coach: “Shall we continue reading then?”

Student: “Fine.”

Coach: “What do you think might happen next?”

Student: “I don’t know.”

These students are pulling their tarps off, but then they stand there and shrug their shoulders. They don’t necessarily see it is their responsibility to begin the work of planting their garden. To be clear, this behavior is just as understandable and relatable as reflexively hiding a knowledge gap. Especially in the world of online school, it can be hard to stoke interest and energy levels to the point of being actively engaged at all times. For some students, simply turning up for class is what they can give at this moment, and that is appreciated. But others may not have realized that they have fallen into an “I don’t know” routine or what that might mean for their learning. In either case, seeing a reflexive “I don’t know” as a habit of avoidance that can be worked through can make all the difference.

But there is a twist. Those serial “I don’t know-ers”? The knee-jerk knowledge gap coverers? The culprits tend to be the same students, often within the same session. How is this possible, when I have so far discussed them as two opposite ends of a spectrum? It turns out that seeing “I don’t know” as a nerve-racking confession or using it as a matter of routine are both ways of taking a step back from active learning. They may be opposites, but they are opposite ends of the same spectrum: disengagement. Inviting a student to acknowledge an “I don’t know” moment is not about stewing in confusion. Likewise, encouraging a student to push past “I don’t know” is never about insisting on an immediate increase in their knowledge level. In both cases, the goal is to flip that brain switch from passive to active.

“I don’t know” is an important phrase, but it is not as important as what comes afterward. To create a successful learning experience, it must be followed up by a desire to fill that space. Ignorance can indeed be fertile soil, but only if we are willing to accept it for what it is and then put in the work to nourish it into what it can become.

About Leah Jarvik

Leah is a coach with NWES with a special focus on reading and writing support. She has also worked with students through organizations including the Seattle Children’s Theatre, Queen Anne Elementary School, Audubon, and abroad in Galway, Ireland, where she had the opportunity to study education and literacy. Outside of her education work, Leah is an actor, writer, and administrator, currently working with Macha Theatre Works to bring fearless female theatre to the stage. She graduated from Haverford College in 2019 with a double major in English and Theatre.