Teacher Advocate

A place for educators and parents to share ideas –

Children and Their Brain Memory


Why Students Forget—and What You Can Do About It

Our brains are wired to forget, but there are research-backed strategies you can use to make your teaching stick.

Illustration of a side view of a brain with bright blue neural pathways


Teachers have long known that rote memorization can lead to a superficial grasp of material that is quickly forgotten. But new research in the field of neuroscience is starting to shed light on the ways that brains are wired to forget—highlighting the importance of strategies to retain knowledge and make learning stick.

In a recent article published in the journal Neuron, neurobiologists Blake Richards and Paul Frankland challenge the predominant view of memory, which holds that forgetting is a process of loss—the gradual washing away of critical information despite our best efforts to retain it. According to Richards and Frankland, the goal of memory is not just to store information accurately but to “optimize decision-making” in chaotic, quickly changing environments. In this model of cognition, forgetting is an evolutionary strategy, a purposeful process that runs in the background of memory, evaluating and discarding information that doesn’t promote the survival of the species.

“From this perspective, forgetting is not necessarily a failure of memory,” explain Richards and Frankland in the study. “Rather, it may represent an investment in a more optimal mnemonic strategy.”

The Forgetting Curve

We often think of memories as books in a library, filed away and accessed when needed. But they’re actually more like spiderwebs, strands of recollection distributed across millions of connected neurons. When we learn something new—when a teacher delivers a fresh lesson to a student, for example—the material is encoded across these neural networks, converting the experience into a memory.

Forgetting is almost immediately the nemesis of memory, as psychologist Hermann Ebbinghaus discovered in the 1880s. Ebbinghaus pioneered landmark research in the field of retention and learning, observing what he called the forgetting curve, a measure of how much we forget over time. In his experiments, he discovered that without any reinforcement or connections to prior knowledge, information is quickly forgotten—roughly 56 percent in one hour, 66 percent after a day, and 75 percent after six days.

So what can be done to preserve the hard work of teaching? After all, evolutionary imperatives—which prune our memories of extraneous information—don’t always neatly align with the requirements of curriculum or the demands of the Information Age. Learning the times tables doesn’t avail when running from lions, in other words, but in the modern world that knowledge has more than proved its mettle.

The Persistence of Memory

The same neural circuitry appears to be involved in forgetting and remembering. If that is properly understood, students and teachers can adopt strategies to reduce memory leaks and reinforce learning.

MIT neuroscientists, led by Richard Cho, explain the mechanisms for synaptic strengthening in a 2015 article, also published in Neuron. When neurons are frequently fired, synaptic connections are strengthened; the opposite is true for neurons that are rarely fired. Known as synaptic plasticity, this explains why some memories persist while others fade away. Repeatedly accessing a stored but fading memory—like a rule of geometry or a crucial historical fact—rekindles the neural network that contains the memory and encodes it more deeply.

Researchers have also learned that not all new memories are created equal. For example, here are two sets of letters to remember:


For readers of English, the second set of letters is more memorable—the more connections neurons have to other neurons, the stronger the memory. The seven letters in NPFXOSK appear random and disjointed, while ORANGES benefits from its existing, deeply encoded linguistic context. The word oranges also invokes sensory memory, from the image of an orange to its smell, and perhaps even conjures other memories of oranges in your kitchen or growing on a tree. You remember by layering new memories on the crumbling foundations of older ones.

5 Teacher Strategies

When students learn a new piece of information, they make new synaptic connections. Two scientifically based ways to help them retain learning is by making as many connections as possible—typically to other concepts, thus widening the “spiderweb” of neural connections—but also by accessing the memory repeatedly over time.

Which explains why the following learning strategies, all tied to research conducted within the past five years, are so effective:

  1. Peer-to-peer explanations: When students explain what they’ve learned to peers, fading memories are reactivated, strengthened, and consolidated. This strategy not only increases retention but also encourages active learning(Sekeres et al., 2016).
  2. The spacing effect: Instead of covering a topic and then moving on, revisit key ideas throughout the school year. Research shows that students perform better academically when given multiple opportunities to review learned material. For example, teachers can quickly incorporate a brief review of what was covered several weeks earlier into ongoing lessons, or use homework to re-expose students to previous concepts (Carpenter et al., 2012; Kang, 2016).
  3. Frequent practice tests: Akin to regularly reviewing material, giving frequent practice tests can boost long-term retention and, as a bonus, help protect against stress, which often impairs memory performance. Practice tests can be low stakes and ungraded, such as a quick pop quiz at the start of a lesson or a trivia quiz on Kahoot, a popular online game-based learning platform. Breaking down one large high-stakes test into smaller tests over several months is an effective approach (Adesope, Trevisan, & Sundararajan, 2017; Butler, 2010; Karpicke, 2016).
  4. Interleave concepts: Instead of grouping similar problems together, mix them up. Solving problems involves identifying the correct strategy to use and then executing the strategy. When similar problems are grouped together, students don’t have to think about what strategies to use—they automatically apply the same solution over and over. Interleaving forces students to think on their feet, and encodes learning more deeply (Rohrer, 2012; Rohrer, Dedrick, & Stershic, 2015).
  5. Combine text with images: It’s often easier to remember information that’s been presented in different ways, especially if visual aids can help organize information. For example, pairing a list of countries occupied by German forces during World War II with a map of German military expansion can reinforce that lesson. It’s easier to remember what’s been read and seen, instead of either one alone (Carney & Levin, 2002; Bui & McDaniel, 2015).

So even though forgetting starts as soon as learning happens—as Ebbinghaus’s experiments demonstrate—research shows that there are simple and effective strategies to help make learning stick.


Comments (18)FOLLOWSubscribe to comments via RSS

Conversations on Edutopia (13)SIGN IN OR REGISTER TO COMMENT


Tim's picture



As a student moving from class to class I found out that notetaking using various strategies or a teacher-provided handout made a tremendous difference when I sat down in the evening to review & do homework. Another clue I learned that if I could apply a math skill quickly in a science lesson , things would stick. Another tactic would be to read the textbook or on-line lesson ahead of the upcoming classroom topic, and perhaps talk it over with a brother or friend (even a girlfriend!). There are numerous methods to retain knowledge but one that is not a weakness is to re-take a course. The speed at which Algebra II has to be presented means that many should repeat the class before moving to say Analysis.Even Einstein had to get help with his Math. He’s not the first or last that needed to do this.



Lisa_MCcoy's picture


Parent. Teacher. Budding Writer

Sometimes healthy competition while playing fun games can help students to improve retention of what they learned. At the end of each lesson, I design an online quiz test for students to check what they have understood. Anf of course, the student who scores the most will be honored in front of the entire class. This imbibes a competitive spirit among students as they start paying close attention to my lessons in order to score the most in the quiz. It is a simple technique to ensure that students are attentive in the classroom. Here’s an example of how the quizzes look like: http://www.cram.com/flashcards/test/unit-1-vocab-316568



carlmc's picture

I’m a big proponent of peer to peer learning and was witness to the power of this process a couple of weeks ago with my daughter and a friend. They both had an upcoming test using a mountain of notecards they had created over the prior weeks. The first thing I had my daughter do was to layout the cards in groupings that explained how the larger concept related to the individual items on the cards and then made her tell me the “story” of that grouping several times. Then, she and her friend did a virtual study group via Facetime in which one girl would ask the other to explain one of the definitions/theories on the card. They did this for a couple of hours, we finally had to tell them to stop. They had fun, they giggled, but they used that time to help each other make those connections to the content and the meaning behind the content. This left me with three questions: 1) Why don’t teachers share strategies like these with students? 2) What would happen if teachers taught these strategies (maybe starting with sharing this article and asking students to respond)? 3) Why couldn’t more class time be devoted to allowing peer to peer learning?



Lois Letchfordtroy2017's picture

Love this article! This knowledge is often forgotten when teaching struggling readers. Recalling the more difficult “sight” words requires combining text with images or experience. Such words become memorable, ties learning to emotion and help students recall words. Thanks again for your work!


Mary Spillers's picture

Very cool article! As many individual students exist is likely the number of strategies we should try, right? Oh, to get inside their minds. Or maybe NOT.


Tim's picture



I recently sat in on a series of English courses as a T/A & tried to help the teacher keep the students’ minds on-task. What is so distracting is the prevelence of smart phones. In their parents’ generation, walkmen were routine collected & sent to the assistant principal. But these devices are more personalized, so kids keep them on their person. Some kids are half- focused on the topic at hand & the other part of their brains drawn to something else. Of course, the kids are also using laptops that sometimes include a audio portion & have to wear ear buds…. Frustration is revealing itself in the need for students to stand up, walk around, even go to the restroom more than once in a 90 minute period. It’s no wonder when these students apply to a community college, they do not pass the English portion of their entrance exams, and then have to re-take high school courses!



faisal's picture


I love to teach Mathematics

“Forgetting” is really a tough challenge for a teacher. Like other teachers, I also face this problem while teaching my students. Whenever I tell my students some new concept, I try to relate it to something that is more interesting and already related to their life. Most of the time this tricks help to retain the required knowledge in student’s mind.


Farah Najam's picture

Farah Najam

Teacher Trainer and write on education

I think you may have information stored away in your mind but are unable to recall it if the right cue or “handle” is missing. In other words, if you learn material one way and a test question asks for the material another way, you may be unable to recall it. To prevent this, it is essential that you learn material using as many of your own words as possible. When you can put something completely and accurately in your own words, it significantly increases your ability to remember. Teachers should help students practice a variety of approaches.



Scott Nealey's picture

I like some of the ideas here. I remember hearing this (and seeing this) at a Wesleyan summer camp back when I was a teen:
10% of what we read
20% of what we hear
30% of what we see
50% of what we see and hear
70% of what we discuss with others
80% of what we personally experience
95% or what we teach others
– Edgar Dale



Consuella Lockhart's picture

This article shares similar concepts to the “… Growing Dendrites” line of thinking. It is interesting that after many years of teaching I still need to be reminded of effective methods to teach students in ways that are best for reaching the varied student population. I embrace the strategies.

Sign in to comment. Not a member? Register.

No comments

The comments are closed.