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A co-educational private school for Preschool–Grade Eight

The Art of Forgetting...and the Science Behind It!

Imagine this: two colleagues, seemingly separated by division, student needs, and curricular content, but united through the science of learning. One of us is a Grade 8 math teacher and student advisor. The other is a Grade 4 homeroom teacher. So there are many differences in our daily goals as educators and how we approach our students. At Far Hills, we are always looking to improve how we are supporting our students throughout their academic journey. A common interest we share is memory, and, specifically, how we help students learn for and beyond the test. We like to think of memory as a system of folders where information is stored as it’s learned and can be taken out when needed. Right? It’s a beautiful thing. The only problem with this is that memory, from a neurodevelopmental perspective, is highly complex and has many factors that influence it. Take the idea of memory and deconstruct that. Are we talking about long-term memory, active working memory, short-term memory? For the sake of this article, we are going to explore long-term memory and active working memory

Let’s begin with a common scenario that we have all faced: walking around the supermarket, we often can’t remember the final item on the list. “I got the eggs, milk, bread, cheese, cereal, and...what was that other thing that I needed?!” Sound familiar? This experience happens because your active working memory has been overly taxed and, as a result, forgotten information. Active working memory is the ability of your brain to hold information with the intention of using it in the immediate short term. Research suggests that working memory is incredibly limited and usually can hold only four to five pieces of information at a time. That’s why, when you are walking around the supermarket, you can only remember the eggs, bread, cheese, and cereal. That sixth item becomes elusive. We live in a digital age where so much in our lives is “smart” and operated by a phone, tablet, or even a watch. Together with applications, we can recall facts in a mere nanosecond or create a list to help us keep track of what we need for the weekly shopping trip! What we don’t realize, though, is that these devices are supporting the limited nature of our working memory by allowing us to create lists that help us remember what that final item is on your shopping list. 

But what about students? How are they coping with the vast amounts of information presented to them in a classroom every day? Well, students are no different, and, in fact, their working may face more limitations than that of a fully-developed adult. Our brains are wired to forget things, literally! Thanks to research in this space, we know that students forget information almost as soon as they have learned it. The saying “in one ear and out the other” isn’t too far fetched. So, if students are only able to hold four to five pieces of information at a time, and they forget information almost as soon as they have learned it, how do they remember anything? This is where long-term memory comes into play. Long-term memory is much more powerful, and its ability to hold information is almost limitless. Typically, long-term memory stores valuable information, such as phone numbers, birthdays, and other information that we can recall quite quickly. The downside is that while long-term memory is incredibly powerful, the information it stores needs to be encoded, and that takes time.


Forgetting Curve

Our interest in memory was piqued when we read the research about the “Ebbinghaus Forgetting Curve.” To our surprise and dismay, we learned that information is forgotten almost immediately after it has been introduced. The visual below illustrates this point. Not only did this piece of research blow up nearly everything that we thought we knew (and made us a little depressed), it also gave us an insight into how we can support students. 

A key component to the “forgetting curve” is the idea of spaced retrieval. When the brain is forced to recall information, research shows that this helps students remember information for the long-term. That means that if we introduce a new topic on Monday, we should force the recall of this information on Tuesday morning. But on Wednesday, we should not discuss it to maximize the amount of time that the brain has to forget the information. With enough time elapsed between Tuesday and Thursday morning, again, we should force the recall of this information. With each spaced recall, we are strengthening the neural pathways in the brain and creating an opportunity for what is called “myelination.” You see, each neuron in the brain is covered in a fatty sheath called myelin. As information is recalled and pushed through that neuron, this fatty sheath gets thicker and thicker, allowing the information to travel faster. The opposite happens when we don’t recall the information, and this process is called “neural pruning.” When neurons are not used, the brain will actually start to prune these to make room for new neurons. 

So, let us bring everything back together. We know that students start to forget information as soon as it has been introduced. We know that their active working memory is highly limited to holding four to five items at a time, and we know that the solution is to get this information into the long-term memory, but this takes time. Thanks to the work of cognitive psychologists and research such as the Ebbinghaus Forgetting Curve, we know that the way to strengthen the memory is through a process of spaced retrieval practice. 


Retrieval Practice

In our classrooms, we have focused our efforts on using retrieval grids as the primary method through which we strengthen memory. A retrieval grid is a low-stakes task intended to force recall of information that has previously been taught. Students are given points, not on the difficulty of questions, but on the recency of when they were studied. For example, if we are in math class in May, there would be more points given for a concept that was taught in September as opposed to April. The focus is on recalling the information that has been forgotten. We have included some examples.

Active retrieval of information not only benefits previously taught the material, but it also primes the brain for incoming data. Research shows that if we can effectively connect prior knowledge with new information, that it is hugely beneficial to long-term understanding. For example, when introducing decimals for the first time, have students retrieve their prior knowledge on place value, a concept that has been taught from their earliest years at school. This strategy helps students make connections with the new material and supports the retention of this information when it has finally been learned. 


Student Voice

You may have heard that math is a somewhat polarizing subject among students, particularly Grades 4-8. So, imagine the excitement that filled the room when we first introduced the retrieval practice grid. We bet that if you close your eyes, you could hear the audible groans! But, much like encoding into long-term memory, give it time, and you will start to see the results. The more that students did this, the more we began to notice a change. First, it actually worked. Students showed more retention over the long term. Secondly, students became more confident, over time, when embracing concepts that they found to be particularly challenging. Now, you may be thinking that math teachers have got some hard numbers to show. In fact, we don’t. We have anecdotes. We have stories and interactions that reaffirm for us the power of retrieval practice. Take a recent interaction with one of our Grade 4 students:

“Are we going to do one of those practice things today? 
“A retrieval practice grid? Yes.” 
“Okay, good. I like those a lot. They help me.”

Short and seemingly trivial, but significant nonetheless. 

A Grade 6 student echoed a similar sentiment when asked to recall a math concept she had learned in Grade 5. She asked, “How am I supposed to remember something I learned last year?”

Providing more retrieval practice is an important answer to that question.



Part of the fabric at Far Hills is not teaching students what to think but how to think. We want them to grapple with concepts that are difficult and challenging. We don’t just want to help our students learn for the test, but to be informed beyond it and use this understanding in the world. Knowledge is essential, and too many times in society, we find this to be lacking. Inspired by experts such as Pooja Agarwal, Patrice Bain, and Mark McDaniel, to name a few, we wanted to help our students remember better. Our intentional application of the research-driven strategy of retrieval practice grids is just one way that we have looked to achieve this goal. We believe passionately in the importance of applying MBE research to our classroom practice. The one guarantee that we have is that 100% of students bring their brain to school each and every day. Understanding the science of learning allows us to transform our teaching and, therefore, the experience of our students. 



About the Authors

Kathy Iuliano, Upper School Math Teacher                   

Kathy Iuliano                                Peter McBride
Upper School Math Teacher        Grade 4 Teacher