The Forgetting Curve

Not only are we fighting weak encoding or storage in our quest for learning, we are also fighting the brain’s natural tendency to forget as soon as possible.

This is encapsulated by the forgetting curve, a concept pioneered by psychologist Hermann Ebbinghaus. Below is a picture of the forgetting curve, courtesy of Wranx.com.

This shows the rate of memory decay and forgetting over time if there is no attempt to move information into long-term memory. If you read something about the French Revolution on Monday, then you’ll typically remember only half of it after four days and retain as little as 30% at around a week’s time. If you don’t review what you’ve learned, it’s very likely you will only retain 10% of what you learned about the French Revolution.

However, if you review and rehearse it, you can see in the graph above how you will retain and memorize more over time. You will bump the retention level back up to 100%, and then the graph will start to become shallower, indicating less decay. It’s as though you are teaching your brain, “This is important. I keep needing to know this, so remember it.”

The goal is to make the forgetting curve shallower—to make it resemble a horizontal line as much as possible. That would indicate very little decay, and doing that requires constant review and rehearsal.

Ebbinghaus found patterns for memory loss and isolated two simple factors that affected the forgetting curve. First, the rate of decay was significantly blunted if the memory was strong and powerful and had personal significance to the person. Second, the amount of time and how old the memory was determined how quickly and severely it decayed. This suggests there is little we can do about forgetting other than to come up with tactics to assign personal significance to information and rehearse more often.

As you can see, forgetting isn’t as simple as having something on the tip of your tongue or rummaging through the stores of your brain. There are very specific processes that make it a near-miracle we actually retain as much as we do. You’re probably also noticing that improving your memory is as much about good encoding and attention as it is proper rehearsing and recall.

Being able to recall information is always the goal, but more realistically, we should be shooting for recognition and to learn how to expertly use cues and hints in our daily lives. I may not be able to recite the lyrics of my favorite songs, but I can sure remember them if I hear the melody. If I become expert at managing cues for myself, I can work around the unavoidable limits of my memory.

The study cycle

Another way to work with the brain and the inbuilt mechanisms of memory is to use what’s called the study cycle. Rather than one technique, this approach is about using a series of different techniques in a particular order, for a particular duration, to maximize learning. In fact, the principles behind the study cycle could explain why tactics such as retrieval practice and spaced repetition work so well.

The cycle consists of five sequential steps to follow. It will help you cement new material and, as you do so, you’ll build a deeper sense of confidence in yourself as you gain knowledge and build on each new development. The cycle is also great for keeping yourself organized and motivated. Often, when we sit down to simply “study,” the intention is so vague that we only waste time and miss out on an opportunity to really learn well. But with a structured, flowing study cycle, we know where we stand—and we can apply the steps to any coursework we like.

The steps are preview, attend, review, study, and assess… and then the cycle is repeated.

The first step is to preview. Don’t just dive in; rather, begin by trying to get a broad overview of what you’re doing, in what context, and why. See the big picture. What this looks like will depend on you and the subject you’re studying.

For example, if you’re reading through an important chapter in a textbook, you might need to start with some skimming, i.e. read through the main headings and subheadings, scan any pictures and diagrams with their titles, look at any summaries at the end, data such as graphs or tables, and bolded sections or pull quotes that have been highlighted as important. This way, you prime and cue your learning.

If your studies are taking a less traditional form, you might still like to begin by going through the material quickly to get an overview. Look through a piece of music quickly and note the time signature, the tempo, the key, and get an idea of the melody. If you’re going through some academic journal articles, go through the abstracts first and broadly see what the research question, methodology and conclusions were in each before reading in detail.

The next step is to attend, i.e. pay attention. Crucially, the preview section helps you direct where your attention goes (that is, onto the most important concepts), but in the second step, you need to apply that attention fully. Here, you want to be as focused and aware as possible. Don’t just sit in a lecture passively, or watch a tutorial video without taking notes.

Read or watch actively. This means you engage with the data coming in. Make notes, ask questions (who, what, where, when, why, how), and have a “dialogue” with the material. Jot questions in book margins and find out how to answer them. Make summaries or simplified diagrams—and use as many of your senses as possible when you encode this new information. When you generate your own study aids and explain the concepts to yourself, you’ll comprehend better, and retain more.

For step 3, we review. Just as we previewed, now we look again and see what ground we’ve covered, and what material has been absorbed. Just the act of revisiting what you’ve taken in reinforces it further. At the end of your study session, stop and take stock. Look again through your notes and summaries, and perhaps even answer some questions you had at the beginning of the session.

You are in essence skimming again, but this time, instead of seeing the big picture of what you are going to learn, you do a quick survey of what you have learnt. Drill a few new concepts, revisit the main themes, and just take a moment to let everything sink in. If you practice retrieval immediately after learning some new data, you are teaching your brain not only to file away important information, but to cement a path via which you can search for and recall that data later on.

Step 4 is to study. The material is there, now you need to make sure it’s taking root in your brain, permanently. The key to this? Repetition. For around 30 to 50 minutes, go over concepts, definitions, problems or ideas, reinforcing your understanding. Pay attention to those parts that are most difficult for you, but remember to keep seeing each unit in relation to the whole. Here, you can draw on all the previous steps to sit with the material and encode it into your brain.

The last step is to assess. Here, you want to check how well the process is going. Check how much you’ve retained, but also ask yourself how well your study techniques are working. Try some tests or worked problems and appraise your performance and memory. Based on the outcome, adjust your approach next time.

You’ll know you’ve properly absorbed the material when you are able to confidently teach the concepts to another person, and feel that you comprehend enough to reproduce it or score well on a test. On the other hand, you might do well with the material but wish to change the study approach, for example spending more or less time on different steps, or using a different active reading technique.

When you’re done, you start again with step one!