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How We Remember (and Forget) Things

The first step to improving memory is understanding the science behind it

Tyler Kleeberger
Nov 9, 2018 · 16 min read
All images: the author

An Exploration of How Memory Works

  • What was the name of the person I met at that event last night?
  • What was that address again (even though those of you with smartphones don’t really need to know addresses anymore)?
  • What day is my friend’s birthday?
  • What is the name of the blender I bought that I was going to tell my friend about?
  • What was that data that I read but am struggling to recall right now?
  • Or that historical fact that won’t quite surface in my brain?

There are a lot of techniques out there to help you remember this type of information. From Kwik Recall to experiential methods, from books by very smart people to emerging research suggesting undisturbed rest is the key to retaining new information, lots of folks offer strategies to boost memory, concentration, and recall. Some are well-rooted, peer-reviewed techniques while others are hacks based on individual experience. Both types can be helpful—and by all means, use them to your advantage.

However, for me, it has been understanding what is behind the techniques—the foundation of memory—that has proven most beneficial for improving my ability to remember stuff. Getting to the psychological roots of memory has allowed me to adapt memory, concentration, and recall to my specific context.

Instead of proposing a unique technique for improving memory, I want to cover the basics and explore the science of how memories exist in the brain.

My aim is to answer the fundamental questions:

  • Why do we remember some things and forget others?
  • Why do we remember some things briefly, but then lose them over time?
  • What do we know about memory and the brain that might help us be more intentional about how we learn and take in information?

Sensory, Short-Term, and Long-Term Memory

The brain’s process of memory is quite complex and involves several forms of memory. Understanding these forms is key to unlocking how information stays in the brain long-term.

Sensory Memory

Every moment you are alive, you are taking in information. You remember very little of this information long-term, but it’s important to acknowledge that memory and learning don’t only occur when you sit down to read or watch something.

This is called sensory memory. Sensory memory is, quite literally, anything that your senses take in during a given moment.

When you feel the touch of your keyboard or phone, breathe in olfactory information, see colors and objects, hear music or conversation or traffic, taste food in your mouth—each and every sensory experience is something that technically becomes a part of your memory.

Most of this information doesn’t last very long—the lifespan is usually about one second. This doesn’t mean that sensory memory is relegated only to the instant, indeterminate information that you happen to taste, touch, feel, smell, or hear. Learning someone’s name, trying to memorize content, or reading a book all start as sensory memory too.

All information, whether meant to be retained long-term or instantly forgotten, is stored in your sensory memory for that blip of a second. This means that your sensory memory is huge; you have an almost infinite capacity to store sensory information, even though it is only guaranteed for a brief second.

You are constantly putting infinitely large pieces of content into your memory, but most of them are gone immediately. So how do we keep this sensory information going?

Short-Term Memory

Memory is often compared to the craft of construction. Processing sensory information is like grabbing a tool; moving the information into short-term memory is like placing that tool on your workbench.

You decide, in every moment, which information you want to consciously focus on. While you are reading this article, you are taking in all sorts of information, from the sounds you are hearing, to that dry taste in your mouth, to how your device feels in your hand. But most of this is happening subconsciously. These pieces of information come into your sensory memory and then vanish.

Whatever you are trying to remember, it begins with the intentional motivation of wanting to remember it.

The words you are reading, however, have captivated your conscious thoughts. Simply by that intentional focus, they move from sensory experiences to short-term memory.

This is called “encoding.”

Encoding is the intentional, conscious recognition of a sensory experience that brings information into your short-term memory because of the focused attention you give it. Conscious processing elevates information from the quickly evaporating sensory memory, but its lifespan is still only about 30 seconds.

Also, a problem with something being in your conscious thoughts is that space is much more limited than with sensory memory. By giving explicit attention to the sensory information, you prevent the information from disappearing instantly, but you also transfer it into a much more limited storage bank. Short-term memory storage can hold five to nine chunks of information, compared to the infinite capacity of sensory memory.

This is the limit of your conscious workbench.

And you still only have about 30 seconds before that memory dissolves.

But here’s the thing—you remember more than five to nine chunks of information, right? There must be a more permanent level of memory then.

Long-Term Memory

First, the good news: Long-term memory has an infinite capacity.

More good news: Long-term memory is capable of an infinite duration.

So you have taken the information from your sensory memory and placed it in short-term storage through a conscious encoding process. But how do you transfer that information into permanent storage, long-term memory?

This is where the bad news comes in: The encoding process is much more difficult. You have to create an association or attach significant meaning to the content in order to store it permanently.

In the field of memory and recall techniques, this is the area where most people focus: finding ways to create associations or attach meaning to help you remember content.

Before we discuss those components of long-term encoding, however, we must cover the various types of long-term memory.

Explicit Long-Term Memory

Any piece of information that requires recall fits in this category. Psychology breaks explicit long-term memory into two forms:

  1. Semantic: Facts, words, or pieces of information that are cognitive in nature. If you have a quote memorized—or statistics or details from a book or story—it is in your semantic long-term memory.
  2. Episodic: Pictures or images that you have ingrained in your brain.

Implicit Long-Term Memory

Any piece of information that is ingrained in your life but doesn’t require intentional recall fits in this category. Again, there are two forms:

  1. Automatic: Procedures or functions that you learned but no longer have to think about, like walking or breathing. Fortunately, our bodies are pretty good at accomplishing this fairly early in life.
  2. Conditioned: Procedures or functions that you have made into muscle memory. You take the information and do it frequently enough that it becomes natural. Neurologically, your myelin sheath is predisposed to make this happen; you have a coating around every neuron that grows stronger every time you engage that function. You literally condition these things into your memory. It is possible to condition yourself to make otherwise unnatural learned behaviors innate to your life. This isn’t always positive. You can make bad habits innate, which is what happens with most addictions or compulsions. Changing behavior is also dependent on conditioning your external environment to become muscle memory.

If you are still reading this, I assume you have a curious mind and desire to encode information into your long-term memory.

Here’s how we do that.

Tips for Encoding Long-Term Memory

The goal for learning, memorizing, or internalizing any style of information is to encode those pieces of information into this long-term storage bin in your brain.

Going from sensory to short-term memory is pretty simple—just give the sensed information your attention. Encoding long-term memory is more difficult.

This is why a lot of information stays short term and why even more information begins the process of becoming long-term but never solidifies and eventually decays. You remember a name or fact or habit, and it stays with you for a day or a week, but then it fades away.

This is called “encoding failure.”

Why Encoding Failure Happens

Remember how you placed a tool on your workbench to move it into short-term storage? Moving something into long-term memory is like taking the tool from that workbench and putting it in a toolbox. However, if you don’t intentionally keep that toolbox within reach, it becomes difficult to access. There are two main types of encoding failure:

  1. Storage Decay: This is when you begin encoding to long-term memory but never complete the process. You either fail to continue to access the information or never fully solidify it. Psychologists call this “extinction.” You place the information in the new environment, but don’t nurture or adapt it to its new location, and it atrophies.
  2. Interference: This is when other information gets in the way. Being distracted, not learning the information correctly, or learning conflicting information can cause interference. Essentially, a lack of intentionality causes the information to stay short term.

How to Avoid Encoding Failure

While there are a vast number of resources available that teach specific techniques, I want to offer the root behaviors that you can adapt to your specific context. To borrow from music theory, learning specific memory techniques is like learning a song in a particular key. It might work for you, but maybe you aren’t able to play in that key. My goal is to give you the standard scales or notation that you can transpose to a key that works for you.

To use another analogy, instead of giving you the recipe, I want to give you the culinary basics that will set you up to cook (encode) whatever you want. So here are the basic requirements, or principles, for encoding to long-term memory that you can adapt to your context.


You’re at a party, and someone comes up to you and starts a conversation. The person says their name and begins telling a story. If you want to remember this person’s name, there is one step that will solidify the information: You have to intentionally process the name. Otherwise, you will lose the information since the short-term time frame is expiring as you’re processing the next piece of content from the conversation.

Whatever you are trying to remember, it begins with the intentional motivation of wanting to remember it. If it is a name, what I will often do is repeat the name out loud in some civilly recognized way: “Nice to meet you, Siam.” If it is a fact or image, I will consciously remind myself that it is important, and I don’t want to lose it in the next 30 seconds. Intentionally visualizing the information in my mind solidifies the memory because of the motivation.

This is the same reason why writing out notes while taking in information (i.e., while reading a book or during a meeting) helps you remember. It isn’t that the notes are now ingrained in your brain, but that the intentional act gives your brain permission to view this information as a priority.

Memory all starts with motivation. But there are some other important principles for encoding information.


The more vivid you can make the information, the more ingrained it will become in your memory. While long-term memory involves various parts of the brain working to reconstruct information and activate piles of neurons collaboratively (this is what keeps the information active in your brain and allows it to continue to be encoded), there is a unique process with emotions that makes encoding to long-term memory more effective.

Not to get all brainy, but the simple version of the process works like this: Encoding involves the prefrontal cortex (your mind’s CEO) and the cerebellum (where motor skills are primarily found), but emotion brings in the amygdala. When this happens, a certain amount of arousal gets paired with the information, making it more solidified in your memory.

Pairing emotion with the information vastly improves the likelihood of the information getting encoded into your long-term memory.

This is why art creates more vivid recall: The art and its ensuing emotions are like a Trojan horse carrying the information to your long-term memory. Communication theory teaches that experience, rather than rhetoric, is what changes minds. This has some truth to it… because the experience is what brings the amygdala into the memory game. This is also why traumatic events stay so ingrained in our memories.

The mood that triggered your aroused encoding when you were first learning the information is also important because being in a similar mood later can trigger that memory. Which brings us to the next principle.

Location and Associations

Have you ever noticed that you remember events with more clarity when you are in a physical space that’s similar to one where the experience occurred? Being in a similar atmosphere triggers the encoded information (similarly to how emotions function in the second principle).

This principle deals more with recall than encoding. The information is encoded in a particular context and, therefore, re-entering that context further solidifies the memory and makes recalling it more likely. Essentially, nostalgia is a powerful memory device. The more technical name for this phenomenon is the “encoding specificity principle.”

The more vivid the environment where the memory is created, the more associations you pair with the memory.

I remember a professor in college giving me the tip that studying in the same space where I was going to take a test would make my recall more effective. The location acts as an association that is congruent with whatever you are trying to learn. Part of this is related to the myelin sheath mentioned above—the neuron coating carries the minute details of associations that trigger the memory more vividly. Similarly, this is why you might crave certain foods during certain seasons or moments.

Intentionally learning in an environment that has a connection to where and when you will need that information is a practical way to embed the information in your long-term memory.

In other words, study where you are going to take the test. Practice your speech on the stage where you’ll be making it public.

The more vivid the environment where the memory is created, the more associations you pair with the memory. The more associations you connect to the memory, the more encoded the information is.

Undisturbed Processing

There is a common reference that the most effective way to encode information is in chunks of about 15-30 minutes. There is even a technique called “pomodoro” that acts as a management tool based on setting a timer for working or learning. You do 25 minutes, then rest for five minutes, with a longer rest of 15 minutes after a certain number of segments.

Why? Because your capacity as a human being is limited, and you have to force yourself into constraints to avoid overloading on information (which would be a form of interference that leads to encoding failure).

However, it’s equally important that you intentionally take time to process the information to ease it into your long-term memory. Various studies have shown that undisturbed intake followed by undisturbed processing allows you time to concentrate on information and retain it. After the event (finishing the book, leaving the meeting, being done with class, etc.), you review the information to process it.

The period of rest forces you to focus on and observe the information, which transitions the memory to your hippocampus for storage.

Patterns and Meaning

Now we are getting into the trendy techniques.

You may have seen people memorize the order of a deck of cards or a list of random words. What these techniques are usually doing is pairing the specific piece of information with a currently known association to give it meaning.

Patterns are a method that links new information to information you already have. You use something familiar (for example, your route to work or your morning routine) to create a link with the new information, then recall that new information based on the previous content.

It would be like memorizing these principles by giving each one a connection to your process of walking up to your house: Getting out of the car is “emotion.” Walking past the trash can is “location and association.”

You can have the desire and motivation to memorize something, but the infrastructure surrounding your life is a more powerful dictator of what will be taken into your memory.

Using the motivation principle where you want to remember the name of someone you’ve just met, I might repeat the name. To include the patterns principle, I will also mentally connect the name to other people who have that name or information that resembles the name. For example, let’s say I’ve just met someone named Siam. I might think: Siam, like the nation state that became Thailand. Now I have a link to help me recall that name later.

Remember, you can only take in so many chunks of information at a time. What patterns do is condense pieces of information into larger chunks. By condensing unfamiliar information with known information, the new information becomes more accessible. By attributing meaning to the information, it becomes encoded alongside what you already value and know.

Using patterns to create meaning is a great way to remember information. It can also be the most unreliable though—unless the information truly has meaning and is embedded properly, it will stay in short-term memory. A person who memorizes a deck of cards or a list of words in one moment probably doesn’t remember that same information a week later. The more meaningless the pattern, the less likely you are to fully encode the information long-term. Patterns and meaning are best used in conjunction with each other.

It is also important to pair this principle with the others. The next one is a good example.

Conditioning to Familiarity

Continuous repetition over time is the most difficult, time-consuming, least meaningful option, but it will encode the information.

Instead of repeating the name or using a pattern, you encounter the person continually over time. Seeing the person and hearing their name repeatedly helps the information get stored more permanently.

Essentially, your external environment will play a role, over time, in what you encode and what you don’t. You can have the desire and motivation to memorize something, but the infrastructure surrounding your life is a more powerful dictator of what will be taken into your memory.

The most practical way to remember something is to do something with the information.

First, remember extinction: If you don’t keep reintroducing the behavior or information, it will go away.

Second, the behavior modification and law of effect, which is based off classical conditioning. You are likely to repeat a behavior or internalize information that has positive effects, and you are likely to avoid that which has negative effects.

The more positive effects associated with the memory or the information, the more likely you are to keep it around. The more you keep it around, the more conditioned it will become internally; psychologists call this “acquisition.”

External environment will lead to internal development. This is true about behavior, and it is also true about memory.

Incarnational Learning

The most practical way to remember something is to do something with the information.

Somehow, you have to move the information from your head to your hands. This creates meaning, emotional connections, and tangible associations. It can also lead to conditioning and the undisturbed intentional processing that is so important.

Actually doing something with what you learn will make it a more permanent part of your toolbox.

The Bad News: Memory Is Malleable

Notice that I haven’t said that memory is permanent? Yes, your long-term memory is infinite both in capacity and time, but that is the ideal.

In addition to limits on how much information you can process at once (see principle number four) and the risks of losing long-term memory (see encoding failure, specifically storage decay), your memory is malleable and can change over time.

Technology corrodes memory because it eliminates the need for encoding.

This is why eyewitnesses are steadily losing value in the courtroom—not only do eyewitnesses usually fail to encode all the information necessary in that moment, but how we remember what happened is continually affected by new pieces of information gained over time. This is also why we tend to romanticize the past; our malleable memory has evolved how we remember the past into something that isn’t as historically accurate as we might claim.

The same is true for what you learn. As you encode more things to long-term memory, the new and old memories adjust to one another and, therefore, affect one another. This can make the information we have more powerful, but it can also make us a bit more unreliable than we would prefer.

Technology Corrodes Memory

You’ve probably heard that oral cultures didn’t have to write down their information because their brains were wired in a way that they were able to remember and retell their stories by word of mouth. In fact, it was part of the ancient Jewish tradition to have the entire Hebrew Scriptures memorized during their lifetime.

Why don’t we still function like this? Because we don’t have to.

As literacy and writing technology advanced, we were able to take information that in previous living conditions was only accessible orally and put it down on paper. This is a great feat of progress, and I imagine we are able to access an exponentially larger amount of information because of this, but I also imagine that our memory muscle has weakened a bit in the process.

Technology corrodes memory because it eliminates the need for encoding.

This doesn’t mean our memory muscle is expelled completely, as you still have information in your long-term memory, and we still are able to spout off speeches, songs, and movie quotes from memory. But it does make encoding more difficult than it might have been in a culture where encoding was a natural necessity for remembering absolutely anything.

We have notes so we don’t have to memorize books or facts. We have GPS and contact lists so we don’t have to memorize directions or phone numbers. I’m not ready to pronounce a moral judgment on this change, but it has made it more difficult to encode information into our long-term memories.

As you go through the journey of learning, remembering, and recalling information, just keep in mind that you are up against a cultural shift that has made this more difficult.

Tyler Kleeberger

Written by

I’m Exploring How to Become the Best Version of Humanity. Here’s what I’ve found so far @ tylerkleeberger.com [Becoming Human] | @TylerKleeberger — on Twitter.

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