How Our Memory Works

Ever wondered how memory experts can instantly remember long digits of numbers but you are still struggling to learn everything you need for an exam? Well in today's blog post I'm going to cover how we can hack how we learn and remember things for longer by understanding how our memory works.

In technical terms studying is about taking information and packaging it in our memory and practising is about our ability to retrieve or recall that information and apply it when it matters. If we can encode, store and retrieve information on demand we can consider that information learned but how do these concepts fit together and how can we use them to learn effectively and just what the heck is the best way to learn something encoding or active recall?

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What Is Information Processing Theory?

Did you know that the first phone numbers were limited to 7 digits as psychologists determined that most errors occurred when the number was increased to 8 digits or higher costing the phone company money?

Well for most of us, remembering digits relies on short-term memory, or working memory—the ability to hold information in our minds for a brief time and work with it (for example multiplying 24 x 17 without using paper would rely on working memory). Another type of memory is episodic memory—the ability to remember the episodes of our lives. If you were given the task of recalling everything you did 2 days ago, that would be a test of episodic memory; you would be required to mentally travel through the day in your mind and note the main events. Memory masters and champions like Guiness World Record holder Simon Reinhard on the other hand can remember upwards of 90 digits by simply looking at a series of cards and we'll look at some strategies to do just that later on in this video.

The concept of memory storage was analysed by American psychologists including George Miller in the 1950s, who developed something called Information Processing Theory which is a cognitive theory that focuses on how information is processed into our memory. The theory describes how our brains filter information, from what we’re paying attention to in the present moment, to what gets stored in our short-term or working memory and ultimately into our long-term memory.

The premise of Information Processing Theory is that creating a long-term memory is something that happens in stages; first we perceive something through our sensory memory, which is everything we can see, hear, feel or taste in a given moment; our short-term memory is what we use to remember things for very short periods, like a phone number; and long-term memory is stored permanently in our brains which episodic memory is a category of.

Information Processing Theory Model

Information Processing Theory essentially compares the human brain to a computer. The ‘input’ is the information we give to the computer while the CPU is likened to our short-term memory, and the hard-drive is our long-term memory.

Our cognitive processes filter information, deciding what is important enough to ‘save’ from our sensory memory to our short-term memory, and ultimately to encode into our long-term memory.  Our cognitive processes include thinking, perception, remembering, recognition, logical reasoning, imagining, problem-solving, our sense of judgment, and planning.

The role of our short-term or working memory

Information is filtered from our sensory memory into our short-term or working memory. From there, we process the information further. Some of the information we hold in our short-term memory is discarded or filtered away once again, and a portion of it is encoded or stored in our long-term memory.

A number of factors impact how we process things in our working memory. These include our individual cognitive abilities, the amount of information we’re being asked to remember, how focused we’re able to be on a given day and how much of our attention we give to the information.

As you can see from the diagram our sensory and working memories have a limited capacity for storing memories. The term "Cognitive load" relates to the amount of information that working memory can hold at one time. Since working memory has a limited capacity, learning methods should avoid overloading it with additional activities that don't directly contribute to learning. So anything from distractions to trying to learn too much without taking breaks and looking after yourself is going to be detrimental here.

We also have the ability to focus on the information we deem to be most important or relevant. Then we use selective processing to bring our attention to those details in an effort to remember them for the future.

Repetition is a crucial factor here; if we want to transfer crucial information from our short-term memory into long-term storage, we must repeat it more than once and this is where active recall and spacing is so important. But as we know from my other videos in the learning series just remembering facts isn't necessarily going to help you to understand a topic or to effectively apply your knowledge so let's look at how memory relates to learning.

The Three Stages of Learning

In 1963 psychologist Artur Melton outlined three related, necessary stages in the learning and memory process: encoding, storage, and retrieval. Encoding is defined as the initial learning of information; storage refers to maintaining information over time; retrieval is the ability to access information when you need it. If you meet someone for the first time at a party, you need to encode their name while you associate that name with their face. Then you need to maintain the information over time. If you see that person a week later, you need to recognize their face and have it serve as a cue to retrieve their name. Any successful act of remembering requires that all three stages be intact. So let's look at encoding first.


Encoding refers to the initial experience of perceiving and processing information so that it can be stored in the brain. Think of encoding as kind of how the brain puts information into an package before it is stored and the package is then sent and unwrapped when we retrieve it.

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Now our brains encode information all the time and as we've seen our brains try and filter out any information that doesn't appear critical and we are selective about what we remember. As a quick example of this you might take the same train or car journey or walk into work everyday but it probably isn't that memorable unless something unusual happens. Equally events that are closely linked to a powerful sensory stimulus are more likely to be stored. For example most people remember natural disasters or a relative passing away or the birth of a child because they are anchored with strong emotional stimuli. In fact in Jordan Belfort's book The Wolf of Wallstreet one of his learning hacks for his sales team is to anchor the feeling of a successful sale into their memory using a powerful scent to help recall this feeling and their sales process ahead of their next sales call.

Psychologists have studied many encoding strategies that can be used during study to improve retention. First, research by Craik & Lockhart, 1972 advises that, as we study, we should think of the meaning of the events we are learning, and we should try to relate new events to information we already know. This helps us form associations that we can use to retrieve information later. This is also something outlined by Herman Ebbinghaus in his suggestions on how to disrupt the forgetting curve and this is why I talk about building context when applying active recall and why interleaving is so important to connect new content to your existing knowledge to aid recall.

Second, visualising information via memory devices like mnemonics also makes events more memorable; creating vivid images out of information can greatly improve later recall as highlighted by Bower & Reitman, 1972 in their paper on mnemonic usage in multilist learning. Creating imagery is part of the technique Simon Reinhard uses to remember huge numbers of digits, but even us non memory masters can all use images to encode information more effectively. The basic concept behind good encoding strategies is to form distinctive memories (ones that stand out since our brains filter things that don't stand out), and to form links or associations among memories to help later retrieval as suggested by Hunt & McDaniel, 1993.

Encoding—the initial registration and packaging of information—is essential in the learning and memory process. Unless an event is encoded, it will not be successfully remembered later. However, just because an event is encoded (even if it is encoded well), there’s no guarantee that it will be remembered later as there are two other key steps in how we learn - storage and retrieval.


Storage is all about how we store the package of information in our brains. When we encode a packet of information a neurobiological change happens in our brains between neurons and their synapses. These changes are termed engrams or memory traces by psychologists and neurobiologists. Memories have to be stored somewhere in the brain, so in order to do so, the brain biochemically alters itself and its neural tissue. Just like you might write yourself a note to remind you of something, the brain “writes” a memory trace, changing its own physical composition to do so. The basic idea is that events (occurrences in our environment) create engrams through a process called consolidation: the neural changes that occur after learning to create the memory trace of an experience. Memory consolidation is the process by which a temporary, short-term memory is transformed into a more stable, long-term memory.

So let's now move on to the final step in learning - retrieval.

Information Processing Theory Model


Psychologist Endel Tulving argued that “the key process in memory is retrieval”. So why should retrieval be given more prominence than encoding or storage? Well for one thing, if information were encoded and stored but could not be retrieved, it would be useless. We encode and store thousands of events—conversations, sights and sounds—every day, creating memory traces. However, we later access only a tiny portion of what we’ve taken in. Most of our memories will never be used—in the sense of being brought back to our mind, consciously. This fact seems so obvious that we rarely reflect on it but is is vital in the context of how we learn as if we learn passively without testing ourselves we'll forget. Our memory storage can't really be impacted but we can actively test ourselves and improve our ability to retrieve information which as we know from my other videos on active recall, the active process of retrieving memories from our brains strengths connections and is a more efficient way to to learn.

So what factors determine how well information can be retrieved from our memory? Well one critical factor is the type of hints, or cues, in the environment. When we encode or package up information as we know if that information is distinctive it will be easier for us to retrieve it. Think of our packages of encoded memories in a warehouse and only one is red or in more practical terms think about a scent evoking a memory without you even trying just like Jordan Belfort tried with his sales team.

Strategies For Improving Your Memory

To improve learning and memory, we need to encode information in conjunction with strong cues that will bring back the remembered information when we need it. But how do we do this? Well let's recall the two critical principles we have discussed: to maximize retrieval, we should construct meaningful cues that remind us of the original experience, and those cues should be distinctive and not associated with other memories. As Ebbinghaus says information should be relevant and well represented with mnemonics and memory cues.

So how can this information be used practically to combine the memory cues of encoding and the self-testing and repetition of active recall and spacing. Well the key is how you integrate mnemonic devices. If we think back to memory masters and how they are able to learn huge lists of numbers and facts they do it by making strong associations in their brain and ordering that information. Take for example the following list of numbers and items. By using rhyming words, a numbered order and visual images you can quickly learn and recall which word is associated with which number.

  1. is a bun.
  2. is a shoe.
  3. is a tree.
  4. is a door.
  5. is knives.
  6. is sticks.
  7. is heaven.
  8. is plate.
  9. is wine.
  10. is hen.

It would probably take you less than 10 minutes to learn this list and practice recalling it several times (remember to use active recall!). This mnemonic device is called the peg word technique as you would then have a set of peg words on which you could “hang” memories. So for example if you then had to remember an un-ordered list of random items like the points in a talk you are giving you could connect the things you are trying to remember to this list by making visual cues. So for example if the first bullet point in a speech you want to make is about your pet hamster you might visualise this in your mind next to a bun to make it standout and easy to remember. The more absurd the better.

Equally for things like medicine when you are learning long lists of information mnemonics like Two Zebras Borrowed My Car for the branches of the facial nerve are great ways to effectively encode and create retrieval cues as you learn and you are using active recall to test yourself on this mnemonic to ensure you know it.

How did Simon Reinhard remember those digits? Essentially he has a much more complex system based on these same principles. In his case, he uses “memory palaces” combined with huge sets of images for digits. For example, imagine mentally walking through the home where you grew up and identifying as many distinct areas and objects as possible. Simon has hundreds of such memory palaces that he uses. Next, for remembering digits, he has memorized a set of 10,000 images. Every four-digit number for him immediately brings forth a mental image. So, for example, 6187 might recall Michael Jackson. When Simon hears all the numbers coming at him, he places an image for every four digits into locations in his memory palace. He can do this at an incredibly rapid rate, faster than 4 digits per 4 seconds when they are flashed visually.

In addition to mnemonics here are four other quick ways to improve your ability to remember when learning anything:

Breaking up information into smaller parts: There’s only so much information we can take on board at once, our so called cognitive load, so when you’re learning you should move at an appropriate pace, giving yourself plenty of breaks and opportunities to process the information.

  • Make it meaningful: You're more likely to retain information that’s meaningful by connecting it to real-life scenarios, and to your own personal experiences so try and visualise and link concepts together as you test yourself.
  • Connect the dots: To optimize the chances of material being retained in long-term memory, you should ‘interleave’ the material, by providing sufficient background information and connecting the current topic to what was previously learned, and to what will be learned next.
  • Repeat, repeat, repeat: One of the simplest ways to encode new facts into long-term memory is to present it more than once. Repeating information in different formats – verbal, written, visual, tactile – is a great way of doing this (you might notice I've been doing this with lots of key concepts – and I'm repeating it here so that you retain it for the future!)

To summarise remembering things involves three related processes: encoding information, storing it and then retrieving it. The key to improving our ability to remember is to improve the processes of encoding and to use techniques that guarantee effective retrieval of information. Good encoding techniques include relating new information to what we already know, forming mental images, and creating associations among information that needs to be remembered. The key to good retrieval is developing effective cues that will lead you back to the encoded information and some of the best cues are sensory and distinct like a scent or strong feeling.

Learn How To Learn
Learn How To Learn helps your get top grades. While saving hours of studying every week.