A Framework and Agenda for Memory Improvement

Version 0.1.0, 2012-03-29

Motivation
My mind is like a murky lake. Along the shore are ropes leading into the water, and at the submerged end of each rope is a net. The ends I can see are questions life asks me that I need to answer from the contents of my mind, and the nets contain the answers I can provide. The ropes are of different lengths, and the nets are of different sizes. The big nets contain detailed and extensive answers, and the small ones contain little but ignorance. The short ropes lead to answers I know that I know and can pull to shore readily. The long ropes are the scary ones. Until the nets have emerged, I never truly know how long the ropes are or what will be at the end. Maybe the nets will have the answers I need; maybe they’ll be disappointingly, frighteningly lacking. Maybe the nets will reach the shore by the time I need the answers; maybe the ropes will be too long for the time I have to pull them. I don’t know how much information is in my mind to meet the needs of the moment or how long it will take to retrieve it.

All this would be fine, except that most of the things I like to do—synthesizing and discussing ideas, programming, being a resource of information for people—require a memory that is clear and reliable, if I want to do them well. And I do. Plus, I like the sense of clarity, awareness, and familiarity I get from knowing things about the world around me.

I’ve had this gripe against my mind for over a decade, and I’ve finally decided to do something about it. I’m studying memory improvement techniques. It’s turning out to be a much more complex topic than I expected, but at this point I’ve gotten far enough to shape my basic ideas on the subject and to form some goals. So to give myself a milestone and something to show for my work so far, I’m writing for you this summary. Since this is an interim report, I’ll continue to develop these ideas as the project progresses. The concepts, terms, organization, and agenda are all subject to change.

Overview
My project has a relatively narrow focus. Memory is a pervasive part of everything we do in everyday life, and there are several types of memory. But while it’s all important, I want to focus on ways to memorize information for long-term recall.

I’m partly aiming for a computer programming approach to human memory. Programming is an excellent grid through which to examine many areas of life, especially areas that involve problem solving or designing systems that will perform tasks intelligently. It’s helpful for these purposes because it involves breaking down a domain into parts, relating them logically, and performing operations on them to achieve specific goals. It’s concrete and practical.

Programming is especially good for dealing with human memory because computers have their own form of memory, and the tasks we need to perform with both types are largely the same. We need to store information, modify it, and retrieve it in various arrangements, though human memory certainly works differently from computer memory in some major ways. I’ll draw out these ideas as I go along.

My overall approach is to view memory as an interconnected set of components that can nevertheless be treated modularly so they can be assembled to solve a large variety of problems. I divide my analysis of memory into three parts: the basic components that are involved storing and retrieving information in memory, the basic skills of memorization that use these components, and the ways we can apply these skills to various memory tasks.

Components of Memory
By the components of memory, I mean the basic structures we create with information in the mind and the basic operations we perform to store and retrieve it.

Memory is a set of subsystems rather than a single structure in the brain {Higbee 2}, and each system handles a different type of information, such as visual or verbal {37-38}. It would be great if I could use the brain’s organization to lay out the principles of memory here. But I don’t know nearly enough about how memory is organized in the brain, and I’m not sure neuroscientists do either {Baddeley 11}. So I’ve attempted to come up with more of a functional framework for arranging the common memory principles and techniques. Most of psychology is about identifying the mind’s API, the things we do from the surface of the mind to achieve the effects we want, regardless of how the brain is doing things on the back end. Still, knowing the implementation can be useful, so I like to hear about the progress neuroscience is making on memory.

To memorize information for recall, you’ll need to transfer it from short-term to long-term memory. Short-term memory lasts only a few seconds and can contain only around seven items at a time. If the information in short-term memory goes through an encoding process, it’s stored in long-term memory and can potentially be accessed for a lifetime {Higbee 19, 20, 23}.

To make this transfer, you’ll need to put to work several factors. So far I’ve grouped them into three categories: description, significance, and maintenance. You’ll need to notice important characteristics and associations of the information, you’ll need to signal to yourself that the information is worth remembering, and you’ll need to keep your memory equipment in working order. The first two, which I’ll call the memorization components, relate to working with specific items of information, and the last relates to the overall operation of your brain’s memory systems. For this summary I’ll only discuss the memorization components, because I’ve done almost no research on the maintenance component, factors such as diet and rest.

Description
My view is that the mind stores information by indexing it according to its properties {50}, which amount to a description of the item. It retrieves information when it receives a reminder, which gives it one or more properties to search by. Memory researchers call the reminders cues {26}. A word, for example, is often recalled based on its first letter, its sound, or its meaning {30}. This is why you can often recall a word by reciting the alphabet, looking for the word’s first letter {100}. You can also see this property indexing at work when you remember the wrong word and find that it resembles the word you’re looking for in one or more of these ways.

Items
For the purposes of this project, an information item is any set of information you’re treating as a unit. It’s actually a stretchy concept. Our minds can almost always subdivide information into smaller pieces or group it into larger ones. Whatever you’re treating as a unit at the time is an item in that context. This expandability of information is a very important feature that makes it possible to create all kinds of useful associations for memory, as we’ll see later.

Some information is easier to think of as a single, simple unit, such as the translation of a single English word into another language, and some is easier to think of as a group of smaller items, such as a grocery list or a whole chapter of a book. I’ll call the simple items unitary items and the groups collective items. Since pretty much any information can be subdivided, it’s technically all collective. But these categories are meant to help you in memorizing. Hence, the way you categorize any particular item is somewhat subjective and relative to your purpose for it at the time. I’ll explore the ways these categories can help you later in the essay.

What kinds of information items are there? An item can be something more like an object or something more like a sentence, and really you could look at any item as one or the other. So you might memorize the flag of each country and treat each flag as an object, but in the back of your mind, you’re also memorizing a statement that goes something like, “The flag of Algeria looks like this.”

Properties
A property of an item of information is anything you can say about it. Really it’s just another piece of information that’s somehow related to the item you’re dealing with. In fact, I think of an item of information as being completely made of its properties. An information item is a set of information that someone has bundled into a package and maybe given a label, which is just another one of its properties. For the purposes of memory, there are at least a couple of ways to look at properties. You can think of a property as a handle for an information item that the mind can grab when it’s looking for the item. And you can also think of properties as parts of the item that you can then focus on as items in themselves.

I also like to think of properties as RDF triples. That is, a property can be stated in terms of three parts: a subject, a predicate, and an object. For example, one property of tree bark is that it’s rough. That is, it has a texture of roughness. “Tree bark” is the subject, “has a texture of” is the predicate, and “roughness” is the object. Splitting up a property in this way can help you think about enhancing and organizing the material you’re studying, which I’ll cover below.

I divide properties into a few somewhat fuzzy categories to help me get a handle on them. One division is between internal and external properties. An internal property is any characteristic that the item has on its own. I’ll call internal properties features. An external property is any connection it has with other information. I’ll call the external properties connections. If I’m looking at a tree, one of its internal properties is that it has green leaves. An external property might be another tree it reminds me of.

Another division I make is between natural and incidental properties. Natural properties are related to the item’s meaning, and incidental properties are any other kind. For example, a natural internal property of the word horse would be its definition in a dictionary or an image of a horse. An incidental internal property would be the way the word looks in a particular font. A natural external property would be the fact that a jockey rides a horse. An incidental external property would be the fact that horse and helicopter start with the same letter. The fact that an item’s storable properties can stray so far from its typical meaning becomes very useful when you’re memorizing information that has very little significance to you or that has no logical structure, such as a list of random words. Memory researchers call these incidental external properties elaborations {Higbee 94}. We will see this feature of memory come into play when we discuss mnemonics.

Storage
I also divide memory storage activity into two categories, active and passive. These categories apply to both description and the other memorization component, significance. Even without consciously trying, your mind engages in memorizing all the time. For example, people tend to remember where they were when a national tragedy took place. It might not always be the memorizing you expect or need, but you can take advantage of this passive activity and use it to supplement your conscious memorizing.

Retrieval
As I mentioned above, the mind retrieves information when it receives a reminder, called a cue. A cue is anything that either reminds you there’s something you need to remember or simply reminds you of something you do remember. It’s like a question for you to answer or a sentence with a blank to fill in. It provides you with some of the properties of the information and leaves you to find the rest of the item.

As with everything else, I divide retrieval of information into several categories. First, like storage, retrieval can happen passively or actively. I’ve observed that cues tend to happen in chains—one thing reminds you of another, which reminds you of another, and so on—and the chains tend to start with cues from your surroundings. The cues that bring up information from your mind without any effort from you are triggering passive retrieval. When the cues remind you of your need or desire to remember something and then you search your mind for the information, you give yourself a series of cues that could trigger your recall, and this search is a process of active retrieval. These cues can be either parallel or chained. That is, the cues may be independent of each other, or each cue may remind you of the next.

It can also happen at different levels of consciousness. Explicit learning is retrieval with a conscious awareness that you’ve recalled something. Implicit learning is retrieval that happens unconsciously; you simply act on the information you’ve retrieved without being aware that you’ve retrieved anything {Baddeley 21}.

And retrieval can happen more or less completely. Recall is the fullest level of retrieval, in which the whole item or set of information is brought to mind with only a starting cue. Recognition is less complete and more or less amounts to identifying the information you’re viewing as information you’ve seen before. Rate of relearning measures a subtle level of retrieval, in which you’re able to relearn information you’ve learned before in less time than you took to learn it at first. Your mind retains traces of the material from the first learning effort, so it doesn’t have to do as much work to learn it to the level of recall again {Higbee 26-27}.

In this project, as I’ve said, I’ll be focusing on conscious storage for recall.

Memory researchers have terms for several patterns of recall. When recall happens because it has been intentionally cued, they call it aided recall. Recall that happens in any order and without a specific external cue is termed free-recall {26}. Recall seems to be easier when it’s aided {100}, so it’s best to concentrate on memorizing specific properties of an item so they can reliably serve as cues. Most of my project will concern this strategy.

When you recall items in a specific order, memory researchers call it sequential learning. When one item cues your recall of a second, they call it paired-associate learning {26}. Most of the memory techniques I’ve seen amount to different forms of aided recall using paired-associate learning. Even sequential learning can be reduced to a series of paired-associate tasks, where each item is the cue for the next in the list {133}.

Interference
A persistent problem for memory is what memory researchers call interference, the problem of confusing parts of something you’ve learned with parts of something else you learned before or after it {34}. This is different from the problem of strong emotions blocking your ability to learn or recall things, which I talk about in the “External emotional significance” section below. That could be seen as another type of interference, but memory researchers don’t call it that.

To combat interference, each item you memorize needs to be unique in a memorable way. That is, it needs to have a unique set of properties. You can think of the items of information as being assigned unique addresses in your memory. The address is made of the item’s unique combination of properties. If two items aren’t meant to live at the same address, assign them different enough sets of properties that they’ll stay separate in your mind. Part of this memory improvement project will be to come up with ways to do that.

Significance
The second major aspect of memorization I identify is significance. For the mind to memorize something, it has to believe that it’s worth remembering. Here are some of the ways that can happen. Again, I’ve grouped them so they’re easier to remember. My categories for significance are familiarity, emotion, expression, timing, and interaction.

Some of the categories from the description discussion apply to various aspects of significance as well—passive and active, internal and external. I’ll expand on them in the sections that follow.

An item can gain significance as you discover its properties, such as other items that connect to it. For example, a man’s name may mean nothing to you and be quite forgettable until you learn he’s a brother you never knew you had. This ability of one item to elevate the significance of other items will be very important for the memory techniques I discuss later.

Familiarity
One obvious type of familiarity is knowledge. Information you’ve learned before is generally more significant to you than new information. This is important for two reasons. First, if you’ve already learned an item but you don’t remember it well, it will still be easier to learn than information you’ve never seen before {27}. Second, as we’ll see in the observation section, you can use more significant information, such as items you’ve already learned, to increase the significance of other information you’re learning {47}.

A different type of familiarity that carries significance is sense. That is, information you can understand is usually more memorable than nonsense. I think of sense as a type of familiarity in that you understand a piece of information when it conforms to your existing, familiar patterns of thought as well as connecting with your prior knowledge.

Emotion
Emotion can lend great significance to information, making it easy to remember, though in some cases emotion can be a hindrance to memory.

The emotion involved doesn’t need to be intense for it to help memory. In fact, it can be very slight. It just needs to be enough to make the material stand out as important in some way. Emotion that’s too intense may distort your understanding of the information anyway.

Internal emotional significance
In terms of emotion, I define internal significance as significance that is derived from the item’s properties.

Internal emotional significance means that the item has properties that catch your attention. The information could be funny, surprising, fascinating, outrageous, impressive, disgusting, frightening, exciting, sensible, or touching, for example. Any property of the information—internal or external, natural or incidental, passive or active—can have significance that aids in remembering that information.

Uniqueness, or novelty, while most important for separating similar information, also adds an element of significance to the information, if the item is unique in some way that feels significant {107}. It carries a sense of specialness: This item is worth paying attention to because it is one of a kind.

On a subtler level, simply having a purpose can make an item more significant, even if it gets its purpose simply from being placed in a list or given a name. These features convey the sense that the item is supposed to be there.

Internal emotional significance can be active or passive. Passive significance is reflected in the simple experience of emotionally reacting to the information you’re studying. The information is the type that is already important to you. Hence, I call this kind of significance reaction. Again, it doesn’t have to be a strong reaction, just a distinct one. A reaction doesn’t necessarily cement the details in your mind, so you may need to supplement your reaction with specific memorizing techniques, but it makes a difference.

Taking the right attitude toward the material you’re learning is one example of active internal emotional significance. That is, you purposely see the information as significant. To do this, you take an interest in what you’re learning. You look for ways the information could be interesting or important or cause some other reaction in you, whether through the information’s features or connections, even though those ways aren’t obvious to you at first.

External emotional significance
I define external emotional significance as significance that the learner imposes on the information, whether actively or passively, because of the way the learner is feeling apart from the information itself. I haven’t explored this topic very far, and the books I’ve read don’t really cover it, so I’ll just mention it briefly.

On the passive side, strong emotions, such as during a traumatic experience, can cement even random facts into your mind. In addition, events that happen directly in relation to the material you’re learning will often lend them significance. For example, the embarrassment of getting an answer wrong in front of other people makes the right information feel very important, and afterward it tends to stick in the mind!

Similarly, the shift from confusion to understanding can give an item significance. Once an incomprehensible item makes sense, the feelings of relief and inspiration you get from finally understanding it can make it more significant.

Necessity is another factor that can catch your attention. If the information is simple enough, knowing you need to know it can make it more memorable. Unless the necessity comes with a lot of stress, that is. Stress works against memory, which I discuss below.

On the active side, you may be able to set an emotional tone for your study time via music, narrative, or some other form of art, and as you interpret the information by that mood, you may see new properties of it pop out as significant.

But emotion also can hinder learning. In particular, stress works against both memorizing and recalling things {64-66}. I believe this is partly because stress and other strong emotions draw your attention away from what you’re learning and recalling, but I suspect there are other processes at work as well. My experience is that the mind can lock up under stress {Gladwell}.

Expression
The mind has several ways of taking in and processing information: visual, verbal, musical, narrative, kinesthetic. I’ll call them modes of expression. Some of these types of information are more memorable than others. It differs from person to person, but there are some trends. Visual information, for example, especially spatial, tends to be very easy for most people to remember {Higbee 37-39}.

Timing
I’ve encountered a few observations related to the timing of memory storage and retrieval relative to other things. I’ll probably try to generalize these later.

You remember items in a list more or less easily depending on their position in the list {53}.

You remember better things you learn just before sleeping and less well things you learn right after sleeping {44}.

Most forgetting happens soon after learning. The rate slows down and levels off after that {35}.

Interaction
Your interaction with the material over time, even without any notable emotion, can lend the material significance.

Attention
Paying attention to the material you’re learning is one of the most basic and important ways of creating significance for it. Of course, you have to pay attention in order to notice things about the information and build up its properties in your mind {59}, but attention also clues your mind in that the information is important. This goes for any active part of memorization.

Repetition
I define repetition as repeated storage of an item in memory. Memory researchers know that spaced repetition is a key factor of learning {78-80}. I don’t know how it works out neurologically, but my interpretation is that being exposed to the same information repeatedly over a long period of time clues the mind in that it’s important.

Many people think this type of repetition is what memorizing is. Reading over the information a few times is their only technique. But by itself, it’s really a very flimsy one, and we have many more resources at our disposal for planting information firmly in our minds {62}, which of course are the subject of this project.

Recitation
I define recitation as repeated retrieval of an item from memory. It seems to me that forcing yourself to recall information using spaced repetition is even more effective than simply exposing yourself to the information {83}. This is why flashcards are an effective study tool.

Memory skills
We can make use of these memorization components by exercising various skills. I don’t think I’ll have a real grasp on this section until I’ve experimented much more with different learning techniques. But I’ve grouped the skills I’ve found so far into several interrelated categories that loosely form a sequence: focusing, observing, selecting, enhancing, organizing, associating, rehearsing, and searching. The first of these is a general skill, the next several are storage skills, and the last is a retrieval skill. To memorize for long-term recall, you need to corral your attention, ask yourself questions about the information, pick out the information you need to know and the other information that will help you remember it, get the information into an easily memorizable form, arrange it all so you can easily link the information together, mentally form the connections, cement the connections over time, and then search your mind for the information when it’s time to recall it. In reality when studying various types of material for different purposes, you’ll mix these skills together rather than following them in a set sequence.

Focusing
Attention is a fundamental requirement both for active memorizing and for retrieval. So the first set of skills you’ll want to employ are those that focus the attention. The goal with these practices is to remove external and internal distractions.

For external distractions, you’ll need to find a place and time that will keep you away from them. Find a quiet spot in the house, turn off the TV, go to the library, whatever circumstances you find the least distracting. You may have to observe yourself for a while and experiment with different setups. I like to sit in my car in a parking lot when I’m doing work that requires concentration.

For internal distractions, you’ll need to settle or temporarily put aside disruptive thoughts and emotions. As I mentioned above, strong emotion, especially stress, can be a distraction from learning. So it pays to learn to relax and to remove stressors from your life. Relaxation techniques such as deep breathing exercises can go a long way to calm intrusive emotions.

For thoughts that pull you away from the task at hand, it helps to write them down or tell them to someone, at least in summary form. That gives the part of your mind that’s concerned about them the assurance that you’ve given those thoughts some of the attention they deserve and that you’ll deal with them later, even if you haven’t completely resolved them now.

And if you’re feeling worried about your memory’s performance when it’s time for recall, then the answer is to build your confidence. Your general confidence in your memory will grow as you practice the skills over time, especially when memorizing isn’t crucial. Then when you need to memorize something and the stakes are higher, studying to the extent that you overlearn the material will build your confidence that you know it, which will reduce your stress when it comes time to recall it {64-66}.

Even if potential distractions are nearby, you may also find certain physical conditions for your study session that put you in a frame of mind for concentrating, such as playing certain kinds of music or simply sitting at a desk or in a room that over time you’ve associated with focused work {69}.

In addition to removing distractions, you can help yourself focus by your attitude—gaining an interest in the material you’re learning. This has the added benefit of making the material more significant, which will make it easier to remember {70-71}.

You can do a number of things to create interest while studying, which I’ll talk about below. But it can help to start the study session by reminding yourself of the reasons focus and interest are important. And if you can find reasons that are actually important to you personally and not simply reasons other people have for learning, that will be more convincing to you.

Observing
The rest of the skills relate to working with the specific information you’re memorizing.

Observation is the skill of directing the attention to the specifics of what you’re learning, now that you’ve focused that attention. It’s the skill of noticing an item’s properties, both internal and external (its features and connections). These are the handles you’ll use to retrieve the information, and the main purpose of observation is to prepare the material you’re learning for planting in your mind via association and rehearsal.

For this skill, keep in mind that I’m using the word item flexibly. An item can be anything from a single word to a whole book, to use a verbal example. An item can be subdivided into other items so you can concentrate on memorizing them separately, or it can be combined with other items to form a new whole, a process I’ll cover in the association section below. Before an item is subdivided, you can think of its sub-items as some of its properties.

One good way to direct your attention is to ask yourself questions. A question is a type of cue. It gives you a set of properties and prompts you to find the item that matches them and to answer with a label that represents the item. The difference between an observation question and a recall cue is that when you’re observing, you’re looking for items in the material you’re studying as well as in your mind.

Since observation plays a part in several of the other memorization skills, questions are a tool that will appear in several of the following sections.

Selecting
The most straightforward task related to observation is what I’ll call selection. This is the skill of identifying which information is worth noticing.

Two other questions will help you discover which information that is. First, what do you need to know from this set of information? Or coming at it from the other side, what cues do you expect to receive for recalling the information? And second, what information will help you remember it? The answer to this one encompasses at least two types of information. One type is information that’s significant to you, since we can use that to raise the significance of less memorable information. The other type is information that may be in your mind at the time you need to remember the item, such as another item you’ve just recalled. This information can act as a cue if you’ve associated it with the item in question.

These two types of information worth noticing are another example of an internal-external division. The cues (which tell you what you need to know) indicate what information is important to your circumstances (which are external to you), and significance indicates what information is important to your mind (which is internal to you). Of course, the same information may be important to both. I’ll call the cue-based information important information and the significance-based information memorable information.

Important information
Two main reasons for observing properties that are related to your expected cues are, first, to make sure you cover everything you need to learn and, second, to decrease your mental load by ruling out the things you don’t.

A first natural question is what your expected cues are. That is, what do you expect to encounter that will prompt you to recall this information?

If the cues aren’t immediately obvious, try approaching the answer by asking yourself what context you’ll be in when you need to recall the information, such as an exam, a meeting, a party, or traveling. In an exam, the cues will be the test questions. In a meeting, they might be questions posed by the other attendees or simply the invitation to begin giving a presentation. At a party, they could be the greetings of the other guests, which would prompt you to recall their names and other information about them. While traveling, the cues might be landmarks, which would prompt you to recall the need to turn, stop, or look for the next landmark.

Once you know the recall context and the types of cues you’ll encounter, you can imagine yourself in that context and begin to list the specific cues you expect to find. For example, who specifically will be at the party? What questions will likely be on the exam? What will the people in the meeting want to know?

And once you have the specific cues, you can observe the responses to them that are available in the information you’re studying.

Memorable information
You will naturally react to much of the information you encounter. This information is already memorable to you, and you probably won’t have trouble remembering at least the gist. The skill is to notice these reactions when they happen so you can take advantage of them to add significance to the rest of the information. You can observe your reactions as you view each item for the first time, asking yourself how you’re reacting to this item, or you can review your reactions after you’ve seen all the material, asking yourself which items you recall reacting to.

Observing your reactions is useful because if you can draw your attention to information that’s significant to you, you’re more likely to recall it when you’re looking for ways to make the other information more memorable.

Enhancing
For the material that doesn’t seem very memorable, you’ll need to associate it with other information that is memorable or with information that draws out its significant aspects. The actual association will come later. First you need to pick out the specific memorable information to associate the forgettable item with. Since this skill involves expanding on each item in various ways and since elaboration is already taken, I’m calling it enhancement. I call the items that will make the item in question more memorable helper items.

When you’re looking for helper items, first tell yourself that there is something interesting about the information, even if you can’t see it yet. Then with that attitude in mind, do some more observing. Sharpen your observation of the information’s features and expand your awareness of its connections. You can do this by asking more questions: How does this information make sense? Understanding is typically an important first step in committing an item to memory. What interests other people about this information {72}? Assume they have a good reason! Why was this information included? Assume it has a real point! How does it relate to other items in the material? It may help to think in terms of relations like causation, implication, similarity, and contrast. What does the information remind you of that’s already familiar to you {53}? This question will be important again when you’re using the skill of translation, which I’ll describe in a later section.

The answers to most of these questions don’t have to make sense. Certainly you should try to understand the material’s actual meaning. But the mind can invent connections that are significant without being logical {94}. Bizarre juxtapositions tend to be memorable, for example {107}. To use our terminology from earlier, an item’s properties can be natural or incidental, so feel free to take advantage of both.

Translating
One important type of enhancement is translation, creating an item that you intentionally view as equivalent to the original item. You can think of translation in terms of the RDF triples I mentioned earlier. An item can be linked to its properties via different relationships. These are the predicates of the triples. The causation, implication, similarity, and contrast from the enhancement questions above are some possible relationships. Equivalence is another one. In this relationship, the property specifies another item, a substitute item, that stands for the one you’re studying {109}, which I’ll call the target item. In identifying this property, you’re translating the item you’re learning into the substitute item. If the substitute item is very memorable and it cues you to remember the original item, then it makes the original item easier to access in your memory. This is the idea behind many mnemonic techniques and systems.

What kinds of items would you need a substitute for? Generally, any item that you expect not to be memorable, anything that seems boring or meaningless to you. More specifically, researchers have found that most people have a harder time remembering words than images, and abstract words such as timeless tend to be harder to remember than concrete words such as apple {38, 57}. People also find proper names hard to remember {192}, even though names are concrete in a way, since they usually represent people and physical objects.

What kinds of substitutes are helpful? A substitute should have at least two characteristics. First, it should have some kind of connection to the target item that makes sense to you. That is, it should share some properties with the target item that are significant to you. For example, you could choose a substitute that sounds similar to the words of the target item, such as substituting celery for salary. Or you could choose a substitute that symbolizes the target, such as imagining a set of balancing scales for the term justice {109}. It’s important for the connection to be meaningful. If you choose a completely arbitrary substitute with no meaningful connection, it will be hard to remember the connection, and the substitute won’t be able to act as a handle very well. Or if you memorize that meaningless connection well and then you run across a target item that the substitute would work much better for, you might confuse the new target with the old one when you’re using the substitute for recall. It’s not important for the connection to be meaningful to everyone, only to you, unless you want the substitute to make it easy for everyone to memorize the item.

The second characteristic of a substitute is that it should represent the target item uniquely. If you choose a substitute that could be tied to a lot of different items, it might be hard to remember which item you need at the time. For example, if you’re memorizing the word frozen yogurt and you picture a bowl of it, you might accidentally recall the word ice cream if you don’t encode more carefully while you’re learning it {119}.

The substitute isn’t meant to be a definition of the target item, only a cue. Its relationship to the target item can be purely incidental. It’s only a handle for pulling the information into your conscious mind. Once it’s there, you can put the substitute out of your mind for the moment and think about the target information normally. This approach lets the substitute do its job of adding significance to meaningless information while keeping the substitute from getting in the way of using the target information itself.

The substitute item will often be in another mode of expression from the original item. It can be helpful to augment your learning by translating the information into the most memorable modes for you and even into multiple modes. Most mnemonic systems are based on translating verbal information into mental images {103}. And in addition to visualizing the information, you might also want to vocalize it, speaking the items out loud.

I often struggle to find a substitute word as quickly as I need in order to memorize things on the fly. I would like to get better at this. It would help to memorize a lot of substitute words beforehand so I don’t have to be creative in the moment when I’m frantically trying to memorize the material in front of me. I want to write a program to create a dictionary of substitute words and phrases for names and common words. I also want to identify commonly used elements, such as days of the week and family relationships, that I can make a special effort to memorize.

You can also take a poetic or musical approach, giving the material a rhythm, making it rhyme {111}, setting it to music, or all three. And if you can, perform this poetry or music for yourself out loud so that your mind can more fully encode the experience.

Since most mnemonic systems take a visual approach and not everyone is visual {118}, I would like to find or develop a system along these auditory lines. The things I’d have to collect would be common rhyming words to translate harder words into, rhymes for commonly needed words, common poetic meters, and familiar melodies. The musical system could also use different aspects of music to encode things, like intervals, chords, keys, time signatures, and key signatures, if those things would be memorable. It would be good to see research about that.

I would also like to explore a kinesthetic approach to memorization, though I’m not sure what it would look like, maybe creating actions that you associate with the information and arranging the actions into sequences to represent the relationships between the items. Sign language might be helpful here.

Organizing
The purpose of organizing is to bring together items that will help you remember more of the material. As I said in the selecting section, if you’re memorizing a set of information, you’ll often want each piece of information to remind you of other information in the set. You’ll also want more significant items to prop up the less significant ones. Thus, it helps to see them close together so you can easily associate them later.

One type of organization is to group the items. If the items are related logically and you’re free to rearrange them, then you can group the information by category {51}. This gives you a chance to associate the category with all the items within it. Restating pairs of items as RDF triples could reveal categories you can group the information into, if the RDF idea helps you. Another type of organization is to arrange the items in a logical sequence, which lets you associate each item with the next in the sequence {133}.

As you’re organizing, there are at least two other general questions to keep in mind. One is which item you should remember first when recalling a set of items {135}. And the other is how you’ll know when you’ve recalled everything you need from the set. To answer the second question, you can observe the total number of items in the group, or if they form a list, the last item in the list. Once you’ve recalled that number of items or that last item, you’ll know you’re done {133}.

Associating
Association is the skill of mentally assigning properties to an item. Or to say it another way, it’s cementing multiple items together in your mind. You can associate as many items as you want, but for simplicity we’ll assume it’s two. You can associate the information actively or take advantage of the passive associating your mind is already doing.

Active association
As I understand it, the way to associate two pieces of information is to create a new whole that incorporates both of them. The new whole, of course, is another item with its own set of properties. You’d think this would just give you more to study and take up more time. The goal, though, is to create associations that are memorable enough that you won’t need to spend much time studying them {166, 180}.

There are several types of wholes you can form through association. If you’re visualizing the items, the new whole could be a scene in your imagination that features the two items interacting {104-105}. If the information is purely verbal, it could be a sentence or rhyme that incorporates them {111}. Another type of whole is a sequence of events that the mind groups together. I place classical and operant conditioning in this category. Pavlov rang a bell and then fed his canine subjects, so later when he rang the bell again, the dogs expected food.

Simply grouping the items can tie them together, at least in short-term memory. If you’re memorizing a series of digits, such as a telephone number, then grouping them into chunks of two or three can keep them in your short-term memory longer. Memory researchers call this practice chunking {20}.

Chunking can also let you create more complicated associations. You can chunk items together that you have associated with other items. For example, an acronym is a chunk of letters—a word—whose letters represent other words. Once you remember the word, you can break it down into its letters and remember the other words the acronym is associated with {98}.

One effective visual way to establish associations in your mind is to group the information spatially. Group the items you’re associating into different regions of a page or some other surface. Along these lines, you could create a map that relates the items to each other in some way, using geography as a metaphor if the information isn’t geographical. Grouping the items physically is effective because the mind remembers at least basic spatial relationships very easily {150-152}.

Another mode of expression that serves in association is storytelling. Humans are narrative beings. We naturally think in terms of coherent sequences of events, and we care about them, especially when they have to do with us. So one type of association that can add significance to the material you’re learning is telling a story that incorporates it {135}, especially a story that relates to your life. It doesn’t have to be realistic, just memorable.

Passive association
Even without consciously trying, your mind associates things all the time. You can take advantage of passive association by controlling the context in which you learn things.

In particular, your mind associates things in your environment with things you’re doing. So if you’re studying for a test, it can help to study in the room you’ll take the test in. The features of the room may remind you of the information you studied there. The same goes for when you’re rehearsing for a performance {67-68}. And as usual, your mind isn’t picky about whether the associations make sense. Most of these associations will probably be for incidental rather than natural properties.

Since interference is always a problem, it helps to memorize different pieces of information in different settings, whether different locations entirely different parts of the place in which you’ll be recalling the information {76-77}. That way, if you remember where you were when you learned that thing you’re trying to recall, there’s a chance something about that setting will cue your recall of the information.

Making use of passive association is easiest to do with your external context—where you are—but it also includes your internal context—what state of mind you’re in. It also helps to try to learn the material in the same mental condition in which you’ll recall it (the same mood, for example). So if you’re going to be sober when you take a test, don’t be drunk while you’re studying for it {69}.

Rehearsing
Even the most memorable information will fade over time and become hard to recall if left alone. So in addition to enhancing and associating the information, you need to rehearse it. Rehearsal can take the form of both repetition and recitation, but recitation will cement the information in your mind more quickly.

You can rehearse through recitation in a number of ways, such as using flashcards or having another person quiz you. But the basic procedure is to present yourself with a cue and then take a few seconds to try to recall the corresponding items. Then receive feedback on your result. If you were able to recall something, check the answer to see if you were right.

If your recall was wrong or you couldn’t recall the item at all, use the feedback as a way to repeat your mental storage of the information, maybe looking for a new way to enhance it. Then cue yourself for the information again later. Feedback both lets you assess your knowledge and sustains your interest in the material {72-73}.

Forgetting takes a certain shape over time. You forget most of what you learn right after you’ve seen it for the first time. After that the rate at which you forget the material slows down and levels off {35}. So your first study session should be a review of the material right after you first encounter it {89}.

Learning also takes a certain shape over time. Your study sessions for the material should be frequent at first, but you can space them out more and more as your recall of the material becomes easier {89-90}. There are several algorithms for this kind of spaced repetition that can help you schedule your learning, such as the Leitner system.

Searching
The mind stores information by indexing it by its properties. These properties are handles you can grab to retrieve the information as you search your mind for it based on those properties. So when you want to recall something and it’s not coming to mind right away, you can try to find it by suggesting properties to yourself that the information might have and seeing if the suggestion brings the information to the surface. Try to think of as many related types of information as you can, and one or more may trigger the memory. For example, if you enter a room and don’t remember why, look around the room in case your purpose was related to any of the objects in it, retrace your steps in case your previous locations gave you a reason to enter the room, and remember what you were talking or thinking about {Higbee 211}. Kenneth Higbee calls this the “think around it” technique {55-56}.

Applications
The components of memory I’ve discussed can be put together and applied to various problems that require memorization. Programmers sometimes write cookbooks that contain example code. The examples solve common problems in a particular language that don’t have immediately obvious solutions. Using the elements of memory in the above analysis as a rudimentary mental programming language, I’d like to do the same for common memory tasks. These applications can be built up in layers, with simpler applications becoming components in more complex ones. I’m organizing this section around tasks rather than the techniques that accomplish them, because each task can encompass a number of techniques. Since this essay is a summary and I haven’t thought very far about most of these applications, I’ll only cover them briefly here.

Holistic information
This category includes memorizing text, images, concepts, and music. With this type of information, it doesn’t work well to break it into a list of small components and then string them together with a series of associations, as in the mnemonic systems below. You have to recall it rapidly and fluidly, sometimes even nonlinearly, so it needs to be stored efficiently as a whole unit. You can think of it as assigning a single value, such as a string, to a variable.

One good tool for rehearsing text is the erasure method, where several words are erased at random from the text before each repetition. This allows the surrounding words to serve as cues for a word that’s been erased.

Dates and times
One useful element to encode mnemonically is dates and times. This gives you a way to timestamp your memories, plans, and any other time-specific information. It would be an essential component of any mental task management system. The technique I have in mind would be to encode each component you needed (day, month, year, hour, minute, etc.), and then associate them all together. Then associate the whole clump with whatever information you want to timestamp.

Names and faces
Remembering names and faces is a very popular use for memory techniques {Higbee 194}. People are very important, but names by themselves are fairly meaningless, and faces can often look alike to the untrained eye. The techniques for remembering them are apparently the same from book to book. The idea is to find a visualizable substitute word for the name and associate it with a distinguishing feature of the face {194-198}. But I have my own spin on the details, and maybe some of the books take this approach too. It can be hard to recognize a distinguishing feature unless you know what the nondescript version would look like {Redman 1-2}, and it’s also harder to identify features when you don’t have a vocabulary for them {Higbee 191}. So I’d like to try using the techniques of caricature artists and, if I’m feeling really enthusiastic, the vocabulary of forensic artists {George chapter 1} to locate and name what’s unique about a person’s face. One benefit of having a technical vocabulary is that you can use substitute words for those terms and associate them with the substitute word for the person’s name. If you’re not very visual, this could be a helpful technique.

Experiences
There are a number of reasons you might want to remember your experiences in detail. For example, you might want to relive your good memories, which can happen more vividly if you remember more about them. It also gives you a better story to tell. If you’re giving eyewitness testimony, you can provide a better account. And if you’re learning a skill, remembering your mistakes and successes with the skill is important.

Probably some of the important factors in remembering experiences are knowing in advance what kinds of things to observe in your experiences, having a reliable way to represent sequence relations to yourself (i.e., this event followed that event), and developing the habit of reviewing the experience right after it happens.

Complex sets of information
This is often a facet of studying for a school or certification exam, but complex information shows up other places too. Many people’s jobs involve knowing complex webs of facts and concepts. What are the best ways to organize and memorize these webs?

Mnemonic systems
A mnemonic (pronounced without the first m) is any method for aiding the memory, though most researchers define it more narrowly in terms of elaborations, aids that rely on what I’ve called incidental external properties. Kenneth Higbee helpfully distinguishes between single-purpose mnemonics, which he calls mnemonic techniques and general-purpose ones, which he calls mnemonic systems {Higbee 94-95}. An example of a single-purpose mnemonic is using the acronym HOMES to remember the Great Lakes: Huron, Ontario, Michigan, Erie, and Superior {98}. Much of this essay has dealt with the principles that seem to lie behind both types of mnemonics. In this section I’ll talk about mnemonic systems.

Memory specialists describe a number of mnemonic systems you can use to memorize certain kinds of lists. Higbee includes five mnemonic systems in Your Memory: Link, Story, Loci, Peg, and Phonetic. The Link system involves visualizing each item of a list and associating that item with the next item in the list {133}. The Story system involves creating a story that incorporates each item in sequence {135}. The Loci system involves memorizing a series of familiar locations, such as the rooms of your home, and then visually associating each item of a list with one of those locations {145}. The Peg system involves memorizing substitutes for a set of numbers or letters and then visually associating each list item with the corresponding number or letter substitute in sequence {157-161}. The Phonetic system involves memorizing a set of consonant sounds for each digit (0-9), translating any numbers you’re memorizing into the consonant sounds of their digits, adding vowel sounds to create words, and, if the numbers are meant to give order to a list, visually associating each list item with the word representing its number in the sequence {173-178}.

One aspect of memorizing complex information is to mnemonically create data structures in your mind, the kinds of data structures that are fundamental to programming. Higbee’s five systems fall under the categories of linked lists (Link, Story) and arrays (Loci, Peg, Phonetic). But there are other data structures: stacks, queues, multidimensional arrays, hash tables, heaps, graphs, weighted graphs, and various trees (binary, red-black, 2-3-4) {Lafore}. We can find ways to organize and associate information to mentally build these and any others we need.

The key to creating these mental data structures and inventing others is to break them down into sets of key-value pairs. To memorize the pairs, you associate the key with the value using the techniques from the association section above.

Even a simple scalar variable is a variable name paired with the value assigned to it. The set of variables in a running program can be thought of as a hash table with the variable names as the keys. And you can think of an array as a hash table with the index numbers as the keys.

If you’re using the data structure in a larger context and you might confuse its items with data from another structure, you could encode the keys using a different method or category (such as using animals for one variable’s keys and plants for another’s), or you could include the variable name with each key. So if you’re using a visual mnemonic technique, you’d create one image that incorporates your substitute images for the variable name, the key, and the value.

This last technique treats the key as an address for the value. The value lives at key X within variable Y. You can extend this technique to account for data structures with several levels, such as trees or multidimensional arrays. This approach also treats the data structure like a database table with a primary key made up of several fields.

In addition to creating the data structures themselves, it’s important to know basic algorithms for inserting, deleting, sorting, and searching for items in them, so I’d like to develop mental versions of those tasks too.

Rehearsal
Another aspect of memorizing complex information is to drill yourself, such as with with flashcards, which are an easy way to take advantage of spaced repetition. People normally use flashcards to study binary facts, such as sets of foreign vocabulary words. But as we’ve seen, key-value pairs can represent most types of information. This includes the points in an outline, the relationships in a concept map, or the cells in a table. So you could conceivably use flashcards to memorize these types of charts as well. I’d like to program a tool that will convert things like outlines and tables into flashcards.

Studying for an exam
My first motivation for learning about memory was to study more effectively for tests and not worry that I didn’t know the material. Studying effectively turns out to be a complex process of planning your study time and place, taking on the right attitude, organizing the material, and using effective memory techniques. Some type of chart would be helpful in making decisions about these steps.

Task management
My latest motivation for learning about memory has been to supplement the productivity system David Allen describes in his book Getting Things Done (often abbreviated GTD). Allen emphasizes recording your tasks in an external system, such as a planner, that is organized by context, because you can’t rely on your mind to remember everything you need to do when you’re in the right time and place for doing it {Allen 16, 21-23}. I think that the way GTD brings together the concepts of context, next actions, and horizons of focus is brilliant and very effective for helping to stay on top of one’s internal and external commitments. I also agree that an external system is easier to rely on than the mind. But is it really true that the mind is useless as a task manager? I think that using memory techniques creatively, it’s possible to do GTD mentally. For example, you could create a substitute item for each context and associate it with your list of next actions for that context, which you could memorize using the Link system. But at the very least, you can use memory techniques to remember tasks long enough to write them down later if you come up with them in the shower.

Next steps
My next step is to begin experimenting with memory techniques by memorizing things that are important to me. I’ll especially concentrate on finding substitute words and developing techniques for selecting, enhancing, and organizing.