Psychologists often distinguish between three necessary processes in learning and memory: encoding, storage, and retrieval (Melton, 1963). 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 her name (Lyn Goff) while you associate her name with her face. Then you need to maintain the information over time. If you see her a week later, you need to recognize her face and have it serve as a cue to retrieve her name. Any successful act of remembering requires that all three stages be intact. However, two types of errors can also occur. Forgetting is one type: you see the person you met at the party and you cannot recall her name. The other error is misremembering (false recall or false recognition): you see someone who looks like Lyn Goff and call the person by that name (false recognition of the face). Or, you might see the real Lyn Goff, recognize her face, but then call her by the name of another woman you met at the party (misrecall of her name).

Whenever forgetting or misremembering occurs, we can ask, at which point in the learning/memory process was there a failure?—though it is often difficult to answer this question with precision. One reason for this inaccuracy is that the three processes are not as discrete as our description implies. Rather, all three processes depend on one another. How we encode information determines how it will be stored and what cues will be effective when we try to retrieve it. And too, the act of retrieval itself also changes the way information is subsequently remembered, usually aiding later recall of the retrieved information. The central point for now is that the three processes—encoding, storage, and retrieval—affect one another, and are inextricably bound together.

Encoding

Memory encoding allows an item of interest to be converted into a construct that is stored in the brain, which can later be recalled.

Memory encoding allows information to be converted into a construct that is stored in the brain indefinitely. Once it is encoded, it can be recalled from either short- or long-term memory. At a very basic level, memory encoding is like hitting “Save” on a computer file. Once a file is saved, it can be retrieved as long as the hard drive is undamaged. “Recall” refers to retrieving previously encoded information.

The process of encoding begins with perception, which is the identification, organization, and interpretation of any sensory information in order to understand it within the context of a particular environment. Stimuli are perceived by the senses, and related signals travel to the thalamus of the human brain, where they are synthesized into one experience. The hippocampus then analyzes this experience and decides if it is worth committing to long-term memory.

Encoding is achieved using chemicals and electric impulses within the brain. Neural pathways, or connections between neurons (brain cells), are actually formed or strengthened through a process called long-term potentiation, which alters the flow of information within the brain. In other words, as a person experiences novel events or sensations, the brain “rewires” itself in order to store those new experiences in memory.

Encoding refers to the initial experience of perceiving and learning information. Psychologists often study recall by having participants study a list of pictures or words. Encoding in these situations is fairly straightforward. However, “real life” encoding is much more challenging.

When you walk across campus, for example, you encounter countless sights and sounds— friends passing by, people playing Frisbee, music in the air. The physical and mental environments are much too rich for you to encode all the happenings around you or the internal thoughts you have in response to them. So, an important first principle of encoding is that it is selective: we attend to some events in our environment and we ignore others. A second point about encoding is that it is prolific; we are always encoding the events of our lives—attending to the world, trying to understand it. Normally this presents no problem, as our days are filled with routine occurrences, so we don’t need to pay attention to everything. But if something does happen that seems strange—during your daily walk across campus, you see a giraffe—then we pay close attention and try to understand why we are seeing what we are seeing.

 

Distinctiveness

Right after your typical walk across campus (one without the appearance of a giraffe), you would be able to remember the events reasonably well if you were asked. You could say whom you bumped into, what song was playing from a radio, and so on. However, suppose someone asked you to recall the same walk a month later. You wouldn’t stand a chance. You would likely be able to recount the basics of a typical walk across campus, but not the precise details of that particular walk. Yet, if you had seen a giraffe during that walk, the event would have been fixed in your mind for a long time, probably for the rest of your life. You would tell your friends about it, and, on later occasions when you saw a giraffe, you might be reminded of the day you saw one on campus. Psychologists have long pinpointed distinctiveness—having an event stand out as quite different from a background of similar events—as a key to remembering events (Hunt, 2003).

Research on distinctiveness has been a focus for memory researchers since at least the 1930s (von Restorff, 1933). Hedwig von Restorff applied the figure/ground concept from Gestalt theory to memory domain. A basic idea from Gestalt theory was that representations of individual experiences are holistic, involving objects (figure) and their surrounding context (ground). Von Restorff took this idea and asked how memory might depend on factors that isolate figure from ground. Here is what she did.

Participants were tested on their memory for 5 lists. Each list had 8 pairs of items. An example of a list can be seen below. Each list had four pairs that were similar. These were called “massed” pairs. Think of them as providing a dull grey background. The other four pairs were all different. These were called “isolates”. They are like a colorful flower, in that they stand out from the massed pairs. The “massed” pairs in the list below were the four pairs of nonsense-syllables. The “isolates” were the remaining four pairs.

Von Restorff used a technique called counter-balancing in her experiment. Counter-balancing can be used to reduce the concern that the outcome of the experiment was due to a stimulus confound, like order effects (which stimuli are presented first) or in the context of this experiment, something specific about the stimuli besides its distinctiveness from the list. Von Restorff would show participants her lists, have a brief conversation with them, and then ask the participants to recall each pair from the list. Her question was whether the “isolated” pairs would be recalled with greater accuracy than the “massed” pairs. In the list above, this would mean better recall for “# – +, 89 – 46, red square – green square, and S – B”, compared to the other four pairs that were all nonsense-syllables.

Von Restorff guarded against the possibility that certain types of stimuli are more memorable than others by counter-balancing, creating 5 lists in total. In the first list, the massed pairs were nonsense syllables, but the “isolated” pairs were used for the massed pairs in the other four lists. For example, the second list could have four massed symbol pairs (like # – +), and the remaining four pairs would be “isolates” from the kinds of pairs. See the image above for an example.

Importantly, Von Restorff averaged across the lists to look at the effect of “massed” vs “isolated” pairs on memory. She found that “isolated” pairs were recalled at higher rates than “massed pairs, and she found this reliably across the lists. Von Restorff had shown that particular stimuli were more or less memorable, not in and of themselves, but in relation to how distinct they were from other stimuli in the set.

 

Emotion

Emotion can also foster the distinctiveness of events in relation to their surroundings; when vivid memories are tinged with strong emotional content, they often seem to leave a permanent mark on us. Public tragedies, such as terrorist attacks, often create vivid memories in those who witnessed them. But even those of us not directly involved in such events may have vivid memories of them, including memories of first hearing about them. For example, many people are able to recall their exact physical location when they first learned about the assassination or accidental death of a national figure. The term flashbulb memory was originally coined by Brown and Kulik (1977) to describe this sort of vivid memory of finding out an important piece of news. The name refers to how some memories seem to be captured in the mind like a flash photograph; because of the distinctiveness and emotionality of the news, they seem to become permanently etched in the mind with exceptional clarity compared to other memories.

Take a moment and think back on your own life. Is there a particular memory that seems sharper than others? A memory where you can recall unusual details, like the colors of mundane things around you, or the exact positions of surrounding objects? Although people have great confidence in flashbulb memories like these, the truth is, our objective accuracy with them is far from perfect (Talarico & Rubin, 2003). That is, even though people may have great confidence in what they recall, their memories are not as accurate (e.g., what the actual colors were; where objects were truly placed) as they tend to imagine. View the video below for a discussion on this topic. Nonetheless, all other things being equal, distinctive and emotional events are well-remembered.

 

Details do not leap perfectly from the world into a person’s mind. We might say that we went to a party and remember it, but what we remember is (at best) what we encoded. As noted above, the process of encoding is selective, and in complex situations, relatively few of many possible details are noticed and encoded. The process of encoding always involves recoding— that is, taking the information from the form it is delivered to us and then converting it in a way that we can make sense of it. We previously discussed some recoding as “chunking” based on expertise.

We sometimes refer to recoding techniques as mnemonics, or memory aids to help us organize information for encoding. For example, you might try to remember the colors of a rainbow by using the acronym ROY G BIV (red, orange, yellow, green, blue, indigo, violet). The process of recoding the colors into a name can help us to remember. However, recoding can also introduce errors—when we accidentally add information during encoding, then remember that new material as if it had been part of the actual experience. We will return to ways this can happen in later sections (e.g. inferences and false memories)

 

Meaningful information

Psychologists have studied many recoding strategies that can be used during study to improve retention. Research advises that, as we study, we should think of the meaning of the events (often referred to as semantic encoding), 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. Semantic encoding is sometimes discussed in the context of “levels of processing” (Craik & Lockhart, 1972). This distinguishes between the encoding of new information – particularly language-based information – based on what aspect of the information we attend to. Structural processing generally involves attending to the physical qualities of a word (e.g. how it is spelled), phonemic processing would include the way a word sounds, and semantic processing involves attending to the meaning of the word (e.g. by relating it to similar or opposite words). In general, we find that retention for information is better when utilizing semantic processing particularly compared to structural processing (Craik & Tulving, 1975).

Related to this is a memory bias we will call the self-reference effect (to be returned to later); we encode information more effectively when we can relate it to our own experience (note that this also requires semantic encoding to be done). From an evolutionary standpoint, it makes sense that we would prioritize information relevant to our experiences over random and arbitrary pieces of information for survival purposes.

Meaningful context

Bransford and Johnson demonstrated an important role for meaningful context to support memory recall and comprehension (Bransford & Johnson, 1972). They had participants read a short paragraph for a later comprehension and memory test. The paragraph is reprinted below.

If the balloons popped, the sound wouldn’t be able to carry since everything would be too far away from the correct floor. A closed window would also prevent the sound from carrying, since most buildings tend to be well insulated. Since the whole operation depends on a steady flow of electricity, a break in the middle of the wire would also cause problems. Of course, the fellow could shout, but the human voice is not loud enough to carry that far. An additional problem is that a string could break the instrument. Then there could be no accompaniment to the message. It is clear that the best situation would involve less distance. Then there would be fewer potential problems. With face to face contact, the lest number of things could go wrong.

 

 

This paragraph was designed to be difficult to comprehend without further context. Each sentence could make some sense by itself, but as a whole, it may not be very clear what this paragraph is about.

(a) Full Context

(b) Partial

The critical manipulation in this experiment was whether participants received additional meaningful context, in the form of a cartoon picture. Figure 5 shows the pictures used in the full and partial context conditions. One group saw the full context cartoon image before they read the paragraph. Another group saw the same image after they read the paragraph. If you thought the paragraph was confusing before, try reading it while looking at this image to get a feel for how it could help support your comprehension of the paragraph.

Another group of participants were given the “partial context” cartoon picture. And, two last groups were not given any context at all. The “no context (1)” group received one opportunity to read the paragraph. The “no context (2)” group got to read the paragraph twice.

After the encoding phase, participants were given a comprehension test and a recall memory test. The question was whether or not the presence or absence of meaningful context would influence comprehension scores, and number of ideas recalled from the paragraph. Figure 6 shows the results from the experiment.

The comprehension test had a maximum score of seven. The context before group had the highest comprehension score (6.1), compared to all other groups. The recall test had a maximum score of 14. Again, the context before group had the highest recall score (8), compared to all other groups. Notably, all of the other groups performed fairly similarly to one another, showing very little influence of reading the paragraph twice, seeing a partial context cartoon, or even getting the full context cartoon after initially reading the paragraph. The conclusion was that, in this case, receiving meaningful context before reading the paragraph was an important pre-requisite for later comprehension and recall.

Imagery and imagination

Additionally, imagining events also makes them more memorable; creating vivid images out of information (even verbal information) can greatly improve later recall. Creating imagery is part of the technique Simon Reinhard uses to remember huge numbers of digits, but we 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), and to form links or associations among memories to help later retrieval. Using study strategies such as the ones described here is challenging, but the effort is well worth the benefits of enhanced learning and retention.

Below are a couple videos that demonstrate how we can employ such strategies. As you watch the first clip, try and connect the explained memory technique to some of the strategies we have discussed so far.

 

At the very least, his technique employs chunking, semantic encoding, the self-reference effect, and imagery, all rolled into one. Similarly, this next speaker discusses a related strategy as the “memory palace.”

 

Inferences and false memories

We emphasized earlier that encoding is selective: people cannot encode all information they are exposed to. However, recoding can add information that was not even seen or heard during the initial encoding phase. Several of the recoding processes, like forming associations between memories, can happen without our awareness. This is one reason people can sometimes remember events that did not actually happen—because during the process of recoding, details got added. One common way of inducing false memories in the laboratory employs a word-list technique. Participants hear lists of 15 words, like door, glass, pane, shade, ledge, sill, house, open, curtain, frame, view, breeze, sash, screen, and shutter. Later, participants are given a test in which they are shown a list of words and asked to pick out the ones they’d heard earlier. This second list contains some words from the first list (e.g., door, pane, frame) and some words not from the list (e.g., arm, phone, bottle). In this example, one of the words on the test is window, which—importantly—does not appear in the first list, but which is related to other words in that list. When subjects were tested, they were reasonably accurate with the studied words (door, etc.), recognizing them 72% of the time. However, when window was on the test, they falsely recognized it as having been on the list 84% of the time. The same thing happened with many other lists the authors used. This phenomenon is referred to as the DRM (for Deese- Roediger-McDermott) effect. One explanation for such results is that, while students listened to items in the list, the words triggered the students to think about window, even though window was never presented. In this way, people seem to encode events that are not actually part of their experience.

Because humans are creative, we are always going beyond the information we are given: we automatically make associations and infer from them what is happening. But, as with the word association mix-up above, sometimes we make false memories from our inferences— remembering the inferences themselves as if they were actual experiences. To illustrate this, Brewer gave people sentences to remember that were designed to elicit pragmatic inferences. Inferences, in general, refer to instances when something is not explicitly stated, but we are still able to guess the undisclosed intention. For example, if your friend told you that she didn’t want to go out to eat, you may infer that she doesn’t have the money to go out, or that she’s too tired. With pragmatic inferences, there is usually one particular inference you’re likely to make. Consider the statement Brewer gave her participants: “The karate champion hit the cinder block.” After hearing or seeing this sentence, participants who were given a memory test tended to remember the statement as having been, “The karate champion broke the cinder block.” This remembered statement is not necessarily a logical inference (i.e., it is perfectly reasonable that a karate champion could hit a cinder block without breaking it). Nevertheless, the pragmatic conclusion from hearing such a sentence is that the block was likely broken. The participants remembered this inference they made while hearing the sentence in place of the actual words that were in the sentence.

Encoding—the initial registration of information—is essential in the learning and memory process. Unless an event is encoded in some fashion, 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.

Memory storage, however, allows us to hold onto information for a very long duration of time—even a lifetime.