memory assignment psychology

Memory Stages: Encoding Storage and Retrieval

Saul Mcleod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul Mcleod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Learn about our Editorial Process

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

On This Page:

“Memory is the process of maintaining information over time.” (Matlin, 2005) “Memory is the means by which we draw on our past experiences in order to use this information in the present’ (Sternberg, 1999).

Memory is the term given to the structures and processes involved in the storage and subsequent retrieval of information.

Memory is essential to all our lives. Without a memory of the past, we cannot operate in the present or think about the future. We would not be able to remember what we did yesterday, what we have done today, or what we plan to do tomorrow.  Without memory, we could not learn anything.

Memory is involved in processing vast amounts of information. This information takes many different forms, e.g., images, sounds, or meaning.

For psychologists, the term memory covers three important aspects of information processing :

Memory Encoding

When information comes into our memory system (from sensory input), it needs to be changed into a form that the system can cope with so that it can be stored.

Think of this as similar to changing your money into a different currency when you travel from one country to another.  For example, a word that is seen (in a book) may be stored if it is changed (encoded) into a sound or a meaning (i.e., semantic processing).

There are three main ways in which information can be encoded (changed):

1. Visual (picture) 2. Acoustic (sound) 3. Semantic (meaning)

For example, how do you remember a telephone number you have looked up in the phone book?  If you can see it, then you are using visual coding, but if you are repeating it to yourself, you are using acoustic coding (by sound).

Evidence suggests that this is the principle coding system in short-term memory (STM) is acoustic coding.  When a person is presented with a list of numbers and letters, they will try to hold them in STM by rehearsing them (verbally).

Rehearsal is a verbal process regardless of whether the list of items is presented acoustically (someone reads them out), or visually (on a sheet of paper).

The principle encoding system in long-term memory (LTM) appears to be semantic coding (by meaning).  However, information in LTM can also be coded both visually and acoustically.

Memory Storage

This concerns the nature of memory stores, i.e., where the information is stored, how long the memory lasts (duration), how much can be stored at any time (capacity) and what kind of information is held.

The way we store information affects the way we retrieve it.  There has been a significant amount of research regarding the differences between Short Term Memory (STM ) and Long Term Memory (LTM).

Most adults can store between 5 and 9 items in their short-term memory.  Miller (1956) put this idea forward, and he called it the magic number 7.  He thought that short-term memory capacity was 7 (plus or minus 2) items because it only had a certain number of “slots” in which items could be stored.

However, Miller didn’t specify the amount of information that can be held in each slot.  Indeed, if we can “chunk” information together, we can store a lot more information in our short-term memory.  In contrast, the capacity of LTM is thought to be unlimited.

Information can only be stored for a brief duration in STM (0-30 seconds), but LTM can last a lifetime.

Memory Retrieval

This refers to getting information out of storage.  If we can’t remember something, it may be because we are unable to retrieve it.  When we are asked to retrieve something from memory, the differences between STM and LTM become very clear.

STM is stored and retrieved sequentially.  For example, if a group of participants is given a list of words to remember and then asked to recall the fourth word on the list, participants go through the list in the order they heard it in order to retrieve the information.

LTM is stored and retrieved by association.  This is why you can remember what you went upstairs for if you go back to the room where you first thought about it.

Organizing information can help aid retrieval.  You can organize information in sequences (such as alphabetically, by size, or by time).  Imagine a patient being discharged from a hospital whose treatment involved taking various pills at various times, changing their dressing, and doing exercises.

If the doctor gives these instructions in the order that they must be carried out throughout the day (i.e., in the sequence of time), this will help the patient remember them.

Criticisms of Memory Experiments

A large part of the research on memory is based on experiments conducted in laboratories.  Those who take part in the experiments – the participants – are asked to perform tasks such as recalling lists of words and numbers.

Both the setting – the laboratory – and the tasks are a long way from everyday life.  In many cases, the setting is artificial, and the tasks are fairly meaningless.  Does this matter?

Psychologists use the term ecological validity to refer to the extent to which the findings of research studies can be generalized to other settings.  An experiment has high ecological validity if its findings can be generalized, that is, applied or extended to settings outside the laboratory.

It is often assumed that if an experiment is realistic or true-to-life, then there is a greater likelihood that its findings can be generalized.  If it is not realistic (if the laboratory setting and the tasks are artificial) then there is less likelihood that the findings can be generalized.  In this case, the experiment will have low ecological validity.

Many experiments designed to investigate memory have been criticized for having low ecological validity.  First, the laboratory is an artificial situation.  People are removed from their normal social settings and asked to take part in a psychological experiment.

They are directed by an “experimenter” and may be placed in the company of complete strangers.  For many people, this is a brand new experience, far removed from their everyday lives.  Will this setting affect their actions? Will they behave normally?

He was especially interested in the characteristics of people whom he considered to have achieved their potential as individuals.

Often, the tasks participants are asked to perform can appear artificial and meaningless.  Few, if any, people would attempt to memorize and recall a list of unconnected words in their daily lives.  And it is not clear how tasks such as this relate to the use of memory in everyday life.

The artificiality of many experiments has led some researchers to question whether their findings can be generalized to real life.  As a result, many memory experiments have been criticized for having low ecological validity.

Matlin, M. W. (2005). Cognition . Crawfordsville: John Wiley & Sons, Inc.

Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review , 63 (2): 81–97.

Sternberg, R. J. (1999). Cognitive psychology (2 nd ed.) . Fort Worth, TX: Harcourt Brace College Publishers.

Related Articles

Eidetic Memory Vs. Photographic Memory

Cognitive Psychology

Automatic Processing in Psychology: Definition & Examples

Controlled Processing in Psychology: Definition & Examples

How Ego Depletion Can Drain Your Willpower

What is the Default Mode Network?

Anterograde Amnesia In Psychology: Definition & Examples

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

8.1 Memories as Types and Stages

Learning objectives.

• Compare and contrast explicit and implicit memory, identifying the features that define each.
• Explain the function and duration of eidetic and echoic memories.
• Summarize the capacities of short-term memory and explain how working memory is used to process information in it.

As you can see in Table 8.1 “Memory Conceptualized in Terms of Types, Stages, and Processes” , psychologists conceptualize memory in terms of types , in terms of stages , and in terms of processes . In this section we will consider the two types of memory, explicit memory and implicit memory , and then the three major memory stages: sensory , short-term , and long-term (Atkinson & Shiffrin, 1968). Then, in the next section, we will consider the nature of long-term memory, with a particular emphasis on the cognitive techniques we can use to improve our memories. Our discussion will focus on the three processes that are central to long-term memory: encoding , storage , and retrieval .

Table 8.1 Memory Conceptualized in Terms of Types, Stages, and Processes

Explicit Memory

When we assess memory by asking a person to consciously remember things, we are measuring explicit memory . Explicit memory refers to knowledge or experiences that can be consciously remembered . As you can see in Figure 8.2 “Types of Memory” , there are two types of explicit memory: episodic and semantic . Episodic memory refers to the firsthand experiences that we have had (e.g., recollections of our high school graduation day or of the fantastic dinner we had in New York last year). Semantic memory refers to our knowledge of facts and concepts about the world (e.g., that the absolute value of −90 is greater than the absolute value of 9 and that one definition of the word “affect” is “the experience of feeling or emotion”).

Figure 8.2 Types of Memory

Explicit memory is assessed using measures in which the individual being tested must consciously attempt to remember the information. A recall memory test is a measure of explicit memory that involves bringing from memory information that has previously been remembered . We rely on our recall memory when we take an essay test, because the test requires us to generate previously remembered information. A multiple-choice test is an example of a recognition memory test , a measure of explicit memory that involves determining whether information has been seen or learned before .

Your own experiences taking tests will probably lead you to agree with the scientific research finding that recall is more difficult than recognition. Recall, such as required on essay tests, involves two steps: first generating an answer and then determining whether it seems to be the correct one. Recognition, as on multiple-choice test, only involves determining which item from a list seems most correct (Haist, Shimamura, & Squire, 1992). Although they involve different processes, recall and recognition memory measures tend to be correlated. Students who do better on a multiple-choice exam will also, by and large, do better on an essay exam (Bridgeman & Morgan, 1996).

A third way of measuring memory is known as relearning (Nelson, 1985). Measures of relearning (or savings) assess how much more quickly information is processed or learned when it is studied again after it has already been learned but then forgotten . If you have taken some French courses in the past, for instance, you might have forgotten most of the vocabulary you learned. But if you were to work on your French again, you’d learn the vocabulary much faster the second time around. Relearning can be a more sensitive measure of memory than either recall or recognition because it allows assessing memory in terms of “how much” or “how fast” rather than simply “correct” versus “incorrect” responses. Relearning also allows us to measure memory for procedures like driving a car or playing a piano piece, as well as memory for facts and figures.

Implicit Memory

While explicit memory consists of the things that we can consciously report that we know, implicit memory refers to knowledge that we cannot consciously access. However, implicit memory is nevertheless exceedingly important to us because it has a direct effect on our behavior. Implicit memory refers to the influence of experience on behavior, even if the individual is not aware of those influences . As you can see in Figure 8.2 “Types of Memory” , there are three general types of implicit memory: procedural memory, classical conditioning effects, and priming.

Procedural memory refers to our often unexplainable knowledge of how to do things . When we walk from one place to another, speak to another person in English, dial a cell phone, or play a video game, we are using procedural memory. Procedural memory allows us to perform complex tasks, even though we may not be able to explain to others how we do them. There is no way to tell someone how to ride a bicycle; a person has to learn by doing it. The idea of implicit memory helps explain how infants are able to learn. The ability to crawl, walk, and talk are procedures, and these skills are easily and efficiently developed while we are children despite the fact that as adults we have no conscious memory of having learned them.

A second type of implicit memory is classical conditioning effects, in which we learn, often without effort or awareness, to associate neutral stimuli (such as a sound or a light) with another stimulus (such as food), which creates a naturally occurring response, such as enjoyment or salivation. The memory for the association is demonstrated when the conditioned stimulus (the sound) begins to create the same response as the unconditioned stimulus (the food) did before the learning.

The final type of implicit memory is known as priming , or changes in behavior as a result of experiences that have happened frequently or recently . Priming refers both to the activation of knowledge (e.g., we can prime the concept of “kindness” by presenting people with words related to kindness) and to the influence of that activation on behavior (people who are primed with the concept of kindness may act more kindly).

One measure of the influence of priming on implicit memory is the word fragment test , in which a person is asked to fill in missing letters to make words. You can try this yourself: First, try to complete the following word fragments, but work on each one for only three or four seconds. Do any words pop into mind quickly?

_ i b _ a _ y

_ h _ s _ _ i _ n

_ h _ i s _

Now read the following sentence carefully:

Then try again to make words out of the word fragments.

I think you might find that it is easier to complete fragments 1 and 3 as “library” and “book,” respectively, after you read the sentence than it was before you read it. However, reading the sentence didn’t really help you to complete fragments 2 and 4 as “physician” and “chaise.” This difference in implicit memory probably occurred because as you read the sentence, the concept of “library” (and perhaps “book”) was primed, even though they were never mentioned explicitly. Once a concept is primed it influences our behaviors, for instance, on word fragment tests.

Our everyday behaviors are influenced by priming in a wide variety of situations. Seeing an advertisement for cigarettes may make us start smoking, seeing the flag of our home country may arouse our patriotism, and seeing a student from a rival school may arouse our competitive spirit. And these influences on our behaviors may occur without our being aware of them.

Research Focus: Priming Outside Awareness Influences Behavior

One of the most important characteristics of implicit memories is that they are frequently formed and used automatically , without much effort or awareness on our part. In one demonstration of the automaticity and influence of priming effects, John Bargh and his colleagues (Bargh, Chen, & Burrows, 1996) conducted a study in which they showed college students lists of five scrambled words, each of which they were to make into a sentence. Furthermore, for half of the research participants, the words were related to stereotypes of the elderly. These participants saw words such as the following:

The other half of the research participants also made sentences, but from words that had nothing to do with elderly stereotypes. The purpose of this task was to prime stereotypes of elderly people in memory for some of the participants but not for others.

The experimenters then assessed whether the priming of elderly stereotypes would have any effect on the students’ behavior—and indeed it did. When the research participant had gathered all of his or her belongings, thinking that the experiment was over, the experimenter thanked him or her for participating and gave directions to the closest elevator. Then, without the participants knowing it, the experimenters recorded the amount of time that the participant spent walking from the doorway of the experimental room toward the elevator. As you can see in Figure 8.3 “Results From Bargh, Chen, and Burrows, 1996” , participants who had made sentences using words related to elderly stereotypes took on the behaviors of the elderly—they walked significantly more slowly as they left the experimental room.

Figure 8.3 Results From Bargh, Chen, and Burrows, 1996

Bargh, Chen, and Burrows (1996) found that priming words associated with the elderly made people walk more slowly.

Adapted from Bargh, J. A., Chen, M., & Burrows, L. (1996). Automaticity of social behavior: Direct effects of trait construct and stereotype activation on action. Journal of Personality & Social Psychology, 71 , 230–244.

To determine if these priming effects occurred out of the awareness of the participants, Bargh and his colleagues asked still another group of students to complete the priming task and then to indicate whether they thought the words they had used to make the sentences had any relationship to each other, or could possibly have influenced their behavior in any way. These students had no awareness of the possibility that the words might have been related to the elderly or could have influenced their behavior.

Stages of Memory: Sensory, Short-Term, and Long-Term Memory

Another way of understanding memory is to think about it in terms of stages that describe the length of time that information remains available to us. According to this approach (see Figure 8.4 “Memory Duration” ), information begins in sensory memory , moves to short-term memory , and eventually moves to long-term memory . But not all information makes it through all three stages; most of it is forgotten. Whether the information moves from shorter-duration memory into longer-duration memory or whether it is lost from memory entirely depends on how the information is attended to and processed.

Figure 8.4 Memory Duration

Memory can characterized in terms of stages—the length of time that information remains available to us.

Adapted from Atkinson, R. C., & Shiffrin, R. M. (1968). Human memory: A proposed system and its control processes. In K. Spence (Ed.), The psychology of learning and motivation (Vol. 2). Oxford, England: Academic Press.

Sensory Memory

Sensory memory refers to the brief storage of sensory information . Sensory memory is a memory buffer that lasts only very briefly and then, unless it is attended to and passed on for more processing, is forgotten. The purpose of sensory memory is to give the brain some time to process the incoming sensations, and to allow us to see the world as an unbroken stream of events rather than as individual pieces.

Visual sensory memory is known as iconic memory . Iconic memory was first studied by the psychologist George Sperling (1960). In his research, Sperling showed participants a display of letters in rows, similar to that shown in Figure 8.5 “Measuring Iconic Memory” . However, the display lasted only about 50 milliseconds (1/20 of a second). Then, Sperling gave his participants a recall test in which they were asked to name all the letters that they could remember. On average, the participants could remember only about one-quarter of the letters that they had seen.

Figure 8.5 Measuring Iconic Memory

Sperling (1960) showed his participants displays such as this one for only 1/20th of a second. He found that when he cued the participants to report one of the three rows of letters, they could do it, even if the cue was given shortly after the display had been removed. The research demonstrated the existence of iconic memory.

Adapted from Sperling, G. (1960). The information available in brief visual presentation. Psychological Monographs, 74 (11), 1–29.

Sperling reasoned that the participants had seen all the letters but could remember them only very briefly, making it impossible for them to report them all. To test this idea, in his next experiment he first showed the same letters, but then after the display had been removed , he signaled to the participants to report the letters from either the first, second, or third row. In this condition, the participants now reported almost all the letters in that row. This finding confirmed Sperling’s hunch: Participants had access to all of the letters in their iconic memories, and if the task was short enough, they were able to report on the part of the display he asked them to. The “short enough” is the length of iconic memory, which turns out to be about 250 milliseconds (¼ of a second).

Auditory sensory memory is known as echoic memory . In contrast to iconic memories, which decay very rapidly, echoic memories can last as long as 4 seconds (Cowan, Lichty, & Grove, 1990). This is convenient as it allows you—among other things—to remember the words that you said at the beginning of a long sentence when you get to the end of it, and to take notes on your psychology professor’s most recent statement even after he or she has finished saying it.

In some people iconic memory seems to last longer, a phenomenon known as eidetic imagery (or “photographic memory”) in which people can report details of an image over long periods of time. These people, who often suffer from psychological disorders such as autism, claim that they can “see” an image long after it has been presented, and can often report accurately on that image. There is also some evidence for eidetic memories in hearing; some people report that their echoic memories persist for unusually long periods of time. The composer Wolfgang Amadeus Mozart may have possessed eidetic memory for music, because even when he was very young and had not yet had a great deal of musical training, he could listen to long compositions and then play them back almost perfectly (Solomon, 1995).

Short-Term Memory

Most of the information that gets into sensory memory is forgotten, but information that we turn our attention to, with the goal of remembering it, may pass into short-term memory . Short-term memory (STM) is the place where small amounts of information can be temporarily kept for more than a few seconds but usually for less than one minute (Baddeley, Vallar, & Shallice, 1990). Information in short-term memory is not stored permanently but rather becomes available for us to process, and the processes that we use to make sense of, modify, interpret, and store information in STM are known as working memory .

Although it is called “memory,” working memory is not a store of memory like STM but rather a set of memory procedures or operations. Imagine, for instance, that you are asked to participate in a task such as this one, which is a measure of working memory (Unsworth & Engle, 2007). Each of the following questions appears individually on a computer screen and then disappears after you answer the question:

Is 10 × 2 − 5 = 15? (Answer YES OR NO) Then remember “S”

Is 12 ÷ 6 − 2 = 1? (Answer YES OR NO) Then remember “R”

Is 10 × 2 = 5? (Answer YES OR NO) Then remember “P”

Is 8 ÷ 2 − 1 = 1? (Answer YES OR NO) Then remember “T”

Is 6 × 2 − 1 = 8? (Answer YES OR NO) Then remember “U”

Is 2 × 3 − 3 = 0? (Answer YES OR NO) Then remember “Q”

To successfully accomplish the task, you have to answer each of the math problems correctly and at the same time remember the letter that follows the task. Then, after the six questions, you must list the letters that appeared in each of the trials in the correct order (in this case S, R, P, T, U, Q).

To accomplish this difficult task you need to use a variety of skills. You clearly need to use STM, as you must keep the letters in storage until you are asked to list them. But you also need a way to make the best use of your available attention and processing. For instance, you might decide to use a strategy of “repeat the letters twice, then quickly solve the next problem, and then repeat the letters twice again including the new one.” Keeping this strategy (or others like it) going is the role of working memory’s central executive —the part of working memory that directs attention and processing. The central executive will make use of whatever strategies seem to be best for the given task. For instance, the central executive will direct the rehearsal process, and at the same time direct the visual cortex to form an image of the list of letters in memory. You can see that although STM is involved, the processes that we use to operate on the material in memory are also critical.

Short-term memory is limited in both the length and the amount of information it can hold. Peterson and Peterson (1959) found that when people were asked to remember a list of three-letter strings and then were immediately asked to perform a distracting task (counting backward by threes), the material was quickly forgotten (see Figure 8.6 “STM Decay” ), such that by 18 seconds it was virtually gone.

Figure 8.6 STM Decay

Peterson and Peterson (1959) found that information that was not rehearsed decayed quickly from memory.

Adapted from Peterson, L., & Peterson, M. J. (1959). Short-term retention of individual verbal items. Journal of Experimental Psychology, 58 (3), 193–198.

One way to prevent the decay of information from short-term memory is to use working memory to rehearse it. Maintenance rehearsal is the process of repeating information mentally or out loud with the goal of keeping it in memory . We engage in maintenance rehearsal to keep a something that we want to remember (e.g., a person’s name, e-mail address, or phone number) in mind long enough to write it down, use it, or potentially transfer it to long-term memory.

If we continue to rehearse information it will stay in STM until we stop rehearsing it, but there is also a capacity limit to STM. Try reading each of the following rows of numbers, one row at a time, at a rate of about one number each second. Then when you have finished each row, close your eyes and write down as many of the numbers as you can remember.

If you are like the average person, you will have found that on this test of working memory, known as a digit span test , you did pretty well up to about the fourth line, and then you started having trouble. I bet you missed some of the numbers in the last three rows, and did pretty poorly on the last one.

The digit span of most adults is between five and nine digits, with an average of about seven. The cognitive psychologist George Miller (1956) referred to “seven plus or minus two” pieces of information as the “magic number” in short-term memory. But if we can only hold a maximum of about nine digits in short-term memory, then how can we remember larger amounts of information than this? For instance, how can we ever remember a 10-digit phone number long enough to dial it?

One way we are able to expand our ability to remember things in STM is by using a memory technique called chunking . Chunking is the process of organizing information into smaller groupings (chunks), thereby increasing the number of items that can be held in STM . For instance, try to remember this string of 12 letters:

You probably won’t do that well because the number of letters is more than the magic number of seven.

Now try again with this one:

Would it help you if I pointed out that the material in this string could be chunked into four sets of three letters each? I think it would, because then rather than remembering 12 letters, you would only have to remember the names of four television stations. In this case, chunking changes the number of items you have to remember from 12 to only four.

Experts rely on chunking to help them process complex information. Herbert Simon and William Chase (1973) showed chess masters and chess novices various positions of pieces on a chessboard for a few seconds each. The experts did a lot better than the novices in remembering the positions because they were able to see the “big picture.” They didn’t have to remember the position of each of the pieces individually, but chunked the pieces into several larger layouts. But when the researchers showed both groups random chess positions—positions that would be very unlikely to occur in real games—both groups did equally poorly, because in this situation the experts lost their ability to organize the layouts (see Figure 8.7 “Possible and Impossible Chess Positions” ). The same occurs for basketball. Basketball players recall actual basketball positions much better than do nonplayers, but only when the positions make sense in terms of what is happening on the court, or what is likely to happen in the near future, and thus can be chunked into bigger units (Didierjean & Marmèche, 2005).

Figure 8.7 Possible and Impossible Chess Positions

Experience matters: Experienced chess players are able to recall the positions of the game on the right much better than are those who are chess novices. But the experts do no better than the novices in remembering the positions on the left, which cannot occur in a real game.

If information makes it past short term-memory it may enter long-term memory (LTM) , memory storage that can hold information for days, months, and years . The capacity of long-term memory is large, and there is no known limit to what we can remember (Wang, Liu, & Wang, 2003). Although we may forget at least some information after we learn it, other things will stay with us forever. In the next section we will discuss the principles of long-term memory.

Key Takeaways

• Memory refers to the ability to store and retrieve information over time.
• For some things our memory is very good, but our active cognitive processing of information assures that memory is never an exact replica of what we have experienced.
• Explicit memory refers to experiences that can be intentionally and consciously remembered, and it is measured using recall, recognition, and relearning. Explicit memory includes episodic and semantic memories.
• Measures of relearning (also known as savings) assess how much more quickly information is learned when it is studied again after it has already been learned but then forgotten.
• Implicit memory refers to the influence of experience on behavior, even if the individual is not aware of those influences. The three types of implicit memory are procedural memory, classical conditioning, and priming.
• Information processing begins in sensory memory, moves to short-term memory, and eventually moves to long-term memory.
• Maintenance rehearsal and chunking are used to keep information in short-term memory.
• The capacity of long-term memory is large, and there is no known limit to what we can remember.

Exercises and Critical Thinking

• List some situations in which sensory memory is useful for you. What do you think your experience of the stimuli would be like if you had no sensory memory?
• Describe a situation in which you need to use working memory to perform a task or solve a problem. How do your working memory skills help you?

Atkinson, R. C., & Shiffrin, R. M. (1968). Human memory: A proposed system and its control processes. In K. Spence (Ed.), The psychology of learning and motivation (Vol. 2). Oxford, England: Academic Press.

Baddeley, A. D., Vallar, G., & Shallice, T. (1990). The development of the concept of working memory: Implications and contributions of neuropsychology. In G. Vallar & T. Shallice (Eds.), Neuropsychological impairments of short-term memory (pp. 54–73). New York, NY: Cambridge University Press.

Bargh, J. A., Chen, M., & Burrows, L. (1996). Automaticity of social behavior: Direct effects of trait construct and stereotype activation on action. Journal of Personality & Social Psychology, 71 , 230–244.

Bridgeman, B., & Morgan, R. (1996). Success in college for students with discrepancies between performance on multiple-choice and essay tests. Journal of Educational Psychology, 88 (2), 333–340.

Cowan, N., Lichty, W., & Grove, T. R. (1990). Properties of memory for unattended spoken syllables. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16 (2), 258–268.

Didierjean, A., & Marmèche, E. (2005). Anticipatory representation of visual basketball scenes by novice and expert players. Visual Cognition, 12 (2), 265–283.

Haist, F., Shimamura, A. P., & Squire, L. R. (1992). On the relationship between recall and recognition memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 18 (4), 691–702.

Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 63 (2), 81–97.

Nelson, T. O. (1985). Ebbinghaus’s contribution to the measurement of retention: Savings during relearning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 11 (3), 472–478.

Peterson, L., & Peterson, M. J. (1959). Short-term retention of individual verbal items. Journal of Experimental Psychology, 58 (3), 193–198.

Simon, H. A., & Chase, W. G. (1973). Skill in chess. American Scientist, 61 (4), 394–403.

Solomon, M. (1995). Mozart: A life . New York, NY: Harper Perennial.

Sperling, G. (1960). The information available in brief visual presentation. Psychological Monographs, 74 (11), 1–29.

Unsworth, N., & Engle, R. W. (2007). On the division of short-term and working memory: An examination of simple and complex span and their relation to higher order abilities. Psychological Bulletin, 133 (6), 1038–1066.

Wang, Y., Liu, D., & Wang, Y. (2003). Discovering the capacity of human memory. Brain & Mind, 4 (2), 189–198.

Introduction to Psychology Copyright © 2015 by University of Minnesota is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

Ch 7: Memory

Memory (Encoding, Storage, Retrieval)

We may be top-notch learners, but if we don’t have a way to store what we’ve learned, what good is the knowledge we’ve gained?

Take a few minutes to imagine what your day might be like if you could not remember anything you had learned. You would have to figure out how to get dressed. What clothing should you wear, and how do buttons and zippers work? You would need someone to teach you how to brush your teeth and tie your shoes. Who would you ask for help with these tasks, since you wouldn’t recognize the faces of these people in your house? Wait . . . is this even your house? Uh oh, your stomach begins to rumble and you feel hungry. You’d like something to eat, but you don’t know where the food is kept or even how to prepare it. Oh dear, this is getting confusing. Maybe it would be best just go back to bed. A bed . . . what is a bed?

We have an amazing capacity for memory, but how, exactly, do we process and store information? Are there different kinds of memory, and if so, what characterizes the different types? How, exactly, do we retrieve our memories? And why do we forget? This chapter will explore these questions as we learn about memory.

“ Memory ” is a single term that reflects a number of different abilities: holding information briefly while working with it (working memory), remembering episodes of one’s life (episodic memory), and our general knowledge of facts of the world (semantic memory), among other types. Remembering episodes involves three processes: encoding information (learning it, by perceiving it and relating it to past knowledge), storing it (maintaining it over time), and then retrieving it (accessing the information when needed). Failures can occur at any stage, leading to forgetting or to having false memories. The key to improving one’s memory is to improve processes of encoding and to use techniques that guarantee effective retrieval. Good encoding techniques include relating new information to what one already knows, 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 the rememberer back to the encoded information.

Learning Objectives

In this chapter, you will

• Define and note differences between the following forms of memory: working memory, episodic memory, semantic memory, collective memory.
• Describe the three stages in the process of learning and remembering.
• Describe strategies that can be used to enhance the original learning or encoding of information.
• Describe strategies that can improve the process of retrieval.
• Explain the brain functions involved in memory; recognize the roles of the hippocampus, amygdala, and cerebellum in memory

Our memory has three basic functions: encoding, storing, and retrieving information. Encoding is the act of getting information into our memory system through automatic or effortful processing. Storage is retention of the information, and retrieval is the act of getting information out of storage and into conscious awareness through recall, recognition, and relearning. There are various models that aim to explain how we utilize our memory. In this section, you’ll learn about some of these models as well as the importance of recall, recognition, and relearning.

To get a good overview of all of these concepts and to pique your interest, you may choose to begin this module by watching John Gabrieli’s lecture on memory. Listen for some key vocabulary terms you’ll learn about soon, particularly:

• the three-stage model of memory
• short-term memory
• serial position effect
• Ebbinghaus forgetting curve
• proactive interference
• retroactive interference
• flashbulb memories
• false memories

You can view the transcript for “Lec 10 | MIT 9.00SC Introduction to Psychology, Spring 2011” here (opens in new window) .

How Memory Functions

• Explain the three types of encoding
• Describe the three stages of memory storage
• Describe and distinguish between procedural and declarative memory and semantic and episodic memory
• Explain retrieval cues and define recall, recognition, and relearning

Varieties of Memory

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 (e.g., 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. Semantic memory is our storehouse of more-or-less permanent knowledge, such as the meanings of words in a language (e.g., the meaning of “parasol”) and the huge collection of facts about the world (e.g., there are 196 countries in the world, and 206 bones in your body). Both of these types of memory are considered long-term memory.  Collective memory refers to the kind of memory that people in a group share (whether family, community, schoolmates, or citizens of a state or a country). For example, residents of small towns often strongly identify with those towns, remembering the local customs and historical events in a unique way. That is, the community’s collective memory passes stories and recollections between neighbors and to future generations, forming a memory system unto itself.

Psychologists continue to debate the classification of types of memory, as well as which types rely on others (Tulving, 2007), but for this module we will focus on episodic memory. Episodic memory is usually what people think of when they hear the word “memory.” For example, when people say that an older relative is “losing her memory” due to Alzheimer’s disease, the type of memory-loss they are referring to is the inability to recall events, or episodic memory. (Semantic memory is actually preserved in early-stage Alzheimer’s disease.) Although remembering specific events that have happened over the course of one’s entire life (e.g., your experiences in sixth grade) can be referred to as autobiographical memory , we will focus primarily on the episodic memories of more recent events.

Three Stages of the Learning/Memory Process

Psychologists distinguish between three necessary stages in the learning and memory process: 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 stage 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 stages are not as discrete as our description implies. Rather, all three stages 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 stages—encoding, storage, and retrieval—affect one another, and are inextricably bound together.

Memory is an information processing system; therefore, we often compare it to a computer. Memory is the set of processes used to encode, store, and retrieve information over different periods of time.

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.

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).

What are the most effective ways to ensure that important memories are well encoded? Even a simple sentence is easier to recall when it is meaningful (Anderson, 1984). Read the following sentences (Bransford & McCarrell, 1974), then look away and count backwards from 30 by threes to zero, and then try to write down the sentences (no peeking back at this page!).

• The notes were sour because the seams split.
• The voyage wasn’t delayed because the bottle shattered.
• The haystack was important because the cloth ripped.

How well did you do? By themselves, the statements that you wrote down were most likely confusing and difficult for you to recall. Now, try writing them again, using the following prompts: bagpipe, ship christening (shattering a bottle over the bow of the ship is a symbol of good luck), and parachutist. Next count backwards from 40 by fours, then check yourself to see how well you recalled the sentences this time. You can see that the sentences are now much more memorable because each of the sentences was placed in context. Material is far better encoded when you make it meaningful.

There are three types of encoding. The encoding of words and their meaning is known as semantic encoding . It was first demonstrated by William Bousfield (1935) in an experiment in which he asked people to memorize words. The 60 words were actually divided into 4 categories of meaning, although the participants did not know this because the words were randomly presented. When they were asked to remember the words, they tended to recall them in categories, showing that they paid attention to the meanings of the words as they learned them.

Visual encoding is the encoding of images, and acoustic encoding  is the encoding of sounds, words in particular. To see how visual encoding works, read over this list of words: car, level, dog, truth, book, value . If you were asked later to recall the words from this list, which ones do you think you’d most likely remember? You would probably have an easier time recalling the words car, dog, and book , and a more difficult time recalling the words level, truth, and value . Why is this? Because you can recall images (mental pictures) more easily than words alone. When you read the words car, dog, and book you created images of these things in your mind. These are concrete, high-imagery words. On the other hand, abstract words like level, truth, and value are low-imagery words. High-imagery words are encoded both visually and semantically (Paivio, 1986), thus building a stronger memory.

Now let’s turn our attention to acoustic encoding. You are driving in your car and a song comes on the radio that you haven’t heard in at least 10 years, but you sing along, recalling every word. In the United States, children often learn the alphabet through song, and they learn the number of days in each month through rhyme: “ Thirty days hath September, / April, June, and November; / All the rest have thirty-one, / Save February, with twenty-eight days clear, / And twenty-nine each leap year.” These lessons are easy to remember because of acoustic encoding. We encode the sounds the words make. This is one of the reasons why much of what we teach young children is done through song, rhyme, and rhythm.

Which of the three types of encoding do you think would give you the best memory of verbal information? Some years ago, psychologists Fergus Craik and Endel Tulving (1975) conducted a series of experiments to find out. Participants were given words along with questions about them. The questions required the participants to process the words at one of the three levels. The visual processing questions included such things as asking the participants about the font of the letters. The acoustic processing questions asked the participants about the sound or rhyming of the words, and the semantic processing questions asked the participants about the meaning of the words. After participants were presented with the words and questions, they were given an unexpected recall or recognition task.

Words that had been encoded semantically were better remembered than those encoded visually or acoustically. Semantic encoding involves a deeper level of processing than the shallower visual or acoustic encoding. Craik and Tulving concluded that we process verbal information best through semantic encoding, especially if we apply what is called the self-reference effect. The self-reference effect is the tendency for an individual to have better memory for information that relates to oneself in comparison to material that has less personal relevance (Rogers, Kuiper & Kirker, 1977). Could semantic encoding be beneficial to you as you attempt to memorize the concepts in this module?

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. 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 (as discussed below).

Psychologists have studied many recoding strategies that can be used during study to improve retention. First, research advises that, as we study, we should think of the meaning of the events (Craik & Lockhart, 1972), 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. Second, imagining events also makes them more memorable; creating vivid images out of information (even verbal information) can greatly improve later recall (Bower & Reitman, 1972). 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 (Hunt & McDaniel, 1993). Using study strategies such as the ones described here is challenging, but the effort is well worth the benefits of enhanced learning and retention.

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 (Deese, 1959; Roediger & McDermott, 1995). 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 (Stadler, Roediger, & McDermott, 1999). 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 (1977) 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 (1977) 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 (see also McDermott & Chan, 2006).

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.

Once the information has been encoded, we somehow have to retain it. Our brains take the encoded information and place it in storage. Storage is the creation of a permanent record of information.

But A-S is just one model of memory. Others, such as Baddeley and Hitch (1974), have proposed a model where short-term memory itself has different forms. In this model, storing memories in short-term memory is like opening different files on a computer and adding information. The type of short-term memory (or computer file) depends on the type of information received. There are memories in visual-spatial form, as well as memories of spoken or written material, and they are stored in three short-term systems: a visuospatial sketchpad, an episodic buffer, and a phonological loop. According to Baddeley and Hitch, a central executive part of memory supervises or controls the flow of information to and from the three short-term systems.

Sensory Memory

In the Akinson-Shiffrin model , stimuli from the environment are processed first in sensory memory : storage of brief sensory events, such as sights, sounds, and tastes. It is very brief storage—up to a couple of seconds. We are constantly bombarded with sensory information. We cannot absorb all of it, or even most of it. And most of it has no impact on our lives. For example, what was your professor wearing the last class period? As long as the professor was dressed appropriately, it does not really matter what she was wearing. Sensory information about sights, sounds, smells, and even textures, which we do not view as valuable information, we discard. If we view something as valuable, the information will move into our short-term memory system.

One study of sensory memory researched the significance of valuable information on short-term memory storage. J. R. Stroop discovered a memory phenomenon in the 1930s: you will name a color more easily if it appears printed in that color, which is called the Stroop effect. In other words, the word “red” will be named more quickly, regardless of the color the word appears in, than any word that is colored red. Try an experiment: name the colors of the words you are given in Figure 7. Do not read the words, but say the color the word is printed in. For example, upon seeing the word “yellow” in green print, you should say “green,” not “yellow.” This experiment is fun, but it’s not as easy as it seems.

Short-Term Memory

Short-term memory (STM)  is a temporary storage system that processes incoming sensory memory; sometimes it is called working memory. Short-term memory takes information from sensory memory and sometimes connects that memory to something already in long-term memory. Short-term memory storage lasts about 20 seconds. George Miller (1956), in his research on the capacity of memory, found that most people can retain about 7 items in STM. Some remember 5, some 9, so he called the capacity of STM 7 plus or minus 2.

Think of short-term memory as the information you have displayed on your computer screen—a document, a spreadsheet, or a web page. Then, information in short-term memory goes to long-term memory (you save it to your hard drive), or it is discarded (you delete a document or close a web browser). This step of rehearsal , the conscious repetition of information to be remembered, to move STM into long-term memory is called   consolidation .

You may find yourself asking, “How much information can our memory handle at once?” To explore the capacity and duration of your short-term memory, have a partner read the strings of random numbers (Figure 8) out loud to you, beginning each string by saying, “Ready?” and ending each by saying, “Recall,” at which point you should try to write down the string of numbers from memory.

Note the longest string at which you got the series correct. For most people, this will be close to 7, Miller’s famous 7 plus or minus 2. Recall is somewhat better for random numbers than for random letters (Jacobs, 1887), and also often slightly better for information we hear (acoustic encoding) rather than see (visual encoding) (Anderson, 1969).

Long-term Memory

Long-term memory (LTM) is the continuous storage of information. Unlike short-term memory, the storage capacity of LTM has no limits. It encompasses all the things you can remember that happened more than just a few minutes ago to all of the things that you can remember that happened days, weeks, and years ago. In keeping with the computer analogy, the information in your LTM would be like the information you have saved on the hard drive. It isn’t there on your desktop (your short-term memory), but you can pull up this information when you want it, at least most of the time. Not all long-term memories are strong memories. Some memories can only be recalled through prompts. For example, you might easily recall a fact— “What is the capital of the United States?”—or a procedure—“How do you ride a bike?”—but you might struggle to recall the name of the restaurant you had dinner when you were on vacation in France last summer. A prompt, such as that the restaurant was named after its owner, who spoke to you about your shared interest in soccer, may help you recall the name of the restaurant.

Long-term memory is divided into two types: explicit and implicit (Figure 9). Understanding the different types is important because a person’s age or particular types of brain trauma or disorders can leave certain types of LTM intact while having disastrous consequences for other types. Explicit memories are those we consciously try to remember and recall. For example, if you are studying for your chemistry exam, the material you are learning will be part of your explicit memory. (Note: Sometimes, but not always, the terms explicit memory and declarative memory are used interchangeably.)

Implicit memories are memories that are not part of our consciousness. They are memories formed from behaviors. Implicit memory is also called non-declarative memory.

Procedural memory  is a type of implicit memory: it stores information about how to do things. It is the memory for skilled actions, such as how to brush your teeth, how to drive a car, how to swim the crawl (freestyle) stroke. If you are learning how to swim freestyle, you practice the stroke: how to move your arms, how to turn your head to alternate breathing from side to side, and how to kick your legs. You would practice this many times until you become good at it. Once you learn how to swim freestyle and your body knows how to move through the water, you will never forget how to swim freestyle, even if you do not swim for a couple of decades. Similarly, if you present an accomplished guitarist with a guitar, even if he has not played in a long time, he will still be able to play quite well.

Explicit memory has to do with the storage of facts and events we personally experienced. Explicit (declarative) memory has two parts: semantic memory and episodic memory. Semantic means having to do with language and knowledge about language. An example would be the question “what does argumentative mean?” Stored in our semantic memory is knowledge about words, concepts, and language-based knowledge and facts. For example, answers to the following questions are stored in your semantic memory:

• Who was the first President of the United States?
• What is democracy?
• What is the longest river in the world?

Episodic memory is information about events we have personally experienced. The concept of episodic memory was first proposed about 40 years ago (Tulving, 1972). Since then, Tulving and others have looked at scientific evidence and reformulated the theory. Currently, scientists believe that episodic memory is memory about happenings in particular places at particular times, the what, where, and when of an event (Tulving, 2002). It involves recollection of visual imagery as well as the feeling of familiarity (Hassabis & Maguire, 2007).

Everyday Connections: Can You Remember Everything You Ever Did or Said?

Episodic memories are also called autobiographical memories. Let’s quickly test your autobiographical memory. What were you wearing exactly five years ago today? What did you eat for lunch on April 10, 2019? You probably find it difficult, if not impossible, to answer these questions. Can you remember every event you have experienced over the course of your life—meals, conversations, clothing choices, weather conditions, and so on? Most likely none of us could even come close to answering these questions; however, American actress Marilu Henner, best known for the television show Taxi, can remember. She has an amazing and highly superior autobiographical memory (Figure 10).

Very few people can recall events in this way; right now, only 12 known individuals have this ability, and only a few have been studied (Parker, Cahill & McGaugh 2006). And although hyperthymesia normally appears in adolescence, two children in the United States appear to have memories from well before their tenth birthdays.

If you’re interested in learning more, watch these Part 1 and Part 2 video clips on superior autobiographical memory from the television news show 60 Minutes .

In this video, Hank Green explains several research studies that helped us better understand implicit memories.

You can view the transcript for “Why Is Riding a Bike “Just Like Riding a Bike?”” here (opens in new window) .

Think It Over

• Describe something you have learned that is now in your procedural memory. Discuss how you learned this information.
• Describe something you learned in high school that is now in your semantic memory.

So you have worked hard to encode (via effortful processing) and store some important information for your upcoming final exam. How do you get that information back out of storage when you need it? The act of getting information out of memory storage and back into conscious awareness is known as retrieval . This would be similar to finding and opening a paper you had previously saved on your computer’s hard drive. Now it’s back on your desktop, and you can work with it again. Our ability to retrieve information from long-term memory  is vital to our everyday functioning. You must be able to retrieve information from memory in order to do everything from knowing how to brush your hair and teeth, to driving to work, to knowing how to perform your job once you get there.

Memory Cues

What factors determine what information can be retrieved from memory? One critical factor is the type of hints, or cues , in the environment. You may hear a song on the radio that suddenly evokes memories of an earlier time in your life, even if you were not trying to remember it when the song came on. Nevertheless, the song is closely associated with that time, so it brings the experience to mind.

The general principle that underlies the effectiveness of retrieval cues is the encoding specificity principle  (Tulving & Thomson, 1973): when people encode information, they do so in specific ways. For example, take the song on the radio: perhaps you heard it while you were at a terrific party, having a great, philosophical conversation with a friend. Thus, the song became part of that whole complex experience. Years later, even though you haven’t thought about that party in ages, when you hear the song on the radio, the whole experience rushes back to you. In general, the encoding specificity principle states that, to the extent a retrieval cue (the song) matches or overlaps the memory trace of an experience (the party, the conversation), it will be effective in evoking the memory. A classic experiment on the encoding specificity principle had participants memorize a set of words in a unique setting. Later, the participants were tested on the word sets, either in the same location they learned the words or a different one. As a result of encoding specificity, the students who took the test in the same place they learned the words were actually able to recall more words (Godden & Baddeley, 1975) than the students who took the test in a new setting. In this instance, the physical context itself provided cues for retrieval. This is why it’s good to study for midterms and finals in the same room you’ll be taking them in.

One caution with this principle, though, is that, for the cue to work, it can’t match too many other experiences (Nairne, 2002; Watkins, 1975). Consider a lab experiment. Suppose you study 100 items; 99 are words, and one is a picture—of a penguin, item 50 in the list. Afterwards, the cue “recall the picture” would evoke “penguin” perfectly. No one would miss it. However, if the word “penguin” were placed in the same spot among the other 99 words, its memorability would be exceptionally worse. This outcome shows the power of distinctiveness : one picture is perfectly recalled from among 99 words because it stands out. Now consider what would happen if the experiment were repeated, but there were 25 pictures distributed within the 100-item list. Although the picture of the penguin would still be there, the probability that the cue “recall the picture” (at item 50) would be useful for the penguin would drop correspondingly. Watkins (1975) referred to this outcome as demonstrating the cue overload principle . That is, to be effective, a retrieval cue cannot be overloaded with too many memories. For the cue “recall the picture” to be effective, it should only match one item in the target set (as in the one-picture, 99-word case).

To sum up how memory cues function: for a retrieval cue to be effective, a match must exist between the cue and the desired target memory; furthermore, to produce the best retrieval, the cue-target relationship should be distinctive.

Types of Retrieval

There are three ways you can retrieve information out of your long-term memory storage system: recall, recognition, and relearning. Recall  is what we most often think about when we talk about memory retrieval: it means you can access information without cues. For example, you would use recall for an essay test. Recognition happens when you identify information that you have previously learned after encountering it again. It involves a process of comparison. When you take a multiple-choice test, you are relying on recognition to help you choose the correct answer. Here is another example. Let’s say you graduated from high school 10 years ago, and you have returned to your hometown for your 10-year reunion. You may not be able to recall all of your classmates, but you recognize many of them based on their yearbook photos.

The third form of retrieval is relearning , and it’s just what it sounds like. It involves learning information that you previously learned. Whitney took Spanish in high school, but after high school she did not have the opportunity to speak Spanish. Whitney is now 31, and her company has offered her an opportunity to work in their Mexico City office. In order to prepare herself, she enrolls in a Spanish course at the local community center. She’s surprised at how quickly she’s able to pick up the language after not speaking it for 13 years; this is an example of relearning.

Recall and Recognition

Psychologists measure memory performance by using production tests (involving recall) or recognition tests (involving the selection of correct from incorrect information, e.g., a multiple-choice test). For example, with our list of 100 words, one group of people might be asked to recall the list in any order (a free recall test), while a different group might be asked to circle the 100 studied words out of a mix with another 100, unstudied words (a recognition test). In this situation, the recognition test would likely produce better performance from participants than the recall test.

We usually think of recognition tests as being quite easy, because the cue for retrieval is a copy of the actual event that was presented for study. After all, what could be a better cue than the exact target (memory) the person is trying to access? In most cases, this line of reasoning is true; nevertheless, recognition tests do not provide perfect indexes of what is stored in memory. That is, you can fail to recognize a target staring you right in the face, yet be able to recall it later with a different set of cues (Watkins & Tulving, 1975). For example, suppose you had the task of recognizing the surnames of famous authors. At first, you might think that being given the actual last name would always be the best cue. However, research has shown this not necessarily to be true (Muter, 1984). When given names such as Tolstoy, Shaw, Shakespeare, and Lee, subjects might well say that Tolstoy and Shakespeare are famous authors, whereas Shaw and Lee are not. But, when given a cued recall test using first names, people often recall items (produce them) that they had failed to recognize before.

For example, in this instance, a cue like George Bernard ________ often leads to a recall of “Shaw,” even though people initially failed to recognize Shaw as a famous author’s name. Yet, when given the cue “William,” people may not come up with Shakespeare, because William is a common name that matches many people (the cue overload principle at work). This strange fact—that recall can sometimes lead to better performance than recognition—can be explained by the encoding specificity principle. As a cue, George Bernard _________ matches the way the famous writer is stored in memory better than does his surname, Shaw, does (even though it is the target). Further, the match is quite distinctive with George Bernard ___________, but the cue William _________________ is much more overloaded (Prince William, William Yeats, William Faulkner, will.i.am).

The phenomenon we have been describing is called the recognition failure of recallable words , which highlights the point that a cue will be most effective depending on how the information has been encoded (Tulving & Thomson, 1973). The point is, the cues that work best to evoke retrieval are those that recreate the event or name to be remembered, whereas sometimes even the target itself, such as Shaw in the above example, is not the best cue. Which cue will be most effective depends on how the information has been encoded.

Retrieval and Reconstruction

Whenever we think about our past, we engage in the act of retrieval. We usually think that retrieval is an objective act because we tend to imagine that retrieving a memory is like pulling a book from a shelf, and after we are done with it, we return the book to the shelf just as it was. However, research shows this assumption to be false; far from being a static repository of data, the memory is constantly changing. In fact, every time we retrieve a memory, it is altered. For example, the act of retrieval itself (of a fact, concept, or event) makes the retrieved memory much more likely to be retrieved again, a phenomenon called the testing effect or the retrieval practice effect (Pyc & Rawson, 2009; Roediger & Karpicke, 2006). However, retrieving some information can actually cause us to forget other information related to it, a phenomenon called retrieval-induced forgetting (Anderson, Bjork, & Bjork, 1994). Thus the act of retrieval can be a double-edged sword—strengthening the memory just retrieved (usually by a large amount) but harming related information (though this effect is often relatively small).

Retrieval of distant memories is reconstructive. We weave the concrete bits and pieces of events in with assumptions and preferences to form a coherent story (Bartlett, 1932). For example, if during your 10th birthday, your dog got to your cake before you did, you would likely tell that story for years afterward. Say, then, in later years you misremember where the dog actually found the cake, but repeat that error over and over during subsequent retellings of the story. Over time, that inaccuracy would become a basic fact of the event in your mind. Just as retrieval practice (repetition) enhances accurate memories, so will it strengthen errors or false memories (McDermott, 2006). Sometimes memories can even be manufactured just from hearing a vivid story. Consider the following episode, recounted by Jean Piaget, the famous developmental psychologist, from his childhood:

One of my first memories would date, if it were true, from my second year. I can still see, most clearly, the following scene, in which I believed until I was about 15. I was sitting in my pram . . . when a man tried to kidnap me. I was held in by the strap fastened round me while my nurse bravely tried to stand between me and the thief. She received various scratches, and I can still vaguely see those on her face. . . . When I was about 15, my parents received a letter from my former nurse saying that she had been converted to the Salvation Army. She wanted to confess her past faults, and in particular to return the watch she had been given as a reward on this occasion. She had made up the whole story, faking the scratches. I therefore must have heard, as a child, this story, which my parents believed, and projected it into the past in the form of a visual memory. . . . Many real memories are doubtless of the same order. (Norman & Schacter, 1997, pp. 187–188)

Piaget’s vivid account represents a case of a pure reconstructive memory. He heard the tale told repeatedly, and doubtless told it (and thought about it) himself. The repeated telling cemented the events as though they had really happened, just as we are all open to the possibility of having “many real memories … of the same order.” The fact that one can remember precise details (the location, the scratches) does not necessarily indicate that the memory is true, a point that has been confirmed in laboratory studies, too (e.g., Norman & Schacter, 1997).

Review the concepts from this section on encoding, storage, and retrieval in the following CrashCourse video:

You can view the transcript for “How We Make Memories: Crash Course Psychology #13” here (opens in new window) .

Check out these resources on memory and learning

• Book: Brown, P.C., Roediger, H. L. & McDaniel, M. A. (2014). Make it stick: The science of successful learning. Cambridge, MA: Harvard University Press. https://www.amazon.com/Make-Stick-Science-Successful-Learning/dp/0674729013
• Web: Retrieval Practice, a website with research, resources, and tips for both educators and learners around the memory-strengthening skill of retrieval practice. http://www.retrievalpractice.org/

Parts of the Brain Involved with Memory

Are memories stored in just one part of the brain, or are they stored in many different parts of the brain? Karl Lashley began exploring this problem, about 100 years ago, by making lesions in the brains of animals such as rats and monkeys. He was searching for evidence of the engram : the group of neurons that serve as the “physical representation of memory” (Josselyn, 2010). First, Lashley (1950) trained rats to find their way through a maze. Then, he used the tools available at the time—in this case a soldering iron—to create lesions in the rats’ brains, specifically in the cerebral cortex. He did this because he was trying to erase the engram, or the original memory trace that the rats had of the maze.

Lashley did not find evidence of the engram, and the rats were still able to find their way through the maze, regardless of the size or location of the lesion. Based on his creation of lesions and the animals’ reaction, he formulated the equipotentiality hypothesis : if part of one area of the brain involved in memory is damaged, another part of the same area can take over that memory function (Lashley, 1950). Although Lashley’s early work did not confirm the existence of the engram, modern psychologists are making progress locating it. Eric Kandel, for example, spent decades working on the synapse, the basic structure of the brain, and its role in controlling the flow of information through neural circuits needed to store memories (Mayford, Siegelbaum, & Kandel, 2012).

Many scientists believe that the entire brain is involved with memory. However, since Lashley’s research, other scientists have been able to look more closely at the brain and memory. They have argued that memory is located in specific parts of the brain, and specific neurons can be recognized for their involvement in forming memories. The main parts of the brain involved with memory are the amygdala, the hippocampus, the cerebellum, and the prefrontal cortex (Figure 13).

First, let’s look at the role of the amygdala in memory formation. The main job of the amygdala is to regulate emotions, such as fear and aggression. The amygdala plays a part in how memories are stored because storage is influenced by stress hormones. For example, one researcher experimented with rats and the fear response (Josselyn, 2010). Using Pavlovian conditioning, a neutral tone was paired with a foot shock to the rats. This produced a fear memory in the rats. After being conditioned, each time they heard the tone, they would freeze (a defense response in rats), indicating a memory for the impending shock. Then the researchers induced cell death in neurons in the lateral amygdala, which is the specific area of the brain responsible for fear memories. They found the fear memory faded (became extinct). Because of its role in processing emotional information, the amygdala is also involved in memory consolidation: the process of transferring new learning into long-term memory. The amygdala seems to facilitate encoding memories at a deeper level when the event is emotionally arousing.

Link to Learning

Hippocampus.

Another group of researchers also experimented with rats to learn how the hippocampus functions in memory processing. They created lesions in the hippocampi of the rats, and found that the rats demonstrated memory impairment on various tasks, such as object recognition and maze running. They concluded that the hippocampus is involved in memory, specifically normal recognition memory as well as spatial memory (when the memory tasks are like recall tests) (Clark, Zola, & Squire, 2000). Another job of the hippocampus is to project information to cortical regions that give memories meaning and connect them with other connected memories. It also plays a part in memory consolidation: the process of transferring new learning into long-term memory.

Injury to this area leaves us unable to process new declarative memories. One famous patient, known for years only as H. M., had both his left and right temporal lobes (hippocampi) removed in an attempt to help control the seizures he had been suffering from for years (Corkin, Amaral, González, Johnson, & Hyman, 1997). As a result, his declarative memory was significantly affected, and he could not form new semantic knowledge. He lost the ability to form new memories, yet he could still remember information and events that had occurred prior to the surgery.

Cerebellum and Prefrontal Cortex

Although the hippocampus seems to be more of a processing area for explicit memories, you could still lose it and be able to create implicit memories (procedural memory, motor learning, and classical conditioning), thanks to your cerebellum. For example, one classical conditioning experiment is to accustom subjects to blink when they are given a puff of air. When researchers damaged the cerebellums of rabbits, they discovered that the rabbits were not able to learn the conditioned eye-blink response (Steinmetz, 1999; Green & Woodruff-Pak, 2000).

Other researchers have used brain scans, including positron emission tomography (PET) scans, to learn how people process and retain information. From these studies, it seems the prefrontal cortex is involved. In one study, participants had to complete two different tasks: either looking for the letter a in words (considered a perceptual task) or categorizing a noun as either living or non-living (considered a semantic task) (Kapur et al., 1994). Participants were then asked which words they had previously seen. Recall was much better for the semantic task than for the perceptual task. According to PET scans, there was much more activation in the left inferior prefrontal cortex in the semantic task. In another study, encoding was associated with left frontal activity, while retrieval of information was associated with the right frontal region (Craik et al., 1999).

Neurotransmitters

There also appear to be specific neurotransmitters involved with the process of memory, such as epinephrine, dopamine, serotonin, glutamate, and acetylcholine (Myhrer, 2003). There continues to be discussion and debate among researchers as to which neurotransmitter plays which specific role (Blockland, 1996). Although we don’t yet know which role each neurotransmitter plays in memory, we do know that communication among neurons via neurotransmitters is critical for developing new memories. Repeated activity by neurons leads to increased neurotransmitters in the synapses and more efficient and more synaptic connections. This is how memory consolidation occurs.

It is also believed that strong emotions trigger the formation of strong memories, and weaker emotional experiences form weaker memories; this is called arousal theory  (Christianson, 1992). For example, strong emotional experiences can trigger the release of neurotransmitters, as well as hormones, which strengthen memory; therefore, our memory for an emotional event is usually better than our memory for a non-emotional event. When humans and animals are stressed, the brain secretes more of the neurotransmitter glutamate, which helps them remember the stressful event (McGaugh, 2003). This is clearly evidenced by what is known as the flashbulb memory phenomenon.

Learn more about flashbulb memories in this brief video.

A flashbulb memory  is an exceptionally clear recollection of an important event (Figure 14). Where were you when you first heard about the 9/11 terrorist attacks? Most likely you can remember where you were and what you were doing. In fact, a Pew Research Center (2011) survey found that for those Americans who were age 8 or older at the time of the event, 97% can recall the moment they learned of this event, even a decade after it happened.

Dig Deeper: Inaccurate and False Memories

I was sitting there, and my Chief of Staff—well, first of all, when we walked into the classroom, I had seen this plane fly into the first building. There was a TV set on. And you know, I thought it was pilot error and I was amazed that anybody could make such a terrible mistake. (Greenberg, 2004, p. 2)

Contrary to what President Bush recalled, no one saw the first plane hit, except people on the ground near the twin towers. The plane hitting the first tower was not initially broadcasted on television because it had been a normal Tuesday morning in New York City until the first plane hit.

Some people attributed Bush’s wrong recall of the event to conspiracy theories. However, there is a much more benign explanation: human memory, even flashbulb memories, can be frail. In fact, memory can be so frail that we can convince a person an event happened to them, even when it did not. In studies, research participants will recall hearing a word, even though they never heard the word. For example, participants were given a list of 15 sleep-related words, but the word “sleep” was not on the list. Participants recalled hearing the word “sleep” even though they did not actually hear it (Roediger & McDermott, 2000). The researchers who discovered this named the theory after themselves and a fellow researcher, calling it the Deese-Roediger-McDermott paradigm.

Forgetting and Other Memory Problems

• Compare and contrast the two anterograde and retrograde amnesia
• Explain encoding failure and give examples of common memory errors, such as transience, absentmindedness, blocking, misattribution, suggestibility, bias, persistence, and interference.
• Describe the unreliability of eyewitness testimony
• Explain the misinformation effect

You may pride yourself on your amazing ability to remember the birthdates and ages of all of your friends and family members, or you may be able recall vivid details of your 5th birthday party at Chuck E. Cheese’s. However, all of us have at times felt frustrated, and even embarrassed, when our memories have failed us. There are several reasons why this happens.

the outstanding fact about K.C.’s mental make-up is his utter inability to remember any events, circumstances, or situations from his own life. His episodic amnesia covers his whole life, from birth to the present. The only exception is the experiences that, at any time, he has had in the last minute or two. (Tulving, 2002, p. 14)

Anterograde Amnesia

There are two common types of amnesia: anterograde amnesia and retrograde amnesia (Figure 15). Anterograde amnesia is commonly caused by brain trauma, such as a blow to the head. With anterograde amnesia , you cannot remember new information, although you can remember information and events that happened prior to your injury. The hippocampus is usually affected (McLeod, 2011). This suggests that damage to the brain has resulted in the inability to transfer information from short-term to long-term memory; that is, the inability to consolidate memories.

Retrograde Amnesia

Retrograde amnesia is loss of memory for events that occurred prior to the trauma. People with retrograde amnesia cannot remember some or even all of their past. They have difficulty remembering episodic memories. What if you woke up in the hospital one day and there were people surrounding your bed claiming to be your spouse, your children, and your parents? The trouble is you don’t recognize any of them. You were in a car accident, suffered a head injury, and now have retrograde amnesia. You don’t remember anything about your life prior to waking up in the hospital. This may sound like the stuff of Hollywood movies, and Hollywood has been fascinated with the amnesia plot for nearly a century, going all the way back to the film Garden of Lies from 1915 to more recent movies such as the Jason Bourne trilogy starring Matt Damon. However, for real-life sufferers of retrograde amnesia, like former NFL football player Scott Bolzan, the story is not a Hollywood movie. Bolzan fell, hit his head, and deleted 46 years of his life in an instant. He is now living with one of the most extreme cases of retrograde amnesia on record.

Encoding Failure

Sometimes memory loss happens before the actual memory process begins, which is encoding failure. We can’t remember something if we never stored it in our memory in the first place. This would be like trying to find a book on your e-reader that you never actually purchased and downloaded. Often, in order to remember something, we must pay attention to the details and actively work to process the information (effortful encoding). Lots of times we don’t do this. For instance, think of how many times in your life you’ve seen a nickel. Can you accurately recall what the front of a U.S. nickel looks like? When researchers Raymond Nickerson and Marilyn Adams (1979) asked this question, they found that most Americans don’t know which one it is. The reason is most likely encoding failure. Most of us never encode the details of the nickel. We only encode enough information to be able to distinguish it from other coins. If we don’t encode the information, then it’s not in our long-term memory, so we will not be able to remember it.

Memory Errors

Psychologist Daniel Schacter (2001), a well-known memory researcher, offers seven ways our memories fail us. He calls them the seven sins of memory and categorizes them into three groups: forgetting, distortion, and intrusion (Table 1).

Let’s look at the first sin of the forgetting errors: transience , which means that memories can fade over time. Here’s an example of how this happens. Nathan’s English teacher has assigned his students to read the novel To Kill a Mockingbird . Nathan comes home from school and tells his mom he has to read this book for class. “Oh, I loved that book!” she says. Nathan asks her what the book is about, and after some hesitation she says, “Well . . . I know I read the book in high school, and I remember that one of the main characters is named Scout, and her father is an attorney, but I honestly don’t remember anything else.” Nathan wonders if his mother actually read the book, and his mother is surprised she can’t recall the plot. What is going on here is storage decay: unused information tends to fade with the passage of time.

In 1885, German psychologist Hermann Ebbinghaus analyzed the process of memorization. First, he memorized lists of nonsense syllables. Then he measured how much he learned (retained) when he attempted to relearn each list. He tested himself over different periods of time from 20 minutes later to 30 days later. The result is his famous forgetting curve (Figure 18). Due to storage decay, an average person will lose 50% of the memorized information after 20 minutes and 70% of the information after 24 hours (Ebbinghaus, 1885/1964). Your memory for new information decays quickly and then eventually levels out.

Are you constantly losing your cell phone? Have you ever driven back home to make sure you turned off the stove? Have you ever walked into a room for something, but forgotten what it was? You probably answered yes to at least one, if not all, of these examples—but don’t worry, you are not alone. We are all prone to committing the memory error known as absentmindedness. These lapses in memory are caused by breaks in attention or our focus being somewhere else.

Cynthia, a psychologist, recalls a time when she recently committed the memory error of absentmindedness .

When I was completing court-ordered psychological evaluations, each time I went to the court, I was issued a temporary identification card with a magnetic strip which would open otherwise locked doors. As you can imagine, in a courtroom, this identification is valuable and important and no one wanted it to be lost or be picked up by a criminal. At the end of the day, I would hand in my temporary identification. One day, when I was almost done with an evaluation, my daughter’s day care called and said she was sick and needed to be picked up. It was flu season, I didn’t know how sick she was, and I was concerned. I finished up the evaluation in the next ten minutes, packed up my tools, and rushed to drive to my daughter’s day care. After I picked up my daughter, I could not remember if I had handed back my identification or if I had left it sitting out on a table. I immediately called the court to check. It turned out that I had handed back my identification. Why could I not remember that? (personal communication, September 5, 2013)

When have you experienced absentmindedness?

“I just went and saw this movie called Oblivion , and it had that famous actor in it. Oh, what’s his name? He’s been in all of those movies, like The Shawshank Redemption and The Dark Knight trilogy. I think he’s even won an Oscar. Oh gosh, I can picture his face in my mind, and hear his distinctive voice, but I just can’t think of his name! This is going to bug me until I can remember it!” This particular error can be so frustrating because you have the information right on the tip of your tongue. Have you ever experienced this? If so, you’ve committed the error known as blocking : you can’t access stored information (Figure 19).

Now let’s take a look at the three errors of distortion: misattribution, suggestibility, and bias. Misattribution happens when you confuse the source of your information. Let’s say Alejandro was dating Lucia and they saw the first Hobbit movie together. Then they broke up and Alejandro saw the second Hobbit movie with someone else. Later that year, Alejandro and Lucia get back together. One day, they are discussing how the Hobbit books and movies are different and Alejandro says to Lucia, “I loved watching the second movie with you and seeing you jump out of your seat during that super scary part.” When Lucia responded with a puzzled and then angry look, Alejandro realized he’d committed the error of misattribution.

What if someone is a victim of rape shortly after watching a television program? Is it possible that the victim could actually blame the rape on the person she saw on television because of misattribution? This is exactly what happened to Donald Thomson.

Australian eyewitness expert Donald Thomson appeared on a live TV discussion about the unreliability of eyewitness memory. He was later arrested, placed in a lineup and identified by a victim as the man who had raped her. The police charged Thomson although the rape had occurred at the time he was on TV. They dismissed his alibi that he was in plain view of a TV audience and in the company of the other discussants, including an assistant commissioner of police. . . . Eventually, the investigators discovered that the rapist had attacked the woman as she was watching TV—the very program on which Thomson had appeared. Authorities eventually cleared Thomson. The woman had confused the rapist’s face with the face that she had seen on TV. (Baddeley, 2004, p. 133)

The second distortion error is suggestibility. Suggestibility is similar to misattribution, since it also involves false memories, but it’s different. With misattribution you create the false memory entirely on your own, which is what the victim did in the Donald Thomson case above. With suggestibility, it comes from someone else, such as a therapist or police interviewer asking leading questions of a witness during an interview.

Memories can also be affected by bias , which is the final distortion error. Schacter (2001) says that your feelings and view of the world can actually distort your memory of past events. There are several types of bias: Stereotypical bias involves racial and gender biases. For example, when Asian American and European American research participants were presented with a list of names, they more frequently incorrectly remembered typical African American names such as Jamal and Tyrone to be associated with the occupation basketball player, and they more frequently incorrectly remembered typical White names such as Greg and Howard to be associated with the occupation of politician (Payne, Jacoby, & Lambert, 2004). Egocentric bias involves enhancing our memories of the past (Payne et al., 2004). Did you really score the winning goal in that big soccer match, or did you just assist? Hindsight bias happens when we think an outcome was inevitable after the fact. This is the “I knew it all along” phenomenon. The reconstructive nature of memory contributes to hindsight bias (Carli, 1999). We remember untrue events that seem to confirm that we knew the outcome all along.

Have you ever had a song play over and over in your head? How about a memory of a traumatic event, something you really do not want to think about? When you keep remembering something, to the point where you can’t “get it out of your head” and it interferes with your ability to concentrate on other things, it is called persistence . It’s Schacter’s seventh and last memory error. It’s actually a failure of our memory system because we involuntarily recall unwanted memories, particularly unpleasant ones (Figure 20). For instance, you witness a horrific car accident on the way to work one morning, and you can’t concentrate on work because you keep remembering the scene.

Alternatively, some memories may be forgotten because we deliberately attempt to keep them out of mind . Over time, by actively trying not to remember an event, we can sometimes successfully keep the undesirable memory from being retrieved either by inhibiting the undesirable memory or generating diversionary thoughts (Anderson & Green, 2001). Imagine that you slipped and fell in your high school cafeteria during lunch time, and everyone at the surrounding tables laughed at you. You would likely wish to avoid thinking about that event and might try to prevent it from coming to mind. One way that you could accomplish this is by thinking of other, more positive, events that are associated with the cafeteria. Eventually, this memory may be suppressed to the point that it would only be retrieved with great difficulty (Hertel & Calcaterra, 2005).

Interference

Sometimes information is stored in our memory, but for some reason it is inaccessible. This is known as interference, and there are two types: proactive interference and retroactive interference  (Figure 21). Have you ever gotten a new phone number or moved to a new address, but right after you tell people the old (and wrong) phone number or address? When the new year starts, do you find you accidentally write the previous year? These are examples of proactive interference: when old information hinders the recall of newly learned information. Retroactive interference happens when information learned more recently hinders the recall of older information. For example, this week you are studying Freud’s Psychoanalytic Theory. Next week you study the humanistic perspective of Maslow and Rogers. Thereafter, you have trouble remembering part of Freud’s theory, his Psychosexual Stages of Development, because you can only remember Maslow’s Hierarchy of Needs.

Dig Deeper: Preserving Eyewitness Memory: The Elizabeth Smart Case

Applications of faulty memory: elizabeth loftus and the misinformation effect.

Cognitive psychologist Elizabeth Loftus has conducted extensive research on memory. She has studied false memories as well as recovered memories of childhood sexual abuse. Loftus also developed the misinformation effect paradigm , which holds that after exposure to incorrect information, a person may misremember the original event.

According to Loftus, an eyewitness’s memory of an event is very flexible due to the misinformation effect. To test this theory, Loftus and John Palmer (1974) asked 45 U.S. college students to estimate the speed of cars using different forms of questions (Figure 23). The participants were shown films of car accidents and were asked to play the role of the eyewitness and describe what happened. They were asked, “About how fast were the cars going when they (smashed, collided, bumped, hit, contacted) each other?” The participants estimated the speed of the cars based on the verb used.

This video explains the misinformation effect.

You can view the transcript for “The Misinformation Effect” here (opens in new window) .

Participants who heard the word “smashed” estimated that the cars were traveling at a much higher speed than participants who heard the word “contacted.” The implied information about speed, based on the verb they heard, had an effect on the participants’ memory of the accident. In a follow-up one week later, participants were asked if they saw any broken glass (none was shown in the accident pictures). Participants who had been in the “smashed” group were more than twice as likely to indicate that they did remember seeing glass. Loftus and Palmer demonstrated that a leading question encouraged them to not only remember the cars were going faster, but to also falsely remember that they saw broken glass.

Studies have demonstrated that young adults (the typical research subjects in psychology) are often susceptible to misinformation, but that children and older adults can be even more susceptible (Bartlett & Memon, 2007; Ceci & Bruck, 1995). In addition, misinformation effects can occur easily, and without any intention to deceive (Allan & Gabbert, 2008). Even slight differences in the wording of a question can lead to misinformation effects. Subjects in one study were more likely to say yes when asked “Did you see the broken headlight?” than when asked “Did you see a broken headlight?” (Loftus, 1975).

Other studies have shown that misinformation can corrupt memory even more easily when it is encountered in social situations (Gabbert, Memon, Allan, & Wright, 2004). This is a problem particularly in cases where more than one person witnesses a crime. In these cases, witnesses tend to talk to one another in the immediate aftermath of the crime, including as they wait for police to arrive. But because different witnesses are different people with different perspectives, they are likely to see or notice different things, and thus remember different things, even when they witness the same event. So when they communicate about the crime later, they not only reinforce common memories for the event, they also contaminate each other’s memories for the event (Gabbert, Memon, & Allan, 2003; Paterson & Kemp, 2006; Takarangi, Parker, & Garry, 2006).

The misinformation effect has been modeled in the laboratory. Researchers had subjects watch a video in pairs. Both subjects sat in front of the same screen, but because they wore differently polarized glasses, they saw two different versions of a video, projected onto a screen. So, although they were both watching the same screen, and believed (quite reasonably) that they were watching the same video, they were actually watching two different versions of the video (Garry, French, Kinzett, & Mori, 2008).

In the video, Eric the electrician is seen wandering through an unoccupied house and helping himself to the contents thereof. A total of eight details were different between the two videos. After watching the videos, the “co-witnesses” worked together on 12 memory test questions. Four of these questions dealt with details that were different in the two versions of the video, so subjects had the chance to influence one another. Then subjects worked individually on 20 additional memory test questions. Eight of these were for details that were different in the two videos. Subjects’ accuracy was highly dependent on whether they had discussed the details previously. Their accuracy for items they had not previously discussed with their co-witness was 79%. But for items that they had discussed, their accuracy dropped markedly, to 34%. That is, subjects allowed their co-witnesses to corrupt their memories for what they had seen.

Improving Memory

Putting It All Together: Improving Your Memory

A central theme of this chapter has been the importance of the encoding and retrieval processes, and their interaction. To recap: to improve learning and memory, we need to encode information in conjunction with excellent cues that will bring back the remembered events when we need them. But how do we do this? Keep in mind 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 . These two conditions are critical in maximizing cue effectiveness (Nairne, 2002).

In 2013, Simon Reinhard sat in front of 60 people in a room at Washington University, where he memorized an increasingly long series of digits. On the first round, a computer generated 10 random digits—6 1 9 4 8 5 6 3 7 1—on a screen for 10 seconds. After the series disappeared, Simon typed them into his computer. His recollection was perfect. In the next phase, 20 digits appeared on the screen for 20 seconds. Again, Simon got them all correct. No one in the audience (mostly professors, graduate students, and undergraduate students) could recall the 20 digits perfectly. Then came 30 digits, studied for 30 seconds; once again, Simon didn’t misplace even a single digit. For a final trial, 50 digits appeared on the screen for 50 seconds, and again, Simon got them all right. In fact, Simon would have been happy to keep going. His record in this task—called “forward digit span”—is 240 digits!

When most of us witness a performance like that of Simon Reinhard, we think one of two things: First, maybe he’s cheating somehow. (No, he is not.) Second, Simon must have abilities more advanced than the rest of humankind. After all, psychologists established many years ago that the normal memory span for adults is about 7 digits, with some of us able to recall a few more and others a few less (Miller, 1956). That is why the first phone numbers were limited to 7 digits—psychologists determined that many errors occurred (costing the phone company money) when the number was increased to even 8 digits. But in normal testing, no one gets 50 digits correct in a row, much less 240. So, does Simon Reinhard simply have a photographic memory? He does not. Instead, Simon has taught himself simple strategies for remembering that have greatly increased his capacity for remembering virtually any type of material—digits, words, faces and names, poetry, historical dates, and so on. Twelve years earlier, before he started training his memory abilities, he had a digit span of 7, just like most of us. Simon has been training his abilities for about 10 years as of this writing, and has risen to be in the top two of “memory athletes.” In 2012, he came in second place in the World Memory Championships (composed of 11 tasks), held in London. He currently ranks second in the world, behind another German competitor, Johannes Mallow. In this section, we will explain the general principles by which you can improve your own memory.

• Recognize and apply memory-enhancing strategies, including mnemonics, rehearsal, chunking, and peg-words

Ways to Enhance Memory

Memory-enhancing strategies.

What are some everyday ways we can improve our memory, including recall? To help make sure information goes from short-term memory to long-term memory, you can use memory-enhancing strategies . One strategy is rehearsal , or the conscious repetition of information to be remembered (Craik & Watkins, 1973). Think about how you learned your multiplication tables as a child. You may recall that 6 x 6 = 36, 6 x 7 = 42, and 6 x 8 = 48. Memorizing these facts is rehearsal.

Another strategy is chunking : you organize information into manageable bits or chunks (Bodie, Powers, & Fitch-Hauser, 2006). Chunking is useful when trying to remember information like dates and phone numbers. Instead of trying to remember 5205550467, you remember the number as 520-555-0467. So, if you met an interesting person at a party and you wanted to remember his phone number, you would naturally chunk it, and you could repeat the number over and over, which is the rehearsal strategy.

You could also enhance memory by using elaborative rehearsal : a technique in which you think about the meaning of the new information and its relation to knowledge already stored in your memory (Tigner, 1999). For example, in this case, you could remember that 520 is an area code for Arizona and the person you met is from Arizona. This would help you better remember the 520 prefix. If the information is retained, it goes into long-term memory.

Mnemonic devices  are memory aids that help us organize information for encoding (Figure 25). They are especially useful when we want to recall larger bits of information such as steps, stages, phases, and parts of a system (Bellezza, 1981). Brian needs to learn the order of the planets in the solar system, but he’s having a hard time remembering the correct order. His friend Kelly suggests a mnemonic device that can help him remember. Kelly tells Brian to simply remember the name Mr. VEM J. SUN, and he can easily recall the correct order of the planets: M ercury, V enus, E arth, M ars, J upiter, S aturn, U ranus, and N eptune. You might use a mnemonic device to help you remember someone’s name, a mathematical formula, or the seven levels of Bloom’s taxonomy.

If you have ever watched the television show Modern Family , you might have seen Phil Dunphy explain how he remembers names:

The other day I met this guy named Carl. Now, I might forget that name, but he was wearing a Grateful Dead t-shirt. What’s a band like the Grateful Dead? Phish. Where do fish live? The ocean. What else lives in the ocean? Coral. Hello, Co-arl. (Wrubel & Spiller, 2010)

It seems the more vivid or unusual the mnemonic, the easier it is to remember. The key to using any mnemonic successfully is to find a strategy that works for you.

Some other strategies that are used to improve memory include expressive writing and saying words aloud. Expressive writing helps boost your short-term memory, particularly if you write about a traumatic experience in your life. Masao Yogo and Shuji Fujihara (2008) had participants write for 20-minute intervals several times per month. The participants were instructed to write about a traumatic experience, their best possible future selves, or a trivial topic. The researchers found that this simple writing task increased short-term memory capacity after five weeks, but only for the participants who wrote about traumatic experiences. Psychologists can’t explain why this writing task works, but it does.

What if you want to remember items you need to pick up at the store? Simply say them out loud to yourself. A series of studies (MacLeod, Gopie, Hourihan, Neary, & Ozubko, 2010) found that saying a word out loud improves your memory for the word because it increases the word’s distinctiveness. Feel silly, saying random grocery items aloud? This technique works equally well if you just mouth the words. Using these techniques increased participants’ memory for the words by more than 10%. These techniques can also be used to help you study.

Using Peg-Words

Consider the case of Simon Reinhard. In 2013, he sat in front of 60 people in a room at Washington University, where he memorized an increasingly long series of digits. On the first round, a computer generated 10 random digits—6 1 9 4 8 5 6 3 7 1—on a screen for 10 seconds. After the series disappeared, Simon typed them into his computer. His recollection was perfect. In the next phase, 20 digits appeared on the screen for 20 seconds. Again, Simon got them all correct. No one in the audience (mostly professors, graduate students, and undergraduate students) could recall the 20 digits perfectly. Then came 30 digits, studied for 30 seconds; once again, Simon didn’t misplace even a single digit. For a final trial, 50 digits appeared on the screen for 50 seconds, and again, Simon got them all right. In fact, Simon would have been happy to keep going. His record in this task—called “forward digit span”—is 240 digits!

Simon Reinhard’s ability to memorize huge numbers of digits. Although it was not obvious, Simon Reinhard used deliberate mnemonic devices to improve his memory. In a typical case, the person learns a set of cues and then applies these cues to learn and remember information. Consider the set of 20 items below that are easy to learn and remember (Bower & Reitman, 1972).

• is a gun. 11 is penny-one, hot dog bun.
• is a shoe. 12 is penny-two, airplane glue.
• is a tree. 13 is penny-three, bumble bee.
• is a door. 14 is penny-four, grocery store.
• is knives. 15 is penny-five, big beehive.
• is sticks. 16 is penny-six, magic tricks.
• is oven. 17 is penny-seven, go to heaven.
• is plate. 18 is penny-eight, golden gate.
• is wine. 19 is penny-nine, ball of twine.
• is hen. 20 is penny-ten, ballpoint pen.

It would probably take you less than 10 minutes to learn this list and practice recalling it several times (remember to use retrieval practice!). If you were to do so, you would have a set of peg words on which you could “hang” memories. In fact, this mnemonic device is called the peg word technique . If you then needed to remember some discrete items—say a grocery list, or points you wanted to make in a speech—this method would let you do so in a very precise yet flexible way. Suppose you had to remember bread, peanut butter, bananas, lettuce, and so on. The way to use the method is to form a vivid image of what you want to remember and imagine it interacting with your peg words (as many as you need). For example, for these items, you might imagine a large gun (the first peg word) shooting a loaf of bread, then a jar of peanut butter inside a shoe, then large bunches of bananas hanging from a tree, then a door slamming on a head of lettuce with leaves flying everywhere. The idea is to provide good, distinctive cues (the weirder the better!) for the information you need to remember while you are learning it. If you do this, then retrieving it later is relatively easy. You know your cues perfectly (one is gun, etc.), so you simply go through your cue word list and “look” in your mind’s eye at the image stored there (bread, in this case).

This peg word method may sound strange at first, but it works quite well, even with little training (Roediger, 1980). One word of warning, though, is that the items to be remembered need to be presented relatively slowly at first, until you have practice associating each with its cue word. People get faster with time. Another interesting aspect of this technique is that it’s just as easy to recall the items in backwards order as forwards. This is because the peg words provide direct access to the memorized items, regardless of order.

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” (elaborate scenes with discrete places) 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, as in the demonstration at the beginning of the module. As noted, his record is 240 digits, recalled in exact order. Simon also holds the world record in an event called “speed cards,” which involves memorizing the precise order of a shuffled deck of cards. Simon was able to do this in 21.19 seconds! Again, he uses his memory palaces, and he encodes groups of cards as single images.

How to Study Effectively

Based on the information presented in this chapter, here are some strategies and suggestions to help you hone your study techniques (Figure 26). The key with any of these strategies is to figure out what works best for you.

• Use elaborative rehearsal : In a famous article, Craik and Lockhart (1972) discussed their belief that information we process more deeply goes into long-term memory. Their theory is called levels of processing . If we want to remember a piece of information, we should think about it more deeply and link it to other information and memories to make it more meaningful. For example, if we are trying to remember that the hippocampus is involved with memory processing, we might envision a hippopotamus with excellent memory and then we could better remember the hippocampus.
• Apply the self-reference effect : As you go through the process of elaborative rehearsal, it would be even more beneficial to make the material you are trying to memorize personally meaningful to you. In other words, make use of the self-reference effect. Write notes in your own words. Write definitions from the text, and then rewrite them in your own words. Relate the material to something you have already learned for another class, or think how you can apply the concepts to your own life. When you do this, you are building a web of retrieval cues that will help you access the material when you want to remember it.
• Don’t forget the forgetting curve : As you know, the information you learn drops off rapidly with time. Even if you think you know the material, study it again right before test time to increase the likelihood the information will remain in your memory. Overlearning can help prevent storage decay.
• Rehearse, rehearse, rehearse : Review the material over time, in spaced and organized study sessions. Organize and study your notes, and take practice quizzes/exams. Link the new information to other information you already know well.
• Be aware of interference : To reduce the likelihood of interference, study during a quiet time without interruptions or distractions (like television or music).
• Keep moving : Of course you already know that exercise is good for your body, but did you also know it’s also good for your mind? Research suggests that regular aerobic exercise (anything that gets your heart rate elevated) is beneficial for memory (van Praag, 2008). Aerobic exercise promotes neurogenesis: the growth of new brain cells in the hippocampus, an area of the brain known to play a role in memory and learning.
• Get enough sleep : While you are sleeping, your brain is still at work. During sleep the brain organizes and consolidates information to be stored in long-term memory (Abel & Bäuml, 2013).
• Make use of mnemonic devices : As you learned earlier in this chapter, mnemonic devices often help us to remember and recall information. There are different types of mnemonic devices, such as the acronym. An acronym is a word formed by the first letter of each of the words you want to remember. For example, even if you live near one, you might have difficulty recalling the names of all five Great Lakes. What if I told you to think of the word Homes? HOMES is an acronym that represents Huron, Ontario, Michigan, Erie, and Superior: the five Great Lakes. Another type of mnemonic device is an acrostic: you make a phrase of all the first letters of the words. For example, if you are taking a math test and you are having difficulty remembering the order of operations , recalling the following sentence will help you: “Please Excuse My Dear Aunt Sally,” because the order of mathematical operations is Parentheses, Exponents, Multiplication, Division, Addition, Subtraction. There also are jingles, which are rhyming tunes that contain keywords related to the concept, such as i before e, except after c .
• Create a mnemonic device to help you remember a term or concept from this module.
• What is an effective study technique that you have used? How is it similar to/different from the strategies suggested in this module?

In this chapter, you learned to

• explain the process of memory
• explain and give examples of forgetting and memory failure
• recognize and apply memory-enhancing strategies

Memory is the set of processes used to encode, store, and retrieve information over different periods of time. Interestingly, our memory is prone to errors and we sometimes remember things that never happened, misconstrue things that did, and forget things we shouldn’t.

More and more memory researchers are digging deeper to better understand the place where memories are stored in the brain, also known as engrams. Fascinating new studies delve into memory reconsolidation, in which researchers more or less re-train a memory so that subjects no longer have the same memory trace. You can imagine the applications of this in helping someone with a phobia or post-traumatic stress disorder, for example, in reducing the efficacy of their fear memory.

Memory is important to our daily functioning and well-being, and it is of particular interest for students (like yourself!) because there is a lot to be remembered and little time to learn it all. You read about Ebbinghaus’ forgetting curve and memory decay and discovered some techniques to counteract forgetfulness, such as using mnemonics, chunking, the peg-word system, and elaborative rehearsal. A 2008 study sought to determine which type of studying is most effective in learning new words and concepts. The study, by Jeffrey D. Karpicke and Henry L. Roediger III, had students learn forty pairs of Swahili words and their meanings in English. After learning all forty words one time through, they were split into 4 groups for the rest of the learning phase:

• A group that studied all 40 words and got tested on all 40 words
• A group that studied only the words they didn’t know already, then were tested on all 40 words
• A group that studied all 40 words, but were tested only on the words they didn’t know
• A group that studied only the words they didn’t know already, then were tested on only the words they didn’t know already

Which way would be your preferred method for learning the new words? Do you ever study this way? A common study technique is to practice with flashcards, then put away the words you already know (similar to groups 2 or 4). Which group do you think learned the words the best a week later? It turns out that when tested one week later, both the first and second groups remembered about 80% of the words, while the third and fourth groups (that were tested only on the words they didn’t already know) only remembered about 35% of the words. This is a significant difference! This study demonstrated the importance of testing and the importance of retrieval practice in learning. This is why you may not want to complain too much if your instructor gives you a pop quiz, and also why it’s a good idea to force yourself to recall information and quiz yourself on the things you learn. [1]

Abel, M., & Bäuml, K.-H. T. (2013). Sleep can reduce proactive interference. Memory, 22(4), 332–339. doi:10.1080/09658211.2013.785570. Retrieved from http://www.psychologie.uni-regensburg.de/Baeuml/papers_in_press/sleepPI.pdf

Anderson, N. S. (1969). The influence of acoustic similarity on serial recall of letter sequences. Quarterly Journal of Experimental Psychology, 21(3), 248–255.

Anderson, R. C. (1984). Role of the reader’s schema in comprehension, learning, and memory. In R. C. Anderson, J. Osborn, & R. J. Tierney (Eds.), Learning to read in American schools: Basal Readers and Content Texts (pp. 243–257). Hillsdale, NJ: Erlbaum.

Atkinson, R. C., & Shiffrin, R. M. (1968). Human memory: A proposed system and its control processes. In K. W. Spence & J. T. Spence (Eds.), The psychology of learning and motivation: Volume 2 (pp. 89–195). New York, NY: Academic Press.

Baddeley, A. (2004). Your memory: A user’s guide. Richmond Hill, Canada: Firefly Books.

Baddeley, A. D., & Hitch, G. (1974). Working memory. In G. H. Bower (Ed.), The psychology of learning and motivation: Advances in research and theory (Vol. 8, pp. 47–89). New York, NY: Academic Press.

Bayley, P. J., & Squire, L. R. (2002). Medial temporal lobe amnesia: Gradual acquisition of factual information by nondeclarative memory. Journal of Neuroscience, 22, 5741–5748.

Bellezza, F. S. (1981). Mnemonic devices: Classification, characteristics and criteria. Review of Educational Research, 51, 247–275.

Benjamin N. Cardozo School of Law, Yeshiva University. (2009). Reevaluating lineups: Why witnesses make mistakes and how to reduce the chance of a misidentification. Retrieved from The Innocence Project website: http://www.innocenceproject.org/docs/Eyewitness_ID_Report.pdf

Berkowitz, S. R., Laney, C., Morris, E. K., Garry, M., & Loftus, E. F. (2008). Pluto behaving badly: False beliefs and their consequences.  American Journal of Psychology, 121 , 643–660

Bernstein, D. M., & Loftus, E. F. (2009b). The consequences of false memories for food preferences and choices.  Perspectives on Psychological Science, 4 , 135–139.

Bernstein, D. M., & Loftus, E. F., (2009a). How to tell if a particular memory is true or false.  Perspectives on Psychological Science, 4 , 370–374.

Bernstein, D. M., Laney, C., Morris, E. K., & Loftus, E. F. (2005). False memories about food can lead to food avoidance.  Social Cognition, 23 , 11–34.

Blockland, A. (1996). Acetylcholine: A neurotransmitter for learning and memory? Brain Research Reviews, 21, 285–300.

Bodie, G. D., Powers, W. G., & Fitch-Hauser, M. (2006). Chunking, priming, and active learning: Toward an innovative approach to teaching communication-related skills. Interactive Learning Environment, 14(2), 119–135.

Bousfield, W. (1935). The occurrence of clustering in the recall of randomly arranged associates. Journal of General Psychology, 49, 229–240.

Bransford, J. D., & McCarrell, N. S. (1974). A sketch of a cognitive approach to comprehension. In W. B. Weimer & D. J. Palermo (Eds.), Cognition and the symbolic processes (pp. 189–229). Hillsdale, NJ: Lawrence Erlbaum Associates.

Braun, K. A., Ellis, R., & Loftus, E. F. (2002). Make my memory: How advertising can change our memories of the past.  Psychology and Marketing, 19 , 1–23.

Briere, J., & Conte, J. (1993). Self-reported amnesia for abuse in adults molested as children. Journal of Traumatic Stress, 6, 21–31.

Carli, L. (1999). Cognitive reconstruction, hindsight, and reactions to victims and perpetrators. Personality and Social Psychology Bulletin, 25(8), 966–979. doi:10.1177/01461672992511005

Ceci, S. J., & Bruck, M. (1993). Child witness: Translating research into policy. Social Policy Report, 7(3), 1–30.

Ceci, S. J., & Bruck, M. (1995). Jeopardy in the courtroom: A scientific analysis of children’s testimony. Washington, DC: American Psychological Association.

Cheit, R. E. (2007). The recovered memory project. Retrieved from http://blogs.brown.edu/recoveredmemory/.

Christianson, S. A. (1992). The handbook of emotion and memory: Research and theory. Hillsdale, NJ: Erlbaum.

Clark, R. E., Zola, S. M., & Squire, L. R. (2000). Impaired recognition memory in rats after damage to the hippocampus. The Journal of Neuroscience, 20(23), 8853–8860.

Corkin, S. (1965). Tactually-guided maze learning in man: Effects of unilateral cortical excisions and bilateral hippocampal lesions. Neuropsychologia, 3, 339–351.

Corkin, S. (1968). Acquisition of motor skill after bilateral medial temporal-lobe excision. Neuropsychologia, 6, 255–264.

Corkin, S., Amaral D. G., González, R. G., Johnson, K. A., & Hyman, B. T. (1997). H. M.’s medial temporal lobe lesion: Findings from magnetic resonance imaging. Journal of Neuroscience, 17(10), 3964–3979.

Craik, F. I. M., & Lockhart, R. S. (1972). Levels of processing: A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 11, 671–684.

Craik, F. I. M., Moroz, T. M., Moscovitch, M., Stuss, D. T., Winocur, G., Tulving, E., & Kapur, S. (1999). In search of the self: A positron emission tomography study. Psychological Science, 10(1), 26–34.

Craik, F. I. M., & Tulving, E. (1975). Depth of processing and the retention of words in episodic memory. Journal of Experimental Psychology, 104(3), 268–294.

Craik, F. I. M., & Watkins, M. J. (1973). The role of rehearsal in short-term memory. Journal of Verbal Learning and Verbal Behavior, 12, 599–607.

Green, J. T., & Woodruff-Pak, D. S. (2000). Eyeblink classical conditioning in aging animals. In D. S. Woodruff-Pak & J. E. Steinmetz (Eds.), Eyeblink classical conditioning: Animal models (Vol. 2, pp.155–178). Boston, MA: Kluwer Academic.

Greenberg, D. L. (2004). President Bush’s false [flashbulb] memory of 9/11/01. Applied. Cognitive Psychology, 18(3), 363–370. doi:10.1002/acp.1016

Devilly, G. J. (2007). If nothing happened why do I still hurt? An update on the memory wars. InPsych, 29(2), 16–18.

Ebbinghaus, H. (1964). Memory: A contribution to experimental psychology (H. A. Ruger & C. E. Bussenius, Trans.). New York, NY: Dover. (Original work published 1885)

Goodman, G. S. (2006). Children’s eyewitness memory: A modern history and contemporary commentary. Journal of Social Issues, 62, 811–832.

Hassabis D., & Maguire E. A. (2007). Deconstructing episodic memory with construction. Trends in Cognitive Sciences, 11(7), 299–306.

Hyman, I. E., Jr., Husband, T. H., & Billings, F. J. (1995). False memories of childhood experiences.  Applied Cognitive Psychology, 9 , 181–197.

Jacobs, J. (1887). Experiments on “prehension.” Mind, 12, 75–79.

Josselyn, J. A. (2010). Continuing the search for the engram: Examining the mechanism of fear memories. Journal of Psychiatry Neuroscience, 35(4), 221–228.

Kapur, S., Craik, F. I. M., Tulving, E., Wilson, A. A., Houle, S., & Brown, G. M. (1994). Neuroanatomical correlates of encoding in episodic memory: Levels of processing effect. Proceedings of the National Academy of Sciences of the United States of America, 91(6), 208–2011.

Lashley K. S. (1950). In search of the engram. Society of Experimental Biology Symposium, 4: Psychological Mechanisms in Animal Behavior. Cambridge, UK: Cambridge University Press.

Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory.  Learning & Memory, 12 (4), 361-366.

Loftus, E. F. (1975). Leading questions and the eyewitness report.  Cognitive Psychology, 7 (4), 560-572.

Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of auto-mobile destruction: An example of the interaction between language and memory. Journal of Verbal Learning and Verbal Behavior, 13, 585–589.

Loftus, E. F., & Pickrell, J. E. (1995). The formation of false memories.  Psychiatric Annals, 25 , 720–725.

Loftus, E. F., Ketcham, K. (1994).  The myth of repressed memory . New York, NY: St. Martin’s Press.

Loftus, E. F., Miller, D. G., & Burns, H. J. (1978). Semantic integration of verbal information into a visual memory.  Journal of Experimental Psychology: Human Learning and Memory, 4 (1), 19.

MacLeod, C. M., Gopie, N., Hourihan, K. L., Neary, K. R., & Ozubko, J. D. (2010). The production effect: Delineation of a phenomenon. Journal of Experimental Psychology: Learning, Memory, and Cognition, 36(3), 671–685.

Mayford, M., Siegelbaum, S. A., & Kandel, E. R. (2012). Synapses and memory storage. New York, NY: Cold Spring Harbor Perspectives in Biology, Cold Spring Harbor Laboratory Press.

McGaugh, J. L. (2003). Memory and emotion: The making of lasting memories. New York, NY: Columbia University Press.

McLeod, S. A. (2011). Anterograde amnesia [Web log post]. Retrieved from http://www.simplypsychology.org/anterograde-amnesia.html

Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 68, 81–87.

Myhrer, T. (2003). Neurotransmitter systems involved in learning and memory in the rat: A meta-analysis based on studies of four behavioral tasks. Brain Research Reviews, 41(2–3), 268–287.

Newseum. (n.d.). G-men and journalists: D. C. sniper [Web log post]. Retrieved from http://www.newseum.org/exhibits-and-theaters/temporary-exhibits/g-men-and-journalists/sniper/

Nickerson, R. S., & Adams, M. J. (1979). Long-term memory for a common object. Cognitive Psychology, 11(3), 287–307.

Paivio, A. (1986). Mental representations: A dual coding approach. New York, NY: Oxford University Press.

Parker, E. S., Cahill, L., & McGaugh, J. L. (2006). A case of unusual autobiographical remembering. Neurocase, 12, 35–49.

Payne, B. K., Jacoby, L. L., & Lambert, A. J. (2004). Memory monitoring and the control of stereotype distortion. Journal of Experimental Social Psychology, 40, 52–64.

Pew Research Center (2011, September 1). Ten years after 9/11: United in remembrance, divided over policies. Washington, DC: People Press.

Pipe, M.-E. (1996). Children’s eyewitness memory. New Zealand Journal of Psychology, 25(2), 36–43.

Pipe, M.-E., Lamb, M., Orbach, Y., & Esplin, P. W. (2004). Recent research on children’s testimony about experienced and witnessed events. Developmental Review, 24, 440–468.

Pyc, M. A., & Rawson, K. A. (2009). Testing the retrieval effort hypothesis: Does greater difficulty correctly recalling information lead to higher levels of memory?  Journal of Memory and Language, 60 , 437–447.

Roediger, H. L. (1980). The effectiveness of four mnemonics in ordering recall.  Journal of Experimental Psychology: Human Learning and Memory, 6 , 558.

Roediger, H. L., & DeSoto, K. A. (in press). The psychology of reconstructive memory. In J. Wright (Ed.), International Encyclopedia of the Social and Behavioral sciences, 2e. Oxford, UK: Elsevier.

Roediger, H. L., III, & McDermott, K. B. (2000). Tricks of memory. Current Directions in Psychological Science, 9, 123–127.

Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention.  Psychological Science, 17 , 249–255.

Roediger, H. L., & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists.  Journal of Experimental Psychology-Learning Memory and Cognition, 21 , 803–814.

Rogers, T. B., Kuiper, N. A., & Kirker, W. S. (1977). Self-reference and the encoding of personal information. Journal of Personal Social Psychology, 35(9), 677–688.

Schacter, D. (2001). The seven sins of memory: How the mind forgets and remembers. New York, NY: Houghton Mifflin.

Stadler, M. A., Roediger, H. L., & McDermott, K. B. (1999). Norms for word lists that create false memories.  Memory & Cognition, 27 , 494–500.

Steinmetz, J. E. (1999). A renewed interest in human classical eyeblink conditioning. Psychological Science, 10, 24–25.

Takarangi, M. K., Parker, S., & Garry, M. (2006). Modernising the misinformation effect: The development of a new stimulus set.  Applied Cognitive Psychology: The Official Journal of the Society for Applied Research in Memory and Cognition, 20 (5), 583-590.

Tigner, R. B. (1999). Putting memory research to good use. College Teaching, 47(4), 149–152.

Tulving, E. (2002, February). Episodic memory: From mind to brain. Annual Review of Psychology, 53, 1–25. doi:10.1146/annurev.psych.53.100901.135114

Tulving, E. (2007). Are there 256 different kinds of memory? In J.S. Nairne (Ed.),  The foundations of remembering: Essays in honor of Henry L. Roediger, III  (pp. 39–52). New York: Psychology Press.

Tulving, E. (1991). Interview.  Journal of Cognitive Neuroscience, 3 , 89–94

Tulving, E., & Bower, G. H. (1975). The logic of memory representations.  The psychology of learning and motivation, 8 , 265-301.

Tulving, E., & Pearlstone, Z. (1966). Availability versus accessibility of information in memory for words.  Journal of Verbal Learning and Verbal Behavior, 5 , 381–391.

Tulving, E., & Thomson, D. M. (1973). Encoding specificity and retrieval processes in episodic memory.  Psychological Review, 80 , 352–373.

van Praag, H. (2008). Neurogenesis and exercise: Past and future directions. NeuroMolecular Medicine, 10(2), 128–140.

Wells, G. L., & Quinlivan, D. S. (2009). Suggestive eyewitness identification procedures and the Supreme Court’s reliability test in light of eyewitness science: 30 years later. Law and Human Behavior, 33, 1–24. doi:10.1007/s10979-008-9130-3

Wrubel, B. (Writer), & Spiller, M. (Director). (2010). The Old Wagon [Television series episode]. In S. Levitan & C. Lloyd (Executive producers), Modern Family. 20th Century Fox Television.

Yogo, M., & Fujihara, S. (2008). Working memory capacity can be improved by expressive writing: A randomized experiment in a Japanese sample. British Journal of Health Psychology, 13(1), 77–80. doi:10.1348/135910707X25244

CC licensed content, original

• Memory. Authored by: Karenna Malavanti.  Provided by:  PressBooks.  License:  License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike

CC licensed content, Shared previously

• Introduction to How Memory Functions.  Provided by : Lumen Learning. License : CC BY: Attribution Located at :  https://pressbooks.online.ucf.edu/lumenpsychology/chapter/outcome-how-memory-functions/
• Introduction to Memory. Authored by : OpenStax College. License : CC BY: Attribution . License Terms : Download for free at https://openstax.org/books/psychology-2e/pages/1-introduction Located at : https://openstax.org/books/psychology-2e/pages/8-introduction .
• Brain picture. Authored by : John Hain. Provided by : Pixabay. License : CC0: No Rights Reserved Located at : https://pixabay.com/en/brain-mind-obsession-work-activity-954823/ .
• How Memory Functions. Authored by : OpenStax College. License : CC BY: Attribution . License Terms : Download for free at https://openstax.org/books/psychology-2e/pages/1-introduction Located at : https://openstax.org/books/psychology-2e/pages/8-1-how-memory-functions
• Memory (Encoding, Storage, Retrieval). Authored by : Kathleen B. McDermott and Henry L. Roediger III for Noba textbook series: Psychology.  License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike   Located at : http://nobaproject.com/textbooks/wendy-king-introduction-to-psychology-the-full-noba-collection/modules/memory-encoding-storage-retrieval .
• Encoding.  Provided by : Lumen Learning. License : CC BY: Attribution Located at : https://pressbooks.online.ucf.edu/lumenpsychology/chapter/how-memory-functions/
• Retrieval.  Provided by : Lumen Learning. License : CC BY: Attribution Located at :  https://pressbooks.online.ucf.edu/lumenpsychology/chapter/reading-retrieval/
• Parts of the Brain Involved with Memory.  Provided by : Lumen Learning. License : CC BY: Attribution Located at : https://pressbooks.online.ucf.edu/lumenpsychology/chapter/parts-of-the-brain-involved-with-memory/
• Introduction to Forgetting and Other Memory Problems.  Provided by : Lumen Learning. License : CC BY: Attribution Located at : https://pressbooks.online.ucf.edu/lumenpsychology/chapter/outcome-forgetting/
• Don’t forget picture. Authored by : Rachel Demsick. Provided by : Flickr. License : CC BY: Attribution
• Problems with Memory. Authored by : OpenStax College. License : CC BY: Attribution . License Terms : Download for free at https://openstax.org/books/psychology-2e/pages/1-introduction Located at : https://openstax.org/books/psychology-2e/pages/8-3-problems-with-memory
• Figure 2.  Authored by : Nicole Dudukovic and Brice Kuhl . Provided by : New York University. Project : The Noba Project. License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike Located at : http://nobaproject.com/textbooks/wendy-king-introduction-to-psychology-the-full-noba-collection/modules/forgetting-and-amnesia .
• Amensia.  Provided by : Lumen Learning. License : CC BY: Attribution Located at : https://pressbooks.online.ucf.edu/lumenpsychology/chapter/problems-with-memory/
• Forgetting.  Provided by : Lumen Learning. License : CC BY: Attribution Located at https://pressbooks.online.ucf.edu/lumenpsychology/chapter/reading-forgetting/
• Forgetting Interactive. Authored by : Jessica Traylor for Lumen Learning. Provided by : Lumen Learning. License : CC BY: Att ribution
• Section on deliberately forgetting memories and image. Authored by : Nicole Dudukovic and Brice Kuhl . Provided by : New York University. Project : The Noba Project. License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike   Located at : http://nobaproject.com/textbooks/wendy-king-introduction-to-psychology-the-full-noba-collection/modules/forgetting-and-amnesia .
• Eyewitness Testimony and Memory Construction.  Provided by : Lumen Learning. License : CC BY: Attribution Located at:  https://pressbooks.online.ucf.edu/lumenpsychology/chapter/reading-eyewitness-testimony-and-memory-construction/
• False Memories and more on the Misinformation Effect. Authored by : Cara Laney and Elizabeth F. Loftus . Provided by : Reed College, University of California, Irvine. Project : The Noba Project. License : CC BY: Attribution   Located at : http://nobaproject.com/textbooks/wendy-king-introduction-to-psychology-the-full-noba-collection/modules/eyewitness-testimony-and-memory-biases .
• Introduction to Improving Memory.  Provided by : Lumen Learning. License : CC BY: Attribution Located at: https://pressbooks.online.ucf.edu/lumenpsychology/chapter/outcome-improving-memory/
• Ways to Enhance Memory.  Provided by : Lumen Learning. License : CC BY: Attribution Located at https://pressbooks.online.ucf.edu/lumenpsychology/chapter/ways-to-enhance-memory/
• Ways to Enhance Memory. Authored by : OpenStax College. License : CC BY: Attribution . License Terms : Download for free at https://openstax.org/books/psychology-2e/pages/1-introduction   Located at : https://openstax.org/books/psychology-2e/pages/8-4-ways-to-enhance-memory .
• The Peg-Word System. Authored by : Kathleen B. McDermott and Henry L. Roediger III . Provided by : Washington University in St. Louis. Project : The Noba Project. License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike   Located at : http://nobaproject.com/textbooks/wendy-king-introduction-to-psychology-the-full-noba-collection/modules/memory-encoding-storage-retrieval .
• Putting It Together: Memory. Provided by : Lumen Learning. License : CC BY: Attribution Located at: https://pressbooks.online.ucf.edu/lumenpsychology/chapter/putting-it-together-memory/
• Flashcards. Authored by : Jonathon Trumball. Provided by : Flicrk. License : CC BY: Attribution   Located at : https://www.flickr.com/photos/jonathantrumbull/49841444 .

All rights reserved content

• Why Is Riding a Bike Just Like Riding a Bike?. Provided by : SciShow Psych. License : All Rights Reserved Located at : https://www.youtube.com/watch?v=Q0wfm9wrhXA&list=PL73K_0Mtyy1_Gf07IuKSc24_yh3tNyDXW&index=13 .
• Endless Memory, Part 1. Provided by : CBS News. License : All Rights Reserved . License Terms : Standard YouTube License Located at : https://www.youtube.com/watch?v=2zTkBgHNsWM .
• How We Make Memories – Crash Course Psychology #13. Provided by : CrashCourse. License : Other . License Terms : Standard YouTube License Located at : https://youtu.be/bSycdIx-C48?list=PL8dPuuaLjXtOPRKzVLY0jJY-uHOH9KVU6
• Psych:  Flashbulb Memory. Authored by : The School of Ireland. License : Other. License Terms : Standard YouTube License Located at : https://www.youtube.com/watch?v=bLaRYETCPJY .
• The Misinformation Effect. Authored by : Eureka Foong. License : Other . License Terms : Standard YouTube License . Located at : https://www.youtube.com/watch?v=iMPIWkFtd88 .
• Karpicke, J. D., & Roedinger, H. L., III. (n.d.). The Critical Importance of Retrieval for Learning. Science, 319, 966-968. doi:10.1126/science.1152408 ↵

set of processes used to encode, store, and retrieve information over different periods of time

holds about seven bits of information before it is forgotten or stored, as well as information that has been retrieved and is being used

type of declarative memory that contains information about events we have personally experienced, also known as autobiographical memory

type of declarative memory about words, concepts, and language-based knowledge and facts

episodic memories of your life

input of information into the memory system

creation of a permanent record of information

act of getting information out of long-term memory storage and back into conscious awareness

input of words and their meaning

input of images

input of sounds, words, and music

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

memory model that states we process information through three systems: sensory memory, short-term memory, and long-term memory

storage of brief sensory events, such as sights, sounds, and tastes

repetition of information to be remembered

the neural processes that occur between an experience and the stabilization of the memory

continuous storage of information

memories we consciously try to remember and recall

type of long-term memory of facts and events we personally experience

memories that are not part of our consciousness

type of long-term memory for making skilled actions, such as how to brush your teeth, how to drive a car, and how to swim

The hypothesis that a retrieval cue will be effective to the extent that information encoded from the cue overlaps or matches information in the engram or memory trace.

The principle stating that the more memories that are associated to a particular retrieval cue, the less effective the cue will be in prompting retrieval of any one memory.

accessing information without cues

identifying previously learned information after encountering it again, usually in response to a cue

learning information that was previously learned

A term indicating the change in the nervous system representing an event; also, memory trace.

some parts of the brain can take over for damaged parts in forming and storing memories

strong emotions trigger the formation of strong memories and weaker emotional experiences form weaker memories

Vivid personal memories of receiving the news of some momentous (and usually emotional) event.

loss of long-term memory that occurs as the result of disease, physical trauma, or psychological trauma

loss of memory for events that occur after the brain trauma

loss of memory for events that occurred prior to brain trauma

loss of information from long-term memory

memory error in which unused memories fade with the passage of time

lapses in memory that are caused by breaks in attention or our focus being somewhere else

memory error in which you cannot access stored information

memory error in which you confuse the source of your information

effects of misinformation from external sources that leads to the creation of false memories

how feelings and view of the world distort memory of past events

failure of the memory system that involves the involuntary recall of unwanted memories, particularly unpleasant ones

old information hinders the recall of newly learned information

information learned more recently hinders the recall of older information

after exposure to additional and possibly inaccurate information, a person may misremember the original event

technique to help make sure information goes from short-term memory to long-term memory

organizing information into manageable bits or chunks

thinking about the meaning of new information and its relation to knowledge already stored in your memory

memory aids that help organize information for encoding

information that is thought of more deeply becomes more meaningful and thus better committed to memory

Psychological Science: Understanding Human Behavior Copyright © by Karenna Malavanti is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

Share This Book

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

5 Module 5: Memory

Memory plays a key role in many areas of our lives, not the least of which is school. To understand why we remember and forget, you need to consider the entire memory process. Here’s a very simple description: First, you have to get information into your memory systems; call this process  encoding . When you need to get information out of memory (for example, when you are taking an exam, or telling a story), you use the process called  retrieval . In between encoding and retrieval we have, of course, memory  storage .

Failure to remember information—that is, forgetting—can occur because of a breakdown at any of the three points (encoding, storage, retrieval). The typical culprits in the failure to remember, however, are encoding and retrieval problems. That’s why most of this module is devoted to encoding and retrieval. But first you need to understand the basic layout of memory, which is a key element of cognition.

This module breaks psychologists’ basic understanding of memory into six sections. First it explains that not all forms of memory are alike and describes some of the different memory systems. The section introduces principles of encoding and explains how recoding is one of the keys to effective memory. The third section describes the processes that take place in the brain when information is encoded and stored in memory. The fourth section covers memory retrieval. The final section describes how memories are constructed and, sometimes, distorted.

5.1 Memory Systems

5.2 Encoding and Recoding

5.3 Memory Storage and Memory in the Brain

5.4 Memory Retrieval

5.5 memory construction and distortion.

encoding : putting information into memory systems

retrieval : taking information out of memory systems

storage :  keeping memories in the brain for future use

READING WITH PURPOSE

Remember and understand.

By reading and studying Module 5, you should be able to remember and describe:

• Distinctions among encoding, storage, and retrieval (5 introduction)
• Characteristics of sensory memory, working memory, and long-term memory (5.1)
• Characteristics of procedural memory and declarative memory (5.1)
• Methods of rehearsal for encoding: repetition, auditory encoding, semantic encoding (5.2)
• Strategies for semantic encoding: elaborative verbal rehearsal, self reference, mental images (5.2)
• Organizing to encode (5.3)
• Concept map and neural networks (5.4)
• Parts of a neuron: axon, dendrites, cell body (5.4)
• Synaptic plasticity (5.4)
• Retrieval cues (5.5)
• Memory distortion (5.6)

By reading and thinking about how the concepts in Module 5 apply to real life, you should be able to:

• Identify different kinds of memory (5.1)
• Characterize your own typical study strategies in terms of encoding and retrieval principles (5.2, 5.3, 5.5)
• Recognize a memory from your own life that might be distorted (5.6)

Analyze, Evaluate, and Create

By reading and thinking about Module 5, participating in classroom activities, and completing out-of-class assignments, you should be able to:

• Devise a strategy for studying that uses encoding and retrieval principles (5.2, 5.3, 5.5)
• Recognize a situation in which you would suspect a memory distortion (5.6)
• Can you think of more than one kind of memory that you have drawn upon?
• Why can you remember a birthday party you attended years ago, but forget what your instructor said seconds ago? 
• Is it true that some memories can last a lifetime?
• Is it true that “you never forget how to ride a bicycle?” 

When you first start to think about it, memory might seem pretty simple.  But consider some of the memories you might have:

• What you had for breakfast this morning
• Your 10th birthday party
• The address someone just left on your voicemail
• Your phone number
• What your best friend looks like
• What a cat is
• How to read
• What you read in section 1.2 of this book
• The answer to question 3 on your History mid-term
• The name of the person you just met
• How to do a cartwheel

All of these phenomena are, at their core, memories, which means that they share some fundamental properties. Yet they have significant differences, too. It has been a major accomplishment of memory researchers to describe the different types of memory systems and processes, and determine the specific properties of each one.

Distinguishing by duration and purpose of the memory

We have two major memory systems that help to explain how memories are stored: working memory (sometimes referred to as short-term memory, although the actual meaning is not identical) and long-term memory. The process of creating a memory that you will remember for a test you will be taking next week and beyond involves both systems working together.

Soon after information is first encountered, it enters the system called working memory, simply by virtue of the fact that you pay attention to it (Baddeley and Hitch, 1974). The best way to understand working memory is to think of it as the current contents of your consciousness—that is, whatever you are thinking about right now. So as you are sitting at your desk staring at a textbook, the words that you pay attention to enter into working memory. You hold information in working memory either because you are going to use it (for example, to solve some problem) or because you will be trying to transfer, or encode it, into long-term memory.

Long-term memory is the memory system that holds information for periods of time ranging from a few minutes to many years. If you do not use or transfer the information in working memory into long-term memory, it will be forgotten, probably in less than thirty seconds (Peterson & Peterson, 1959).

One fact you should realize about working memory is that its capacity is limited. Psychologists had thought that people can generally hold about 7 pieces, or  chunk s, of information in working memory at one time (Miller, 1956). A chunk is a unit of meaningful information. For example, an individual letter might be a chunk. If the letters can be ordered to form words or abbreviations, then these are the chunks. More recently, however, researchers have proposed that memory capacity is a function of time, not quantity. Specifically, our working memory may hold the amount of information that we can process in about two seconds (Baddeley, 1986, 1996).

If you manage to get the information from working memory encoded into long-term memory, it is possible that you can retain that information for many years. It can even last a lifetime; picture a 92 year-old grandmother who still tells stories about her childhood in Italy. Also, although that “I can’t study any more because my brain is full” feeling may make you think otherwise, you can essentially store a limitless amount of information in long-term memory (Landauer, 1986).

One of the keys to good memory, then, is to have effective strategies for encoding information into long-term memory (see section 5.2). You typically store the general meaning of information in long-term memory, however, rather than precisely what you encountered (Brewer, 1977).

Working memory and long-term memory are not the only two memory storage systems. Another one is called  sensory memory , and it actually comes into play before working memory does (Sperling, 1960; Crowder & Morton, 1969). Sensory memory is an extremely accurate, very short duration system. It essentially stores the information taken in by the senses, vision and hearing, just long enough (about a second) to allow you to direct attention to it so you can get the information into working memory.

Distinguishing by the kind of information in the memory

Can you do a backflip? Former World’s Strongest Man Eddie Hall can.

Procedural Memory

This ability to do a backflip is a skill, or a memory, like riding a bicycle, tying one’s shoes, or hitting a tennis ball. These types of memories, however, seem very different from remembering what you had for dinner last night or remembering that Albany is the capital of New York.

Psychologists, too, have noticed this distinction and have given the two kinds of memories different names.  Procedural memory refers to skills and procedures. These are memories for things that you can do.  Declarative memory refers to facts and episodes (Cohen & Eichenbaum, 1993). Declarative memory is further subdivided into  semantic memory —your general store of knowledge, such as facts and word meanings, and  episodic memory — memory for events, or episodes from your life. So, if you remember that Bismarck is the capital of North Dakota, it is semantic memory, unless you remember the exact time that you learned this fact (in 5th grade social studies, for example), in which case it would be episodic memory. So you see, as the details about when we first learned some piece of information fade, episodic memories can become semantic memory.

https://youtube.com/watch?v=8Ik57i3e7NE

Declarative Memory

Procedural memory seems to operate by different rules than declarative memory. For example, when we talk about transferring information from working memory to long-term memory (encoding) and retrieving information from long-term memory back into working memory, we are talking about declarative memory only. There is no working memory for procedures. Acquiring a procedural memory typically takes much more practice than acquiring a declarative memory does. But once a skill is acquired (that is, once it becomes part of your procedural memory), it may well be there to stay. So, at least for some people, it is probably true that you never forget how to ride a bicycle.

(See Module 9 for a related distinction called explicit and implicit memory)

chunk : a unit of meaningful information

declarative memory : memory for facts and episodes

episodic memory : the part of declarative memory that refers to specific events or episodes from someone’s life

long-term memory : an essentially unlimited, nearly permanent memory storage system

procedural memory : memory for skills and procedures

semantic memory : the part of declarative memory that refers to one’s general store of knowledge

sensory memory : a very short (about one second), extremely accurate memory system that holds information long enough for an individual to pay attention to it

working memory : a short-term memory storage system that holds information in consciousness for immediate use or to transfer it into long long-term memory

• Think about the last time you forgot something. Was the forgetting a problem with working memory or long-term memory?
• What is your most interesting procedural memory? Have you ever tried to teach it to someone else? If so, how did you do it?
• What is your earliest declarative memory? (Use an episode from your life rather than trying to figure out the first fact that you learned.) Do you think that your declarative memory is good or poor?

5.2 Recode to Encode

• Have you ever finished reading a short section from a textbook and immediately realized that you have already forgotten what you just read?
• Have you ever looked at the first question on an exam for which you thought you had studied well and thought, “I have never seen this concept before in my life; am I in the right room?”
• Do you find yourself able to remember unimportant material for a class (for example, material not on the test) and unable to remember important material?
• Please turn to the beginning of Module 5. Notice the description and list of all the sections that fit within the Module. Now go find a couple of textbooks from your other classes and look at the outlines in the first pages of some chapters or at least at the table of contents. (Seriously, go look! We’ll wait.) Why are these outlines included?

Think about your best friend for a moment. What were they wearing the last time you were together? You will often find yourself unable to remember information like this. Why? Because you probably never attempted to encode that information from working memory into long-term memory. You didn’t look at your friend and say, “Lisa looks so good today; I’m going to remember what she is wearing!”

Certainly, information sometimes makes it into long-term memory without you engaging in purposeful encoding. Perhaps you have an annoying song going through your head right now. It is not very likely that when you first heard the song, you said to yourself, “Hey, I better make sure I memorize this song.” (You might be interested to know that psychologists have studied this phenomenon of annoying songs you cannot get out of your head. They call them earworms –see Jakubowski et al. 2017). But do not count on this accidental encoding to provide you with a solid memory when you need it. The simple truth is if you want to be able to retrieve information from long-term memory, you have to do a very good job of putting it in there in the first place.

How do you effectively encode information into long-term memory?

The basic strategy that people use to encode information from working memory into long-term memory is  rehearsal. All of the encoding strategies in this module are kinds of rehearsal. The simplest kind of rehearsal is straight  repetition.  Imagine trying to learn your French vocabulary words by mentally running through the vocabulary list over and over until you get them all right. It works ok, as long as the test was soon after you finish studying (about 15 seconds seems to be the ideal delay; anything more than that and you start forgetting). Although it may be one of the most common rehearsal strategies and is the one favored by many students, repetition is probably one of the least effective. Call this encoding without recoding. And the advice about it bears repeating: Encoding without recoding (in other words, straight repetition) is a poor way to encode information from working memory into long-term memory.

One specific situation in which many people have difficulty encoding is when they read textbooks. Have you ever read a paragraph, realized that you have immediately forgotten it, and as a consequence decided to re-read it? Often, the problem is that you are merely reading the words over in your head, making sure you can “hear” yourself silently saying the words. In this case, you are  recoding : transforming the information from one form into another. But the transformation in this case is minor and not very useful. Psychologists call it  auditory encoding or  acoustic encoding . Auditory encoding is ok. Many students rely on it, and with enough effort they do fairly well at school.

In order to remember better, however, there is no question that you should try to move to the next level of recoding, in which you transform the information into something meaningful. For example, Craik and Tulving (1975) developed the idea of  semantic encoding (Craik & Tulving 1975). Semantic means “meaning,” so semantic encoding refers to mentally processing the meaning of information. For example, you should pay attention to patterns and relationships and their significance, rather than just the words or numbers themselves.

Psychologist F. I. M. Craik and his colleagues demonstrated the benefits of using semantic encoding in a famous series of experiments during the 1970’s (Craik and Lockhart, 1972; Craik and Tulving, 1975). These experiments examined what Craik termed  levels of processing. In a typical experiment, participants would read a list of words with instructions that would encourage one specific type of encoding. The shallowest encoding strategy (or level of processing) required participants to pay attention to the visual appearance and shapes of the letters only. For example, a shallow encoding strategy would be to count how many straight and curved letters there are in each word. Note that you do not even need to read the words in order to use this strategy, so it would seem to be quite a poor recoding strategy. Somewhat “deeper” encoding strategies were those that required participants to pay attention to more properties of the words, such as the auditory qualities. For example, judging whether the word rhymes with a specific word is a deeper encoding strategy, an acoustic one. Note that you do not need to encode the meaning of the words in order to use this strategy.

The deepest level of processing, the one that requires meaningful recoding, is semantic encoding, or paying attention to the words’ meanings. A specific task to encourage semantic encoding might be to judge whether the word makes sense in the following sentence: “The __ fell down the stairs.”

Craik’s research consistently showed that memory was better the deeper the processing. Semantic processing was better than acoustic processing, which was better than visual processing. This is a basic principle of memory that you can start using today to improve your memory: to effectively encode, you should recode information in a way that allows you to process the meaning of what you are trying to remember.

auditory (acoustic) encoding: encoding from working memory into long-term memory by paying attention to the sounds of words only

levels of processing: strategies that affect how well a memory is encoded. Craik and Tulving’s research demonstrates that deeper processing (that is, semantic encoding) leads to better memory than shallower processing (that is, encoding based on auditory and visual properties)

recoding : transforming information to be encoded into a different format

rehearsal: the basic strategy that people use to encode information from working memory into long term memory

semantic encoding: encoding from working memory into long-term memory by paying attention to the meaning of words

How Can You Recode for Meaning?

One main reason that recoding for meaning helps to create solid memories is that it takes advantage of the format of information when it is stored in long-term memory. Try this: Tell a few minutes of the story “Goldilocks and the Three Bears” or any other story you know from your childhood. Did you tell the story word-for-word the way it was told to you? Probably not. But still you remembered the characters and the sequence of events quite well. Typically (but not always), long-term memory stores information by meaning, taking advantage of patterns and creating links between concepts and people and events (Bransford, Barclay, & Franks; 1972; Brewer, 1977). This tendency allows you to recall the general story, but not the precise story, whether it is a children’s fantasy, a description in a textbook, or some event that happens to you. When you make special efforts to encode meaning, you are playing to the natural tendencies and strengths of your long-term memory.

Any way that you can make information meaningful should help make your efforts to remember more successful. Here are some useful strategies that you can use for reading textbooks and remembering lectures and other course material:

Elaborative Verbal rehearsal and Self-Reference

Try elaborative verbal rehearsal, which is basically restating what you have just read or heard in your own words. After reading a short section or paragraph, pretend that a friend has asked you to explain it. Or pretend that you are trying to teach the material to someone. Although this can be difficult to do, the payoff is tremendous. In one study that compared high-performing and low-performing students who were taking General Psychology, the use of elaborative verbal rehearsal was the most important difference (Ratliff-Crain and Klopfleisch, 2005).

Use the  self-reference effect by trying to apply the material to yourself (Forsyth & Wibberly, 1993; Fujita, & Horiuchi, 2004, Jackson et al. 2019). Suppose you were trying to teach some course content to someone else. You might decide to use some real-life examples to help your students understand the material. Well, it turns out that this strategy is extremely powerful for remembering the material yourself. Continually ask yourself, “Can I think of an example of this concept from my own life?” or even simply, “How does this apply to me?” Creating a mental link between the course material and what it means to you is one of the very best ways to encode meaning. With practice, you should be able to use this strategy in many of your courses. The self-reference effect is very robust; it has been demonstrated with children, college students, older adults (with and without mild cognitive impairment), and adults and adolescents with autism (Jackson et al 2019; Lind et al. 2019).

Keep in mind as you consider trying these strategies that they can be hard to do, at least at first. It is certainly harder, and more time consuming, to do elaborative verbal rehearsal than to simply read a textbook chapter once. But it is no more time consuming than re-reading a chapter a few times because you know you will not be able to remember it. Also keep in mind that, as you get better at using the strategies, they grow more effective and get easier to use.

elaborative verbal rehearsal : an encoding technique that encourages semantic processing by restating to-be-remembered information in your own words, as if teaching it to someone else

self-reference effect : an encoding technique that encourages semantic processing by applying to-be-remembered information to yourself

Organize information.

Imagine that you are visiting a city for the first time. You have only a vague idea of where you are and you need to get to the post office. What you need is a map. A map can help you to learn where important things are and can help you figure out how to find them.

That is what the organizational aids in this book are, as well as the chapter outlines (and tables of contents) in other books and even web sitemaps. They are maps. They are useful for helping you effectively transfer information from working memory into long-term memory because they organize that information in a meaningful way.

If you can organize information meaningfully (or take advantage of a meaningful organization provided for you), it will be more effectively encoded into long-term memory (Bransford, Brown, & Cocking, 1999; Halpern, 1986). The beauty of this strategy from a practical standpoint in school is that often the work is done for you. Someone has already gone to the trouble of coming up with a meaningful organizational scheme. Use the chapter outlines to plot your route through your textbook. Pay attention during the first five minutes of lecture when your professor gives you a preview of the day’s lecture and activities.

Signaling Meaning in Advance

One of the reasons that outlines and previews help you put information into long-term memory is that they alert you in advance to the types of information you’ll be encountering. Sometimes just a little bit of information goes a long way. Even something as simple as knowing the title of reading material before you start reading allows you to organize the information so that it makes sense and can be remembered.

John Bransford and his colleagues demonstrated this kind of effect by asking two groups of research participants to remember a paragraph. For the first group, the paragraph alone was presented. Here is one of their paragraphs. See how well you think you would remember it:

The procedure is actually quite simple. First you arrange things into different groups. Of course, one pile may be sufficient depending on how much there is to do. If you have to go somewhere else due to lack of facilities that is the next step, otherwise you are pretty well set. It is important not to overdo things. That is, it is better to do too few things at once than too many. In the short run, this may not seem important but complications can easily arise. A mistake can be expensive as well. At first the whole procedure will seem complicated. Soon, however, it will become just another facet of life. It is difficult to foresee any end to the necessity of this task in the immediate future, but then one never can tell. After the procedure is completed one arranges the materials into different groups again. Then they can be put into their appropriate places. Eventually they will be used once more and the whole cycle will then have to be repeated. However, that is part of life (from Bransford and Johnson, 1972).

Do you think you would do a good job on a memory test for this paragraph? Bransford and Johnson’s participants did very poorly. Although the individual sentences are meaningful, it is difficult to see how they are related to each other—in other words, how they are organized.

The second group of participants read the same paragraph, but before doing so, they were given the title “Doing the Laundry.” Now that you know the title, go back and read the paragraph again and see if it makes sense. If you are like most of Bransford and Johnson’s participants, providing a title makes the paragraph much easier to understand and remember.

What Bransford and Johnson demonstrated is that the title allows readers to make inferences—that is, to use their background knowledge to tie the paragraph together. For example, in the second sentence, the title allows you to draw the inference that the word “things” refers to “clothes.” Inferences like these relate the formerly meaningless paragraph to the knowledge about the world that you already have. By providing a title, Bransford and Johnson allowed participants to activate their own knowledge about the way the world is organized before they started reading the paragraph. The title gave them preexisting memory hooks on which to hang the new words that they were reading.

Highlighting Relationships

In order for the technique of organizing to encode to work, you have to find the organization meaningful. That is, you have to see the organization as more than simply a list of topics. You need to learn to recognize the typical relationships between concepts. An outline or a table of contents, with items indented different amounts and different formatting for various levels of headings, also shows the relationships among the topics: which concepts can be grouped together, which are more important than others. To a very large degree, organizing information to improve encoding is simply a matter of paying attention to these types of relationships.

One very important relationship is between a general principle and an example of that principle. Look for clues in the text of your book, such as introductory phrases (“for example,” “the main idea is,” and the like). When you have identified whether a given statement is a general principle or an example, try to generate the other. If you think it is the general principle, try to come up with a new example. If you think it is an example, make sure you can identify the general principle.

Here are three other types of relationships you should make a habit of distinguishing in the materials you want to remember:

• Causes and effects.  For example, if we were doing an experiment on violent video games and aggression, the independent variable, exposure to violent video games, is the supposed cause, and the dependent variable, aggressiveness, is the supposed effect (see sec 2.3).
• Parts and wholes.  For example, a neuron is essentially a small part of the brain (the brain is made up of billions of neurons). Neurons themselves are composed of parts, including the cell body, dendrites, and axons (see secs 5.3/11.1).
• Levels of a hierarchy. A hierarchy is an organization system in which lower-level, or subordinate categories are included under higher-level, or superordinate categories. For example, the levels of living things that you probably learned in biology—kingdom, phylum, class, order, etc.—are organized in a hierarchy.

Any organization scheme that you come up with yourself will be particularly effective. Because you find it personally meaningful, a self-generated scheme will be easily and effectively encoded into long-term memory. You would be doing yourself a tremendous favor if you adopted a good strategy for generating these organizational schemes.

• In your own words, why is rephrasing textbook material in your own words an effective strategy for encoding information into long-term memory?
• Why can it be difficult to assemble something using a poorly written instruction manual?
• Try to think of a situation in your life where you were unable to understand or remember something because you did not know how it was organized.
• Why is it difficult to understand or remember a movie for which you missed the first 30 minutes ?

5.3 Memory Encoding and the Brain

What do you think of when you think of “dog”? Diagram your thoughts about “dog” by following these directions:

• On a sheet of paper draw a small circle in the middle of the page and write the word “dog” in the circle.
• Draw a short line out from this first circle and draw another circle at the end of the line; inside the new circle write a word that relates to the word dog(perhaps “tail”).
• Continue to draw lines out from the concept of dog and draw circles into which you write words that are related to dog. Also, draw some lines out from some of the new concepts and add concepts related to them. For example, if you wrote down “tail” you might connect it to a circle with the word “wag.”
• When you are finished writing down new concepts, take a few minutes to draw lines connecting some of the concepts that seem to be related.

The network of interrelated items that you have just created is a  concept map . Yours might look something like this:

A concept map is, among other things, a good way to organize information for encoding into long-term memory. It signals the meanings of a number of related concepts and highlights the relationships among them (remember our discussion in section 5.3?). A concept map is also a simple representation of how networks of concepts are formed in the brain.

Creating Memories in the Brain: Activation and Synaptic Plasticity

You may already know that the brain is made up of billions of cells called  neurons. For now, you can think of the brain as simply a very large collection of neurons. The neurons are all connected to each other in an extraordinarily complex pattern (one neuron can be simultaneously connected to many other neurons, all of which can be connected to many other neurons, and so on down the line). Neurons are connected to each other by axons , which look like single long branches extending from the cell body, which is the round part of the neuron, and by  dendrite s, which are smaller branches splitting off from the cell body. (Each neuron has a single axon but many dendrites.) Electrical and chemical activity that takes place through pathways created by these interconnected neurons determines everything we say, think, feel, or do (see sec 11.1).

The neurons are involved in two significant ways when you encode information:

• Activation . When you encode information and move it into memory, many neurons throughout the brain become active. The neural activity is pulses of electricity that are caused by chemicals called ions (electrically charged particles) briefly changing locations in your brain. The ions (sodium, which is abbreviated Na+) rush into the axon of a neuron. This movement of ions produces a brief electrical charge inside the neuron, which is then transmitted to many other neurons (see Module 11 for details).
• Synaptic plasticity . In order to store information for a long time, the brain has to change its very structure—that is, the neurons themselves must change. Brain researchers currently believe that the change in structure can occur either within the individual neurons or through the connections among the billions of neurons in your brain. The connections are called synapses, hence the name synaptic plasticity. Changes that occur inside the neuron cause the neuron to produce more or fewer of the chemicals that it uses to communicate with other neurons, which are called neurotransmitters (see sec 11.3). The synapses are located at the spaces where the axon of one neuron is situated next to the dendrites of a neighboring neuron. Two things can happen in response to changing levels of neurotransmitters: the axons and dendrites can extend or retract, hence changing, ever so slightly, the structure of your brain; and the surface of the neuron can change by having more or fewer receptive areas for neurotransmitters.  Both of these events are forms of synaptic plasticity and occur whenever new information is encountered.

These two kinds of changes, especially activation, happen extremely quickly. And the changes of synaptic plasticity can last a very long time, perhaps even forever. Think about it: any time you have a new experience your brain immediately changes its electrical activity and changes its structure permanently.

activation : the electrical charging of a neuron, which readies it to communicate with other neurons

axon : the single tube in a neuron that carries an electrical signal away, toward other neurons

dendrite : one of the many branches on a neuron that receive incoming signals

neuron : the basic cell of the nervous system; our brain has billions of neurons

neurotransmitter : chemical that carries a neural signal from one neuron to another

synapse : the area between two adjacent neurons, where neural communication occurs

synaptic plasticity : the brain’s ability to change its structure through tiny changes in the surfaces of neurons or in their ability to produce and release neurotransmitters

Storing Memories Across the Brain: Neural Networks

So far, we have just been thinking about connections between two neurons. Let us return now to the idea that neurons are connected to each other in massive three-dimensional, dynamic, organic versions of the concept map. We call these many interconnected neurons  neural network s. Many neuroscientists believe that most memories are not stored in a specific area of the brain but are spread out in interconnected neural networks across many areas of the brain. In other words, brain activation and synaptic plasticity for memories travel throughout the brain.

This neural network idea offers an explanation for why encoding meaning works so well in forming long-lasting memories. When you start searching through your brain for information—a memory—you will have a greater chance of hitting a unit of that information with a neural network that is spread out and contains a lot of information. A larger, more detailed network that uses lots of neurons will be easier to activate and use than a smaller network.

• Describe in your own words the changes that take place in your brain when you encode new information into long-term memory.
• Draw a concept map that includes the concepts from this module.

Have any of the following ever happened to you?

• You know a fact but can’t come up with it. You have the feeling that it is on the “tip of your tongue.”
• You blank out on a test question. After a mighty struggle to remember, you give up and leave the question unanswered (or you make a wild guess). Then, the correct answer hits you on the way home like a slap in the head.
• You (temporarily) forget the name of someone who you know very well.
• You (temporarily) forget your own phone number.
• Is it true that you always find your keys in the last place you look for them? (Answer: Yes, because most people stop looking after they find what they were looking for.)

It is the day of the big Political Science mid-term. You have been studying for days. You feel as if your head is so full of political facts, principles, and theories that it is going to explode. Your professor walks in and asks if there are any questions before she hands out the exam. “Please,” you silently beg, “hand out the exam now, before I forget everything I studied.” After ten minutes of questions from classmates (that you don’t listen to because you are too nervous), you get your exam. Question #1: How much of the U.S. government’s budget is spent on foreign aid? You know this. You just studied it last night. It is in your head somewhere if you could only find it. Why can’t you remember? You are struggling with retrieval.

Understanding (and Improving) Retrieval

Memory retrieval (withdrawing information from long-term memory for use in working memory) is largely a matter of coming up with and using effective retrieval cues. In familiar terms, retrieval cues are reminders, any information that automatically leads you to remember something. More scientifically, you can think of retrieval cues as entry points into the neural network associated with a particular memory (see sec 5.3).

You might also think of retrieval cues this (decidedly less scientific) way:  Any specific memory you have floating around in your head (the amount of U.S. foreign aid, for example) is slippery. To pull it out of long-term memory and into working memory, you need a hook, something attached to the specific memory that you can grab onto. A retrieval cue is that hook. The very best hooks are ones that you put there yourself during recoding.

To create potential retrieval cues for yourself while you’re studying, you can use the encoding principles we have already described: encode meaning and organize information. The more cues you create through this recoding and the better they are, the better your chances of being able to “grab onto one” when you need it.

Now you might begin to understand why straight repetition is only a mediocre study strategy. To be sure, the repetition of a concept and its definition provide you with a possible retrieval cue. A formerly meaningless term and definition, completely disconnected from the rest of the knowledge in your head, is not the world’s greatest hook, however.

In contrast, consider a retrieval cue that is based on memories from your own life. For example, suppose when trying to encode the concept  procedural memory into your long-term memory, you remembered the time you helped your little sister learn how to tie her shoes. The formerly meaningless concept, procedural memory, now becomes part of your memory for this event.

Importantly, you would probably have a fairly detailed memory of such an event. Any of these details can serve you as a possible retrieval cue. Can you picture the smile on your little sister’s face when she finally got her shoes tied right? That can be your hook. Do you remember the feeling of frustration before she caught on? That can be your hook. And so on. Literally anything you might remember about the event can work to remind you of the concept  procedural memory.

That is the beauty of making the information personally meaningful (remember, it is called the self reference effect). It becomes embedded in a rich network of information that is the easiest stuff in the world for you to remember—information about yourself. The specific hook, or retrieval cue, can be any aspect of the event that you can recall. Add this to the recoding that you did based on organization (for example, attending to the relationship between procedural and declarative memory) and by rephrasing the material in your own words, and you have an extremely powerful set of potential retrieval cues, a set of hooks that give you an excellent chance of being able to grab one when you need it.

memory retrieval : withdrawing information from long-term memory into working memory

retrieval cue : a reminder that leads to the withdrawal of information from long-term memory into working memory

Providing a Match Between Encoding and Retrieval

Sometimes, even extensive encoding is not enough to give you a good retrieval cue when you need it. Or, perhaps, you didn’t do a careful job of encoding. What then? Is there still a way to make retrieval cues work in your favor? Fortunately, the answer is yes.

The general strategy that you use to make retrieval cues available and useful is to try to provide some kind of match between the encoding and retrieval situations. This idea is known as the encoding specificity principle (Tulving & Thomson, 1973). If your physiological state or the external environment (the context) is similar during both encoding and retrieval, you have a better chance of coming up with a retrieval cue (Murnane & Phelps, 1993; Smith, 1979). For example, suppose you drank four cups of coffee, each with an extra shot of espresso, when you were encoding information for a big test. You might consider ingesting a bit of caffeine before retrieval time.

Even seemingly trivial aspects of the external environment, such as your location in a room, can be just the match you need to give you a retrieval cue. But hold on before you decide to wear the same clothes every day to take advantage of the encoding specificity effect.  Think about what we are saying. The encoding specificity effect allows you to remember something in a situation that closely matches the situation at encoding. That might be helpful for an exam, but is that what you really want to accomplish? For example, suppose you are studying to be a nurse. Do you really want to remember some important medical concept ONLY when you are sitting at your desk, wearing your favorite blue shirt, and chewing peppermint flavored gum? We thought not. If you really want to learn something, to be able to retrieve it in many future situations, you would do best to simulate that when you encode it. In other words, engage in multiple encoding episodes, and vary the context in each (Bjork & Bjork 2011). This is hard. In fact, it is one of the list of strategies known as desirable difficulties . These are strategies that are difficult to use and make you feel as if you are not learning, but in reality lead to much more effective (and lasting) learning (Bjork & Bjork 2011; Smith, Glenberg & Bjork, 1978). You might also consider some of the strategies we have recommended previously (e.g., elaborative verbal rehearsal and generating self-references) to be other types of desirable difficulties. As we said previously, they can be hard to use, but they are extremely effective.

Saving the Best for Last: Retrieval Practice (and Spacing)

So, do you think that the principles we have shared so far can help you in your quest to improve your memory? Well, we have terrific news: We have saved some of the best news for last. There is one strategy that may have been first suggested by Aristotle and has been examined in research for over 100 years. Time and again, this strategy has been found to lead to better memory than re-studying material (Brown, Roediger, & McDermott, 2014). And very few students use this strategy (Karpicke, Butler, & Roediger, 2009). OK, have we kept you in enough suspense? Here it is: If you want to be able to retrieve information from memory, one of the most important things you should do is to PRACTICE retrieving that information (sorry for yelling, but this is that important. And not just once. You should practice retrieval over time, spacing out your practice sessions as much as you can. (Soderstrom, Kerr, and Bjork 2016; Karpicke and Roediger, 2008). Many students believe that it is more efficient to do all of their studying at one time, but the spacing effect shows that the very opposite is true.

This is obviously great news because you do not need to recode information or come up with new examples, or struggle with organization to use these strategies. You only need to intentionally practice and organize your time.

Just as a reminder or clarification: we are certainly not saying that you should only practice retrieval with the spacing effect. We are saying that it is the one strategy that may have the largest impact on your ability to remember. So, to summarize, allow us to present a guide to studying that is based on some the best principles of memory that psychologists have to offer.

• Spend some time surveying the material before you start reading it. Figure out how it is organized by reading previews and summaries, and paying attention to outlines.
• Recode for meaning while you read: periodically pause and reflect on what you have just read. Rephrase material and come up with examples from your own life (elaborative verbal rehearsal with self-reference). Note relationships between different concepts. Pay attention to how the current information fits into what you have already learned.
• Practice retrieving while you are reading. During some of your periodic pauses, cover up what you just read. Try to retrieve the definitions of key terms. Try to generate your elaborative verbal rehearsals without looking at the text.
• Practice retrieval after reading. Use practice quizzes, flash cards, quizlet, etc. It is far more effective if you have to come up with the answers yourself rather than just recognizing the answer (like in a multiple-choice question).
• Come up with a schedule that allows you to take advantage of the spacing effect.

desirable difficulties : strategies that are difficult to use and make you feel as if you are not learning, but lead to much more effective and lasting learning

spacing effect : the finding that information that is learned and practiced over a period of time (instead of all at once) is remembered better

• Try to remember a time that you had a temporary retrieval failure. What retrieval cue eventually helped you to remember?
• What specific types of retrieval cues do you think work best for you?
• Do you have any memories in which you see yourself in the third person, as if you were watching yourself on television? Doesn’t that seem odd, considering the fact that you never experience yourself that way?
• Have you ever had an argument with someone about an event that happened in which the main point of disagreement is that the two of you remember the event differently? Were you both sure that you were right?

College student Charles was always proud of his memory. In school, he rarely took notes and often had to read a chapter a single time only in order to remember it well enough to get a good grade on an exam. He also had many detailed autobiographical memories, several dating back to when he was a very small child. For example, he remembered his mother coming home from the hospital when his brother was born; he was two years, four months old. Or he remembered an early haircut, perhaps his first visit to the barber. He was sitting in the barber’s chair, eating a lollipop (covered with hair, no doubt), while his whole family stood around and watched.

One evening during Charles’s sophomore year, he and his family decided to watch some old videos from the family to celebrate his parents’ anniversary. Then, suddenly, Charles saw his memory on the television screen. It was his first haircut. His parents had obviously wanted to remember the event for the rest of their lives, so they decided to capture it on film. There in the family room Charles saw his entire memory played out on the screen, and he realized that he did not, in fact, have a memory of his first haircut. He had a memory of the home movie of his first haircut and had mistakenly believed that it was a memory of the actual event. Charles also knew this because he had just learned this concept in his psychology class. Forgetting the actual source of a memory is very common; it is called  source misattribution (Schacter, 2001). It is one form of memory distortion.

The early sections of this module emphasized how employing good encoding and retrieval skills can lead you to remember information more effectively. Somewhat hidden in those discussions, however, is an important observation about the way memory works. Although it is fair to accept the existence of different memory systems, such as working memory and long-term memory, it is not fair to assume that information gets copied into these systems perfectly, to be replayed accurately and in its entirety every time the correct retrieval cue is accessed. Memory, it turns out, is much more dynamic than that.

Instead of thinking of memory as something to be recorded and played back, it is more accurate to say you construct memories of events as you go along. The idea of  memory construction might be hard to accept at first, but it is the simplest way to explain how memories for events change over time. Not only do some of the details of memories fade (as you might realize), but new details also creep into them. For example, imagine that someone tells you a very unusual story that does not make a great deal of sense to you. The story is from a non-Western culture and is quite difficult for you to follow (assuming you are from a Western culture, of course). Over time, as you attempt to recall this story, it will begin to resemble stories that are more familiar to you, with many of the cultural idiosyncrasies forgotten and replaced by themes and details more typical of Western culture (see Window 2).

A number of factors may render a memory incomplete or inaccurate. The kind and amount of processing that takes place at encoding can have a huge impact on the contents of an eventual memory. Also, minor distortions that are consistent with one’s view of the world often creep in. Imagine that you are visiting your psychology professor’s office for the first time. After leaving, you are asked to report what was in the office. Most people have beliefs about what sorts of objects would be in a professor’s office (such as desk, telephone, books), and they would be likely to think they remembered seeing these objects even if they were not actually in the professor’s office. Nearly one-third of the participants in a study similar to the situation just described reported seeing books in a professor’s office—even though the office had been specifically set up without books to test if participants would falsely remember them (Brewer & Treyens 1981).

Elizabeth Loftus and her colleagues have pioneered research on the  misinformation effect , perhaps the most dramatic demonstration of the way that memory can be distorted. Loftus’s research has demonstrated that information given to people after an event occurs, even at retrieval, can lead to memory distortions. For example, research participants who had been shown a slide show of a car accident were later misled to believe that a stop sign was pictured in one of the slides. Many of these participants on a subsequent memory test mistakenly reported that they had seen the stop sign (Loftus, Miller, and Burns, 1978).

In another experiment, research participants were asked one of two questions after viewing a videotape of an accident between two cars. In one condition, they were asked, “How fast were the cars going when they hit each other?” In the other condition, participants were asked, “How fast were the cars going when they smashed into each other?” One week later, participants who had been asked the “smashed” version of the question were more likely to report seeing broken glass in the video (Loftus, Schooler, and Wagenaar, 1985).

The misinformation effect has been demonstrated many times, even leading participants to remember events that did not occur at all, such as spilling a punch bowl or being lost in a mall as a child (Hyman and Pentland, 1996; Loftus and Pickrell, 1995).

• memory construction : the process of building up a recollection of an event, rather than “playing” a memory, as if it were a recording
• misinformation effect : a memory distortion that results when misleading information is presented to people after an event has occurred
• source misattribution : a memory distortion in which a person misremembers the actual source of a memory
• Can you think of a memory from your life that you would be willing to admit might be a memory distortion?

putting information into memory systems

taking information out of memory systems

keeping memories in the brain for future use

a short-term memory storage system that holds information in consciousness for immediate use or to transfer it into long long-term memory

an essentially unlimited, nearly permanent memory storage system

a unit of meaningful information

a very short (about one second), extremely accurate memory system that holds information long enough for an individual to pay attention to it

memory for skills and procedures

memory for facts and episodes

the part of declarative memory that refers to one’s general store of knowledge

the part of declarative memory that refers to specific events or episodes from someone’s life

an encoding technique that encourages semantic processing by restating to-be-remembered information in your own words, as if teaching it to someone else

an encoding technique that encourages semantic processing by applying to-be-remembered information to yourself

a pictorial representation of the relationships between a set of related concepts

the single tube in a neuron that carries an electrical signal away, toward other neurons

one of the many branches on a neuron that receive incoming signals

the electrical charging of a neuron, which readies it to communicate with other neurons

the brain’s ability to change its structure through tiny changes in the surfaces of neurons or in their ability to produce and release neurotransmitters

the basic cell of the nervous system; our brain has billions of neurons

chemical that carries a neural signal from one neuron to another

the area between two adjacent neurons, where neural communication occurs

interconnected group of neurons

withdrawing information from long-term memory into working memory

a reminder that leads to the withdrawal of information from long-term memory into working memory

strategies that are difficult to use and make you feel as if you are not learning, but lead to much more effective and lasting learning

the finding that information that is learned and practiced over a period of time (instead of all at once) is remembered better

a memory distortion in which a person misremembers the actual source of a memory

the process of building up a recollection of an event, rather than “playing” a memory, as if it were a recording

a memory distortion that results when misleading information is presented to people after an event has occurred

Introduction to Psychology Copyright © 2020 by Ken Gray; Elizabeth Arnott-Hill; and Or'Shaundra Benson is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

Share This Book

• Utility Menu

GA4 Tracking Code

fa51e2b1dc8cca8f7467da564e77b5ea

• Make a Gift
• Join Our Email List
• How Memory Works

Memory is the ongoing process of information retention over time. Because it makes up the very framework through which we make sense of and take action within the present, its importance goes without saying. But how exactly does it work? And how can teachers apply a better understanding of its inner workings to their own teaching? In light of current research in cognitive science, the very, very short answer to these questions is that memory operates according to a "dual-process," where more unconscious, more routine thought processes (known as "System 1") interact with more conscious, more problem-based thought processes (known as "System 2"). At each of these two levels, in turn, there are the processes through which we "get information in" (encoding), how we hold on to it (storage), and and how we "get it back out" (retrieval or recall). With a basic understanding of how these elements of memory work together, teachers can maximize student learning by knowing how much new information to introduce, when to introduce it, and how to sequence assignments that will both reinforce the retention of facts (System 1) and build toward critical, creative thinking (System 2).

Dual-Process Theory

Think back to a time when you learned a new skill, such as driving a car, riding a bicycle, or reading. When you first learned this skill, performing it was an active process in which you analyzed and were acutely aware of every movement you made. Part of this analytical process also meant that you thought carefully about why you were doing what you were doing, to understand how these individual steps fit together as a comprehensive whole. However, as your ability improved, performing the skill stopped being a cognitively-demanding process, instead becoming more intuitive. As you continue to master the skill, you can perform other, at times more intellectually-demanding, tasks simultaneously. Due to your knowledge of this skill or process being unconscious, you could, for example, solve an unrelated complex problem or make an analytical decision while completing it.

In its simplest form, the scenario above is an example of what psychologists call dual-process theory. The term “dual-process” refers to the idea that some behaviors and cognitive processes (such as decision-making) are the products of two distinct cognitive processes, often called System 1 and System 2 (Kaufmann, 2011:443-445). While System 1 is characterized by automatic, unconscious thought, System 2 is characterized by effortful, analytical, intentional thought (Osman, 2004:989).

Dual-Process Theories and Learning

How do System 1 and System 2 thinking relate to teaching and learning? In an educational context, System 1 is associated with memorization and recall of information, while System 2 describes more analytical or critical thinking. Memory and recall, as a part of System 1 cognition, are focused on in the rest of these notes.

As mentioned above, System 1 is characterized by its fast, unconscious recall of previously-memorized information. Classroom activities that would draw heavily on System 1 include memorized multiplication tables, as well as multiple-choice exam questions that only need exact regurgitation from a source such as a textbook. These kinds of tasks do not require students to actively analyze what is being asked of them beyond reiterating memorized material. System 2 thinking becomes necessary when students are presented with activities and assignments that require them to provide a novel solution to a problem, engage in critical thinking, or apply a concept outside of the domain in which it was originally presented.  

It may be tempting to think of learning beyond the primary school level as being all about System 2, all the time. However, it’s important to keep in mind that successful System 2 thinking depends on a lot of System 1 thinking to operate. In other words, critical thinking requires a lot of memorized knowledge and intuitive, automatic judgments to be performed quickly and accurately.

How does Memory Work?

In its simplest form, memory refers to the continued process of information retention over time. It is an integral part of human cognition, since it allows individuals to recall and draw upon past events to frame their understanding of and behavior within the present. Memory also gives individuals a framework through which to make sense of the present and future. As such, memory plays a crucial role in teaching and learning. There are three main processes that characterize how memory works. These processes are encoding, storage, and retrieval (or recall).

• Encoding . Encoding refers to the process through which information is learned. That is, how information is taken in, understood, and altered to better support storage (which you will look at in Section 3.1.2). Information is usually encoded through one (or more) of four methods: (1) Visual encoding (how something looks); (2) acoustic encoding (how something sounds); (3) semantic encoding (what something means); and (4) tactile encoding (how something feels). While information typically enters the memory system through one of these modes, the form in which this information is stored may differ from its original, encoded form (Brown, Roediger, & McDaniel, 2014).

• Retrieval . As indicated above, retrieval is the process through which individuals access stored information. Due to their differences, information stored in STM and LTM are retrieved differently. While STM is retrieved in the order in which it is stored (for example, a sequential list of numbers), LTM is retrieved through association (for example, remembering where you parked your car by returning to the entrance through which you accessed a shopping mall) (Roediger & McDermott, 1995).

Improving Recall

Retrieval is subject to error, because it can reflect a reconstruction of memory. This reconstruction becomes necessary when stored information is lost over time due to decayed retention. In 1885, Hermann Ebbinghaus conducted an experiment in which he tested how well individuals remembered a list of nonsense syllables over increasingly longer periods of time. Using the results of his experiment, he created what is now known as the “Ebbinghaus Forgetting Curve” (Schaefer, 2015).

Through his research, Ebbinghaus concluded that the rate at which your memory (of recently learned information) decays depends both on the time that has elapsed following your learning experience as well as how strong your memory is. Some degree of memory decay is inevitable, so, as an educator, how do you reduce the scope of this memory loss? The following sections answer this question by looking at how to improve recall within a learning environment, through various teaching and learning techniques.

As a teacher, it is important to be aware of techniques that you can use to promote better retention and recall among your students. Three such techniques are the testing effect, spacing, and interleaving.

• The testing effect . In most traditional educational settings, tests are normally considered to be a method of periodic but infrequent assessment that can help a teacher understand how well their students have learned the material at hand. However, modern research in psychology suggests that frequent, small tests are also one of the best ways to learn in the first place. The testing effect refers to the process of actively and frequently testing memory retention when learning new information. By encouraging students to regularly recall information they have recently learned, you are helping them to retain that information in long-term memory, which they can draw upon at a later stage of the learning experience (Brown, Roediger, & McDaniel, 2014). As secondary benefits, frequent testing allows both the teacher and the student to keep track of what a student has learned about a topic, and what they need to revise for retention purposes. Frequent testing can occur at any point in the learning process. For example, at the end of a lecture or seminar, you could give your students a brief, low-stakes quiz or free-response question asking them to remember what they learned that day, or the day before. This kind of quiz will not just tell you what your students are retaining, but will help them remember more than they would have otherwise.
• Spacing.  According to the spacing effect, when a student repeatedly learns and recalls information over a prolonged time span, they are more likely to retain that information. This is compared to learning (and attempting to retain) information in a short time span (for example, studying the day before an exam). As a teacher, you can foster this approach to studying in your students by structuring your learning experiences in the same way. For example, instead of introducing a new topic and its related concepts to students in one go, you can cover the topic in segments over multiple lessons (Brown, Roediger, & McDaniel, 2014).
• Interleaving.  The interleaving technique is another teaching and learning approach that was introduced as an alternative to a technique known as “blocking”. Blocking refers to when a student practices one skill or one topic at a time. Interleaving, on the other hand, is when students practice multiple related skills in the same session. This technique has proven to be more successful than the traditional blocking technique in various fields (Brown, Roediger, & McDaniel, 2014).

As useful as it is to know which techniques you can use, as a teacher, to improve student recall of information, it is also crucial for students to be aware of techniques they can use to improve their own recall. This section looks at four of these techniques: state-dependent memory, schemas, chunking, and deliberate practice.

• State-dependent memory . State-dependent memory refers to the idea that being in the same state in which you first learned information enables you to better remember said information. In this instance, “state” refers to an individual’s surroundings, as well as their mental and physical state at the time of learning (Weissenborn & Duka, 2000). 
• Schemas.  Schemas refer to the mental frameworks an individual creates to help them understand and organize new information. Schemas act as a cognitive “shortcut” in that they allow individuals to interpret new information quicker than when not using schemas. However, schemas may also prevent individuals from learning pertinent information that falls outside the scope of the schema that has been created. It is because of this that students should be encouraged to alter or reanalyze their schemas, when necessary, when they learn important information that may not confirm or align with their existing beliefs and conceptions of a topic.
• Chunking.  Chunking is the process of grouping pieces of information together to better facilitate retention. Instead of recalling each piece individually, individuals recall the entire group, and then can retrieve each item from that group more easily (Gobet et al., 2001).
• Deliberate practice.  The final technique that students can use to improve recall is deliberate practice. Simply put, deliberate practice refers to the act of deliberately and actively practicing a skill with the intention of improving understanding of and performance in said skill. By encouraging students to practice a skill continually and deliberately (for example, writing a well-structured essay), you will ensure better retention of that skill (Brown et al., 2014).

For more information...

Brown, P.C., Roediger, H.L. & McDaniel, M.A. 2014.  Make it stick: The science of successful learning . Cambridge, MA: Harvard University Press.

Gobet, F., Lane, P.C., Croker, S., Cheng, P.C., Jones, G., Oliver, I. & Pine, J.M. 2001. Chunking mechanisms in human learning.  Trends in Cognitive Sciences . 5(6):236-243.

Kaufman, S.B. 2011. Intelligence and the cognitive unconscious. In  The Cambridge handbook of intelligence . R.J. Sternberg & S.B. Kaufman, Eds. New York, NY: Cambridge University Press.

Osman, M. 2004. An evaluation of dual-process theories of reasoning. Psychonomic Bulletin & Review . 11(6):988-1010.

Roediger, H.L. & McDermott, K.B. 1995. Creating false memories: Remembering words not presented in lists.  Journal of Experimental Psychology: Learning, Memory, and Cognition . 21(4):803.

Schaefer, P. 2015. Why Google has forever changed the forgetting curve at work.

Weissenborn, R. & Duka, T. 2000. State-dependent effects of alcohol on explicit memory: The role of semantic associations.  Psychopharmacology . 149(1):98-106.

• Designing Your Course
• In the Classroom
• Getting Feedback
• Equitable & Inclusive Teaching
• Advising and Mentoring
• Teaching and Your Career
• Teaching Remotely
• Tools and Platforms
• Comprehending and Communicating Knowledge
• Motivation and Metacognition
• Promoting Engagement
• Bok Publications
• Other Resources Around Campus

Memory (Types + Models + Overview)

In cognitive psychology, the study of memory is quite important for many applications. When we experience events, we take the information our senses gathered and store it in various forms of memories so we can learn and grow as people. 

Memory is the structure and processes involved in the encoding, storage, and retrieval of information, including both procedural and declarative information.

Cognitive psychologists quickly realized how fallible our memories are, and although there are some people who can display amazing feats of recall, we know that false memories can be created pretty easily. Nevertheless, we still aren't completely sure how they are stored or retrieved. 

In most contemporary models, there are 3 processes of memory: encoding, storage, retrieval.

Encoding : The process of converting raw perception data from our sensory organs into information that can be easily stored in our brain.

Encoding can happen in one of three ways: Visual, Acoustic, or Semantic. Semantic seems to be the best for storing long term information.

Visual encoding is when you can close your eyes and see your notes from class.

Acoustic encoding is as simple as repeating something to yourself over and over again. 

Semantic encoding is giving meaning to something you wish to remember. For example, if you are studying to memorize the name of the states for a free recall test, you can remember a chef named MIMAL (an acronym for Minnesota, Iowa, Missouri, Arkansas, Louisiana) cooking some Kentucky fried chicken to put meaning to otherwise random information:

Storage : The process of taking encoded information and storing it in your memory for future use.

We will talk about the many types of storage in a bit. Remembering that there are 3 main processes of memory is a great example of the function of storage.

Retrieval : The process of pulling information from our memory

One of the most important parts of memory, is remembering something. It should be noted that errors in memory can happen both in storage and retrieval. One of the easiest ways to help the process of retrieval is to organize information, such as lecture notes. Even better, there's an image below that organizes the different types of memory. 

Psychologists have also categorized memory to further study the function and processes of each. 

Here's a quick rundown of the types of memory that your brain holds (If you're coming from my email... don't worry, I'm hiring a graphic artist to make this more visually pleasing):

Sensory Memory

There are 3 main types of sensory memory: Iconic, Echoic, and Haptic. Sensory memory holds a quick flash of information from our sensory organs, so fast and short-lived that most of it doesn't make it to our conscious awareness unless we focus our attention on it.

Iconic Memory is the trace of visual information that lasts less than 4 seconds. When you use a sparkler to draw your name, and then hide the sparkler to still see your name written, your brain is using iconic memory to see the leftovers. 

Echoic Memory is auditory information that stays in your memory for less than 2 seconds. 

Haptic Memory lasts less than 1 second and consists of information from touching things. 

Short Term Memory

Almost everyone knows what short term memory is, the ability to hold certain information like a phone number in your head until you can write it down. It seems to be limited to under 18 seconds and around 5-9 items. We can increase the duration by rehearsing what we want to remember, and increase the capacity by chunking it.

Working Memory

In most classifications, working memory is a form of short-term memory that can be manipulated in the mind. A better definition could be " a form of short term memory that allows us to achieve a goal or solve a problem by manipulating information".

For example, I could ask you to multiply 5 times 7 in your head. You would very quickly come up with 35. 

However, if I asked you to multiply 35 by 7, you will need some time to do the math in your head. In doing so, you're using your working memory capacity. 

Next, if I ask you to multiply 245 by 35... you may forget to carry a number or even forget one of the original factors. This is because your working memory is limited in time and capacity. 

It should be noted that working memory has been link to higher intelligence .

Without going into detail, there are 3 main parts of working memory: the Visuospatial Sketchpad, the Phonological Loop, and the Episodic buffer. 

The Visuospatial Sketchpad is the part of your mind that you can create images with. When you think of a three-dimensional object and rotate it, or when you think of the way to get to your friends house, you are using this sketchpad. 

The Phonological Loop is the part of your brain that can repeat audible sounds. Repetition of a word or phrase in the loop causes it to stick longer in your memory. Note that the loop lasts only 2 seconds, that means the more syllables you can fit in those 2 seconds, the more information you can hold. 

The Episodic Buffer is still a bit of a mystery, but it seems to tie the Visuosptial Sketchpad and the Phonological Loop together, and make a more realistic memory. When we use our imagination to daydream, we are putting the buffer to use. 

Long Term memory

There are two main types of long term memory , explicit and implicit. For all we know, this form of storage is semi-permanent and can last forever. Think of long term memory like a hard drive you can access for any information you've deemed important in the past. 

Explicit memory , also known as declarative memory , hold facts and information that we can directly understand. 

One type of explicit memory is Episodic Memory . Episodic memory is the type of memory that stores events or experiences in order that they happened. For example, you might remember that on your 10th birthday, you had cake first, then you opened gifts, and then you played with your new toys. 

One type of explicit memory is Semantic Memory . Semantic memory is the type of memory that stores the meaning of words and events. For example, remembering what date your birthday is shows a perfect example of semantic memory. Another example of semantic memory is understanding what the meaning of a 'birthday' is. 

Implicit memory , also known as non-declarative memory, holds information that we don't know we know. This might sound confusing, but a quick example is riding a bike. You can explain to your friend how to ride a bike with words, but they still won't have a good understanding of the process until they ride the bike themselves. 

One type of implicit memory is Procedural Memory . Riding a bicycle is a perfect example of this, as is the knowledge or memory of any skill. Procedural memory consists of the skill-based actions you learn and commit to memory. You can drive a car with a manual transmission, and then 20 years later, still 'remember' how to drive the same car. 

Another type of implicit memory is the concept of priming . Since I have been talking about riding bikes and driving cars, if I were to ask you to fill in the blanks of the word below, I could 'prime' you to think of a certain word.

You could think of tied, tips, tick, time, tint, or tide. However, you probably thought of tire . Priming is when the exposure to one stimulus (the car and bike) influences the response to another stimulus (fill in the blank). 

A flashbulb memory is a form of a long-term memory that holds a significant piece of our history with us. Usually emotions are involved, and we feel very confident in these memories, even if we misremember very important parts.

Atkinson Shiffrin Model

The Atkinson-Shiffrin Model of Memory seems to be one of the best representations of memory that we have to date. Even though there are many studies that seem to prove some functions of the model, there are still weaknesses in the theory. 

Richard Atkinson and Richard Shiffrin developed the theory in 1968 and theorized that information is processed in the sensory organs first, then moves through a short term memory process, until it is finally stored in long term memory. 

Without going into too much detail here, this model has been supported by almost everything mentioned above, including working memory and the phonological loop. 

It does not, however, explain decay theory, or why we forget things as time goes on. 

The other main theory of memory psychologists seem to side with is called the Levels of Processing. 

Levels of Processing Model

The Levels of Processing theory was developed by Craik and Lockhart in 1972. They theorized that memory depends primarily on how deep information is processed and encoded. 

The less we pay attention to information, and the less we think about it, the less it is encoded. 

The more we manipulate the information, or attach an emotional meaning to it, we encode it more. 

When you take a piece of information and tie it with another piece of information, like remembering your friend's name is Jake because he looks like the 'Jake from State Farm' character, you are also encoding that memory deeper. 

Here is an example of 3 different levels, each with a deeper version of processing, which represents a more encoded and stable memory. 

• Shallow : is this word in capital letters? (an example of physical characteristics )
• Deep : does the word rhyme with another word? (an example of the sound of a word)
• Deepest : does this word fit in this sentence? (an example of the meaning of a word)

There is evidence to support this theory, as when you ask participants to remember a word, and then give them these questions, those who answered the questions that facilitated the deepest encoding (questions about the meaning of the word) were more likely to remember the word after a distraction task. 

Here's a great video that explains more studies on the Levels of Processing model: 

Serial Position Effect

Hermann Ebbinghaus was a German cognitive psychologist who studied memory. He is credited for finding the Serial Position Effect , in which he theorizes that people are more likely to remember information depending on it's position in a list. 

The Primacy Effect

The Primacy Effect is a psychological phenomenon that occurs when participants are more likely to remember the beginning item of a list more than items in the middle. 

The primacy effect becomes quite important for first impressions and anchoring, as the memory you leave in someone's mind first sets the precedence for future interactions. 

The Recency Effect

As you can see above, The Recency Effect is more powerful than the primacy effect, especially when there are more items in the list. 

There's a famous study on memory called the Murdock Study (the results are shown above). 

Bennet Murdock gave a list of words to participants in 1962. He then asked them to recall as many words as they could without a cue, a form of free recall. The first words in the list they were given were likely to be remembered about 50% of the time, compared to an average of 16% of 'middle words'. The last words in the list though, were 80% likely to be remembered, showing the power of the recency effect. 

False Memories

If there's one thing cognitive psychologists can be sure of, it's that memory is very fallible. That is, we often remember things wrong, or completely create a false memory. 

One of the issues that causes lapses in storing and retrieving information is called interference. Interference happens when the process of learning is disrupted either by something you have learned in the past, or something you are currently learning. 

Proactive Interference is when older information makes it much more difficult to learn something new. An example of this would be calling your new significant other your old significant other's name.

On the other hand, Retroactive Interference is when new information prevents you from recalling old memories. One example of this would be learning your sister's new phone number, as learning the updated string of digits might make you forget the old string of digits. 

Check out this full guide to memory errors if you're curious about more.

We should also probably talk about amnesia and how it relates to memory. 

Retrograde amnesia is when the ability to recall information that happened before the onset of their amnesia. If you've ever seen a scene in a movie where a football player gets hit really hard, and then doesn't remember who he is, who's president, or what day it is, they were affected with retrograde amnesia. Most retrograde amnesiacs are affected either through an injury to the brain or an illness like Alzheimer's disease.

Anterograde amnesia is when the ability to store new information in long-term memory has been corrupted. A common example to show anterograde amnesia is Dory from Finding Nemo, as the character can't remember events after a few seconds has passed. Lucy from the movie Fifty First Dates also had a form of anterograde amnesia. 

It may be confusing to try to distinguish the different types of amnesia, but noting the differences allows us to study different function in memory, namely encoding and recall. If you get confused, just remember that "R"etrograde amnesia affects "R"ecall. 

Photographic Memories

On another page, I explain in depth that there have been no real documented cases of photographic memory . Nobody in history has ever been able to free recall 100% everything that has happened to them. However, there has been cases of a variation called Eidetic Memory.

Eidetic Memory is the ability to recall images a few seconds after visual exposure with a high accuracy of details, and without using a memory device. Eidetic memory is pretty common (up to 10%) in children under the age of 10. 

One famous study of a person with a phenomenal memory capacity is Solomon Shereshevsky, otherwise known as S. S. had a rare form of a perception disorder, called 'fivefold synesthesia' in which all of his senses were tangled. Imagine drinking coffee, and then hearing a train go by, seeing yellow, and feeling sandpaper. When S. received information from one sensory organ, connected information from other organs would light up and feed him seemingly meaningless information. 

Cognitive psychologists theorized that this helped him remember better, due to an extreme amount of encoding that happened in the brain. S. could listen to a 10 minute speech and repeat the speech back word for word. He could also memorize very complex math formulas and poems in other languages. 

One quirky phenomenon that also seems to tie in your experiences with memory is state-dependent memory . This is when the retrieval of a memory is much more likely to happen when you are in the same state that you created it. For example, if someone were high on drugs, they would be more likely to remember what they learned once they became high again. 

Another way to improve your memory is by using mnenomics. 

How to Memorize Quicker and Study Better

Mnemonics are simply tools used to help you store more information in your memory by using less effort. There are many different types of mnemonics, including these below that most people have found useful:

Acronym : An abbreviation for a phrase or sentence.

The acronym "ROY G. BIV" is a famous acronym to help memorize the order of colors in a rainbow.

Acrostics : A sentence or poem that is constructed with the letters in an acronym. 

A great example of an acrostic is the "My Very Educated Mother Just Served Us Nine Pizzas" to remember the order of the planets from the sun. 

Mind Palace : An imaginary location in your mind where each room stores information on a certain subject.

Sherlock Holmes is one of the most famous characters to utilize and popularize the Mind Palace Technique . This Mnemonic requires practice, but can seemingly store a large amount of data very quickly and for long periods of time.

Chunking : When you break up information into smaller pieces. 

When you remember a phone number and break it up into groups of 3 or 4 digits, you are breaking the information into digits. 

Rote Memorization : The process of repeating information so often the likelihood of it being stored in long-term memory is higher.

Studying with flash cards for 10 minutes at a time throughout the day is a perfect way to learn using rote memorization. 

Related posts:

• Semantic Encoding (Definition + Examples)
• Clive Wearing (Amnesia Patient)

Long Term Memory

• Sensory Memory (Definition + Examples)
• Semantic Memory (Definition + Examples + Pics)

Reference this article:

About The Author

Memory Topics:

Free Memory Test

Primacy Effect

Recency Effect

Episodic Memory

Semantic Memory

Photographic Memory

Memory Tricks

Memory Palace

Rote Memorization

Atkinson and Shiffrin Model

Proactive Interference

Retroactive Interference

State Dependent Memory

PracticalPie.com is a participant in the Amazon Associates Program. As an Amazon Associate we earn from qualifying purchases.

Follow Us On:

Youtube Facebook Instagram X/Twitter

Psychology Resources

Developmental

Personality

Relationships

Psychologists

Serial Killers

Psychology Tests

Personality Quiz

Memory Test

Depression test

Type A/B Personality Test

© PracticalPsychology. All rights reserved

Privacy Policy | Terms of Use

What Is Memory?

Reviewed by Psychology Today Staff

Memory is the faculty by which the brain encodes, stores, and retrieves information. It is a record of experience that guides future action.

Memory encompasses the facts and experiential details that people consciously call to mind as well as ingrained knowledge that surface without effort or even awareness. It is both a short-term cache of information and the more permanent record of what one has learned. The types of memory described by scientists include episodic memory, semantic memory , procedural memory , working memory , sensory memory , and prospective memory .

Each kind of memory has distinct uses—from the vivid recollections of episodic memory to the functional know-how of procedural memory. Yet there are commonalities in how memory works overall, and key brain structures, such as the hippocampus, that are integral to different kinds of memory.

In addition to memory’s role in allowing people to understand, navigate, and make predictions about the world, personal memories provide the foundation for a rich sense of one’s self and one’s life—and give rise to experiences such as nostalgia .

To learn more, see Types of Memory , How Memory Works , and Personal Memories and Nostalgia .

Memory loss is the unavoidable flipside of the human capacity to remember. Forgetting, of course, is normal and happens every day: The brain simply cannot retain a permanent record of everything a person experiences and learns. And with advancing age, some decline in memory ability is typical. There are strategies for coping with such loss—adopting memory aids such as calendars and reminder notes, for example, or routinizing the placement of objects at risk of getting lost.

In more severe cases, however, memory can be permanently damaged by dementia and other disorders of memory . Dementia is a loss of cognitive function that can have various underlying causes, the most prominent being Alzheimer’s disease. People with dementia experience a progressive loss of function, such that memory loss may begin with minor forgetfulness (about having recently shared a story, for example) and gradually progress to difficulty with retaining new information, recognizing familiar individuals, and other important memory functions. Professional assessment can help determine whether an individual’s mild memory loss is a function of normal aging or a sign of a serious condition.

Memory disorders also include multiple types of amnesia that result not from diseases such as Alzheimer’s, but from brain injury or other causes. People with amnesia lose the ability to recall past information, to retain new information, or both. In some cases the memory loss is permanent, but there are also temporary forms of amnesia that resolve on their own.

To learn more, see Memory Loss and Disorders of Memory .

Though memory naturally declines with age, many people are able to stay mentally sharp. How do they do it? Genes play a role, but preventative measures including regular exercise, eating a healthy diet , and getting plenty of sleep—as well as keeping the brain active and challenged—can help stave off memory loss.

The science of memory also highlights ways anyone can improve their memory , whether the goal is sharpening memory ability for the long term or just passing exams this semester. Short-term memory tricks include mnemonic devices (such as acronyms and categorization), spacing apart study time, and self-testing for the sake of recalling information. Sleep and exercise are other memory boosters .

Through committed practice with memory-enhancing techniques, some people train themselves to remember amazing quantities of information, such as lengthy sequences of words or digits. For a small number of people, however, extraordinary memory abilities come naturally. These gifted rememberers include savants, for whom powerful memory coincides with some cognitive disability or neurodevelopmental difference, as well as people with typical intellects who remember exceptional quantities of details about their lives.

To learn more, see How to Improve Memory and Extraordinary Memory Abilities .

Memory is a key element in certain mental health conditions : Abnormal memory function can contribute to distress, or it can coincide with an underlying disorder. Forgetfulness is associated with depression ; connections in memory, such as those involving feared situations or drug-related cues, are an integral part of anxiety and substance use disorders; and post- traumatic symptoms are entwined with the memory of traumatic experiences.

In fact, experiences such as distressing memories and flashbacks are among the core symptoms of post-traumatic stress disorder. For someone with PTSD , a range of cues—including situations, people, or other stimuli related to a traumatic experience in some way—can trigger highly distressing memories, and the person may seek to avoid such reminders.

As a feature of various mental disorders, aberrant or biased memory function can also be a target for treatment. Treatments that involve exposure therapy , for example, are used to help patients reduce the power of trauma-related memories through safe and guided encounters with those memories and stimuli associated with the trauma.

To learn more, see Memory and Mental Health .

A few studies have suggested that recalling the past with fondness and gratitude can increase self-control, but a recent meta-analysis challenges this idea.

It remains a matter of scientific debate whether the beta amyloid buildup is the cause of Alzheimer’s or a feature of it. It’s time to look at “out of the clump” fresh approaches.

Researchers developed a method to transform students' writing over 30 years ago. What happened to it?

The evidence strongly points to the perils of long-term use of benzos. This warning is more credible after recent studies have revealed the mechanisms of cognitive impairments.

Has your loved one told you something happened that you’re not sure is true? It could be a false memory.

Older U.S. adults and their families have reason to consider space and place for optimizing older adults' short term memory and attentional needs.

We all grow up with stories about our parents, childhood, and challenges. They form our unique way of looking at life and ourselves, but stories can be distorted. Time to upgrade?

It may require very little daily cannabis consumption to produce long-term neuroprotection in the older brain.

A woman at my gym walks on the treadmill backwards; sometimes quickly, sometimes slowly. After months of watching her and wondering when she might fall, I asked her about it.

Personal Perspective: We are thrilled by even the least coincidental of stories, but do they shape our lives with meaning? Or are they meaningless, random connections?

• Find a Therapist
• Find a Treatment Center
• Find a Psychiatrist
• Find a Support Group
• Find Online Therapy
• United States
• Brooklyn, NY
• Chicago, IL
• Houston, TX
• Los Angeles, CA
• New York, NY
• Portland, OR
• San Diego, CA
• San Francisco, CA
• Seattle, WA
• Washington, DC
• Asperger's
• Bipolar Disorder
• Chronic Pain
• Eating Disorders
• Passive Aggression
• Personality
• Goal Setting
• Positive Psychology
• Stopping Smoking
• Low Sexual Desire
• Relationships
• Child Development
• Self Tests NEW
• Therapy Center
• Diagnosis Dictionary
• Types of Therapy

At any moment, someone’s aggravating behavior or our own bad luck can set us off on an emotional spiral that threatens to derail our entire day. Here’s how we can face our triggers with less reactivity so that we can get on with our lives.

• Emotional Intelligence
• Gaslighting
• Affective Forecasting
• Neuroscience

Browse Course Material

Course info.

• Prof. John D. E. Gabrieli

Departments

• Brain and Cognitive Sciences

As Taught In

• Cognitive Science

Learning Resource Types

Introduction to psychology, memory ii: amnesia and memory systems.

« Previous | Next »

Session Overview

Session activities.

Read the following before watching the lecture video.

• [ Sacks ] Chapter 2 “The Lost Mariner” (pp. 23-42)
• Study outline for K&R Chapter 5 (PDF)
• [ Stangor ] Chapter 8, “Remembering and Judging”

Lecture Videos

View Full Video Lecture 11: Memory II: Amnesia and Memory Systems View by Chapter The Importance of Memory Anterograde Amnesia: Patient H.M. and the Role of the Hippocampus in Memory Formation Types of Memory and Q&A about Patient H. M. Retrograde Amnesia Neural Memory Systems and the Effect of Huntington’s and Alzheimer’s Diseases on Memory Video Resources Removed Clips Lecture Slides (PDF - 2.0MB)

Discussion: Memory

So, if the essential task of a memory system is to carry information forward in time, what properties should that system have? Think about the memory devices you use in everyday life: A USB stick, a post-it note, your mind, etc. What do they need to be able to do?…  Read more »

Check Yourself

Name, describe and give examples of the two types of explicit memory and the three types of implicit memory.

› View/hide answer

The three types of explicit memory are semantic memory and episodic memory. Semantic memory is our facts and general knowledge about the world. The three types of implicit memory are procedural memory, priming, and learning through conditioning. Procedural memory consists of or motor and cognitive skills, or know how to do certain things. Priming is enhanced identification of objects and words, or changes in behavor as a result of recent experiences. Learning through conditioning is learning to expect rewards or punishment under certain conditions.

Examples of each type of memory:

Semantic: The sky is blue, dogs have fur, Africa is below Europe.

Explicit Memory: What you had for breakfast, your first date, what you did for your birthday.

Procedural: How to hit a baseball, how to do simple arithmetic, how to start your car.

Priming: Seeing a river and someone says they are going to the bank. Priming will make it more likely for you to think they are going to the bank of a river or stream rather than a bank to withdraw money.

Learning through conditioning: After several years in elementary school you learn to associate a good report card with the expectation of a reward, such as cookies or a new toy from your parents.

Further Study

These optional resources are provided for students that wish to explore this topic more fully.

You are leaving MIT OpenCourseWare

• Bipolar Disorder
• Therapy Center
• When To See a Therapist
• Types of Therapy
• Best Online Therapy
• Best Couples Therapy
• Best Family Therapy
• Managing Stress
• Sleep and Dreaming
• Understanding Emotions
• Self-Improvement
• Healthy Relationships
• Student Resources
• Personality Types
• Guided Meditations
• Verywell Mind Insights
• 2024 Verywell Mind 25
• Mental Health in the Classroom
• Editorial Process
• Meet Our Review Board
• Crisis Support

Different Types of Memories

The 4 Main Types of Memory and the Function of Each

Toketemu has been multimedia storyteller for the last four years. Her expertise focuses primarily on mental wellness and women’s health topics. 

Huma Sheikh, MD, is a board-certified neurologist, specializing in migraine and stroke, and affiliated with Mount Sinai of New York.

Jan Hakan Dahlstrom / Getty Images

• 4 Main Types
• Their Function
• How They're Formed
• Ways to Improve

Memory is the ability to store and retrieve information when people need it. The four general types of memories are sensory memory, short-term memory, working memory, and long-term memory. Long-term memory can be further categorized as either implicit (unconscious) or explicit (conscious).

Together, these types of memory make us who we are as individuals, yet we don’t put a lot of thought into how memory works . It’s a phenomenon that involves several processes and can be split into different types, each of which plays an important role in the retention and recall of information.

4 Main Types of Memories 

For years, researchers and experts have debated the classification of memories. Many agree that there are four main categories of memory, with all other types of memory tending to fall within these major categories. 

Memory is sometimes also classified into stages and processes. People who classify memory into only two distinctive types, implicit and explicit memory , believe that other types of memory—like sensory, short-term, and long-term memory—aren’t different types but more so stages of memory .

Sensory Memory 

Sensory memory allows you to remember sensory information after the stimulation has ended. Remembering the sensation of a person’s touch or a sound you heard in passing is sensory memory.

Researchers who classify memory more as stages than types believe that all other memories begin with the formation of sensory memories. Typically, sensory memory only holds onto information for brief periods.

When a sensory experience keeps recurring and you start to attach other memories to it, the sensory experience stops living in your sensory memory. It might move to your short-term memory or more permanently to your long-term memory.

There are three types of sensory memory:

• Iconic memory , which is obtained through sight
• Echoic memory , which is auditory
• Haptic memory, which is through touch

Short-term Memory 

As the name implies, short-term memory allows you to recall specific information about something for a brief period. Short-term memory is not as fleeting as sensory memory, but it’s also not as permanent as long-term memory. Short-term memory is also known as primary or active memory.

Short-term memories only last an estimated 15 to 30 seconds. When you read a line in a book or a string of numbers that you have to recall, that’s your short-term memory at work.

You can keep information in your short-term memory by rehearsing the information. For example, if you need to recall a string of numbers, you might keep repeating them to yourself until you input them. However, if you are asked to recall those numbers about 10 minutes after inputting them, you’d most likely be unable to. 

Working Memory

Working memory is a type of memory that involves the immediate and small amount of information that a person actively uses as they perform cognitive tasks . While some view working memory as a fourth distinct type of memory, it can fall under the classification of short-term memory and, in many cases, is even used interchangeably. 

Long-term Memory

We store a vast majority of our memories in our long-term memory . Any memory we can still recall after 30 seconds could be classified as long-term memory. These memories range in significance, from recalling the name of a friendly face at your favorite coffee shop to important bits of information like a close friend’s birthday or your home address.

There is no limit to how much our long-term memory can hold and for how long. We can further split long-term memory into two main categories: explicit and implicit long-term memory.

Explicit Long-term Memory  

Explicit long-term memories are memories we consciously and deliberately take time to form and recall. Explicit memory holds information such as your best friend’s birthday or your phone number. It often includes major milestones in your life, such as childhood events, graduation dates, or academic work you learned in school.

In general, explicit memories can be episodic or semantic.

• Episodic memories are formed from particular episodes in your life. Examples of episodic memory include the first time you rode a bike or your first day at school.
• Semantic memories are general facts and bits of information you've absorbed over the years. For instance, when you recall a random fact while filling in a crossword puzzle, you pull it from your semantic memory.

Conditions such as Alzheimer’s disease heavily affect explicit memories.

Implicit Long-term Memory 

We are not as deliberate with forming implicit memories as we are with explicit ones. Implicit memories form unconsciously and might affect the way a person thinks and behaves.

Implicit memory often comes into play when we are learning motor skills like walking or riding a bike. If you learned how to ride a bike when you were 10 and don't pick it up again until you are 20, implicit memory helps you remember how to ride it. 

We can retrieve long-term memories in a few different ways. The three types of memory retrieval are recall, recognition, and relearning.

Why Do We Have Different Types of Memory?

Each different type of memory we have is important, and they all have various functions. Your short-term memory allows you to process and understand the information in an instant. When you read a paragraph in a book and understand it, that’s your short-term memory at work. 

Your most treasured and important memories are held in your long-term memory. Your long-term memory facilitates how to walk, talk, ride a bike, and engage in daily activities. It also allows you to recall important dates and facts.

In your day-to-day activities, you are bound to find yourself relying on your long-term memory the most. From waking up and brushing your teeth to getting on the right bus to commute to work, recalling all of these steps is facilitated by your long-term memory. 

How These Types of Memories Are Formed

Memories are made in three distinct stages. It starts with encoding. Encoding is the way external stimuli and information make their way into your brain. This could occur through any of your five senses .

The next stage is storage, where the information we take in is stored. It is either stored briefly, like with sensory and short-term memory, or more permanently, like with long-term memory.

The final stage is recall. Recall is our ability to retrieve the memory we’ve made from where it is stored. This process also outlines how sensory memory might be turned into short-term memory or short-term memory into long-term memory. 

How to Improve Your Memory 

It’s commonplace to hear people complain about having poor memory . When we try to recall information and can’t, we feel that our memory has failed us.

The good news is that it is possible to improve your memory and make the process of encoding, storing, and recalling information more seamless. Here are a couple of tips to improve your memory : 

• Take care of your body . If you take care of your body by eating a balanced diet, exercising regularly, and getting enough sleep, you improve your brain health , which helps you process and recall memories better. 
• Exercise your mind . There are several activities and puzzles you could do to give your mind a great workout. 
• Take advantage of calendars and planners . Clear up memory space in your brain by using calendars and planners to remember the little things like shopping lists and meeting times. 
• Stay mentally active . Reading, writing, and constantly learning help you remain mentally active, which can improve your memory.

Stangor C, Walinga J. 9. 1 Memories as types and stages . In: Introduction to Psychology 1st Canadian Edition .

Camina E, Güell F. The neuroanatomical, neurophysiological and psychological basis of memory: current models and their origins .  Front Pharmacol . 2017;8:438. doi:10.3389/fphar.2017.00438

Duke University. How long is short-term memory?

Queensland Brain Institute. Types of memory .

University of Central Florida. Retrieval . General Psychology .

Harvard Health Publishing. 7 ways to keep your memory sharp at any age .

By Toketemu Ohwovoriole Toketemu has been multimedia storyteller for the last four years. Her expertise focuses primarily on mental wellness and women’s health topics.

Learn More Psychology

• Memory Psychology

10 Influential Memory Theories and Studies in Psychology

Discover the experiments and theories that shaped our understanding of how we develop and recall memories..

Permalink Print   |  

How do our memories store information? Why is it that we can recall a memory at will from decades ago, and what purpose does forgetting information serve?

The human memory has been the subject of investigation among many 20th Century psychologists and remains an active area of study for today’s cognitive scientists. Below we take a look at some of the most influential studies, experiments and theories that continue to guide our understanding of the function of memory.

1 Multi-Store Model

(atkinson & shiffrin, 1968).

An influential theory of memory known as the multi-store model was proposed by Richard Atkinson and Richard Shiffrin in 1968. This model suggested that information exists in one of 3 states of memory: the sensory, short-term and long-term stores . Information passes from one stage to the next the more we rehearse it in our minds, but can fade away if we do not pay enough attention to it. Read More

Information enters the memory from the senses - for instance, the eyes observe a picture, olfactory receptors in the nose might smell coffee or we might hear a piece of music. This stream of information is held in the sensory memory store , and because it consists of a huge amount of data describing our surroundings, we only need to remember a small portion of it. As a result, most sensory information ‘ decays ’ and is forgotten after a short period of time. A sight or sound that we might find interesting captures our attention, and our contemplation of this information - known as rehearsal - leads to the data being promoted to the short-term memory store , where it will be held for a few hours or even days in case we need access to it.

The short-term memory gives us access to information that is salient to our current situation, but is limited in its capacity.

Therefore, we need to further rehearse information in the short-term memory to remember it for longer. This may involve merely recalling and thinking about a past event, or remembering a fact by rote - by thinking or writing about it repeatedly. Rehearsal then further promotes this significant information to the long-term memory store, where Atkinson and Shiffrin believed that it could survive for years, decades or even a lifetime.

Key information regarding people that we have met, important life events and other important facts makes it through the sensory and short-term memory stores to reach the long-term memory .

Learn more about Atkinson and Shiffrin’s Multi-Store Model

2 Levels of Processing

(craik & lockhart, 1972).

Fergus Craik and Robert Lockhart were critical of explanation for memory provided by the multi-store model, so in 1972 they proposed an alternative explanation known as the levels of processing effect . According to this model, memories do not reside in 3 stores; instead, the strength of a memory trace depends upon the quality of processing , or rehearsal , of a stimulus . In other words, the more we think about something, the more long-lasting the memory we have of it ( Craik & Lockhart , 1972). Read More

Craik and Lockhart distinguished between two types of processing that take place when we make an observation : shallow and deep processing. Shallow processing - considering the overall appearance or sound of something - generally leads to a stimuli being forgotten. This explains why we may walk past many people in the street on a morning commute, but not remember a single face by lunch time.

Deep (or semantic) processing , on the other hand, involves elaborative rehearsal - focusing on a stimulus in a more considered way, such as thinking about the meaning of a word or the consequences of an event. For example, merely reading a news story involves shallow processing, but thinking about the repercussions of the story - how it will affect people - requires deep processing, which increases the likelihood of details of the story being memorized.

In 1975, Craik and another psychologist, Endel Tulving , published the findings of an experiment which sought to test the levels of processing effect.

Participants were shown a list of 60 words, which they then answered a question about which required either shallow processing or more elaborative rehearsal. When the original words were placed amongst a longer list of words, participants who had conducted deeper processing of words and their meanings were able to pick them out more efficiently than those who had processed the mere appearance or sound of words ( Craik & Tulving , 1975).

Learn more about Levels of Processing here

3 Working Memory Model

(baddeley & hitch, 1974).

Whilst the Multi-Store Model (see above) provided a compelling insight into how sensory information is filtered and made available for recall according to its importance to us, Alan Baddeley and Graham Hitch viewed the short-term memory (STM) store as being over-simplistic and proposed a working memory model (Baddeley & Hitch, 1974), which replace the STM.

The working memory model proposed 2 components - a visuo-spatial sketchpad (the ‘inner eye’) and an articulatory-phonological loop (the ‘inner ear’), which focus on a different types of sensory information. Both work independently of one another, but are regulated by a central executive , which collects and processes information from the other components similarly to how a computer processor handles data held separately on a hard disk. Read More

According to Baddeley and Hitch, the visuo-spatial sketchpad handles visual data - our observations of our surroundings - and spatial information - our understanding of objects’ size and location in our environment and their position in relation to ourselves. This enables us to interact with objects: to pick up a drink or avoid walking into a door, for example.

The visuo-spatial sketchpad also enables a person to recall and consider visual information stored in the long-term memory. When you try to recall a friend’s face, your ability to visualize their appearance involves the visuo-spatial sketchpad.

The articulatory-phonological loop handles the sounds and voices that we hear. Auditory memory traces are normally forgotten but may be rehearsed using the ‘inner voice’; a process which can strengthen our memory of a particular sound.

Learn more about Baddeley and Hitch’s working memory model here

4 Miller’s Magic Number

(miller, 1956).

Prior to the working memory model, U.S. cognitive psychologist George A. Miller questioned the limits of the short-term memory’s capacity. In a renowned 1956 paper published in the journal Psychological Review , Miller cited the results of previous memory experiments, concluding that people tend only to be able to hold, on average, 7 chunks of information (plus or minus two) in the short-term memory before needing to further process them for longer storage. For instance, most people would be able to remember a 7-digit phone number but would struggle to remember a 10-digit number. This led to Miller describing the number 7 +/- 2 as a “magical” number in our understanding of memory. Read More

But why are we able to remember the whole sentence that a friend has just uttered, when it consists of dozens of individual chunks in the form of letters? With a background in linguistics, having studied speech at the University of Alabama, Miller understood that the brain was able to ‘chunk’ items of information together and that these chunks counted towards the 7-chunk limit of the STM. A long word, for example, consists of many letters, which in turn form numerous phonemes. Instead of only being able to remember a 7-letter word, the mind “recodes” it, chunking the individual items of data together. This process allows us to boost the limits of recollection to a list of 7 separate words.

Miller’s understanding of the limits of human memory applies to both the short-term store in the multi-store model and Baddeley and Hitch’s working memory. Only through sustained effort of rehearsing information are we able to memorize data for longer than a short period of time.

Read more about Miller’s Magic Number here

5 Memory Decay

(peterson and peterson, 1959).

Following Miller’s ‘magic number’ paper regarding the capacity of the short-term memory, Peterson and Peterson set out to measure memories’ longevity - how long will a memory last without being rehearsed before it is forgotten completely?

In an experiment employing a Brown-Peterson task, participants were given a list of trigrams - meaningless lists of 3 letters (e.g. GRT, PXM, RBZ) - to remember. After the trigrams had been shown, participants were asked to count down from a number, and to recall the trigrams at various periods after remembering them. Read More

The use of such trigrams makes it impracticable for participants to assign meaning to the data to help encode them more easily, while the interference task prevented rehearsal, enabling the researchers to measure the duration of short-term memories more accurately.

Whilst almost all participants were initially able to recall the trigrams, after 18 seconds recall accuracy fell to around just 10%. Peterson and Peterson’s study demonstrated the surprising brevity of memories in the short-term store, before decay affects our ability to recall them.

Learn more about memory decay here

6 Flashbulb Memories

(brown & kulik, 1977).

There are particular moments in living history that vast numbers of people seem to hold vivid recollections of. You will likely be able to recall such an event that you hold unusually detailed memories of yourself. When many people learned that JFK, Elvis Presley or Princess Diana died, or they heard of the terrorist attacks taking place in New York City in 2001, a detailed memory seems to have formed of what they were doing at the particular moment that they heard such news.

Psychologists Roger Brown and James Kulik recognized this memory phenomenon as early as 1977, when they published a paper describing flashbulb memories - vivid and highly detailed snapshots created often (but not necessarily) at times of shock or trauma. Read More

We are able to recall minute details of our personal circumstances whilst engaging in otherwise mundane activities when we learnt of such events. Moreover, we do not need to be personally connected to an event for it to affect us, and for it lead to the creation of a flashbulb memory.

Learn more about Flashbulb Memories here

7 Memory and Smell

The link between memory and sense of smell helps many species - not just humans - to survive. The ability to remember and later recognize smells enables animals to detect the nearby presence of members of the same group, potential prey and predators. But how has this evolutionary advantage survived in modern-day humans?

Researchers at the University of North Carolina tested the olfactory effects on memory encoding and retrieval in a 1989 experiment. Male college students were shown a series of slides of pictures of females, whose attractiveness they were asked to rate on a scale. Whilst viewing the slides, the participants were exposed to pleasant odor of aftershave or an unpleasant smell. Their recollection of the faces in the slides was later tested in an environment containing either the same or a different scent. Read More

The results showed that participants were better able to recall memories when the scent at the time of encoding matched that at the time of recall (Cann and Ross, 1989). These findings suggest that a link between our sense of smell and memories remains, even if it provides less of a survival advantage than it did for our more primitive ancestors.

8 Interference

Interference theory postulates that we forget memories due to other memories interfering with our recall. Interference can be either retroactive or proactive: new information can interfere with older memories (retroactive interference), whilst information we already know can affect our ability to memorize new information (proactive interference).

Both types of interference are more likely to occur when two memories are semantically related, as demonstrated in a 1960 experiment in which two groups of participants were given a list of word pairs to remember, so that they could recall the second ‘response’ word when given the first as a stimulus. A second group was also given a list to learn, but afterwards was asked to memorize a second list of word pairs. When both groups were asked to recall the words from the first list, those who had just learnt that list were able to recall more words than the group that had learnt a second list (Underwood & Postman, 1960). This supported the concept of retroactive interference: the second list impacted upon memories of words from the first list. Read More

Interference also works in the opposite direction: existing memories sometimes inhibit our ability to memorize new information. This might occur when you receive a work schedule, for instance. When you are given a new schedule a few months later, you may find yourself adhering to the original times. The schedule that you already knew interferes with your memory of the new schedule.

9 False Memories

Can false memories be implanted in our minds? The idea may sound like the basis of a dystopian science fiction story, but evidence suggests that memories that we already hold can be manipulated long after their encoding. Moreover, we can even be coerced into believing invented accounts of events to be true, creating false memories that we then accept as our own.

Cognitive psychologist Elizabeth Loftus has spent much of her life researching the reliability of our memories; particularly in circumstances when their accuracy has wider consequences, such as the testimonials of eyewitness in criminal trials. Loftus found that the phrasing of questions used to extract accounts of events can lead witnesses to attest to events inaccurately. Read More

In one experiment, Loftus showed a group of participants a video of a car collision, where the vehicle was travelling at a one of a variety of speeds. She then asked them the car’s speed using a sentence whose depiction of the crash was adjusted from mild to severe using different verbs. Loftus found when the question suggested that the crash had been severe, participants disregarded their video observation and vouched that the car had been travelling faster than if the crash had been more of a gentle bump (Loftus and Palmer, 1974). The use of framed questions, as demonstrated by Loftus, can retroactively interfere with existing memories of events.

James Coan (1997) demonstrated that false memories can even be produced of entire events. He produced booklets detailing various childhood events and gave them to family members to read. The booklet given to his brother contained a false account of him being lost in a shopping mall, being found by an older man and then finding his family. When asked to recall the events, Coan’s brother believed the lost in a mall story to have actually occurred, and even embellished the account with his own details (Coan, 1997).

Read more about false memories here

10 The Weapon Effect on Eyewitness Testimonies

(johnson & scott, 1976).

A person’s ability to memorize an event inevitably depends not just on rehearsal but also on the attention paid to it at the time it occurred. In a situation such as an bank robbery, you may have other things on your mind besides memorizing the appearance of the perpetrator. But witness’s ability to produce a testimony can sometimes be affected by whether or not a gun was involved in a crime. This phenomenon is known as the weapon effect - when a witness is involved in a situation in which a weapon is present, they have been found to remember details less accurately than a similar situation without a weapon. Read More

The weapon effect on eyewitness testimonies was the subject of a 1976 experiment in which participants situated in a waiting room watched as a man left a room carrying a pen in one hand. Another group of participants heard an aggressive argument, and then saw a man leave a room carrying a blood-stained knife.

Later, when asked to identify the man in a line-up, participants who saw the man carrying a weapon were less able to identify him than those who had seen the man carrying a pen (Johnson & Scott, 1976). Witnesses’ focus of attention had been distracted by a weapon, impeding their ability to remember other details of the event.

Which Archetype Are You?

Are You Angry?

Windows to the Soul

Are You Stressed?

Attachment & Relationships

Memory Like A Goldfish?

31 Defense Mechanisms

Slave To Your Role?

Are You Fixated?

Interpret Your Dreams

How to Read Body Language

How to Beat Stress and Succeed in Exams

More on Memory Psychology

Test your short-term memory with this online feature.

Memory Test

False Memories

How false memories are created and can affect our ability to recall events.

Why Do We Forget?

Why do we forget information? Find out in this fascinating article exploring...

Conditioned Behavior

What is conditioning? What Pavlov's dogs experiment teaches us about how we...

Interrupt To Remember?

Explanation of the Zeigarnik effect, whereby interruption of a task can lead to...

Sign Up for  Unlimited Access

• Psychology approaches, theories and studies explained
• Body Language Reading Guide
• How to Interpret Your Dreams Guide
• Self Hypnosis Downloads
• Plus More Member Benefits

You May Also Like...

Brainwashed, nap for performance, making conversation, psychology of color, persuasion with ingratiation, why do we dream, master body language, dark sense of humor linked to intelligence, psychology  guides.

Learn Body Language Reading

How To Interpret Your Dreams

Overcome Your Fears and Phobias

Psychology topics, learn psychology.

• Access 2,200+ insightful pages of psychology explanations & theories
• Insights into the way we think and behave
• Body Language & Dream Interpretation guides
• Self hypnosis MP3 downloads and more
• Behavioral Approach
• Eye Reading
• Stress Test
• Cognitive Approach
• Fight-or-Flight Response
• Neuroticism Test

© 2024 Psychologist World. Home About Contact Us Terms of Use Privacy & Cookies Hypnosis Scripts Sign Up

Faculty Resources

Assignments

The assignments in this course are openly licensed, and are available as-is, or can be modified to suit your students’ needs. Selected answer keys are available to faculty who adopt Waymaker, OHM, or Candela courses with paid support from Lumen Learning. This approach helps us protect the academic integrity of these materials by ensuring they are shared only with authorized and institution-affiliated faculty and staff.

If you import this course into your learning management system (Blackboard, Canvas, etc.), the assignments will automatically be loaded into the assignment tool, where they may be adjusted, or edited there. Assignments also come with rubrics and pre-assigned point values that may easily be edited or removed.

The assignments for Introductory Psychology are ideas and suggestions to use as you see appropriate. Some are larger assignments spanning several weeks, while others are smaller, less-time consuming tasks. You can view them below or throughout the course.

You can view them below or throughout the course.

CC licensed content, Original

• Assignments with Solutions. Provided by : Lumen Learning. License : CC BY: Attribution

CC licensed content, Shared previously

• Pencil Cup. Authored by : IconfactoryTeam. Provided by : Noun Project. Located at : https://thenounproject.com/term/pencil-cup/628840/ . License : CC BY: Attribution

General Psychology Copyright © by OpenStax and Lumen Learning is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.

Share This Book

Faculty Resources

Assignments.

The assignments in this course are openly licensed, and are available as-is, or can be modified to suit your students’ needs. Selected answer keys are available to faculty who adopt Waymaker, OHM, or Candela courses with paid support from Lumen Learning. This approach helps us protect the academic integrity of these materials by ensuring they are shared only with authorized and institution-affiliated faculty and staff.

If you import this course into your learning management system (Blackboard, Canvas, etc.), the assignments will automatically be loaded into the assignment tool, where they may be adjusted, or edited there. Assignments also come with rubrics and pre-assigned point values that may easily be edited or removed.

The assignments for Introductory Psychology are ideas and suggestions to use as you see appropriate. Some are larger assignments spanning several weeks, while others are smaller, less-time consuming tasks. You can view them below or throughout the course.

You can view them below or throughout the course.

Discussion Grading Rubric

The discussions in the course vary in their requirements and design, but this rubric below may be used and modified to facilitate grading.

• Assignments with Solutions. Provided by : Lumen Learning. License : CC BY: Attribution
• Pencil Cup. Authored by : IconfactoryTeam. Provided by : Noun Project. Located at : https://thenounproject.com/term/pencil-cup/628840/ . License : CC BY: Attribution

Search form

What makes a memory it may be related to how hard your brain had to work.

(© stock.adobe.com)

The human brain filters through a flood of experiences to create specific memories. Why do some of the experiences in this deluge of sensory information become “memorable,” while most are discarded by the brain?

A computational model and behavioral study developed by Yale scientists suggests a new clue to this age-old question, they report in the journal Nature Human Behavior .

“ The mind prioritizes remembering things that it is not able to explain very well,” said Ilker Yildirim, an assistant professor of psychology in Yale’s Faculty of Arts and Sciences and senior author of the paper. “If a scene is predictable, and not surprising, it might be ignored.”

For example, a person may be briefly confused by the presence of a fire hydrant in a remote natural environment, making the image difficult to interpret, and therefore more memorable. “Our study explored the question of which visual information is memorable by pairing a computational model of scene complexity with a behavioral study,” said Yildirim.

For the study, which was led by Yildirim and John Lafferty, the John C. Malone Professor of Statistics and Data Science at Yale, the researchers developed a computational model that addressed two steps in memory formation — the compression of visual signals and their reconstruction.

Based on this model, they designed a series of experiments in which people were asked if they remembered specific images from a sequence of natural images shown in rapid succession. The Yale team found that the harder it was for the computational model to reconstruct an image, the more likely the image would be remembered by the participants.

“ We used an AI model to try to shed light on perception of scenes by people — this understanding could help in the development of more efficient memory systems for AI in the future,” said Lafferty, who is also the director of the Center for Neurocomputation and Machine Intelligence at the Wu Tsai Institute at Yale. 

Former Yale graduate students Qi Lin (Psychology) and Zifan Lin (Statistics and Data Science) are co-first authors of the paper.

Health & Medicine

Media Contact

Bess Connolly : [email protected] ,

Shaping policy: ISPS workshop delves into executive branch dynamics

Meet Yale Internal Medicine: Allison Gaffey

In stroke response, speed is key; Yale study reveals where delays are worst

Physical frailty may put people at greater risk of depression.

The findings of a new Yale study suggest physical frailty may be a risk factor for depression — and a target for intervention.

• Show More Articles