charles p. thompson
patricia j. bauer rebecca m. starr
graphics, diagrams, and videos
henry l. roediger iii lisa geraci
gabriel a. radvansky
david e. copeland
myths, mysteries, and realities
elizabeth j. marsh
structures and functions
peter e. morris
In the early twenty-first century there is general agreement among memory researchers that memory consists of a number of distinctly different types of memory rather than one single memory. A brief overview of the major divisions in memory will help put autobiographical memory in context. Philosophers have long made a distinction between knowinghow (e.g., knowing how to ride a bicycle) and knowing what (e.g., knowing what a bicycle is). Modern research has verified the distinction between these two types of memory, and they are currently called procedural or implicit memory (knowing how) and declarative or explicit memory (knowing what). In 1972 Endel Tulving divided declarative memory into semantic and episodic memory. Semantic memory, because it contains general information such as facts, names, and important historical dates, could be described as a person's knowledge of the world. Episodic memory refers to a person's memory of events.
Autobiographical memory is a large and important subset of episodic memory containing those events that constitute the story of one's life. In the words of Katherine Nelson, autobiographical memory is "specific, personal, long-lasting, and (usually) of significance to the self-system. Phenomenally, it forms one's personal life history" (p. 8). If the first meeting with a loved one involves going to a movie, that event stands a good chance of becoming part of autobiographical memory. Other occasions on which movies are attended, however, will be remembered for a short time but probably will not become part of autobiographical memory. Instead, those events will contribute to generic memory. Generic memory contains memory for frequently occurring events such as brushing teeth or going to a movie. When asked about such events, it is unlikely that a specific instance of toothbrushing or going to a movie will be remembered.
The Organization of Autobiographical Memory
Autobiographical memory is organized as nested clusters of events that are all highly interconnected. Take the memory of a lawyer as a hypothetical example. Under the topic of school, that person would find events for elementary school, secondary school, college, and law school. Nested under each of those categories would be the events for each year (e.g., sophomore in college). Under the category of sophomore in college would be the events for each semester, which, in turn, would be grouped in categories such as academic events (e.g., classes), jobs, and friends. All these autobiographical events would be accessible in a number of ways. A particular event might involve a certain year in college, a particular job, and certain friends. That event could be accessed when thinking about school, friends, or jobs.
The topic of school is just one example of the many topics that have many subcategories. Other such topics include marriage, jobs, and military service. Just like the clusters of events nested under topics, the topics also are highly interconnected. The end result is a memory system that has the ability to retrieve the memory of a particular event from a large number of starting points. The most obvious example of the power of autobiographical memory to retrieve events is involuntary memory–memories that just pop into mind. In a 1998 article Dorthe Berntsen described her studies of involuntary memories, which showed that people average six to eight such memories every day.
Memory for Autobiographical Events
Remembering an autobiographical event usually involves both retrieving the content of the event (remembering what) and placing it in time (remembering when). Of course, memory for both fades over time. Autobiographical memory can be either reproductive or reconstructive. When it is reproductive, virtually all the details are retrieved from memory. When it is reconstructive, a few major points are retrieved from memory and the rest is constructed from generic memory. People are very good at reconstructing memory from generic events, and they are usually not aware that they are doing so. One of the consequences is that memory for old events is often wrong. Sometimes the error is minor and sometimes it is not.
Memory researchers have shown that memory for the content of the event gradually changes from being almost entirely reproductive to being, after about a year, almost entirely reconstructive. By contrast, memory for when an event occurred is almost always entirely reconstructive.
There are three additional distinctive characteristics of memory for autobiographical events. First, as time passes, the number of events that can be recalled drops off rapidly at first and then more slowly–a negatively decelerating curve. Second, older people show what David C. Rubin and his colleagues called a "reminiscence bump." Older people recall more events for the period when they were in their twenties than predicted by the negatively decelerating memory curve. Typically, many important life events (such as college graduation, marriage, and children) occur when people are in their twenties. Research has shown that the reminiscence bump can be attributed to these important life events. Third, almost all people show infantile amnesia. When people are asked to recall events from their childhood, they usually cannot recall events prior to age three. Not only are they unable to recall memories before age three, but the number of memories retrieved between ages three and six is also markedly below the number available after that period. Infantile amnesia is an intriguing puzzle because researchers have shown that children under age three can report details of isolated specific events and, most important, can remember them for up to two years. There is a growing consensus that the answer to the puzzle may lie in the development of autobiographical memory.
The Development of Autobiographical Memory
By the early twenty-first century there was considerable evidence that children learn how to talk about memories with others. They learn how to tell their life stories as a narrative. This is the social interaction view of autobiographical memory. This view proposes that infantile amnesia is overcome when children learn how to retain their memories in a recoverable form by turning them into narratives.
One strong source of support for the social interaction view has been the investigation of mother-child discussions of past events. These discussions can be classified as narrative or pragmatic. The narrative conversations focused on what happened when, where, and with whom. The pragmatic conversations used memory to retrieve specific information such as "Where did you put your book?" Children of mothers who used the narrative type of discussion remember more about the events than children of mothers who used the pragmatic type of discussion.
Autobiographical Memory as an Expert System: Implications for Learning
Experts learn new material in their field much faster than novices, and they retain that material much better as well. The reason for their outstanding performance in learning and memory is that they have a highly organized and detailed memory for their area of expertise. This allows them to relate new material to one or more pieces of information that they already know. Metaphorically speaking, they have many potential pegs on which they can hang new information. When they have to retrieve the new information, they can follow a well-beaten path to that information.
Autobiographical memory is also a highly organized and detailed memory. When it is possible to relate new information to life events, autobiographical memory functions in the same way as an expert system. The new information will be learned faster and remembered better than information that cannot be related to life events (or to another expert system).
Life Is Pleasant–and Autobiographical Memory Makes It Better
In studies of subjective well-being conducted around the world, people generally report that they are happy with their life. In the United States, this positive feeling is found in people with physical disabilities, people with mental illness, low-income people, minorities–in short, it is found for virtually all categories. Research on autobiographical memory shows two sources for this positive feeling of well-being. First, life events are generally pleasant with positive events occurring roughly twice as often as negative events. This is true for childhood memories, involuntary memories, and adult memories.
Second, the general level of pleasantness typically is enhanced when remembering life events. That occurs because the emotion attached to the events fades over time but the emotion for unpleasant events fades much faster than the emotion for pleasant events. Thus, the overall emotional tone becomes more pleasant for autobiographical memory. The mechanism responsible for this change appears to be the rehearsal (thinking about or talking about) of pleasant events.
For most people, autobiographical memory is a very positive and useful part of memory. It is equivalent to an expert system and therefore can be very helpful in learning new material. Most important, it holds the story of one's life. That story is typically very pleasant and, because negative emotions fade rapidly, becomes more pleasant as time passes. People's lives would be much reduced without their access to autobiographical memory.
See also: Memory, subentries on Development of, Myths, Mysteries, and Realities.
Berntsen, Dorthe. 1998. "Voluntary and Involuntary Access to Autobiographical Memory." Memory 6:113–141.
Diener, Ed, and Diener, Carol. 1996. "Most People Are Happy." Psychological Science 7:181–185.
Fivush, Robyn; Haden, Catherine; and Reese, Elaine. 1995. "Remembering, Recounting, and Reminiscing: The Development of Autobiographical Memory in Social Context." In Constructing Our Past: An Overview of Autobiographical Memory, ed. David C. Rubin. New York: Cambridge University Press.
Hudson, Judith A. 1990. "The Emergence of Autobiographic Memory in Mother-Child Conversation." In Knowing and Remembering in Young Children, ed. Robyn Fivush and Judith A. Hudson. New York: Cambridge University Press.
Nelson, Katherine. 1993. "The Psychological and Social Origins of Autobiographical Memory." Psychological Science 4:7–14.
Rubin, David C.; Rahhal, Tamara A.; and Poon, Leonard W. 1998. "Things Learned in Early Adulthood Are Remembered Best." Memory and Cognition 26:3–19.
Thompson, Charles P.; Skowronski, John J.; Larsen, Steen; and Betz, Andrew. 1996. Autobiographical Memory: Remembering What and Remembering When. New York: Erlbaum.
Tulving, Endel. 1972. "Episodic and Semantic Memory." In Organization of Memory, ed. Endel Tulving and Wayne Donaldson. New York: Academic Press.
Waldfogel, Samuel. 1949. "The Frequency and Affective Character of Childhood Memories." Psychological Monographs 62 (whole no. 291).
Walker, W. Richard; Vogl, Rodney J.; and Thompson, Charles P. 1997. "Autobiographical Memory: Unpleasantness Fades Faster than Pleasantness over Time." Applied CognitivePsychology 11:399–413.
Charles P. Thompson
Traditionally, the construct of memory has been divided into a number of different types, defined largely in terms of the length of time over which information is retained or stored. For example, memory is divided into a very brief (on the order of milliseconds) sensory store for visual or acoustic properties of a stimulus; short-term or working memory, in which information can be stored and manipulated for about twenty seconds; and long-term memory, in which information can be stored virtually permanently. Long-term memory can be further divided into storage of procedures or skills, such as how to tie a shoe, and storage of explicit or declarative memories, such as memories of personal events or of general knowledge about the world. The study of the development of each of these systems can aid in understanding the cognitive abilities of both children and adults. Because working memory has important implications for learning and education, it is the focus of this entry.
Defining and Measuring Working Memory
Whereas short-term memory refers to the storage of information over brief delays, working memory refers to the capacity to store information for brief periods and to manipulate it during storage. A prominent model of working memory suggests that it is a multicomponent resource consisting of a limited-capacity central executive or "work space," where processing takes place, and two storage components, one for verbal information and one for spatial information. Working memory underlies a variety of complex cognitive tasks, including reading comprehension and mental arithmetic. For example, mentally adding the numbers 12 and 49 requires that both numbers be held in mind as the operation of addition is performed. Because conscious manipulation of information depends on working memory, one must examine its development in order to understand the abilities of different aged children to comprehend, learn, and remember the information taught to them.
Unlike the capacity for long-term memory, which is considered to be virtually unlimited, the capacity for working memory is limited to a few items. Indeed, the increase in the number of items that can be stored and manipulated at a time (referred to as the working memory "span") is a major source of age-related change in working memory. Moreover, at any given age, there are differences among individuals in their working memory spans. Measures of working memory span thus are integral to the study of working memory. Methods of assessing working memory include the reading span task, the A-not-B task, and the imitation task.
The reading span task. A classic measure of working memory in adults is the reading span task. Reading span is assessed by having adults read a series of sentences and then recall the final word of each of the sentences in the order that they read them. The reading span task requires both the storage and manipulation of information: The reader must store the last word of each sentence while reading subsequent words and sentences. Measures have also been developed to assess working memory throughout childhood, and these measures reveal systematic increases in working memory capacity across age.
The A-not-B task. In the second half of the first year of life, working memory most frequently is assessed by the A-not-B task. In the A-not-B task, a small toy is hidden in one of two identical wells (Well A) in full view of the infant. After a brief delay, the infant is allowed to reach into Well A to find the toy. Following several "A" trials, the toy is hidden in the second well (Well B). Even though the infants watch as the toy is hidden in Well B, they often reach to Well A again, making the "A-not-B error." Overcoming the A-not-B error, and thus, successfully searching in Well B, requires that infants (1) remember where they saw the toy hidden (requiring storage of information) and (2) inhibit the learned tendency to reach to Well A (requiring processing of information). As working memory ability increases, infants are able to withstand longer delays without making the A-not-B error. The delay that infants are able to tolerate without making the error increases about two seconds per month between the ages of seven to twelve months.
The imitation task. In the second year of life, working memory can be assessed using imitation. In a standard imitation task designed to assess short-term or long-term memory, props are used to produce a sequence of actions (e.g., making a rattle by putting a ball into a nesting cup [step 1], covering it with another cup [step 2], and shaking the cups to make a rattle [step 3]). The child then is allowed to imitate the sequence either immediately (as a measure of short-term memory) or after a delay (as a measure of long-term memory). To assess working memory, the steps of several sequences are presented in interleaved order. That is, rather than the steps of a single event in sequence (A-1, A-2, A-3, with the alphabetic character referring to the sequence and the number referring to a step in the sequence), the child sees, for example, A-1, B-1, C-1, A-2, B-2, C-2, A-3, B-3, C-3. The child is then provided with the materials for each of the sequences in turn (e.g., all of the materials for sequence A) and is encouraged to produce the sequences. The interleaving of the sequences during presentation requires that the child not only store the information for each individual step but also attend to subsequent steps and integrate the steps into their respective sequences. Researchers have used the imitation task with seventeen- and twenty-month-old children, finding increases in performance, and therefore in working memory, with age.
Tasks for assessing older children. Working memory may be assessed in older children with an adaptation of the reading span task and with a similar task using numbers. Both tasks indicate increases in working memory across the age range of seven to thirteen years. In addition, children with reading disabilities perform at lower levels on both tasks than do their normal age-mates, and children with arithmetic disabilities have trouble with the number task. Thus, working memory plays an important role in the development of reading and number skills during middle childhood. Adult levels of performance on working memory tasks are reached by the high school years.
Factors Affecting Developmental Changes in Working Memory
Developmental changes in working memory may be due to several factors, including brain maturation, increases in the speed of information processing, increases in knowledge, better use of strategies, and more effective management of attention. For example, the processes involved in working memory are largely dependent on the prefrontal cortex of the brain. The prefrontal cortex matures late relative to other brain regions, such as those involved in sensory and motor processes, and does not reach full maturity until adolescence or even early adulthood. Thus, the time courses of development of the functions of working memory and of the brain regions thought to support them are closely linked. Brain maturation also involves a process called myelination, in which a fatty substance surrounds the nerve cells and aids in the conduction of brain impulses. Myelination may increase the speed of processing, thereby increasing working memory abilities as children mature: Faster processing allows for the storage of more information before it decays from working memory.
Other factors that may affect the development of working memory include increased knowledge, strategy use, and management of the focus of attention. Breadth of knowledge affects working memory to the extent that new information can be linked to existing knowledge. For example, it is easier to store nine letters that form three words that are already stored in long-term memory (e.g., p-e-n, d-o-g, ha-t) than to store a list of nine random letters in working memory (e.g., p-o-h-e-d-t-n-g-a). The learning of and increased efficiency in the use of strategies also aids working memory. For example, as children reach the late grade-school years, they begin to spontaneously use rehearsal (the strategy of repeating the information mentally) when they attempt to remember something new. Working memory also develops with age as children gain increasing control over the focus of their attention. This permits them to attend to more information, switch the focus of attention as needed, and inhibit attention to irrelevant information. All three of these factors–increased knowledge, strategy use, and management of attention–likely play a role in the development of working memory throughout childhood.
Working memory involves the conscious storage and manipulation of information that is integral to the performance of complex cognitive tasks. It is clear that working memory develops throughout childhood, as children are able to hold increasingly more information "online" even as they perform a greater number of mental manipulations on the information. Because working memory underlies so much of mental functioning, it is important to understand its development, as well as the sources and implications of individual differences in it.
See also: Memory, subentry on Myths, Mysteries, and Realities.
Baddeley, Alan. 1981. "The Concept of Working Memory: A View of Its Current State and Probable Future Development." Cognition 10:17–23.
Baddeley, Alan, and Hitch, Graham. 1974. "Working Memory." In The Psychology of Learning and Motivation, ed. Gordon A. Bower. New York: Academic Press.
Bauer, Patricia J.; Van Abbema, Dana L.; and DE Haan, Michelle. 1999. "In for the Short Haul: Immediate and Short-Term Remembering and Forgetting by Twenty-Month-Old Children." Infant Behavior and Development 22:321–343.
Bauer, Patricia J.; Wenner, Jennifer A.; Dropik, Patricia L.; and Wewerka, Sandi S. 2000. "Parameters of Remembering and Forgetting in the Transition from Infancy to Early Childhood." Monograph of the Society for Research in Child Development 65 (4).
Case, Robbie D.; Kurland, Midian; and Goldberg, Jill. 1982. "Operational Efficiency and the Growth of Short-Term Memory Span." Journal of Experimental Child Psychology 33:386–404.
Cowan, Nelson. 1997. "The Development of Working Memory." In The Development of Memory in Childhood, ed. Nelson Cowan. Hove, East Sussex, Eng.: Psychology Press.
Daneman, Meredyth, and Carpenter, Patricia. 1980. "Individual Differences in Working Memory and Reading." Journal of Verbal Learning and Verbal Behavior 19:450–466.
Diamond, Adele. 1985. "Development of the Ability to Use Recall to Guide Action, as Indicated by Infants' Performance on A not B." Child Development 56:868–883.
Gathercole, Susan. 1998. "The Development of Memory." Journal of Child Psychology and Psychiatry 39:3–27.
Luciana, Monica, and Nelson, Charles A. 1998."The Functional Emergence of Prefrontally-Guided Working Memory Systems in Four-to Eight-Year-Old Children." Neuropsychologia 36:273–293.
Siegal, Linda S., and Ryan, Ellen B. 1989. "The Development of Working Memory in Normally Achieving and Subtypes of Learning Disabled Children." Child Development 60:973–980.
Starr, Rebecca M.; De Haan, Michelle; and Bauer, Patricia J. 2001. "Piecing It Together: Assessing Working Memory in Preverbal Children." Paper presented at the biennial meeting of the Society for Research in Child Development, Minneapolis, MN.
Patricia J. Bauer
Rebecca M. Starr
GRAPHICS, DIAGRAMS, AND VIDEOS
Graphics, diagrams, and videos are frequently used to enhance learning of verbal material. Indeed, as much as half of the space in K–12 textbooks is devoted to graphics and diagrams, and videos are frequently presented in classrooms. Furthermore, recent technological advances have made possible the use of additional, primarily visual, materials for instruction, such as animation and hypertext.
Presumably, graphics, diagrams, video, and other visual materials are used to make information accessible and memorable. But how might such visual materials be exploited to facilitate learning and memory? When are such displays actually beneficial for learning, and when are they simply decorative or even distracting? This brief review begins with a discussion of general research on how visual media displays aid comprehension and enhance memory for verbal material, and the circumstances in which visual materials are distracting and perhaps even reduce comprehension memory of verbal material. This discussion incorporates guidelines for the design of visual displays for effectively enhancing memory in the context of specific commonly used displays such as graphic organizers, graphs, diagrams, and videos.
Main Benefits of Graphics, Diagrams, and Videos
Visual displays and videos play a number of important roles in learning. Perhaps the most cited cognitive explanation for the benefits of presenting information both visually and verbally is Allan Paivio's dual-coding theory. In classic memory studies, Paivio and his colleagues demonstrated that people were better at remembering lists of words coded visually and verbally, rather than merely verbally. One explanation for the superiority of dualcoding is that by encoding information to be learned in two modalities rather than a single modality, people have multiple retrieval cues that help them access information, thus enhancing memory.
A second general benefit of visuospatial displays is that they are visually appealing. Viewers' attention is attracted to these displays, and viewers are more likely to study them for longer periods of time. This, in turn, can lead to enhancement of memory for information depicted in them. For example, one study of memory for materials taught in introductory psychology courses found that students recalled ideas and examples presented in videos and in-class demonstrations better than information presented in the text alone.
In addition to directly enhancing memory for information, diagrams, graphics, and videos can also make complex information easier to comprehend. Specifically, visual representation can make complex information "visually obvious" and thus require less cognitive effort to understand than text-based descriptions of the same information. Better comprehension, along with more cognitive resources that can be allocated to learning and memory, will together enhance memory for the information to be learned.
Concepts that Visual Displays Are Most Useful in Communicating
Visual displays are particularly beneficial to the comprehension of some classes of concepts that often involve specialized types of displays. First, visual displays are useful for communicating cause- and-effect information. For example, a diagram can help illustrate how turning a key can unlock a door. When such displays are designed to highlight the cause- and-effect sequence (e.g., by animating one portion at a time or by using a sequence of arrows), viewers' comprehension and memory for the cause- and-effect information is enhanced.
Second, visual displays are frequently useful for representing relationships amongst elements (e.g., a Venn diagram, a text-based graphic organizer, a scientific model). One benefit of such representations is that they can facilitate problem solving. Another benefit is that they provide concrete representation of key concepts or elements and their relationships. Graphic organizers, for example, are often used to represent relationships among the main ideas in a text. For example, information in a text can be summarized in matrix form such that similar concepts are closer together along one or more dimensions. Research has suggested that representations that group relevant concepts, such as matrices, can significantly enhance memory for text compared to representations that simply summarize materials, such as outlines. Indeed a general principle that is relevant for any diagram intended to represent relationship elements, including graphic organizers but also including graphs, flowcharts, and so on, is that information that is closely related be placed close together on a page or related visually (e.g., via Gestalt principles of grouping).
Third, visual displays are useful for communicating information that is intrinsically visuospatial. For example, visual displays of a map of a building or a drawing of how different parts of a car engine fit together communicate information that is difficult to describe verbally. Not all intrinsically visuospatial displays, however, are equally beneficial. One general guideline is to design displays that facilitate integrating relevant information (placing text and graphics together) to reduce working memory load and allow viewers to focus on learning relevant content. A 2001 book by Richard Mayer on multimedia learning includes a number of guidelines for the design of such displays.
Fourth, visual displays provide natural mappings to quantitative information (e.g., more is higher) and thus increase comprehension and memory for quantitative information. One difficulty associated with graphs is that students often make interpretation errors and therefore remember erroneous data. In a 2002 article, Priti Shah and James Hoeffner discuss a set of guidelines for teachers and other graph designers who need to depict data for students. These guidelines include making relevant trends visually salient in the graph and writing text to be compatible with information in the graph.
Additional Benefits of Visual Displays
In addition to making some concepts easier to understand, diagrams, graphics, and videos tend to focus viewers' or readers' attention and thus highlight important information. Displays or videos can guide a viewer's attention from one step to the next in a description of causal information or in instructions. For example, a sequence of arrows might highlight how a mechanical device, such as a bicycle pump or a toilet, works, or a sequence of panels might instruct someone how to bake cookies. Such displays, by highlighting information or key elements in a sequence, help students learn and remember relevant information.
In addition to the cognitive aspects of how they influence memory, visual displays and videos serve a social function beneficial to memory. In particular, visual displays and videos provide a common motivating experience for students. In "anchored instruction," students view movies with built-in problems that serve as a reference point for lessons on a wide variety of topics such as solving mathematical problems, discussing social issues, and understanding physics concepts. The common anchor may provide a social and personal context for information to be learned.
The use of graphics, diagrams, and videos includes not just presenting such visual information to students but also asking them to create them. Creating visual artifacts or inscriptions appears to be motivating to students, especially when they share their products with fellow students. Furthermore, developing them forces students to consider the important elements and relationships and also to identify what information they understand and what they do not. Thus, the creation of graphics, diagrams, and videos can be used to enhance comprehension and memory for to-be-learned information.
Drawbacks of Displays and Videos
Despite the benefits of graphics, diagrams, and videos for helping students comprehend and remember important information, there are some cases in which displays and videos can be harmful. Specifically, because graphics, diagrams, and videos attract attention, it is possible that in many cases such visual presentations serve as seductive details detracting attention from important information and thus impair rather than enhance learning. A concrete example of a display that may serve as a seductive detail is a picture, in a scientific text about how lightning is formed, of someone who was struck by lightning. Although the intention of such a picture might be to interest the students in the content of the text, research has found that, in fact, displays such as these are actually distracting and reduce the quality of readers' understanding of the scientific content of the text. Videos, also, can serve as or include seductive details detracting viewers from the main message of a particular lesson.
In summary, this general discussion of visual displays suggests that diagrams, graphics, and videos can help users comprehend relevant information and enhance memory for that information. The content and format of the information, however, should be consistent with the goals of communication. When the content is not consistent with the goals of communication, students may remember irrelevant or inaccurate information.
See also: Literacy, subentry on Learning from Multimedia Sources; Media and Learning; Reading, subentry on Content Areas.
Clark, James M., and Paivio, Allan. 1991. "Dual Coding Theory and Education." Educational Psychology Review 3:149–210.
Larkin, Jill H., and Simon, Herbert A. 1987. "Why a Diagram Is (Sometimes) Worth Ten Thousand Words." Cognitive Science 11:65–99.
Mayer, Richard E. 1993. "Illustrations that Instruct." In Advances in Instructional Psychology, ed. Robert Glaser. Hillsdale, NJ: Erlbaum.
Mayer, Richard E. 2001. Multimedia Learning. New York: Cambridge University Press.
Mayer, Richard E.; Heiser, Julie; and Lonn, Steve. 2001. "Cognitive Constraints on Multimedia Learning: When Presenting More Material Results in Less Understanding." Journal of Educational Psychology 93:187–198.
Michas, Irene C., and Berry, Dianne C. 2001. "Learning a Procedural Task: Effectiveness of Multimedia Presentations." Applied Cognitive Psychology 14:555–575.
Oestermeier, Uwe, and Hesse, Friedrich W. 2000. "Verbal and Visual Causal Arguments." Cognition 75:65–104.
Robinson, Daniel H. 2002. Educational Psychology Review 14 (Special issue on text adjuncts).
Robinson, Daniel H., and Skinner, Christopher H. 1996. "Why Graphic Organizers Facilitate Search Processes: Fewer Words or Computationally Efficient Indexing?" Contemporary Educational Psychology 21:166–180.
Shah, Priti, and Hoeffner, James. 2002. "Review of Graph Comprehension Research: Implications for Instruction." Educational Psychology Review 14:47–49.
Vanderbilt University. The Cognition AND Technology Group at Vanderbilt. 1997. The Jasper Project: Lessons in Curriculum, Instruction, Assessment, and Professional Development. Mahwah, NJ: Erlbaum.
Vanderstoep, Scott W.; Fagerlin, Angela; and Feenstra, Jennifer S. 2000. "What Do Students Remember from Introductory Psychology?" Teaching of Psychology 27:89–92.
Implicit memory refers to the expression of past events on current behavior when people are not trying to retrieve these past events and when they are usually not even aware of the events' influence. This process is different from explicit memory, which refers to conscious attempts to retrieve memories of past events; in implicit memory tests there is no conscious effort to retrieve. The customary use of the terms memory or remembering refers to explicit, conscious recollection during which people attempt to travel back in time to mentally relive or reexperience past events. Many behaviors people perform, however, reflect past learning even when they are not consciously attempting to retrieve; therefore, these behaviors reflect the manifestation of implicit memory. Some of these behaviors involve motor skills. When people tie their shoes or ride a bicycle or walk, they need not consciously retrieve their first attempts to learn these skills. The same is true of other types of learning. It is much easier to read a passage of text that one has read before, even if not consciously trying to remember the original time the passage was read. As these examples indicate, implicit learning is sometimes referred to as occurring rather automatically or at least to having an automatic component.
As a Reflection of Conscious Learning
Implicit memory measures are sometimes said to reflect unconscious learning because densely amnesic brain-damaged patients typically show intact uses of implicit memory. The data in Figure 1 are from a 1984 experiment by Peter Graf, Larry Squire, and George Mandler. They compared brain-damaged participants who displayed serious impairments on explicit memory tests such as recall and recognition to age- and education-matched control participants. In one test condition, both groups of participants studied lists of words and attempted to recall them in any order (free recall). As can be noted on the left of the graph in Figure 1, the patients recalled the words much worse than did the controls. This pattern reflects the patients' deficit on an explicit memory test, in which they were asked to consciously retrieve past events.
In the implicit test, both groups studied the lists of words but were tested by being shown three-letter stems of words with the instruction to produce the first word that came to mind in response to each stem clue. So, if the word chair had been in the list, participants would get cha and be asked to say the first word that came to mind (chain, chapter, challenge and so on–each stem had at least ten possible
completions). If chair had not been presented in the list, people in both groups produced it about 10 percent of the time (the dashed line on the right side of Figure 1). However, if chai had been presented in the list, both patients and the control participants produced the word about 45 percent of the time. The fact that both groups completed the word so much above the base rate reflects priming, the basic measure of implicit memory tests. Priming is defined as the difference between performance on a test when the relevant information has been presented and performance when the relevant information has not been recently presented. Therefore, the amount of priming reflected in the data in Figure 1 was about 35 percent (45% in the primed condition minus the 10% base rate). Although the participants were told to produce any word that came to mind, the presentation of chair in the list primed them to produce that word rather than another on the test.
This priming effect reflects a use of memory, but not a conscious or intentional use of memory. Because the patients were densely amnesic and probably did not remember even studying the list of words, the priming may be said to be unconscious (in this sense). The amnesic patients produced just as much priming as did control participants. Because the patients had suffered brain damage that impaired their use of explicit memory processes, it appears that the brain mechanisms and processes that underlie explicit and implicit memory tests are quite different. Put another way, the results show that memory is not a unitary entity; people with certain types of brain damage can be severely impaired on one type of memory test and unaffected on other types of tests.
Implicit Memory Tests
The study of implicit memory began in psychology in the early 1980s and in the early twenty-first century there is a large amount of literature on the topic. There seem to be at least two distinct types of implicit memory tests, perceptual and conceptual.
Perceptual memory tests. Perceptual implicit memory tests challenge the perceptual system by presenting impoverished test stimuli to which participants respond. The word stem completion test already described (cha ) is one such test. Others are word identification (presenting words very briefly and having participants guess what they are), and word fragment completion (naming words from fragments such as l_p_a_t. (That fragment is hard if not recently primed [with word elephant ].) If pictures are used as study materials, then the test can involve giving fragmented forms of pictures or having them be gradually clarified through a series of successively fuller fragments until the participant can identify the picture. Again, the measure in all cases is priming–as reflected by more accurate or faster completion of the target when it has been studied relative to when it has not been studied.
Factors that greatly affect priming on perceptual implicit memory tests are often quite different from those that affect performance on most explicit memory tests in both patients and in healthy control participants, indicating further that these two types of tests seem to be measuring different processes. For example, modality of presentation of words strongly affects performance on perceptual implicit tests. Visual presentation of words enhances priming on visual tests, whereas auditory presentation enhances priming on auditory implicit tests (e.g., presenting words describing noise with auditory cues for identification). Modality generally matters little in tests of explicit memory. On the other hand, factors that can have a great effect on explicit memory tests can have little or no effect on priming on implicit tests. For example, when participants read pairs of words (hot and cold ) or generate the second word from a clue such as "opposite of cold," they scored better on an explicit test of recognition for the words they generated, but exhibited more priming for the words they just read on an implicit test, in which they had to quickly identify the word. The data are shown in Figure 2.
The results described above can be explained, at a general level, by the theory of transfer appropriate processing. This principle states that performance on memory tests will be enhanced if there is a match between the conditions of study and test, which will permit the study experience to transfer better to the test. For example, if the test involves deciphering a fragmented or briefly presented word given visually (classified as a perceptual test), then performance on this test should benefit from prior visual presentation more than from a prior auditory presentation or from generating the word, as is indeed the case. Practice reading a visual word (versus hearing or generating it) transfers better to a test that also involves reading words.
Conceptually driven tests. Whereas most implicit tests depend on perceptual processing, most explicit memory tests depend heavily on the meaning of the concepts or events that are being remembered. These tests are called conceptually driven tests because, when people are trying to retrieve past events, it is the meaning of the events that is important. Generating a word involves more attention to meaning than simply reading it, and so generating produced greater explicit recognition in results shown in Figure 2. Again, this finding is in accord with the transfer appropriate processing theory. The transfer appropriate processing theory can account for a large body of findings although some problems remain.
Although explicit memory tests are usually driven by meaning or by conceptual information, there is a class of implicit memory tests that is also conceptually driven. These tests are probably the most relevant for education, but they have not yet been studied as much as perceptual implicit tests. One class of conceptual implicit memory tests that has been studied is the general knowledge test. "What animal did Hannibal use to help him cross the Alps in his attack on Rome?" and "What is the name of the ship that carried the pilgrims to America in 1620?" are examples of questions on general knowledge tests. Prior exposure to the words elephant or Mayflower before the questions are asked increases correct answers to these questions, which reflects priming of concepts. Free association tests ("say the first word that you think of to the stimulus word tusk ") and category association tests ("list as many African animals as you can in thirty seconds") are other examples of conceptually driven implicit memory tests. These priming effects again seem to be indicative of implicit retrieval because they also appear in brain-damaged patients with severe difficulties in explicit expressions of memory.
In some sense, much of education is intended to permit people the automatic, unconscious retrieval of facts, routines, and principles when they need them. Education is meant to provide learning experiences that will, at least in some cases, last a lifetime. Of course, not all facts and principles will be remembered for that long. Much information learned in the classroom will be forgotten (at least when explicit tests are given). The hope is that one's general knowledge and skills (writing, thinking logically)
will survive. There are no studies of residual, implicit retention of formal education but such studies will surely come in the future.
See also: Memory, subentries on Myths, Mysteries, and Realities, Structures and Functions.
Blaxton, Teresa A. 1989. "Investigating Dissociations among Memory Measures: Support for a Transfer-Appropriate Processing Framework." Journal of Experimental Psychology: Learning, Memory, and Cognition 15:657–668.
Gardiner, Howard; Boller, Francois; Moreines, Judith; and Butters, Nelson. 1973. "Retrieving Information from Korsakoff Patients: Effects of Categorical Cues and Reference to the Task." Cortex 9:165–175.
Graf, Peter; Squire, Larry R.; and Mandler, George. 1984. "The Information that Amnesic Patients Do Not Forget." Journal of Experimental Psychology: Learning, Memory, and Cognition 10:164–178.
Jacoby, Larry L. 1983. "Remembering the Data: Analyzing Interactive Processes in Reading." Journal of Verbal Learning and Verbal Behavior 22:485–508.
Jacoby, Larry L., and Dallas, Mark. 1981. "On the Relationship between Autobiographical Memory and Perceptual Learning." Journal of Experimental Psychology: General 110:306–340.
McDermott, Kathleen B., and Roediger, Henry L. 1996. "Exact and Conceptual Repetition Dissociates Conceptual Memory Tests: Problems for Transfer Appropriate Processing Theory." Canadian Journal of Experimental Psychology 50:57–71.
Roediger, Henry L. 1990. "Implicit Memory: Retention without Remembering." American Psychologist 45:1043–1056.
Roediger, Henry L., and McDermott, Kathleen B. 1993. "Implicit Memory in Normal Human Subjects." In Handbook of Neuropsychology, ed. François Boller and Jordan Grafman. Amsterdam: Elsevier.
Schacter, Daniel L. 1987. "Implicit Memory: History And Current Status." Journal of Experimental Psychology: Learning, Memory, and Cognition 13:501–518.
Squire, Larry R. 1987. Memory and the Brain. New York: Oxford University Press.
Tulving, Endel. 1985. "How Many Memory Systems Are There?" American Psychologist 40:385–398.
Vaidya, Chandan J.; Gabrieli, John D. E.; Keane, Margaret M.; and Monti, Laura A. 1995. "Perceptual and Conceptual Memory Processes in Global Amnesia." Neuropsychology 9:580–591.
Henry L. Roediger III
Mental models, also called situation models, are mental representations of the state of affairs in a real or possible world. They serve as mental simulations of events. For reading, a mental model represents the situation described by the text rather than the text itself. The creation of a coherent mental model is the goal of comprehension.
Mental models are complex representations that contain many different types of information. This includes a spatial-temporal framework about the spatial context in which an event occurred and the time period in which the event transpired (i.e., where and when it occurred). They also contain tokens to represent entities, such as people, animals, objects, and ideas. These tokens might have properties associated with them, such as physical characteristics, emotions, or names. Within a framework there may be structural relations that define the event. This can include spatial relations (e.g., the umpire is behind home plate), ownership relations (e.g., the players are using the shortstop's ball), social relations (e.g., the two teams are bitter rivals), and so forth. Finally, because events are dynamic, several frameworks can be joined by linking relations that contain temporal order and causal information.
The Role of Experience
Mental model creation involves integrating prior knowledge with what has been given. This allows inferences to be drawn for information that has not been provided. Of course, the more knowledge a person has, the more likely it is that an adequate mental model will be constructed. For example, when watching a baseball game, a person with a lot of baseball knowledge will better understand the structure of the game, the causal and goal-related relations among the players, and the sequence of events.
The structure of one's experience influences the creation of mental models. Suppose a person reads a text on a topic that the reader has a fair amount of knowledge of, such as going to a baseball game. In this case, there is a certain sequence in which the events occur (e.g., buying a ticket before finding one's seat). Even if two events are adjacent in the text, reading times increase as the distance between them in the standard sequence increases. So when building mental models, people consult their knowledge systematically. It is as if they are scanning sequentially through their knowledge to assess where the current events fit. The greater the distance, the longer the scanning process and the more that needs to be inferred.
Mental models are essentially an amalgam of the given information that can be acquired through a film, book, lecture, discussion, and so forth, along with prior knowledge that a person has in long-term memory. The use of mental models is found in a wide variety of circumstances, including language comprehension and memory.
Mental models are critical for understanding. When people comprehend language, they create three types of mental representations. The simplest is a verbatim representation of what was heard or read. This is forgotten very quickly unless there is something important about the exact wording, as with a joke. At a more abstract level is the propositional textbase. This is a representation of the idea units that were expressed. For example, the sentences "The ball was hit by the batter" and "The batter hit the ball" would correspond to the same propositional representation. This representation is forgotten less rapidly. Finally, at the most abstract and highest level is the mental model. This is a referential representation of the described events. The mental model is a representation of what the message is about. In contrast, the verbatim and textbase levels are representations of the message itself but may serve as scaffolding from which to build a mental model.
While the goal of comprehension is to construct a mental model, its organization and function can influence comprehension itself. During reading, people keep track of what is going on in the described situation. For example, readers may keep track of the spatial location of a protagonist in a story. When that person moves from one location to another, knowledge about people or objects in the old location become less available. Switching from one spatial framework to another influences what information is readily available during comprehension. Moreover, the further the protagonist moves from the original location, the less available the information becomes. A similar thing occurs for temporal frameworks. Short time periods are more likely to be part of the same time frame, whereas long time periods are more likely to include a shift to a new time frame, and hence a new situation. Information that was relevant to the original situation is less available after a large time shift. Finally, people also monitor a protagonist's goals. Information that is relevant to current, unsatisfied goals is more available than information relating to goals that were successfully completed. The prior goal information is no longer maintained in the current mental model.
When the structure of the situation changes, reading times increase, as if readers are monitoring the described events. This includes changes in space, time, entities, causality, or the goals of the protagonist. When a major change in the described situation occurs, people update their mental models. In addition to monitoring event changes, people may also notice inconsistencies with what has been described before. Such inconsistencies result in increased reading times as the reader tries to resolve what they know of the situation with the current information.
One of the most important dimensions that people monitor is causality. Information varies in the degree of its causal importance. Information that plays an active role in the described situation is causally more important. Such information is typically read more quickly. Presumably, this is because it can be more easily integrated into the current mental model.
Mental models are also involved in memory. At very long periods of time, this is the representation that will dominate a person's recollections. Many of the influences during comprehension carry over into memory. For example, shifts in a situation during comprehension result in the memory being organized around those shifts. Also, causally important parts of an event are better remembered than less important parts. It should be noted that the ease with which information is integrated into a mental model has an influence on the ability to identify that situation later. Continuous and consistent descriptions are remembered better than discontinuous, inconsistent descriptions.
Mental models include both given information and inferences a person generates. With the passage of time, it becomes difficult to disentangle these two. People often mistakenly identify information as having been encountered before if it is consistent with the previously described situation, even when that information is new.
How information refers to the world is important for how it is represented in mental models. This has important consequences for memory. When given a large set of related information, a person can integrate this information into one mental model if the information can be interpreted as being consistent with a single situation in the world. Otherwise, it may be stored in separate mental models. When a person needs to remember one piece of information, if there are related mental models containing related but irrelevant information, this will produce interference, causing the memory retrieval to be slower and more error prone. If, however, the information is integrated into a single model, there is no such cost to memory.
While these findings suggest that a mental model can influence memory retrieval, it is also possible to remove these influences to a certain degree. As mentioned earlier, people create multiple representations during comprehension, including verbatim, propositional, and mental model representations. The mental model will contain many inferences and will also capture the perspective of the comprehender. If the mental model is discredited in some way, such as asking a person to take a different perspective on the text that was read, then the person will rely less on the mental model and more on the propositional representation. For example, people reading a description of a baseball game might originally be told that the home team was going to make the playoffs. Then when the person is asked to recall the story, they could be told that the story was about a team that ended up in last place. This shift in perspective will cause a decrease in the number of inferences a person reports and also increase memory for those previously unremembered propositions that are consistent with the new perspective. Thus, the person has disregarded their mental model during memory retrieval.
Mental models are mental representations of specific states of affairs in the world. They are created using the knowledge a person has at hand, along with prior knowledge. The organization and extensiveness of this prior knowledge is of great importance. People use mental models during comprehension as the basis for their understanding. Changes in the described situations cause people to update their mental models, which has a tangible effect on the comprehension process itself. Finally, mental models appear to be the form of mental representation that is stored in memory for long periods of time. The ability of a person to remember information in part reflects the organization and structuring of information into mental model.
See also: Learning, subentry on Knowledge Acquisition, Representation, and Organization; Reading, subentry on Comprehension.
Albrecht, Jason E., and O'Brien, Edward J. 1995. "Goal Processing and the Maintenance of Global Coherence." In Sources of Coherence in Reading, ed. Robert F. Lorch and Edward J. O'Brien. Hillsdale, NJ: Erlbaum.
Bower, Gordon H.; Black, John B.; and Turner, Terrence J. 1979. "Scripts in Memory for Text." Cognitive Psychology 11:177–220.
Garnham, Alan. 1982. "Situation Models as Representations of Text." Memory and Cognition 9:560–565.
Hasher, Lynn, and Griffin, Mary. 1978. "Reconstructive and Reproductive Processing in Memory." Journal of Experimental Psychology: Human Learning and Memory 4:318–330.
Johnson-Laird, Philip N. 1983. Mental Models: Towards a Cognitive Science of Language, Inference, and Consciousness. Cambridge, MA: Harvard University Press.
Morrow, Daniel G.; Greenspan, Steven L.; and Bower, Gordon H. 1987. "Accessibility and Situation Models in Narrative Comprehension." Journal of Memory and Language 26:165–187.
Radvansky, Gabriel A., and Copeland, David E. 2000. "Functionality and Spatial Relations in Situation Models." Memory and Cognition 28:987–992.
Radvansky, Gabriel A., and Zacks, Rose T. 1991. "Mental Models and the Fan Effect." Journal of Experimental Psychology: Learning, Memory, and Cognition 17:940–953.
Suh, Soo Y., and Trabasso, Thomas. 1993. "Inferences during Reading: Converging Evidence from Discourse Analysis, Talk-Aloud Protocols, and Recognition Priming." Journal of Memoryand Language 32:279–300.
Van Dijk, Tien A., and Kintsch, Walter. 1983. Strategies in Discourse Comprehension. New York: Academic Press.
Zwaan, Rolf A. 1996. "Processing Narrative Time Shifts." Journal of Experimental Psychology: Learning, Memory, and Cognition 22:1,196–1,207.
Zwaan, Rolf A.; Magliano, Joseph P.; and Graesser, Arthur C. 1995. "Dimensions of Situation Model Construction in Narrative Comprehension." Journal of Experimental Psychology: Learning, Memory, and Cognition 21:386–397.
Zwaan, Rolf A., and Radvansky, Gabriel A. 1998. "Situation Models in Language Comprehension and Memory." Psychological Bulletin 123:162–185.
Gabriel A. Radvansky
David E. Copeland
Metamemory refers to a person's knowledge about the contents and regulation of memory. The term originally derives from the work of John H. Flavell in the early 1970s. Metamemory enables a person to reflect on and monitor her memory. In addition, metamemorial knowledge plays an important role in planning, allocation of cognitive resources, strategy selection, comprehension monitoring, and evaluation of performance.
This entry begins with a description of the two main structural components of metamemory–declarative knowledge, which enables a person to evaluate the contents of memory, and procedural knowledge, which enables a person to monitor and regulate memory performance. It next summarizes important developmental trends in metamemory, then discusses several important educational implications of metamemory research, including the relationships among metamemory, strategy instruction, and self-regulation.
Declarative and Procedural Aspects of Metamemory
Most theorists distinguish between declarative and procedural components of metamemory. The declarative component corresponds to statable knowledge about the contents and contexts of memory use and includes knowledge of memory's contents, knowledge of essential intellectual tasks such as reading and problem solving, and conditional knowledge about why and when strategies are most effective. The procedural component includes knowledge about procedural skills necessary to manage memory efficiently, including control processes such as planning and evaluating and monitoring processes such as judgments of learning. Some theorists, but especially those interested in the relationship between metamemory and social cognition, have proposed a third component, usually referred to as a beliefs component, that regulates affect, social cognition, and efficacy judgments of memory performance. The focus here, however, is on the declarative and procedural components.
The declarative component includes at least three distinct subcomponents: knowledge of contents and capacity, knowledge of tasks, and conditional knowledge about optimal memory performance. The content subcomponent enables a person to assess whether he possesses enough knowledge to meet task demands. The task subcomponent allows a person to determine whether he fully understands task demands and possesses adequate resources to perform the task. The conditional knowledge subcomponent, which many view as the most important of the three, helps a person determine why, when, and where to use a particular strategy or under what conditions he is most likely to achieve optimal performance. Conditional knowledge plays an especially important role in self-regulation.
The procedural component includes control and monitoring subcomponents. The control subcomponent includes regulatory processes such as planning, selection of relevant information, resource allocation decisions, selection of relevant strategies, and inferencing. The monitoring subcomponent includes a variety of self-assessment strategies such as ease-of-learning judgments, judgments of learning prior to beginning a task, feeling-of-knowing judgments made during learning, and comprehension-monitoring judgments made during or after a task. Most theories of metamemory assume that control processes directly regulate cognition and performance, whereas monitoring processes inform the precision of control decisions. Thus, control processes are at a higher level than monitoring processes, even though both reciprocally inform one another.
Development of Metamemory
A number of researchers have studied the development of metamemory, and four main conclusions can be drawn from this research. The first conclusion is that metamemory awareness is rather poor in children until the age of ten or older. Younger children frequently find it difficult to monitor the contents of memory, estimate the resources needed to complete a task, select appropriate strategies for a task, and monitor their learning. As a consequence, self-regulation is quite poor among children younger than ten years of age. Even among adults, however, metamemory awareness is poor, sometimes leading to overconfidence and illusions of knowing.
A second conclusion is that metamemory development is incremental and continuous. Development appears to be linear in nature with a steady increase in metamemory awareness, control, and monitoring from preschool through early puberty. Research generally does not reveal significant breaks or jumps in metamemory ability, suggesting continuous development over a ten-year period from early childhood through adolescence. It is less clear whether metamemory awareness continues to develop in adults, although most research indicates that awareness increases within specific domains as expertise develops.
A third conclusion is that metamemorial knowledge is self-constructed in nature through individual and interactive problem solving, as well as explicit strategy instruction and monitoring training. One essential element of the construction process is self-generated and other-generated feedback that increases knowledge of the contents of memory and tasks. A second essential element is modeling, in which an individual has the opportunity to observe and emulate skilled models. Thus far, researchers have failed to detect a strong link between metamemory and either intellectual ability or traditional measures of working memory speed and capacity. This suggests that metamemory awareness develops independent of other individual differences in memory.
The final conclusion is that metamemory facilitates strategy use and performance. For example, correlations between metamemory and memory performance typically range from .30 to .50, even in younger children between the ages of five and ten years. The correlation may be even stronger in adults and experts. Knowledge about the contents of one's memory as well as tasks clearly should affect performance. In addition, declarative knowledge appears to be correlated with regulatory awareness. The more one knows about memory, the better able one is to regulate one's performance.
Metamemory and Learning
Metamemory affects learning in many ways but especially with respect to the efficient use of limited cognitive resources, strategy use, and comprehension monitoring. Children and adults often experience difficulty learning because of cognitive overload–that is, too much mental work to do and too few cognitive resources at their disposal. Research reveals that declarative and procedural knowledge enables learners to use available resources more efficiently because they are better able to plan, sequence, and monitor learning tasks.
A second way that metamemory improves learning is through the flexible use of cognitive learning strategies. Research indicates that self-regulated learners use a diverse repertoire of strategies that are controlled using conditional knowledge in metamemory. Strategy use is highly correlated with skilled problem solving. Research also suggests that strategy training increases metamemory awareness, provided that conditional knowledge about the strategies is embedded within the instruction. In 1999 Roger Bruning, Gregg Schraw, and Royce Ronning provided a step-by-step summary of cognitive strategy instruction that includes feedback and modeling from peers, tutors, and teachers. Strategy instruction is especially effective for helping students develop conditional knowledge that enables them to select the most appropriate strategy and monitor its usefulness.
A third way that metamemory improves learning is comprehension monitoring. Unfortunately, many children and adults do not monitor with a high degree of accuracy. Monitoring training helps learners monitor more successfully and also improves performance. Strategy instruction also improves monitoring even when monitoring instruction is not included as part of the instruction. Thus, either strategy instruction or monitoring training improve monitoring accuracy. Combining strategy instruction and monitoring training within the same intervention helps learners construct the control and monitoring subcomponents of regulatory knowledge described above.
Metamemory research has not had a major impact on classroom instruction. The research suggests, however, that children acquire and construct metamemory knowledge in three distinct ways. One way is hands-on experience that provides declarative knowledge about tasks as well as procedural knowledge about optimal performance. A second way is through skilled models who provide detailed feedback–especially conditional feedback–that enables the student to distinguish between effective and less-effective strategies. A third way is through self-reflection and group reflection in which students explicitly discuss the effectiveness of different strategies and ways to improve performance in the future. Thus, there are many ways to improve metamemory awareness through classroom activities.
Several learning interventions have been developed that promote metamemory development and awareness. For example, in 1984 Annemarie S. Palincsar and Ann L. Brown described a program of reciprocal teaching that promotes the self-regulation of metamemory strategies. The program involves the teacher gradually handing over control of reading processes to the student in a small-group format. The teacher first models effective strategies (e.g., finding the main idea of a passage) then provides scaffolding to the students as they attempt to do the same while receiving feedback from their peers regarding the strategies they employ.
Metamemory is knowledge about memory. Metamemory awareness develops late and incrementally yet has an important impact on memory and cognitive performance. Metamemory is not linked strongly to other cognitive factors such as intelligence and memory capacity. Rather, it develops as a function of experience, guided modeling and feedback, and individual and group reflection.
See also: Learning to Learn and Metacognition; Reading, subentry on Comprehension.
Alexander, Joyce M.; Carr, Martha; and Schwanenflugel, Paula J. 1995. "Development of Metacognition in Gifted Children: Directions for Future Research." Developmental Review 15:1–37.
Bruning, Roger H.; Schraw, Gregg; and Ronning, Royce R. 1999. Cognitive Psychology and Instruction, 3rd edition. Upper Saddle River, NJ: Prentice Hall.
Butler, Deborah L., and Winne, Philip H. 1995. "Feedback and Self-Regulated Learning: A Theoretical Synthesis." Review of Educational Re-search 65:245–282.
Dixon, Roger A. 2000. "The Concept of Metamemory: Cognitive, Developmental, and Clinical Issues." In Memory Disorders in Psychiatric Practice, ed. German E. Berrios and John R. Hodges. New York: Cambridge University Press.
Flavell, John H. 1971. "First Discussant's Comments: What Is Memory Development the Development Of?" Human Development 14:272–278.
Metcalfe, Janet. 2000. "Metamemory: Theory and Data." In The Oxford Handbook of Memory, ed. Endel Tulving and Fergus Craik. New York: Oxford University Press.
Nelson, Thomas O., and Narens, Louis. 1994. "Why Investigate Metacognition?" In Metacognition: Knowing about Knowing, ed. Janet Metcalfe and Arthur P. Shimamura. Cambridge, MA: MIT Press.
Palincsar, Annemarie S., and Brown, Ann L. 1984. "Reciprocal Teaching of Comprehension-Fostering and Comprehension-Monitoring Activities." Cognition and Instruction 1:117–175.
Schneider, Wolfgang. 1999. "The Development of Metamemory in Children." In Attention and Performance XVII: Cognitive Regulation of Performance, ed. Daniel Gopher and Asher Koriat. Cambridge, MA: MIT Press.
Schneider, Wolfgang, and Pressley, Michael. 1997. Memory Development between Two and Twenty, 2nd edition. Mahwah, NJ: Erlbaum.
Schraw, Gregg. 2001. "Promoting General Metacognitive Awareness." In Metacognition in Learning and Instruction, ed. Hope J. Hartman. Norwell, MA: Kluwer.
Schraw, Gregg, and Moshman, David. 1995. "Metacognitive Theories." Educational Psychology Review 7:351–372.
Stone, N. J. 2000. "Exploring the Relationship between Calibration and Self-Regulated Learning." Educational Psychology Review 12:437–476.
Sweller, John; Van Merrienboer, Jeroen J.; and Paas, Fred G. 1998. "Cognitive Architecture and Instructional Design." Educational Psychology Review 10:251–296.
MYTHS, MYSTERIES, AND REALITIES
Why is it that people remember some things and forget others? How long do people remember things? What kinds of cues are likely to help a person remember a forgotten item? These are just a few of the many questions of interest to memory researchers. This entry reviews some of the important questions in the field of memory research and describes how psychologists use experimental methods to answer these questions. It also describes some of the major findings and rebuts some of the common myths about memory. This discussion is structured around the three stages of memory: encoding, storage, and retrieval.
Encoding refers to the intake of information and creation of a memory trace. In a typical memory experiment, the encoding phase involves presentation of the to-be-remembered stimuli, such as nonsense syllables, words, pictures, stories, films, or staged events. In real life, encoding includes all forms of perception, from watching a movie to having a conversation. Encoding may be intentional in that subjects are forewarned to memorize the items or incidental in that subjects learn the to-beremembered material through performance of another task such as making a category judgment. In educational settings, encoding is intentional when students deliberately study the meanings of vocabulary words, learn facts for a test, or memorize a famous speech. In everyday life, however, most things are learned incidentally. Examples in the education domain include students learning about a historical period by watching films, role-playing, and reading memoirs.
Storage or retention refers to the maintenance of the memory trace over time. In most laboratory experiments, the retention interval is quite short and the subject does an unrelated task during that time. In the education domain, there may be a retention interval of several weeks between learning and testing; students may continue to practice the target information during the retention interval.
Retrieval involves later accessing that memory trace. There are many different ways to test memory. Explicit tests require subjects to consciously remember events from the study phase. Most educational tests are explicit; students know they are being tested and that they should remember facts from class and textbooks. Explicit educational tests include essay, short-answer, multiple-choice, and true-false tests; these roughly correspond to the laboratory tests of free recall, cued recall, forced choice, and old-new recognition. Implicit tests measure the effect of previous experience on a task that does not require the subject to consciously refer back to the study phase. In education, pure implicit tests are rare although many explicit tests may tap a student's implicit knowledge (e.g., essay tests implicitly test a student's knowledge of grammar). In the laboratory, there are many different implicit tests. For example, a subject who had recently seen a list that included the word octopus would complete the word stem "oct—" with "octopus" at a higher rate than subjects who had not seen the list.
In the following sections, some of the facts and myths associated with each of the three stages of memory are described.
Key questions about encoding include what kinds of things are easily memorized and what study strategies can be employed to ensure later memory.
Not all materials are remembered equally well. Pictures are remembered better than words, and in general memory is better for distinctive items. Likewise, concrete words are better remembered than abstract words. Good teachers often apply this finding by using concrete analogies to explain abstract phenomena or theories, such as when the movement of gas molecules is compared to the movement of billiard balls on a pool table.
Not all study strategies are equal. In general, elaborative encoding yields the best memory. Elaboration involves going beyond the stimulus at hand to create a richer memory trace. For example, rather than simply repeating a to-be-memorized vocabulary word, a student might think of other words similar in sound and meaning, draw a picture that somehow represents the word and its definition, or write sentences using the word in context. In perhaps the most famous laboratory demonstration of this, Fergus I. M. Craik and Endel Tulving looked at subjects' memory for words after perceptual, phonemic, or semantic processing in a 1975 study. For example, if all subjects studied the word EAGLE, one group decided if the word was in uppercase letters (perceptual), the second group decided if it rhymed with legal (phonemic), and the third group decided if it was an animal (semantic). All of these questions would have been answered affirmatively, but memory was best following semantic processing, next best with phonemic processing, and worst after perceptual processing. This is the classic levels of processing effect. The educational implication is that incidental study can be just as effective as intentional memorization. If students are studying via a semantic or other elaborative task, the resulting memory can be just as strong even if they are not forewarned about the upcoming memory test.
Encoding is not like taking pictures with a camera; not everything is recorded. Instead, encoding is selective. The levels of processing effect is an example of this; depending on the instructions, subjects directed their attention to different features of the target word. More generally, what students encode will be a function of what they already know and how well they can understand and link the incoming information to their prior knowledge. A schema is the term for a person's knowledge representation of a concept or domain. Without a schema, the understanding and interpretation of incoming information is difficult. For example, in a 1977 study by D. James Dooling and Robert E. Christiaansen, subjects had poor memories for such passages as "With hocked gems financing him/our hero bravely defied all scornful laughter that tried to defy his scheme/Your eyes deceive, he said–an egg not a table correctly typifies this unexplored planet." Good memory required knowledge that the upcoming passage would be about Christopher Columbus. Schemas also serve to direct a subject's attention to particular schema-relevant details and to allow for inferences. For example, according to a 1977 study conducted by James Pichert and Richard Anderson, students who read a story about two boys playing hooky and spending the day at home remembered different things depending on which of two perspectives had been instantiated at encoding: home buyer or burglar. Subjects who read the story with the perspective of a burglar attended to and remembered better such details as that the house's side door was unlocked, a fact unlikely to be relevant to a home buyer.
Another fact about encoding is that more is not necessarily better; massed study is not a good idea. While many students choose to cram for exams the night before, the data clearly suggest that spaced study opportunities are preferable. The same holds true for rehearsal of to-be-remembered information, which is described in the next section on activities during the retention interval.
Encoding is a necessary but not sufficient condition for later memory. As time passes, it becomes less and less likely that a person will be able to retrieve the target event. In 1985 Herman Ebbinghaus first documented the now classic forgetting function; he taught himself series of consonant-vowel-consonant trigams and tested his memory after varying time lags. Memory dropped off quickly at first, but eventually forgetting leveled out over time to a fairly stable level. Most laboratory studies involve fairly short retention intervals; in 1984, however, Harry P. Bahrick examined knowledge of Spanish following retention intervals of up to fifty years (participants reported very little use of Spanish during that time). Again, there was a sharp drop in knowledge by three to six years poststudy, but after that initial drop, knowledge was surprisingly stable over the next twenty-five years. Bahrick termed this long-term retention the permastore.
Rehearsal during the retention interval aids memory; not all forms of rehearsal, however, are equal. Simply repeating a to-be-remembered item will not necessarily lead to enhanced memory. A student who writes a fact over and over will not remember that fact as well as a student who takes a more active approach to rehearsal. One of the best strategies is that of expanding rehearsal combined with self-testing. For example, the student who wants to learn a vocabulary word should not simply stare at the word paired with its definition. Rather, she should test herself and produce the definition of the word from memory; after a short delay she should repeat the process, and so on, incrementally increasing the delay until the retention interval is at the desired length.
Memories do not lie dormant during the retention interval but are affected by the new information that continues to enter the system. In one classic demonstration of interference, subjects saw a slide show of a traffic accident involving a car passing a stop sign. In the next phase of the experiment, subjects in the experimental condition read a narrative description of the slide show that included a misleading reference to a yield sign. Control subjects also read a narrative, but it did not contain the misinformation. All subjects were later asked whether they had seen a stop sign or a yield sign. Subjects who had been exposed to the misleading post-event information were more likely to mistakenly say they had seen a yield sign than the control group. Although the exact mechanisms underlying the misinformation effect are still under debate, in at least some circumstances the misinformation works to block or interfere with access to the original memory.
No single test of memory is perfect. No one test yields an absolute measure of what is in memory; rather, one can ascertain what is accessible only under a particular set of test conditions. The failure to recall part of a list is not necessarily synonymous with forgetting those words. Rather, they may be available in memory but not accessible given the current retrieval cues. When asked to write down all the words from a studied list, a subject may not be able to recall studying the word robin. This allegedly forgotten word, however, may be recalled in response to the category cue "birds" or correctly labeled as "old" on a test that re-presents the word robin for an old-new decision. Similarly, a student who is unable to produce an answer on an essay test may recognize it on a multiple-choice test.
Conclusions about memory may vary across tests. Take, for example, the effects of word frequency on memory. Following study of a word list, words that occur with high frequency in the language (e.g., tree ) are recalled with a higher probability than are words that occur with low frequency in the language (e.g., ecru ). The opposite result, however, is obtained on recognition memory tests. When subjects are asked to label words as "old" or "new," they do a better job with low frequency than high frequency words. This paradox is one that continues to interest researchers.
So, how then to get the best performance possible on a memory test? The general rule is that the test should match study as much as possible. Returning to the levels of processing effect described earlier, semantic processing leads to better memory in part because most memory tests are semantic in nature. When subjects are given a phonological test (e.g., did you study a word that rhymes with beagle ?), performance is better when words are encoded as rhymes than when they are categorized. Effects of test expectancy are nicely explained within this framework. Performance on an open-ended (essay or free recall) test suffers if students are incorrectly led to expect a multiple-choice test. Depending on which test is expected, students study differently. Students expecting a multiple-choice test focus less on relations between items and spend less time preparing than do students expecting a more open-ended test. The way students study for multiple-choice tests does not match the demands of the recall test; hence, performance suffers when students are surprised with the unexpected version of the test. A good educator will make clear the test demands early in a course so that students will tailor their study strategies appropriately.
Memory is not like a tape that can be played back perfectly at test. Rather, memory is reconstructive. In one example of this, from the 1977 study of Dooling and Christiansen, subjects read a paragraph that began "Carol Harris was a problem child from birth. She was wild, stubborn and violent." Right before the test phase, some of the subjects were told that Carol Harris was really Helen Keller. These informed subjects were much more likely to incorrectly identify the statement "She was deaf, dumb, and blind" as having been in the original paragraph than subjects who were not informed of Harris's true identity. Subjects made use of their knowledge at test to reconstruct what they read during the first part of the experiment. Schemas are as active during test taking as they are during encoding, and they provide retrieval cues and allow for reconstruction.
There are two very general requirements for effective memory: quality encoding and appropriate retrieval cues. These principles are exemplified in a classic study method, the SQ3R method, which Francis P. Robinson described in 1970. SQ3R stands for: s urvey, q uestion, r ead, ehearse, and eview. Students begin by surveying the textbook chapter before reading it, to become familiar with its organization. As they read the chapter, they form questions that they then answer. Finally, they rehearse and test themselves on what they have just read, and review all the material repeatedly. Each of these activities links to basic memory processes. The initial survey of the chapter leads students to set up a schema for the chapter that guides both encoding and later retrieval. The questions students create serve as retrieval cues later on. Answering these questions, repeated rehearsing, self-testing, and reviewing the material are all forms of retrieval practice that will aid memory. Studying a textbook chapter need not be a mystery to students.
See also: Memory, subentries on Autobiographical Memory, Implicit Memory, Metamemory, Structures and Functions.
Ayers, Michael S., and Reder, Lynne M. 1998. "A Theoretical Review of the Misinformation Effect: Predictions from an Activation-Based Memory Model." Psychonomic Bulletin and Re-view 5:1–21.
Bahrick, Harry P. 1984. "Semantic Memory Content in Permastore: Fifty Years of Memory for Spanish Learned in School." Journal of Experimental Psychology: General 113:1–29.
Craik, Fergus I. M., and Lockhart, Robert S. 1972. "Levels of Processing: A Framework for Memory Research." Journal of Verbal Learning and Verbal Behavior 11:671–684.
Craik, Fergus I. M., and Tulving, Endel. 1975. "Depth of Processing and the Retention of Words in Episodic Memory." Journal of Experimental Psychology: General 104:268–294.
Dempster, Frank N. 1988. "The Spacing Effect: A Case Study in the Failure to Apply the Results of Psychological Research." American Psychologist 43:627–634.
Dooling, D. James, and Christiansen, Robert E. 1977. "Episodic and Semantic Aspects of Memory for Prose." Journal of Experimental Psychology: Human Learning and Memory 3:428–436.
Hall, John F. 1954. "Learning as a Function of Word Frequency." American Journal of Psychology 67:138–140.
Hyde, Thomas S., and Jenkins, James J. 1969. "Differential Effects of Incidental Tasks on the Organization of Recall of a List of Highly Associated Words." Journal of Experimental Psychology 82:472–481.
Kinsbourne, Marcel, and George, James. 1974. "The Mechanism of the Word-Frequency Effect on Recognition Memory." Journal of Verbal Learning and Verbal Behavior 13:63–69.
Loftus, Elizabeth F.; Miller, David G.; and Burns, Helen J. 1978. "Semantic Integration of Verbal Information into a Visual Memory." Journal of Experimental Psychology: Human Learning and Memory 4:19–31.
Morris, C. Donald; Bransford, John D.; and Franks, Jeffrey J. 1977. "Levels of Processing versus Transfer Appropriate Processing." Journal of Verbal Learning and Verbal Behavior 16:519–533.
Pichert, James W., and Anderson, Richard C. 1977. "Taking Different Perspectives on a Story." Journal of Educational Psychology 69:309–315.
Robinson, Francis Pleasant. 1970. Effective Study. New York: Harper and Row.
Rundus, Dewey. 1977. "Maintenance Rehearsal and Single-Level Processing." Journal of Verbal Learning and Verbal Behavior 16:665–681.
Schmidt, Stephen R. 1991. "Can We Have a Distinctive Theory of Memory?" Memory and Cognition 19:523–542.
Tulving, Endel, and Pearlstone, Zena. 1966. "Availability versus Accessibility of Information in Memory for Words." Journal of Verbal Learning and Verbal Behavior 5:381–391.
Tulving, Endel, and Thomson, Donald M. 1973. "Encoding Specificity and Retrieval Processes in Episodic Memory." Psychological Review 80:359–380.
Tversky, Barbara. 1973. "Encoding Processes in Recognition and Recall." Cognitive Psychology 5:275–287.
Whitten, William B., and Bjork, Robert A. 1977. "Learning from Tests: Effects of Spacing." Journal of Verbal Learning and Verbal Behavior 16:465–478.
Elizabeth J. Marsh
STRUCTURES AND FUNCTIONS
In the study of memory there have been many metaphors adopted in the search for an explanation of the memory process. The fourth century b.c.e. Greek philosopher Aristotle compared memorizing to making impressions in wax, and the idea that memories are copies of reality that a person stores and later retrieves has been widespread. This is sometimes called the storehouse metaphor, and many of the ways in which people talk about memory (searching for memories, bringing them back from the recesses of one's mind) assume such a metaphor. The computer metaphor that has been popular with psychologists researching memory is a version of the storehouse view. It conceptualizes the stages involved in remembering in terms of encoding, storage, and retrieval in which information is entered into memory, retained, and then found again at a later time. Thinking about remembering in this way can be valuable, but it can lead to the incorrect assumption that what is remembered is a simple copy of what was originally experienced. In reality, much that is remembered captures the gist rather than the details of the original experience, and remembering is often a process of reconstruction. Examples of constructive remembering can be found in research on false memories. Elaborate and detailed false memories of events from an individual's past can be easily created. More mundanely, hearing a list of close associates to a particular word leads to recall of the word itself even though it was not presented. One alternative to the storehouse metaphor is the correspondence metaphor that emphasizes the deviation between the memory and the original experience.
Researchers who study memory use a number of terms to subdivide the enormous field. One major distinction is that between explicit and implicit memory. Explicit memory refers to the conscious recall of information. Conscious awareness of past experiences involves explicit memories. Often, however, people are influenced by experiences that are not consciously recallable. For example, the ease and speed with which a person solves the anagram rbocoilc depends upon how recently the person has encountered the word broccoli. This facilitation reflects implicit memory. Processing of new information is primed by past experiences without conscious awareness. The distinction between explicit and implicit memory may reflect different underlying memory systems. Quite different timescales and sensitivities have been demonstrated for some explicit and implicit memory tasks. The differences may arise, however, from the processing requirements of the tasks rather than from different memory systems.
A distinction that overlaps with explicit and implicit memory is that between episodic and semantic memory. This distinction, associated with Endel Tulving, is between memory for events and memory for facts. Episodic memory is for events that people can remember happening, whereas semantic memory is for facts that people know about the world without necessarily retaining any recollection of the situation in which they learned the information. One's memory for eating breakfast on a particular morning is an episodic one, whereas one's memory that Coca-Cola is a drink is a semantic one. One area of episodic memory is autobiographical memory–memory for personal events in one's own life. Autobiographical memories from the first two years of life are very rare, while memories from the late teens and early twenties are more frequently held than the average. Certain autobiographical memories seem to be so distinct and full of the apparently irrelevant details from the original event that they have been called flashbulb memories because the nature of the memory is similar to a photograph of the moment. Archetypal examples of flashbulb memories are associated with hearing or seeing particularly dramatic events such as the assassination of a famous person or a major accident.
Submemories. One approach to understanding the structure of memory has been to seek separate submemories that are responsible for retaining information over differing time periods. In 1968 Richard Atkinson and Richard Shiffrin proposed a model with three types of memory: a sensory store, a short-term store, and a long-term memory. Visual information, for example, is believed to be retained for about one second in a sensory store while perceptual processing takes place. Similar sensory memories aid in the processing of acoustic and other inputs. Beyond the perceptually based sensory memories is the short-term memory, which retains information for a few seconds before selected elements of that information are transferred to a long-term memory. Atkinson and Shiffrin recognized that there were control processes in short-term memory that influence what is attended to and processed. The Atkinson and Shiffrin model has been elaborated into the working memory system, which has been particularly investigated by Alan Baddeley and his colleagues. Baddeley has subdivided the working memory into several subcomponents, the most heavily researched of which are the phonological loop, the visuospatial sketchpad, and the central executive. The phonological loop holds a couple of seconds of speech sounds and plays a role in reading. The visuospatial sketchpad is used in the creation of mental images and in the solution of visual and spatial problems. The central executive is a controlling attentional system that supervises and coordinates current cognitive processing.
Formal models of memory. A number of formal models of memory that can be run as computer simulations have been developed. Among the most influential of these are Jerome Raaijmaker's and Richard Shiffrin's 1981 SAM model, James McClelland, David Rumelhart, and Geoffrey Hinton's 1986 PDP model, and John Anderson's 1993 ACT model.
SAM (Search of Associative Memory) is a mathematical model based upon items and the strength of associations between them. It is particularly appropriate to the learning of lists of words. Each word has a memory strength as a result of it being studied, and each word has an associate strength with the other words in the studied list. The memory strength is combined with the association between the word and the context in which it was learned to produce a strength that is the basis of recognition or retrieval. The model can account for many of the memory phenomena associated with the learning of lists, but it shares with the other two formal models described here the difficulty that many of its assumptions are not based on observations and are difficult to test.
The PDP (Parallel Distributed Processing) model is a neural network model inspired by the analogy of neural circuits in the brain. The network consists of units that are connected to form a network. The strengths of the connections (weights) are adjusted as the network is trained to produce correct responses. Activation spreads through the network and the weightings direct that spread. A response is selected when it achieves a sufficient level of activation. One feature of neural network models is that memory is not located in one place but is captured by particular patterns of activation over many units and links. The neural network models are attractive in apparently simulating the structure of the brain. The choice of the particular structure of units and their interconnections, however, turns out to be important for each simulation of human memory. A general representation that is applicable to many types of remembering has yet to be developed.
The ACT framework is a production system theory for both memory of facts and skills. Anderson has developed several versions of ACT including ACT-R (Adaptive Control of Thought-Rational). Production rules are condition-action rules of the form: If this is the condition, then execute that action. Within the system, units of information are linked by associations, with the association strength being increased through use. The ACT models were developed to account for problem solving and skill acquisition as well as memory. As with the other formal models discussed here, there are many assumptions that make a model difficult to evaluate.
What is remembered of a particular event depends upon the way in which it is processed. Elaborate processing that emphasizes meaning and associations that are familiar leads to good recall. So, for example, the word albatross would be remembered poorly if only the font in which it was printed was noticed and little thought was given to its meaning. It is much more likely to be remembered, however, if at the time the word is read the reader thinks about how albatrosses are white seabirds living in southern oceans. On the other hand, if what is encountered is difficult to understand, then not only will it be poorly remembered but what is remembered may be distorted by an effort to comprehend the meaning.
The processing of new information draws very heavily upon memory of past experience. Schemas have been developed for often-encountered familiar situations such as going to a supermarket or eating at a restaurant. These schemas guide understanding and memory of the new events but may also lead to memory errors by adding expected events that did not actually occur. Information that is organized on the basis of one's existing knowledge is much easier to learn and remember than is disorganized information. So, for example, a list of the names of animals is much easier to memorize if it is categorized according to type of animals (domestic, farm, wild) and if the categories are laid out in a structured way. Experts in an area memorize new information within their area of expertise much more quickly than do novices. So, soccer fans easily learn new soccer scores and chess masters memorize real board configurations easily.
When material is restudied to strengthen the memory of it, the shorter the interval between the first and second study periods, the less the improvement in recall. This spacing effect is large, so that studying in two spaced sessions can produce twice as much recall as a single session of equal length. The rereading of factual material makes only a small contribution to the further learning of it. Testing oneself by retrieving studied material, however, is a particularly effective technique for improving memory.
What is remembered depends upon the information that is available to cue recall when it is retrieved. In 1983 Tulving summarized much research in the encoding specificity principle. This principle asserts that retrieval is successful to the extent that the cues available at retrieval match those that were processed by the learner at the study phase. The retrieval cues may be aspects of the material that was studied, but they also include environmental cues and the mood and mental state of the learner.
The learning of information that is similar creates a problem for retrieval. There is interference from similar material learned earlier (proactive interference) and from material encountered since the original learning (retroactive interference), and these reduce recall. More insidious are misinformation effects. These occur when misleading information is presented, for example, to eyewitnesses during questioning. The misleading information is then frequently recalled, and the original information becomes very difficult to retrieve.
When tested across time, forgetting follows a logarithmic curve–information loss is rapid initially but then information is lost more slowly. Nevertheless, the fate of information that has been initially very well learned is rather different. Where facts, names, or foreign-language vocabulary have been used repeatedly but are no longer regularly recalled, the pattern of their forgetting is an initial loss over a three-year period, after which recall may be equally good with delays of one or twenty-five years.
See also: Memory, subentry on Myths, Mysteries, and Realities.
Anderson, John R. 1993. Rules of the Mind. Hillsdale, NJ: Erlbaum.
Baddeley, Alan D. 1997. Human Memory: Theory and Practice. Hove, Eng.: Psychology Press.
Bahrick, Harry P. 1984. "Semantic Memory Content in Permastore: Fifty Years of Memory for Spanish Learned in School." Journal of Experimental Psychology: General 113:1–29.
Bartlett, Frederick C. 1932. Remembering. Cambridge, Eng.: Cambridge University Press.
Bower, Gorden H.; Black, John B.; and Turner, Terrence J. 1979. "Scripts in Memory for Text." Cognitive Psychology 11:177–220.
Bower, Gorden H.; Clark, Mical C.; Lesgold, Alan M.; and Winzenz, David. 1969. "Hierarchical Retrieval Schemes in Recall of Categorised Word Lists." Journal of Verbal Learning and Verbal Behavior 8:323–343.
Bransford, John D., and Johnson, Marcia K. 1972. "Contextual Prerequisites for Understanding: Some Investigations of Comprehension and Recall." Journal of Verbal Learning and Verbal Behavior 11:717–726.
Carrier, Mark, and Pashler, Harold. 1992. "The Influence of Retrieval on Retention." Memory and Cognition 20:633–642.
Chase, William G., and Simon, Herbert A. 1973. "The Mind's Eye in Chess." In Visual Information Processing, ed. William G. Chase. New York: Academic Press.
Conway, Martin A. 1996. "Autobiographical Memory." In Memory, ed. Elizabeth L. Bjork and Robert A. Bjork. San Diego, CA: Academic Press.
Craik, Fergus I. M., and Tulving, Endel. 1975. "Depth of Processing and the Retention of Words in Episodic Memory." Journal of Experimental Psychology: General 104:268–294.
Dempster, Frank N. 1996. "Distributing and Managing the Conditions of Encoding and Practice." In Memory, ed. Elizabeth L. Bjork and Robert A. Bjork. San Diego, CA: Academic Press.
Eich, Eric, and Metcalfe, Janet. 1989. "Mood Dependent Memory for Internal versus External Events." Journal of Experimental Psychology: Learning, Memory, and Cognition 15:443–455.
Fritz, Catherine O.; Morris, Peter E.; Bjork, Robert A.; Gelman, Rochel; and Wickens, Thomas D. 2000. "When Further Learning Fails: Stability and Change following Repeated Presentation of Text." British Journal of Psychology 91:493–511.
Haberlandt, Karl. 1999. Human Memory: Explorations and Application. Boston: Allyn and Bacon.
Jacoby, Larry L. 1983. "Remembering the Data: Analyzing Interactive Processes in Reading." Journal of Verbal Learning and Verbal Behavior 22:485–508.
Koriat, Asher, and Goldsmith, Morris. 1996. "Memory Metaphors and the Real Life/Laboratory Controversy: Correspondence versus Storehouse Conceptions of Memory." Behavioural and Brain Sciences 19:167–228.
Loftus, Elizabeth F., and Loftus, Geoffrey R. 1980. "On the Permanence of Stored Information in the Human Brain." American Psychologist 35:585–589.
McClelland, James L.; Rumelhart, David E.; and Hinton, Geoffrey E. 1986. "The Appeal of Parallel Distributed Processing." In Parallel Distributed Processing: Explorations in the Microstructure of Cognition, ed. David E. Rumelhart, James L. McClelland, and the PDP Group. Cambridge, MA: MIT Press.
Morris, Peter E.; Tweedy, Margaret; and Gruneberg, Michael M. 1985. "Interest, Knowledge, and the Memorising of Soccer Scores." British Journal of Psychology 76:415–425.
Raaijmakers, Jerome G., and Shiffrin, Richard M. 1981. "SAM: Search of Associative Memory." Psychological Review 88:93–134.
Roediger, HenryL., III, and McDermott, Kathleen B. 1999. "Distortions of Memory." In The Oxford Handbook of Memory, ed. Endel Tulving and Fergus I. M. Craik. Oxford: Oxford University Press.
Roediger, HenryL., iii; Weldon, Mary S.; and Challis, Bradford H. 1989. "Explaining Associations between Implicit and Explicit Measures of Retention: A Processing Account." In Varieties of Memory and Consciousness: Essays in Honour of Endel Tulving, ed. Henry L. Roediger and Fergus I. M. Craik. Hillsdale, NJ: Erlbaum.
Rubin, David C., and Wenzel, Amy E. 1996. "100 Years of Forgetting: A Quantitative Description of Retention." Psychological Review 103:734–760.
Tulving, Endel. 1983. Elements of Episodic Memory. Oxford, Eng.: Oxford University Press.
Tulving, Endel, and Schacter, Daniel L. 1990. "Priming and Human Memory Systems." Science 247:301–306.
Peter E. Morris
"Memory." Encyclopedia of Education. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/education/encyclopedias-almanacs-transcripts-and-maps/memory-0
"Memory." Encyclopedia of Education. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/education/encyclopedias-almanacs-transcripts-and-maps/memory-0
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Most people recognize that their memories are changing as they grow older. They have a harder time coming up with names; they have a harder time finding things they need; they have to rely more on external memory cues such as notes or calendars. In fact, research results support these perceptions. The bad news from this research is that memory declines are experienced throughout the adult life span and not just in the older ages. Forty-year-olds as a group are worse than twenty-year-olds, and fifty-year-olds are worse than thirty-year-olds. The good news is that research shows that, unlike the serious and ubiquitous memory declines associated with Alzheimer's disease and other dementias, memory changes associated with healthy aging are selective (e.g., Zack et al.). Some memory tasks show large and reliable adult age differences (e.g., working memory, episodic memory), while other memory tasks show little or no effects of age (e.g., semantic memory, implicit memory).
Figure 1 shows the results from study of 345 adults ranging in age from the twenties to the eighties (Park, Lautenschlager, et al.). Different types of memory were tested, including working memory (computation span), episodic memory (free recall of a word list), and semantic memory (defining words in a vocabulary test). The results were plotted in deviation units from the mean for all the participants on any test (z scores). As can be seen in the graph, the memory changes occur across the entire adult life span and are not limited to old age. Second, the graph shows that age has selective effects on memory. Working memory and episodic memory decline significantly across the life span, while semantic memory increases significantly.
Other theories suggest that age differences in memory depend on the extent of deliberate cognitive processing or cognitive resources required to perform the task (e.g., Park). According to this view, the size of age differences in different memory tasks is determined by the amount of cognitive resources needed to adequately remember in those tasks. Other theories suggest that age effects are limited to specific memory structures or types (e.g., Craik). Clearly, the explanation for the differential effects of age with different memory tasks depends on how one conceptualizes memory.
Memory stage theory
Memory stage theory separates memory into the temporal, sequential components that define any act of remembering. Information first has to be perceived or experienced (i.e., encoding). Then the information has to be maintained over a retention interval of some length of time (i.e., storage). Finally, the information has to be produced at the time memory is tested (i.e., retrieval). Early researchers believed that adult age differences in memory were located primarily at retrieval, the final of the three stages. Early laboratory research, for example, demonstrated that age differences were large when the recall of a word list was measured (with instructions such as "Write down all the words you can remember having seen on the list presented earlier."). Age differences, however, were greatly reduced or even eliminated when recognition memory was used to test memory at retrieval (with instructions such as "Select the words on this list that were presented on the list that you saw earlier."). Because the use of a recognition memory task is assumed to reduce the retrieval requirement of the memory task, it was then inferred that the locus of the age effect must be retrieval. Such findings were prevalent in the 1960s and 1970s.
More recent research, however, has clearly demonstrated that recognition memory is not totally insensitive to aging, and the stage theory lost its appeal because of the methodological difficulties in isolating one memory stage from another in different age groups. In order to isolate retrieval, for example, everything must be held constant until the time retrieval is tested. This is difficult to accomplish in aging research, however, because adults of different ages may process information differently at one of the earlier stages, thus violating the requirement that all be held constant until retrieval (Smith).
The major reason, however, for the loss of interest in identifying the stage at which aging had its effects is clear evidence that age has effects on all stages of memory: encoding, storage, and retrieval. For reasons not directly related to memory stage theory, however, memory research in the 1970s and early 1980s focused heavily on the encoding stage of memory. This focus on encoding was due to the development of a conceptual view of memory, the "levels of processing" framework, which proposed that the ability to remember was determined by the extent of semantic processing during the encoding of the to-be-remembered information (Craik and Lockhart). For this reason, much research on memory and aging during this period focused on the nature of encoding processes in different age groups. Even with the magnitude of the research effort, however, the relationship between aging and levels of processing is still unclear. The research did, however, suggest that encoding is especially affected by adult aging. For example, the memory performance of older adults, relative to younger adults, is more detrimentally affected by performing a divided attention task during the encoding stage of a memory task, but not if the divided attention task occurs at retrieval (Park, Smith, et al.).
Memory system theory
Another view of memory that has both behavioral and neurological support considers memory not as a unitary construct but as a collection of component systems. The general view is that memory consists of sensory memory, short-term memory, and long-term memory. Short-term memory is further divided into primary memory and working memory, and long-term memory is divided into episodic memory, semantic memory, and procedural memory. These memory systems differ in the nature of how memories are represented and in how these representations are maintained and retrieved. They also differ considerably in how they are affected by adult aging.
Sensory memory. After an event is experienced, it is first represented very briefly in the sensory system. Here the information is represented as it is processed and analyzed by the attentional and perceptual systems. There has been very little work on this type of memory and aging, but some research does suggest that older adults are less efficient in this early type of processing, especially in the visual system. It should be pointed out, however, that differences in sensory-perceptual processing would be an unlikely explanatory construct for memory differences found in later memory systems because later memory differences vary according to what system is examined (Craik). Adequate perceptual processing of the to-be-remembered stimulus would seem to be a requirement for all types of long-term memory, and the fact that some long-term memory systems are minimally affected by aging while others show large effects would not support an explanation that relied solely on faulty processing at the very early stage of processing.
Primary memory. Primary memory refers to the number of items that can be represented in the mind at one time. Primary memory is typically measured by digit- or word-span tasks. For example, when strings of numbers are presented one at a time at one-second intervals, primary memory would be the number of items that could be repeated back without errors. The digit-span test found on most intelligence tests is a measure of primary memory. When primary memory is tested by digit-span tests with individuals of different ages, no reliable age differences are found (Craik). Another measure of primary memory is recall of the last few items presented on a word list. Again, research finds no age differences in the ability to recall the most recently presented items in a word list.
Working memory. Age differences are found, however, on a measure of short-term memory called working memory, which takes into account both the ability to keep things in mind and, at the same time, the ability to process information. Working memory, unlike primary memory, requires individuals to keep information in mind while engaging in another processing task. One commonly used working memory task is reading span. Individuals read a series of short sentences (e.g., "The girl hit the ball.") and answer questions about the sentence (e.g., "Who hit?"). At the same time, individuals have to remember the last word in each sentence (e.g., "ball") and report the words when told to do so. The number of sentences presented varies, and reading span is the greatest number of words that can be remembered without making an error. Because working memory tasks require simultaneous storage (remembering the words) and processing (reading the sentences and answering the questions), it is a better simulation of everyday information processing.
Working memory is used to understand a conversation or to write an e-mail message on the computer. Other working memory tasks have been developed that involve different kinds of information processing, such as arithmetic calculations (computational span) and spatial manipulations (spatial working memory). Regardless of the type of information involved, however, large, reliable age differences are found on working memory tasks (Zacks et al.). Therefore, while the more passive primary memory tasks, such as simple digit span, do not show age differences, differences are found with working memory measures. As will be discussed later, working memory capacity is considered by many researchers to be a fundamental mechanism for more complex memory processing.
Long-term memories are not kept in conscious awareness, as short-term memories are, but instead have to be retrieved into consciousness when they are needed.
Episodic memory. Episodic memories are recollections that are actively retrieved as previous personal experiences. For this reason, episodic memory is sometimes called autobiographical memory. The memory is a reconstruction of an earlier experience very much like looking something up in an internal cognitive diary. For this reason, contextual information about when and how an event was originally experienced is often used to guide retrieval. "What did I have for dinner last night?" "Where did I park my car?" "Did I take my medicine this morning?" "Did you see Joan at the party last night? To answer each question, one attempts to reconstruct the original event.
Older adults do worse on most episodic memory tasks than do younger adults (see Figure 1). In the laboratory, typically a list of words or some other to-be-remembered information is presented to individuals, and later, after a retention interval, memory is tested. Because the items presented are commonly used words, they are already known to the individuals. The memory task, therefore, is to remember the words in the particular context of the original list. Episodic memory requires one to put what one is trying to remember in a specific context. Even though the magnitude of age differences varies considerably among different memory tasks using different materials and types of tests, older adults tend to have greater problems with episodic remembering than do younger adults.
As will be discussed later, the variable that seems important in determining the magnitude of age differences is the degree to which the memory task involves deliberate processing by the individual. At both encoding and retrieval, the more intentional processing required to perform the task, the larger the age differences that will be found with that task. For example, free recall of a word list requires more deliberate processing than recognition tasks, and age differences are larger on free recall (Craik). Instead of trying to actively recall the items, individuals in a recognition task only have to pick out the words they saw earlier on a longer list of words.
Because episodic memory is so dependent on contextual information, one of the reasons for older adults' poorer performance on these tasks is probably their inability to encode and remember contextual information easily. Older adults, for example, do not do as well as younger adults in identifying the way in which information was presented to them (i.e., source memory). They do worse when asked to remember whether a word was presented in uppercase or lowercase, spoken by a male or a female voice, in one color versus another, or in the upper part of a computer screen or the lower part (Zacks et al.). These tasks require individuals to remember contextual detail. Because older adults encode less contextual detail, they do not do as well on tasks in which contextual detail provides the cues for retrieval. In fact, because older adults encode less context, they have problems distinguishing events they actually experience from those they have only thought about, a phenomenon called "reality monitoring." In a reality-monitoring task, individuals either read words at encoding or generate words in response to some cue. Older individuals have greater problems in determining whether remembered events were the ones read or the ones imagined in response to the cue (Norman and Schacter).
In addition to the problems associated with remembering context itself, older adults have problems with binding the context with the to-be-remembered information. In one study, for example, younger and older adults were presented with pairs of words and asked to generate a sentence that included both words. There were no age differences in the nature of sentences generated, but older adults did have more problems generating sentences, especially for unrelated word pairs that required them to generate the binding sentence through deliberate processing (Smith et al.). Older adults were better able to generate sentences when the two words were related to one other. They were also better able to recall one word from the word pair when given the other word as a cue. By having related word pairs, there was less need to bind the two words together because their relationship provided an existing bond. Again, because less deliberate processing was required in both the encoding and the retrieval conditions when related pairs were used, age differences were smaller. In fact, research has shown that age differences in the ability to recall a target picture when another picture is given as a cue depends on the relationship of the cue to the target. Age differences are large when the two pictures are unrelated, but smaller when the two pictures are either semantically related or presented as perceptually interacting (Park, Smith, et al. 1990).
One interesting type of episodic memory, "prospective memory," does not involve remembering something from the past, but instead involves intending to do something in the future. "Stop by the store when you leave work, and bring home some milk." "When you see Wanda, tell her to look at my new Web page." "Take two of these pills every other day after lunch." These are examples of prospective memory tasks. In the laboratory, prospective memory tasks simulate these real-world examples (e.g., "Press the key when you see a word with an 'R' in it" or "Press the key every ten minutes"). The prospective task is combined with some other cognitive task, such as trying to study a word list for a later memory test. With simple laboratory tasks, however, such as pressing a key when a certain letter is found in a word, age differences in prospective memory are often not found. Again, the determinant of whether age differences are found seems to be the degree of deliberate recollection required to perform the task, either for the prospective task or for the background task. As the difficulty of either task is increased, requiring more deliberate processing, age differences are increased.
Age differences are often larger in time-based tasks (e.g., individuals are asked to press a computer key every ten minutes while performing another computer cognitive task) than in event-based tasks (e.g., individuals are asked to press the key when a certain cue word appears). Because event-based prospective remembering involves less deliberate processing, given the external cue, age differences sometimes were not found. It is also clear that prospective memory errors in older adults increase when the background task they have to perform becomes more demanding in terms of processing resources (Einstein et al.).
Semantic memory. Not all remembering requires one to reconstruct the experience of encoding. There are many examples of remembering without reference to how or when what one is trying to remember was originally learned. There is access to a great deal of knowledge that has lost all connection to the context of its original episodic learning. "What is the capital of North Dakota?" "What bug has eight legs and weaves webs?" "Where were you born?" Answering these questions requires semantic memory. Semantic memories are retrieved conceptually rather than contextually, and represent accumulated knowledge. Instead of using a cognitive diary, semantic memory is like looking something up in an internal cognitive encyclopedia. Of course, the information is not alphabetically organized, but instead organized conceptually or semantically.
As mentioned earlier, tests of semantic memory typically show either no age differences or improvement over the adult life span (see Figure 1). Vocabulary tests and tests of general knowledge (such as found in Trivial Pursuit games) show either no age differences or increases for older adults up until very late in life (eighties or nineties). In Figure 1, vocabulary knowledge increased steadily through the seventies and showed only a slight decline in the eighty-year-old group.
There have also been attempts to examine the architecture of semantic memory (i.e., the way semantic organization is conceptually associated). Free association tests are one way to look at semantic organization. Individuals are given a word and asked to generate another word, the first word that comes to mind when thinking about the word given. A category name is given in another type of test (e.g., vehicle), and individuals are asked to generate the first five vehicles they can think of. If semantic information in memory is organized in different ways by different age groups, then there should be qualitative differences in the nature of the responses given on free association tests or category generation tests. If older adults' semantic memories are organized differently, then the organization should produce differences in the strength of associations between different concepts. Norms of free associations, however, as well as norms of generating instances in categories, show no differences between age groups (Smith and Earles).
One aspect of semantic memory that does seem to decline with aging is the ability to find a word, given its definition. This phenomenon extends to finding proper names and to the "tip-of-the-tongue" phenomenon (Craik). A tip-of-the-tongue state is created when a person knows that he or she knows something but cannot think of it at the moment. Often one can generate information about the answer that is correct but cannot think of the answer itself. Some of this effect (word finding, name finding, tip-of-the-tongue), however, is associated with older adults simply being slower to respond. Some research suggests equivalent word finding in different age groups with difficult words (Craik). Other research suggests that older adults eventually can resolve tip-of-the-tongue states when given enough time (MacKay and Abrams).
Procedural memory. Several times in this entry it has been stated that age differences in memory seem to increase when the degree of deliberate processing required to remember increases. Procedural memories are assumed not to require any deliberate, intentional processing at all. They instead involve only automatic processing and, in fact, do not even require conscious awareness of the effects.
Procedural memory tasks, sometimes called implicit memory tasks, often use repetition priming as a measure. For example, individuals first examine a list of words (stand, chair, . . . radio), not aware that a later memory test is involved. Rather, they are told to make some judgment about the words, such as to rate the pleasantness of each word on a five-point scale. Then several other word tasks are performed. Finally, a series of word stems is presented (fe___, ra___, . . . bl___) and the individuals are asked to complete the stem with the first word that comes to mind. Some of the word stems could be completed with a word presented earlier on the list. Even though they are not aware that the word stem list contains stems for words seen earlier, individuals will use the presented words to complete the stems at a level greater than chance. This increase in "remembering" previously presented items represents implicit or procedural memory.
As might be expected, given the lack of deliberate recollection, age differences are typically not seen on implicit memory tasks (Zacks et al.). If they are found, they are very small, especially when compared with the large effects seen in explicit episodic recall.
In summary, the memory systems approach has been very useful in describing when significant age differences in memory are found. Whether or not memory systems eventually are supported by neuroscientific data, they have provided a useful conceptual framework for organizing memory phenomena and for showing dissociations with age.
Another view of memory is more closely based on the observation that age differences in memory tasks seem to be determined by the degree of deliberate processing required to perform the task. Deliberate processing requires processing resources, and if processing resources are diminished in older adults, then the ability to engage in deliberate processing will be reduced. According to this view, age differences in memory are assumed to be caused by an age-related reduction in cognitive resources available to perform memory tasks as well as other cognitive tasks. Support for this theoretical position comes from studies which show that individual differences in measures of cognitive resources can account for age-related differences in memory performance. This research approach is represented in Figure 2. The circles in the figure represent individual differences in age, memory, and cognitive resources. Overlap in the circles represents shared variance among the variables. The age-related variance in memory is reflected by the overlap in the age and memory circles (a + b). The degree to which processing resources mediate the relationship between age and memory is shown by b.
Four mechanisms have been suggested as estimates of cognitive resources: perceptual speed, working memory, inhibitory function, and sensory function (Park).
Perceptual speed. Older adults are slower at performing simple perceptual/motor operations. In one test, for example, individuals are asked to look at two strings of letters (e.g., xpltvg — xpltvg) and indicate in the space between them whether the strings are the same or different. The number of letter comparisons that can be completed in ninety seconds declines significantly across the life span. Perceptual speed is assumed to be an estimate of the efficiency of neural functioning, and thus to be a possible mechanism to account for age differences on memory and other cognitive tasks (Salthouse). Timothy Salthouse has produced an impressive amount of evidence that individual differences on simple measures of perceptual speed can account for most of the age-related variance in complex cognitive tasks, even those that do not require completion in a given time (i.e., speeded).
Working memory. Many researchers believe that working memory is a good measure of processing resources. Like perceptual speed, individual differences in working memory can account for much of the age-related differences on long-term memory tasks. Denise Park and her colleagues conducted a study with over 300 adults of different ages that measured perceptual speed, working memory, and different measures of long-term episodic memory. The long-term memory measures included free recall of a word list (looking at a word list and then recalling as many words as possible), cued recall (presenting word pairs at encoding and then presenting one word from each pair as a cue for the other word at retrieval), and spatial recall (remembering what quadrant of the computer screen words had been presented in earlier) (Park, Smith, et al. 1996). This study showed that when perceptual speed as a construct was included in a model of memory performance, it accounted for essentially all of the age-related variance in memory performance. Measures of working memory, however, were also important in the model with the more effortful measures of episodic memory, free and cued recall. Speed alone accounted for the age differences in the less effortful spatial recall task, but both speed and working memory were necessary to account for the age differences in free and cued recall, tasks that are assumed to require more processing resources. These results suggest that no single mechanism may be adequate and that multiple measures may be necessary to account for age differences in memory.
Inhibitory function. Another construct that has been suggested as the mechanism for cognitive resources is inhibition (Hasher and Zacks). Inhibitory function allows the individual to focus on information relevant to the task and suppress information that may be activated but is irrelevant to the task. Lynn Hasher and Rose Zacks suggest that older adults are less able to inhibit irrelevant information, and thus cannot focus as well on the information needed to perform the task. According to this view, it is not working memory capacity that is limited in older adults, but the inability to inhibit irrelevant information from cluttering up the content of working memory. The result of this "mental clutter" is that older adults experience more interference at both encoding and retrieval. There is a great deal of evidence that older adults are in fact deficient in inhibiting irrelevant information when performing memory tasks (Zacks et al.).
Sensory function. Paul Baltes and Ulman Lindenberger, in their large-scale Berlin Aging Study, found that auditory and visual acuity can account for much of the age-related variance on a variety of cognitive tasks, including associative memory. In one study, they found that sensory function accounted for over 90 percent of the age-related variance in cognition. Other research, however, has shown that this relationship is not simply due to the fact that poorer vision and hearing cause a decline in cognition. Instead, Baltes and Lindenberger suggest that the sensory measures are one of a large number of physical and cognitive variables that reflect the efficient functioning of the nervous system. According to their view, there is a "common cause" related to biological aging that affects a variety of abilities, both cognitive and somatic, are affected by aging.
In summary, different theoretical mechanisms have been proposed to account for age differences in memory performance. Each mechanism has been shown to be important, and research is needed to better understand the relationship among the different constructs. It is becoming clear that no single mechanism can account for all age-related variance in memory performance, and future research will address the relationship among the mechanisms when predicting performance on different types of memory tasks. All of the theoretical mechanisms, however, assume that older adults have more limited processing resources.
One theme that has emerged from the discussion is that age differences in memory are determined by the degree of deliberate processing. Fergus Craik has suggested that memory performance is determined by an interaction between internal (self-initiated processing) and external (environmental support) factors (Zacks et al.). The amount of deliberate processing required in a task decreases as the task itself becomes more supportive. As mentioned earlier, a great deal more processing resources are needed to remember the words in a free recall task than in a recognition task. In a recognition task, the words themselves serve as retrieval cues and the processing required to recognize is minimal. No explicit cues, however, are provided in a free recall task, and the individual must engage in a great deal of self-initiated processing in order to retrieve the words. Age differences in recall therefore are much greater than age differences in recognition (Craik). As the amount of deliberate processing increases, age differences should increase; as the environmental support provided by the task increases, age differences should decrease.
There have been some research attempts to determine the extent to which a task requires deliberate processing versus the extent to which it relies on automatic processing. One such attempt is known as the "remember-know" procedure. After individuals correctly identify words in a recognition memory experiment, they are asked to estimate whether the word was deliberately recollected ("remember") or whether the recognition was based on familiarity, with no specific recollection of encoding the word ("know"). Several different experiments have found that older adults produce a smaller proportion of "remember" judgments for the words they recognize, and a greater proportion of "know" judgments (Zacks et al.). This finding implies a reduced ability to deliberately recollect the items at the time of test and a greater reliance on familiarity.
Another method for examining deliberate and automatic remembering has been developed by Larry Jacoby and his colleagues. The "process dissociation" procedure actually provides quantitative estimates of the deliberate and automatic processing requirements of different memory tasks. As an example of process dissociation, Jennings and Jacoby looked at age differences in recognition memory. Younger and older participants first looked at a list containing words that they simply read. Then they listened to a second list and were told they would be tested on the second list later. Following the two lists, they were given two different recognition tests. In both tests they were given pairs of words, one of which they saw earlier, either as a word they read in list 1 or as a word they heard in list 2. The second word in the pair was a new word they had not seen or heard previously.
On the first memory test, they were misinformed that one word in each pair had been presented auditorially in list 2, and the other word was either new or one that they read in list 1. They were to pick the word that they had heard in list two (exclusion test). If they picked a word that was presented in list 1, they could do that only through familiarity, because if they had recollected the word, they would have correctly rejected it because it was a list 1 word. In the second memory test, they were told that one word from each pair was a new item, and they were to pick the one they had either seen or heard before. In this case, their judgments could be based on either familiarity or recollection (inclusion test). By subtracting the estimate of recognition due to familiarity derived from the first test (exclusion) from the scores on the second test (inclusion), an estimate of recall based on recollection alone could be derived. The results showed that the age effects were limited to the deliberate recollection component of recognition memory. Estimates of familiarity showed no age effects. This analytical procedure provides further support for the conclusion that age effects are determined by the extent of deliberate processing required in a task.
Dementia: age-related memory pathologies
So far, the discussion has been limited to healthy older adults. For most of this research, good health is a requirement for participation in the research. A small percentage of older adults, however, develop dementias that have a primary symptom of memory loss. There are many types of dementia, the most common one being Alzheimer's disease, which accounts for over two-thirds of all cases.
Because there are memory changes associated with normal, healthy aging, it is very difficult to diagnose Alzheimer's disease and other dementias early. There are many neuropsychological memory tests that can determine the progression of the disease once it has been established, but it is much more difficult to determine the early signs of dementia that distinguish Alzheimer's disease from normal memory change and that could be used as a diagnostic test. Unfortunately, the types of memory that are associated with very early dementia (episodic memory and working memory) are the very ones most affected in normal aging (Hodges). This means that the boundary between healthy memory change and unhealthy memory change is often not clear. One possible early difference is in the ability to remember things after retention intervals (delayed recall). One of the earliest symptom of Alzheimer's disease seems to be the loss of newly learned information after delay intervals (Albert and Killian). Forgetting rates often are the same in healthy adults if information is learned to the same criterion of performance. Alzheimer's patients, on the other hand, show greater delayed recall and more forgetting over the retention interval.
Very accurate cognitive diagnosis, however, remains difficult until the patient reaches the mild to moderate level, when other memory changes occur that are not typically associated with normal aging except for the very old (e.g., semantic memory and visuospatial memory). Category fluency (generating instances of categories) and providing verbal definitions seem to show the greatest sensitivity to early Alzheimer's disease (Hodges).
Anderson D. Smith
See also Alzheimer's Disease; Brain; Dementia; Memory Dysfunction, Drug Treatment; Memory, Everyday; Memory Training; Metamemory; Neuropsychology.
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The history of the idea of memory is associated with the cultural uses of two kinds of memory, episodic and semantic. Episodic memory concerns the conscious recall of particular events. Interest in its nature dates from antiquity, and mnemonic techniques for strengthening memory's resources, known as the "art of memory," were developed as rhetorical skills. Semantic memory deals in tacit understandings—habits of mind and implicit knowledge on the boundary between the conscious and the unconscious. In modern times, scholars have treated it as a realm apart from episodic memory in light of a newly discovered awareness of the significance of the social contexts of collective memory.
The Ancient Art of Memory
In ancient Greek mythology, Mnemosyne, the goddess of memory, was revered as mother of the Muses of the arts and sciences. Ever since, students of memory have acknowledged memory's creative power to evoke the imaginative forms through which humankind represents the reality of its experience. The ancient idea of memory was grounded in the concept of mimesis, according to which memory and imagination are reverse sides of the creative act of "imitating nature." In the primarily oral culture of ancient Greece, the rhapsodes were renowned for their prodigious powers of memory, which allowed them to sing the Homeric epics, the repositories of the Greek heritage and the foundation of Greek cultural identity. But the use of memory in oral tradition was uncritical, and scholars have made much of the differences between the intuitive poetic storytelling of rhapsodes and the studied analytical use of memory among the literate rhetoricians of an incipient manuscript culture.
A changing conception of memory, therefore, is coeval with the passage from primary orality to manuscript literacy (beginning about the seventh century b.c.e.), which permitted a newfound critical perspective on memory's nature. By late antiquity, the idea of memory as remembered episode had come to be closely associated with the art of memory, a rhetorical technique of displacement for accurately recalling facts and stories worthy of remembrance. The art located data difficult to remember within easily remembered imaginary structures of places and images. The discovery of this method for associating the unfamiliar with the familiar is attributed to the Greek poet Simonides of Ceos (556–468 b.c.e.) and was developed especially by Roman rhetoricians. The Rhetorica ad Herennium (82 b.c.e.), attributed by some to Cicero, is the oldest such manual to have survived from antiquity. Throughout the Middle Ages and Renaissance, the art found expression in ever more complex mnemonic schemes, until it was marginalized by new encyclopedic reference books for storing knowledge in the emerging print culture of the Enlightenment.
The English historian Frances A. Yates (1899–1981) was the first modern scholar to analyze the history of the intellectual uses of mnemonic technique. She grounds this critical perspective in two seminal conceptions of memory derived from ancient Greek philosophy, one formulated by Plato (c. 428–348 or 347 b.c.e.), the other by Aristotle (384–322 b.c.e.). Plato emphasized the power of memory to open pathways to the archetypes of transcendental knowledge. Aristotle presented a down-to-earth analysis of memory's powers of recognition and recall and described mnemonics as a guarantor of the capacity of a well-ordered mind to hold fast to its learning. Yates was especially interested in the ambition the Neoplatonist rhetoricians of the Renaissance had to construct imaginary memory palaces whose architectural structures were purported to mirror those of an ideal universe and so to provide hermetic keys to correspondences between earthly and transcendental realities. But the rise of empirical science in the seventeenth century undercut the art of memory's idealist presuppositions, and while the art remained an elegant technique for the rhetorical display of erudition, it was soon acknowledged that its methods led only to a philosophical dead end.
Modern Memory and Personal Identity
The spread of print literacy by the eighteenth century transformed the cultural understanding of episodic memory. In print culture, collective knowledge could be easily preserved in readily accessible, alphabetically indexed reference books, rendering obsolete the practical applications of the art of memory in information retrieval. The psychological effect was to free memory for personal reflection on formative life experience, particularly that of childhood. The idea of memory thenceforth came to be closely allied with autobiographical soul-searching. The prototypes for this genre of self-analysis were the Confessions (1762) by the French philosopher Jean-Jacques Rousseau (1712–1778) and the Prelude (1805) by the English poet William Wordsworth (1770–1850). But for early twentieth-century readers, the most poignant introspective evocation of the past was that of the French writer Marcel Proust (1871–1922), who, in his multivolume novel In Search of Lost Time (1913–1927), marveled at the way an impromptu experience of sensory recall could spontaneously awaken the brilliant immediacy of an entirely forgotten cultural world. For the literati of the modern age, recovered memory was perceived to be the surest route to the discovery of the deep sources of personal identity.
Memory reconceived as the search for self was given a scientific foundation by the Austrian physician Sigmund Freud (1856–1939). Just as Plato had recourse to memory as a means for lifting the soul to an awareness of an ideal world, so Freud aspired to employ memory to open passageways leading to truths hidden in the unconscious. He invented psychoanalysis as a therapeutic technique for helping his patients cope with their neuroses, which he attributed to repressed memories of trauma earlier in their lives. Freud thought of the unconscious psyche as a subterranean archive where forgotten memories of unresolved issues pressed their unanswered claims on the conscious mind in ways that impaired its capacity to deal with present realities. In recovering repressed memories, patients would come to recognize the sources of their inner conflicts and so gain self-knowledge that would enable them to act more effectively in their present endeavors. Like the art of memory, Freud's psychoanalytic technique used the principle of displacement. Seemingly innocuous dreams, "screen memories," and slips of the tongue were often place markers for trauma in an individual's life history, providing clues to more troubling memories buried in the unconscious. The skilled psychoanalyst could help patients recover them.
The Social Frameworks of Collective Memory
In the early twentieth century, near the time when Freud's findings were being popularized, sociologists began to inquire into the nature of semantic memory as a realm of remembrance of a different order—socially conditioned memory, often tacitly understood. Here the memory was considered in its social context, as subject to social and cultural influences. The French philosopher Henri Bergson (1859–1941) prepared the way at the turn of the twentieth century by pointing out the difference between the memory of specific events and the memory of enduring attitudes, a distinction he correlated with that between the moment and duration. The French sociologist Maurice Halbwachs (1877–1945) elaborated a more complete theory of collective memory during the 1920s. For him, collective memory is a function of social power, and its expression varies with the social settings in which we find ourselves. We localize images of the past within imaginary frameworks that conform to our social understanding. For that reason, collective memory is provisional until it is evoked within specific social contexts, and its form and strength is relative to the social forces that impinge on our present circumstances. Without such social props, collective memory cannot survive. Halbwachs was especially insightful about how commemorative practices assimilate specific images of episodic memory into the idealized structures of semantic memory. As for its place in the history of ideas, Halbwachs's theory draws on the method of the art of memory to demonstrate how the strategic mobilization of commemorative monuments in mnemonic landscapes reinforces officially sanctioned collective memory.
The Fragility of Memory in a Postmodern Age
In the twenty-first century, we know more about memory than ever before, but trust its resources less. The idea of memory, conceived as the keystone of identity for the nineteenth century, has been reconceived as the debris of lost identities, the free-stones of aging memory palaces that have fallen into ruins. Since the last quarter of the twentieth century, the topic has inspired intense interest among historians, literary critics, folklorists, sociologists, anthropologists, psychologists, and neurobiologists. Across the curriculum, scholars are as one in noting that memory is easily and often remodeled, almost always distorted, and hence unreliable as a guide to the realities of the past. The idea of memory, therefore, is noteworthy for its fragility, vulnerable as it is not only to the vagaries of the mind but also to social, political, and cultural forces that would alter or obliterate it.
On the edge of fragile memory lies nostalgia, the most elusive of memory's protean forms and one beginning to receive critical attention. An admixture of sweetness and sorrow, it expresses a longing for a vanishing past often more imaginary than real in its idealized remembrance. Nostalgia exercised a powerful appeal in the Romantic sentiments of the nineteenth century, tied as it was to regret over the passing of ways of life eroded by economic and social change, a generalized popular enthusiasm for innovation, and rising expectations about what the future might hold. Nostalgia was the shadow side of progress. Chastened by the disappointments of the twentieth century, however, the idea of progress has fallen on hard times, and nostalgia presents itself as an even more diffuse longing for a fantasy world that never existed (for example, the classless society in Communist propaganda). So reconceived, nostalgia has come to be criticized as a dangerous surrender to anarchistic illusion that contributes to memory's vulnerability to exploitation and misuse.
Situated at an interdisciplinary crossroads, the idea of memory has yet to promote an exchange between humanists and scientists, though they make their way along converging avenues of research. Scientists have moved away from Freud's claim about the integrity of memory's images. Steady research in psychology over the course of the twentieth century exposed the intricacies of the mental process of remembering, which involves complex transactions among various regions of the brain. For psychologists, remembering is conceived as a dynamic act of remodeling the brachial pathways along which neurons travel as they respond to sensory stimuli. The images of memory are encoded in neural networks, some in short-term and some in long-term configurations, and so are mobilized as conscious memories in multifold and continually changing ways. Memory resides in these ephemeral expressions, and its images are constantly subject to revision in the interplay of well-established patterns and chance circumstances that governs recall.
Some neuroscientists propose that memory is an adaptive strategy in the biological life process. Drawing on Charles Darwin's theory of natural selection, the American neuroscientist Gerald Edelman (1929–) argues that there is a selective process by which memory cells cluster in the neuronal groups that map neural pathways. He identifies two repertoires of such clusters in the gestation of the brain, one, primarily genetic, in embryo, and the other, primarily adaptive, after birth. They establish the categories of recognition through which the brain thenceforth processes external stimuli, though these categories are continually modified as the brain adapts to new life experience. In this sense, each act of recollection is a creative process that entails a reconfiguration of synaptic connections. There is an intriguing analogy between Edelman's two stages of memory cell formation and the mnemonist's two-step reinforcement of memory in repertoires of places and images. There is a resonance as well between Edelman's notion of the brain's mapping of neural pathways and Halbwachs's conception of the topographical localization of social memory. Both affirm the constructive nature of the act of memory in the interplay of recognition and context.
Cultural Contexts of Memory in the
Among contexts contributing to the idea of memory's fragility in the twenty-first century, one might highlight the following:
The one-way transit to amnesia in the pathologies of dementia.
The degree to which the workings of memory elude research in the biological sciences is dramatized by the difficulties of understanding the perplexing diseases that lead to the deterioration of memory in old age. Freud's faith in the prospect of memory retrieval is difficult to reconcile with the insurmountable barriers erected by the ravages of dementia. An unfortunate by-product of longevity in the affluent Western world has been an increasing susceptibility to the maladies of memory impairment with advancing years. Alzheimer's disease is the most dreaded among an array of forms of dementia that rob victims of their memories and by consequence of their identities. Here there can be no recall of the past from the oblivion imposed by neurological degeneration. Alzheimer's disease has come to serve as a cultural metaphor for twenty-first century fears of trends that promote not only personal but also social amnesia.
Media and the eclipse of tradition in mass culture.
The twenty-first century is characterized by its present-mindedness, but ironically has little regard for the presence of the past. We live in a consumer society whose interest lies in using and then discarding the resources of the present, not conserving them for future generations. Tradition, once valued as the bequest of the wisdom of past generations to the present one, is dismissed as trivial to the manufactured pursuit of immediate gratification in which the hallmarks of tradition are redeployed as the kitsch of consumerism, divested of the social and cultural frameworks that once defined social identity.
The media work their pervasive influence thanks to a revolution in the technologies of communication in the late twentieth century. The invention of new forms of electronic communication—notably the personal computer, linked by the Internet to a worldwide web of memory banks in cyberspace—so vastly expanded the capacity and facilitated the ease of information retrieval that it reshaped both perception and learning in ways analogous to those that accompanied the transition from orality to literacy (during which the art of memory was invented), and then from manuscript to print culture (when the interconnection of memory and personal identity was established). In this respect, the organization of knowledge on computer screens and Internet Web pages departs from its linear organization in print culture, to be reconfigured spatially on Web sites and in icons reminiscent of the places and images of the art of memory. Temporal models (timelines) are replaced by spatial ones (hyperlinks among Web sites).
The revolution in media communication accelerated the fraying of older forms of social and cultural identity. The media mold images in pervasive and homogeneous ways by virtue of their expanded control of the networks of communication, and favor tendentious publicity over deliberation. The media deepen present-mindedness, since their imperative is to publicize images of recent events as quickly as possible before moving on to others even more recent and enticing in their prurient interest. They evoke a sense of immediacy in which the past is glossed over and the future reduced to idle speculation. The mnemonic power of forms of publicity to incite interest prevails over the force of ideas, undermining the value of cultural traditions that once provided sure reference points of collective identity.
A reluctance to mourn.
In the late twentieth century, historians too turned avidly to research on memory, more specifically to the relationship between memory and the dissolving cultural identities of the postmodern age. Whereas scholars of the nineteenth century had looked to formative beginnings, those of the late twentieth century were more interested in irresolute endings. During the 1970s, social historians such as Philippe Ariès, Pierre Chaunu, and Michel Vovelle launched studies of changing attitudes toward death and mourning across several centuries, in some sense as a response to the denial of death and the difficulties of mourning common in the late twentieth century. For comparison, Ariès portrayed the nineteenth century as a golden age of mourning. He noted newly intense expressions of personal mourning, made manifest in lavish funeral rituals and ornate commemorative monuments in cemeteries reconceived as gardens for meditation. Mourning in the nineteenth century confirmed personal identity by integrating the rituals of private mourning into well-established public traditions. The twentieth century, he claimed, was conspicuous for its reluctance to face death's realities and its diminished capacity to devote time and intensity to the process of coming to terms with the loss of loved ones.
The politics of memory.
Historians soon extended their inquiry to encompass public commemoration—what the U.S. psychologist Peter Homans has characterized as the mourning of symbolic loss. During the 1980s, historical scholarship addressed the politics of memory, especially as it was displayed in the nineteenth-century commemorative practices that solemnized the building of nation-states in their use of icons of sacred moments (for example, national holidays) and avatars of patriotism (such as "founding fathers"). Given the challenges facing the nation-state in an age more acutely aware of the need for global perspectives on humankind, the historians' perspective on the making of national memory tended to dwell on its present-minded politics and geographical parochialism. Such research drew heavily on Halbwachs's theory of collective memory, as historians sought to rein in memory's claims on the past. In parallel with the efforts of philosophers and literary critics to deconstruct the forms of cultural discourse, historians sought to expose the building blocks from which practices of public commemoration had been constructed. They juxtaposed and to some degree reduced the reverential task of commemoration to its efficacious use in consolidating political allegiances.
Eric Hobsbawm and Terence Ranger's The Invention of Tradition (1983) and Pierre Nora's Les lieux de mémoire (1984–1992) stand out as pioneering studies in this field. Both seek to expose memory's role in the making of political identities that have become suspect in their biases and whose appeal at the turn of the twenty-first century began to wane. Nora's book on the making of the French national memory provided a method for digging through the accumulating layers of mementos that contributed to the making of political identity over long periods of time. It inspired a host of studies dealing with like political uses of memory in countries around the world.
Traumatic memories of atrocities.
The twentieth century witnessed episodes of genocide and mass destruction on a scale that traumatized entire populations into collective repression. Reckoning with these unhappy memories demanded a new approach. Concerned that the worst atrocities might be glossed over and forgotten, historians undertook an inquiry into a relationship of a different order between memory and history. These investigations reiterated Freud's thesis about the necessity of "working through" the trauma of repressed memory to uncover harsh and painful truths about crimes against humanity. They concluded that some memories cannot be easily tamed by history, and that they maintain their singularity at the limits of history's powers of representation. Memories of the Holocaust of European Jewry are the most studied among them.
The problems involved in historicizing the memory of the Holocaust was the subject of the much-publicized "historians' controversy" in Germany during the 1980s. One group of historians contended that it was time to place the Holocaust in historical context. Another countered that no extant conceptual framework is adequate for doing so. It argued for the importance of the preliminary task of gathering testimony from Holocaust survivors still struggling to come to terms with their painful memories. Meditating on the differences between memory and history, the Israeli historian Saul Friedländer (b. 1932) wondered whether history could ever do justice to the existential meaning the Holocaust held for its victims. His question is whether the immediacy of memory can ever be reduced to the selective perspectives and conceptual abstractions of historical interpretation. He suggests that traumatic memory may be a realm of human understanding whose meaning is to some degree incommensurable with historical explanation. The conversation among historians about the limits of history's claims on traumatic memory lingered into the 1990s, and the European Holocaust served as a point of departure for studies of other instances of genocide in the late twentieth century, the memory of which presented obstacles to adequate historical interpretation.
History's Claims on Memory: A Remedy or a Poison?
The dispute about the relationship between memory and history was put in philosophical perspective by the French phenomenologist Paul Ricoeur (b. 1913). After reviewing the many routes of scholarly inquiry into the idea of memory at the turn of the twenty-first century, he closes his analysis with a meditation on the concerns of the historians of the Holocaust about history's premature claims on memory. In considering why history must first beg pardon of memory, he guides our attention to Plato's philosophical dialogue Phaedrus, an evocation of the debate among the ancients about differences between the remembered and the written word that provides an analogy with the current debate about memory's relationship to history. In this dialogue, Plato's teacher Socrates ruminates on whether efforts to tame memory to the critical perspectives of writing have merit. He poses the question: Is writing as an aid to memory a remedy or a poison? The written word can be a remedy in the sense that it secures knowledge in an enduring form. But it does so by setting limits on the depiction of the past and so discards with a certain finality alternate ways of evoking its presence. Memory, by contrast, may at any moment rescue the past from oblivion. Its uses reside not only in its resources for preservation but also in those for creation. Its virtue lies in its ontological claim to body forth the imaginative forms that make conscious knowledge of human experience possible. History at its best deepens human understanding in its accurate reporting and intelligent interpretation of the past, and it strives to be conclusive. But memory's fidelity to the experience of the past is the basis of its openness toward the future, and it resists closure. Memory stands "as a little miracle" in its distinctive capacity to trigger the creative imagination in a way no other faculty of mind can.
The U.S. intellectual historian David Gross (b. 1940) adapts that insight to consider the status of memory in the twenty-first century. He notes the readiness of society to consign to oblivion all that stands in the way of present-minded expectations. He sorts out the intellectuals of late modernity into those who would discard and those who would value the past remembered. He highlights modern "rememberers" who have argued persuasively for the importance of the past to their present concerns—among them Proust and Freud, but also the nineteenth-century German philosopher Friedrich Nietzsche (1844–1900) and the twentieth-century German literary critic Walter Benjamin (1892–1940).
Benjamin in particular fascinated scholars because of his aphoristic insight into memory's remedy for the deficiencies of the timeworn claims of the modern vision of history on the contemporary age. Especially provocative is his interpretation of the painting Angelus Novus (1920) by the surrealist artist Paul Klee, a tableau of the angel of history looking back sadly on the events of the modern age, not as milestones of civilization's advance but rather as remnants of its failed projects and endless disappointments. A disillusioned socialist nostalgic for the heroics of the nineteenth-century revolutionary tradition, Benjamin longed for memory's spark to jump-start an alternative future. Neglected memories, he maintained, respond to our imaginative gaze like heliotropes opening to the sun.
Although assailed by all the pressures of present-minded perspectives that deny the importance of recollecting the past, the rememberers appeal to the present age by calling to mind the striking diversity and rich complexity of past human experience, and so deepen understanding of the timefulness of the human condition in its manifold meanings. Memory's claim on the past, they argue, lies in its creative capacity to resurrect lost worlds worthy of our consideration. Their insight recalls the ancients' reverence for the goddess Mnemosyne, who out of the eons of humankind's lost primordial past brought into consciousness the imaginative forms from which all the arts and sciences would spring.
See also Autobiography ; Death ; Ritual: Public Ritual ; Tradition .
Ariès, Philippe. The Hour of Our Death. Translated by Helen Weaver. Oxford: Oxford University Press, 1991.
Boym, Svetlana. The Future of Nostalgia. New York: Basic Books, 2001.
Edelman, Gerald M. Neural Darwinism: The Theory of Neuronal Group Selection. New York: Basic Books, 1987.
Gillis, John R., ed. Commemorations: The Politics of National Identity. Princeton, N.J.: Princeton University Press, 1994.
Gross, David. Lost Time: On Remembering and Forgetting in Late Modern Culture. Amherst: University of Massachusetts Press, 2000.
Havelock, Eric. Preface to Plato. Cambridge, Mass.: Harvard University Press, 1963.
Hobsbawm, Eric, and Terence Ranger, eds. The Invention of Tradition. Cambridge, U.K.: Cambridge University Press, 1983.
Homans, Peter, ed. Symbolic Loss: The Ambiguity of Mourning and Memory at Century's End. Charlottesville: University Press of Virginia, 2000.
Hutton, Patrick H. History as an Art of Memory. Hanover, N.H.: University Press of New England, 1993.
Matsuda, Matt K. The Memory of the Modern. New York: Oxford University Press, 1996.
Nora, Pierre, ed. Les lieux de mémoire. 3 vols. Paris: Gallimard, 1984–1992.
Olney, James. Memory and Narrative: The Weave of Life-Writing. Chicago: University of Chicago Press, 1998.
Ricoeur, Paul. La mémoire, l'histoire, l'oubli. Paris: Editions du Seuil, 2000.
Rosenfield, Israel. The Invention of Memory: A New View of the Brain. New York: Basic Books, 1988.
Roth, Michael, and Charles Salas, eds. Disturbing Remains: Memory, History, and Crisis in the Twentieth Century. Los Angeles: Getty Research Institute, 2001.
Schacter, Daniel L. Searching for Memory: The Brain, the Mind, and the Past. New York: Basic Books, 1996.
Yates, Frances A. The Art of Memory. Chicago: University of Chicago Press, 1966.
Patrick H. Hutton
"Memory." New Dictionary of the History of Ideas. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/memory
"Memory." New Dictionary of the History of Ideas. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/memory
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We can remember a telephone message for the few seconds it takes to write it down. But we can also remember things over very long periods of time. For example, adults may still remember some of the things they were taught at school — both general abilities, such as how to add numbers together, and specific things, such as the translation of ‘la plume de ma tante’. Additionally, we can also remember (though unconsciously) many of the skills attained through life, such as how to ride a bicycle or play the piano. There are many different ways in which humans and other animals remember things. It follows that memory cannot be conceptualized simply and that there are likely to be a variety of different, interacting memory systems.
Much of our sense of who we are as individuals depends on a particular kind of memory, involving recollection of our own past experiences, feelings, and relationships. One only has to imagine not being able to recall what has happened in one's past, or whether or not one even has family and friends, to realize how disruptive and distressing severe amnesia (such as occurs in Alzheimer's disease) can be, both to the patients themselves and to those close to them.
Psychologists have long drawn distinctions between different types of memory systems and memory processes. As early as 1890 William James distinguished between ‘primary memory’ (information one is presently aware of) and ‘secondary memory’ (information in the psychological past). Current ideas still maintain a distinction between short-term memory and long-term memory, evidenced by impairments of one or the other in brain-damaged patients. However, early ‘multistore models’, which proposed separate short-term and long-term memory stores, have now been discredited as being too simplistic.
The idea of a unitary short-term store has now largely been replaced by the concept of ‘working memory’. The working memory system is concerned with both active processing and short-term storage of information and allows one to plan for the future and to bring together thoughts and ideas. Damage to the frontal lobes seems to impair working memory: patients with such damage function rather normally apart from being impaired in the use of stored knowledge to guide appropriate behaviour. Experiments on monkeys have shown that individual nerve cells in certain parts of the frontal cortex not only fire impulses when certain objects are seen by the monkey but continue to respond when the object disappears from view, as if holding a memory of the object. Furthermore, studies on the effects of damage of the frontal lobes in monkeys suggest that different forms of working memory can be localized to specific regions of the prefrontal cortex — the front part of the frontal lobes.
The concept of a single long-term store has also been replaced, by the view that there are several interacting long-term memory systems. There have been many attempts to subdivide long-term memory, but none has proved entirely successful. Another early distinction was between ‘episodic memory’ and ‘semantic memory’. Episodic memory is autobiographical recollection of personally experienced events (such as what you had for breakfast), whereas semantic memory is general knowledge about the world, factual information and its meaning (such as the fact that breakfast is a kind of meal). Despite a clear conceptual difference, there is less evidence that these two types of memory rely on different memory systems in the brain. Indeed, semantic and episodic memory would appear to be strongly interdependent. For instance, retrieving semantic information may depend upon recalling the particular episodic event or events during which the semantic knowledge was gained. Likewise, it has been argued that recalling an episodic event (for example, remembering seeing an elephant at the zoo) depends on intact semantic memory (the definition of an elephant). Both types of memory may therefore rely on common underlying neural structures.
An alternative distinction was made between ‘declarative memory’ and ‘procedural memory’. Declarative memory refers to knowing ‘what’, and includes both semantic and episodic information, whereas procedural memory refers to knowing ‘how’, and relates to skilled behaviour without the need for conscious recollection, such as the ability to remember how to drive a car. Support comes from observation of certain patients with amnesia who seem to have relatively intact procedural learning abilities (they can still learn how to do things) in the face of impaired declarative learning (e.g. not remembering where they are). However, the distinction between declarative and procedural knowledge is imprecise and many kinds of behaviour involve aspects of both. Furthermore, some patients with severe amnesia are capable of certain feats of memory (such as learning new factual information) that cannot be explained by procedural learning alone.
A further theoretical distinction was made between ‘explicit memory’ and ‘implicit memory’. Explicit memory is said to be involved in tasks that require conscious recollection of previous experiences, whereas tasks that are facilitated in the absence of conscious recollection are said to depend on implicit memory. Many traditional methods used to test memory involve the person being asked to remember specific experiences, and are therefore measures of explicit memory. For instance, the memory of a previously-seen list of words could be tested by free recall (‘Tell me the words that were on that list you saw earlier’), by recognition (‘Was this word among the list you saw?’), or by cued recall (‘Complete these letters to form a word that occurred on the list’).
To demonstrate implicit memory it is necessary to show that a person has a long-term memory of a past experience although they can't consciously recall it. For example, the perceptual identification of words presented extremely briefly is easier if the words have previously been seen. Amnesic patients perform relatively normally on such ‘repetition priming’ tasks, as well as being able to acquire new motor skills, yet they are impaired on most tests of explicit memory. However, the distinction between explicit and implicit memory is again rather general and does not account for all of the patterns of long-term memory performance in amnesic subjects. Furthermore, the theory does nothing to address the fact that amnesic subjects can still form conscious short-term memories, which clearly involve explicit learning.
Observations that amnesic patients can retain some information briefly but not for long periods of time led to the development of the ‘consolidation theory’. This suggests that immediate experiences are somehow crystallized into long-term memory, and that this process is disrupted in amnesia. The theory also maintains that the process of memory consolidation occurs over a period of time, during which memory traces are particularly vulnerable to permanent disruption by such things as a blow to the head, certain drugs, electric shock to the brain, etc. However, consolidation theory cannot account for the fact that apparently lost memories can sometimes be retrieved subsequently.
‘Context-dependent theories’ on the other hand propose that each memory trace (for instance of a particular person) is encoded together with information about the associated context (where you met the person), and that subsequent retrieval of the memory may be facilitated by reinstating the context. (Everyone is familiar with the fact that it is difficult to remember the names of even close friends when you meet them in unexpected places.) This theory is supported by the remarkable observation that divers recall more words learnt underwater when subsequently tested underwater than when tested on land, and vice versa. Learning while under the influence of certain drugs is also context-dependent, being better recalled when the same drug is administered.
Related ‘state-dependent theories’ maintain that agents or procedures that induce amnesia do not permanently disrupt memories but rather ‘re-encode’ the memory traces in association with the brain state induced by the amnesic agent or procedure. Patients who have electroconvulsive shock (for instance, to treat depression) often complain of loss of memories; and this procedure indubitably disrupts long-term memory when given experimentally to rats. But rats can retrieve their lost memories after a subsequent shock, because this puts the brain back into the condition in which the information was ‘re-encoded’, thereby providing an additional cue to aid remembering.
Although it is hard to verify whether a deficiency of memory reflects re-encoding or permanent memory loss, the importance of forgetting should not be underestimated. Although the brain has a huge capacity for memories, it must be finite. Since the brain appears to be able to form associations between disparate stimuli very easily, so it is important for it to be able to forget meaningless or arbitrary associations and remember only those associations that prove consistent or relevant. It has been theorized that inappropriate associations in the brain may specifically be weakened during the phase of sleep in which rapid eye movements and vivid dreams occur (REM sleep).
It is intuitively obvious that memories of all sorts involve functional changes in the brain, sometimes occurring remarkably quickly. Much of what we know about learning and memory has been gained from clever experiments involving the training of animals, both intact and with brain damage, as well as from studies of normal and amnesic human beings. But over the past few decades neurophysiologists and molecular biologists have made great strides in their understanding of the cellular mechanisms of learning and memory. One fruitful approach has involved examining basic forms of learning in animals with relatively simple nervous systems, such as the marine snail Aplysia. This animal withdraws its gill apparatus reflexly when the ‘mantle’ around it is touched, and the circuit of sensory and motor nerve cells responsible for this has been defined. This reflex is subject to habituation (if the touch to the gill is repeated time after time), and to sensitization (if the touch is coupled with other stimulation).
It turns out that these simple forms of short-term implicit learning involve changes in the effectiveness of synaptic transmission (mainly changes in the amount of transmitter substance per nerve impulse released at a particular synapse in the circuit). Longer-term memory requires new protein synthesis and the growth of new or larger synapses.
More complicated forms of learning may involve elaboration of a common set of molecular mechanisms. For instance, most animals can learn to associate one stimulus with another (such as the association formed between the sound of a bell and the sight of food in Pavlovs' famous experiments on classical conditioning). The underlying neural change, just as for sensitization in Aplysia, is thought to involve increased release of transmitter substance at synapses in the circuit associating the two forms of stimulation.
In recent years, attention has focused on a primitive part of the cerebral cortex called the hippocampus, which is tucked inside, under the lower edge of the temporal lobe of the cerebral hemispheres. Extensive damage to this general region in humans can cause devastating retrograde amnesia, which virtually eliminates the capacity to form new long-term conscious memories, while leaving old semantic and personal memories relatively intact. Traditionally, the hippocampus itself has been considered the seat of human episodic memory. However, recent research with monkeys has revealed several, functionally dissociable memory systems in this region of the temporal lobe. These include the perirhinal cortex, for object memory, and the amygdala, for memory for the emotional significance of stimuli and events. These individual areas, each with its different specialization, may then contribute to a broader-based temporal lobe memory system providing the basis of both episodic and semantic memory. The monkey's hippocampus may have a relatively restricted role in memory for spatial location.
In rodents, the hippocampus certainly seems particularly involved in spatial memory: when it is damaged, rats and mice cannot remember their way around mazes. It turns out that the connections between certain nerve cells in the hippocampus are remarkably ‘plastic’. Synapses can be strengthened simply by a brief burst of nerve impulses, so that single impulses will subsequently (and for very long periods of time) evoke much bigger electrical responses in the receiving cell. Much is now known about the molecular basis of this phenomenon, called long-term potentiation. This mechanism may provide the basis of, or at least contribute to, many forms of learning, in several different regions of the brain, ranging from perceptual learning in young animals to human explicit memory.
Memory is central to the human condition and has been investigated at many levels. Neuroscientists have studied the molecular and cellular mechanisms of memory in animals and humans, and psychologists have contributed to our understanding about the different kinds of processes involved in memory through research with amnesic patients and normal subjects. Temporal lobe dysfunction is commonly associated with declarative or explicit memory impairments. However, since most amnesic patients either exhibit diffuse brain damage (Korsakoff's syndrome) or have focal damage to a range of different structures, our present understanding of which particular neural systems are important for different memory processes has come predominantly from animal ‘models’ of human amnesia.
Mark J. Buckley
Bolhuis, J. (2000). Brain, perception, memory: advances in cognitive neuroscience. Oxford University Press.
Eysenck, M. W. (1995). Cognitive psychology: a student's handbook, (3rd edn). Erlbaum, Hove.
See also amnesia; brain; cerebral cortex; limbic system.
"memory." The Oxford Companion to the Body. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/memory
"memory." The Oxford Companion to the Body. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/memory
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Since the 1980s, collective memory has become an intensely studied topic across the social sciences. This sudden remarkable interest may be attributed to a rising preoccupation with dissolving collective identities in the face of new historical realities—globalizing economic and cultural trends, the reconfiguration of gender relations, and a media revolution with far-reaching implications for the organization of knowledge. The scholarly discourse about collective memory parallels another about the distinguishing traits of a “postmodernism” temper.
Serious efforts in the social sciences to understand the dynamics of collective memory, however, date from the early twentieth century in the research of the French sociologist Maurice Halbwachs (1877–1945). He contended that memory must be investigated within its social settings. The present attitudes, beliefs, and traditions of social groups determine the way memories are evoked, and these are continually remodeled as the interests and fortunes of such groups change. The strength of a collective memory is a function of the relative power of such social forces.
By placing his accent on collective memory, Halbwachs took issue with the Viennese neurologist Sigmund Freud (1856–1939), who a generation before had addressed the issue of memory as a task of exploring the workings of the individual mind. Freud believed in the autonomy of personal memory, and developed an analytical technique for recovering repressed memories from the unconscious psyches of his patients. His critics claim that he never worked out a plausible theory of collective memory. For Halbwachs, by contrast, all memory is socially conditioned in that personal memories are always evoked within specific social settings. Without these social props, personal memories tend to fade away.
In explaining the malleability of memory in the face of social forces, Halbwachs proposed that social groups— families, religious cults, political organizations, and other communities—develop strategies to hold fast to their images of the past through places, monuments, and rituals of commemoration. His La topographie légendaire des évangiles en terre sainte (The Legendary Topography of the Gospels in the Holy Land, 1941) was a pioneering case study of the way an imagined past is localized, conflated, and idealized over time in a commemorative landscape. In his theory, the ancient art of memory as a technique of mnemonic displacement was reinvented as a political strategy for anchoring cultural traditions.
For several decades, Halbwachs’s theory of collective memory was largely ignored. But it was rediscovered during the 1970s, to become a working model for burgeoning scholarship in this field. The newfound interest in collective memory has had three principal venues of research: the politics of memory; the changing uses of memory that followed from the invention of new technologies of communication; and a deepening meditation on the memory of the Holocaust.
This interest reflected an emerging critical perspective on modern traditions once naively honored as the remembered heritage of a commonly imagined past. In France, for example, a lively debate emerged during the 1980s about how, and even whether, to celebrate the bicentenary of the French Revolution (1789–1799), hitherto conceived as the enduring moral touchstone of modern French national identity. Many of these studies investigated the making of the identity of the modern state. The most influential was The Invention of Tradition (1983), an anthology edited by English scholars Eric Hobsbawm and Terence Ranger that explored the political uses of tradition in the construction of collective identity. They challenged the long-standing interpretation of tradition as a heritage that impinges on the present through its inertial power and argued that traditions are conceptions of the past invented in the present and periodically refashioned to serve reformulated political goals. Collective memory, they argued, is inspired by present circumstances, and calls into being a serviceable past. In like manner, the anthropologist Benedict Anderson wrote an influential study of the way “imagined communities” are constructed as public memories to give concrete affirmation to otherwise abstract ideals. From a somewhat different perspective, the sociologist Mary Douglas examined the workings of institutional memory, in which bureaucratic solutions to organizational problems are rapidly forgotten only to be invented anew.
By the turn of the twenty-first century, a vast scholarly literature had been produced on the politics of memory, extending investigations beyond commemoration into a wide range of institutional and cultural practices. Noteworthy among these are studies of the making of national identity by Pierre Nora, Les lieux de mémoire (Places of Memory, 1984–1992) for France; Michael Kammen, Mystic Chords of Memory (1991) for the United States; Yael Zerubavel, Recovered Roots (1995) for Israel; and Wulf Kansteiner, In Pursuit of German Memory (2006). All display intellectual sophistication in moving beyond commemorative rites to the many cultural forms in which collective memory is embedded. Over time, the study of collective memory has become an impressive strategy for interpreting cultural history.
A parallel but independent line of scholarly inquiry has explored the cultural consequences of advances in the technologies of communication. This research was inspired by the media revolution of the late twentieth century, which stimulated curiosity about earlier thresholds in the process—notably from orality to manuscript literacy in antiquity, and the democratization of print culture during the eighteenth century. Contributors to this scholarship have been varied—classicists interested in Homer as a collective name for epic storytellers, anthropologists in the living oral traditions of Africa, intellectual historians in the emergence of the republic of letters during the Enlightenment, literary critics in the reflective autobiographical soul searching that print culture for the first time made possible. Less has been written to date on the effects of media on cultural memory, but J. David Bolter has pointed out the way electronic memory localized in the icons and Web sites of the computer screen mimics the organizational technique of the ancient art of memory in its images and places. Though contributions to this field were made by specialists, the cumulative effect has been to produce a sweeping new perspective on cultural history from antiquity to the present.
Somewhat apart are scholarly reflections on the painful process through which Holocaust survivors sought to deal with the trauma they had suffered. This topic reintroduced Freud’s psychoanalytic approach in that it exposed the need for survivors to work through repressed memories of their ordeal before the historical meaning of the Holocaust could be adequately addressed. Beyond inventorying such living testimony, scholars raised the question of how these recovered memories might be historicized within the narratives of modern history. This scholarship provoked the “historians’ controversy” of the mid-1980s in Germany about whether such an atrocity could be conveyed within the limits of historical representation. The Holocaust, initially viewed as one among the many horrors of World War II (1939–1945), came toward century’s end to be reconceived as a singular experience whose memory needed to be processed collectively before an account of its nature could be integrated into any acceptable historical narrative.
The debate about the limits of historical representation shows how the study of collective memory has unsettled the established conventions of historical narration. During the 1970s, the American scholar Hayden White launched an inquiry into the strategies through which historians compose their interpretations, and so shifted historiographical interest from the evidentiary content of historical research to the rhetorical forms of historical writing. One consequence was to reveal the mnemonic character of historical narrative as a technique for selecting and ordering judgments about what is worth remembering out of the past. Challenging the “noble dream” of historical objectivity, historiographers such as Peter Novick turned to the task of exposing the bias, distortions, and omissions of the master narratives of modern history. Novick points out how American historians once naively presented a past they wanted to remember. From the founding of the American Historical Association in 1884 until well into the twentieth century, eminent historians tended to favor a patriotic view of American identity that denied the divisive realities of class conflict, racial and ethnic discrimination, and the diverse viewpoints of an expanding immigrant population.
As this historiography of patriotic consensus fragmented from the mid-twentieth century, a new generation of practicing historians sought to reclaim the forgotten past of women, African Americans, and other marginalized groups, while those with a theoretical bent proposed new categories of conceptualization to frame a more complex historical memory, notably through models for gender studies, the history of collective mentalities, and global history. In the process, they subverted the political identities previously highlighted by modern historiography. The conventional model of a directional modern history, originally conceived as a story of ongoing progress, became an uncertain guide to historical writing. This loss of direction coupled with a sense of accelerating time promoted by larger contemporary trends—advertising that incites the fads of consumerism, the ongoing technological innovations through which global communication approaches the instantaneous—led to the collapse of the future-oriented conception of historical time in favor of one that stresses the urgency of present-day problems. The French historiographer François Hartog has characterized this rethinking of the mnemonics of historical time as a “new regime of historicity,” one that privileges present concerns over past intentions as a point of departure for historical inquiry.
Memory’s subversion of the grand narrative of modern history has legitimized some novel approaches to historical interpretation—an encounter model in global history, a shift from history’s story to history’s topics in historical exposition, the genealogical reading of the past to point out its discontinuities vis-à-vis the present, and efforts to recapture “sublime” moments of historical experience through historical reenactment.
The scholarly discourse about memory across the curriculum in the late twentieth century reveals its essential paradox—the fragility of its representations of the past in relation to the durability of its resources to imagine that past anew.
SEE ALSO Collective Memory; Freud, Sigmund; History, Social; Holocaust, The; Psychoanalytic Theory
Anderson, Benedict. 2006. Imagined Communities: Reflections on the Origin and Spread of Nationalism. Rev. ed. London: Verso.
Confino, Alon, and Peter Fritzsche, eds. 2002. The Work of Memory: New Directions in the Study of German Society and Culture. Urbana: University of Illinois Press.
Douglas, Mary. 1986. How Institutions Think. Syracuse, NY: Syracuse University Press.
Friedlander, Saul, ed. 1992. Probing the Limits of Representation: Nazism and the “Final Solution.” Cambridge, MA: Harvard University Press.
Hartog, François. 2003. Régimes d’historicité: Présentisme et expériences du temps. Paris: Seuil.
Hobsbawm, Eric, and Terence Ranger, eds. 1983. The Invention of Tradition. Cambridge, U.K.: Cambridge University Press.
Hutton, Patrick. 1993. History as an Art of Memory. Hanover, NH: University Press of New England.
Matsuda, Matt. 1996. The Memory of the Modern. New York: Oxford University Press.
Nora, Pierre, ed. 1984–1992. Les lieux de mémoire. 3 vols. Paris: Gallimard.
Novick, Peter. 1988. That Noble Dream: The “Objectivity Question” and the American Historical Profession. Cambridge, U.K: Cambridge University Press.
Ong, Walter. 1982. Orality and Literacy: The Technologizing of the Word. London: Methuen.
Schacter, Daniel. 2001. The Seven Sins of Memory: How the Mind Forgets and Remembers. Boston: Houghton Mifflin.
Patrick H. Hutton
"Memory." International Encyclopedia of the Social Sciences. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/memory
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The ability to store and later recall previously learned facts and experiences.
The brain's capacity to remember remains one of the least understood areas of science. What is understood is that memory is a process that occurs constantly and in varying stages. The memory process occurs in three stages: encoding, storage, and retrieval. Conditions present during each of these stages affect the quality of the memory, and breakdowns at any of these points can cause memory failure.
Stages of Memory
The first stage, encoding, is the reception by the brain of some physical input that is changed into a form that the memory accepts. When a person is introduced to someone new, for example, that person's name becomes a part of memory. Before information can be encoded, it first must be recognized and noted by the recipient. During the second stage, storage, learned facts or experiences are retained in either short-term or long-term memory. In the third, or retrieval, stage, memory allows the previously learned facts or experiences to be recalled. Each of these stages play an important role in both short-term and long-term memory, although it is believed they work differently depending on which memory is used.
As the term implies, short-term memory is used for items that need recall over short periods of time, sometimes as little as seconds. It is believed that short-term memories are encoded either visually or acoustically. Visual encoding is primary for recalling faces, places, and other visual experiences, while acoustic encoding is most important for verbal material. After looking up a number in a telephone book, for example, most people repeat the number to themselves several times before dialing the number. Rather than visualizing the written form of the numbers, the sound of the words becomes the means for recall. Experiments have demonstrated the importance of acoustic coding in the ability to recall lists of words or letters as well. When subjects were asked to recall a sequence of letters, those who made errors replaced the correct letter with a similarly sounding letter, for example "D" instead of "T."
Adequate operation of short-term memory is crucial when performing such everyday activities as reading or conversing. However, the capacity of short-term memory is quite limited. Studies have shown consistently that there is room in short-term memory for an average of seven items, plus or minus two (known as magic number seven). In experiments in which subjects are asked to recall a series of unrelated numbers or words, for example, some are able to recall nine and others only five, but most will recall seven words. As the list of things to be remembered increases, new items can displace previous items in the current list. Memory uses a process called "chunking" to increase the capacity of short-term memory. While most people still can use only seven "slots" of memory, facts or information can be grouped in meaningful ways to form a chunk of memory. These chunks of related items then act as one item within short-term memory.
Long-term memory contains information that has been stored for longer periods of time, ranging from a few minutes to a lifetime. When translating information for long-term memory, the brain uses meaning as a primary method for encoding. When attempting to recall a list of unrelated words, for instance, subjects often try to link the words in a sentence. The more the meaning of the information is elaborated, the more it will be recalled. Voices, odors, and tastes also are stored in long-term memory, which indicates that other means of encoding besides meaning, are also used. Items are regularly transferred back and forth from short-term to long-term memory. For example, rehearsing facts can transfer short-term memory into long-term. The chunking process in long-term memory can increase the capacity of short-term memory when various chunks of information are called upon to be used.
The breakdown in the retrieval of information from either memory can be the result of various factors, including interference, decay, or storage problems. In addition, researchers believe it is unlikely that all experiences or facts are stored in memory and thus are available for retrieval. Emotional factors, including anxiety, also contribute to memory failure in certain situations. Test anxiety , for example, may cause a student to forget factual information despite how well it has been learned. Amnesia , a partial or total loss of memory, may be caused by stroke, injury to the brain, surgery, alcohol dependence, encephalitis, and electroconvulsive therapy (ECT) .
Many methods can be used to improve memory. Long-term memory may be improved using mnemonic, or memory-aiding, systems. One, the "method of loci" system, encourages an association between various images and unrelated words. The "key word" method of learning a foreign language links the pronunciation of a new word with a picture that corresponds to the sound of the word. Context is another powerful memory aid that recognizes that people recall more easily facts or events
FALSE AND RECOVERED MEMORIES
As of the late 1990s, research into recovered memories was characterized by tremendous controversy. A leading researcher in this subject, Elizabeth Loftus, conducted studies on over 20,000 subjects, and pointed to evidence she felt was convincing that memory is both fragile and unreliable. Her work supported, the notion that eyewitness accounts of events are often inaccurate, and that false memories can be created through suggestion in approximately 25% of the population. Loftus's work calls into question the validity of memories that are recovered under coaching or questioning; such memories have provided the basis for countless lawsuits brought against adults who are accused of molesting children. Her research has shown that emotional state— either low points, such as boredom or sleepiness or high points, such as stress or trauma—decrease the reliability of memory. She has also shown that experiencing violent and traumatic events decreases the accuracy of memory. Loftus theorizes that memory is suggestible and deteriorates over time. In her classic study, known as "Lost in the Shopping Mall," she demonstrated that subjects—children and teenagers—could be induced to remember being lost in a mall at an early age, even though it never actually happened, by simply questioning them about it as if it had happened.
One of the problems with the recovery of repressed memories is the very process of recovery. Many individuals recover memories while in therapy, under hypnosis , or in some other situation where the possibility of suggestion is powerful. In the late 1990s, in response to the swelling controversy over recovered memories, the American Medical Association, American Psychiatric Association , and American Psychological Association all issued guidelines to help practitioners deal with reports of recovered memories, especially of sexual abuse during childhood . In general, most physicians, psychiatrists, and psychologists suggest that recovered memories be corroborated through external investigation, and that alternative explanations for the existence of the memories be considered before any legal action be taken based on them.
False memory syndrome is dividing the field of professional psychotherapy . Some psychotherapists believe that to question the interpretation of and belief in recovered memories is to undermine the possibility of the existence of repression; others see the challenge to recovered memories as a sign of society's refusal to confront a serious problem with child abuse and abuse of women. Others contend that there are no psychoanalytic theories to support forgetting of traumatic events, or their detailed recall after the passage of time.
more easily if they are placed in the same environment in which they learned them. For example, a person is more likely to recall specific memories from high school if they go to the school and retrace their paths.
Imposing a meaningful organization on an unrelated group of facts or words also improves memory. The EGBDF notes that represent the lines on a musical staff often are recalled using the sentence, "Every good boy does fine." The sentence has nothing to do with music; rather, it places a meaning on letters that, at first glance, seem random. Another notable mnemonic system, the PQRST method, is helpful in assisting students learn textbook material. The letters correspond to the five steps of the method: preview, question, read, self-recitation and test.
Questions of the reliability and fragility of memory have surrounded the controversy of false and recovered memory that surface under questioning primarily by psychotherapists. As lawsuits based upon recovered memory have been filed against adults accused of molesting children and in at least one case, the death of a childhood friend, recovered memories have come under scrutiny and questions raised about the validity, especially when memory has been recovered under coaching. Researcher Elizabeth Loftus, who conducted studies on 20,000 subjects, found that false memories could be created through suggestion in 25% of the population; eye witness accounts, she found, are often inaccurate. The emotional state of either low points, such as boredom or sleepiness or high points, such as stress or trauma, decrease the accuracy of memory, Loftus found. She theorizes that memory deteriorates over time and is vulnerable to suggestion. In one study, known as "Lost in the Shopping Mall," Loftus demonstrated that subjects, children and teenagers, could be induced to remember being lost in a mall at an early age by simply questioning them about the experience as if it happened.
In response to increasing controversy over recovered memories, the American Medical Association, American Psychiatric Association and American Psychological Association all issued guidelines to help practitioners deal with reports of recovered memories, especially of sexual abuse during childhood. Before any legal action is taken based on recovered memories, most physicians, psychiatrists, and psychologists suggest that recovered memories receive corroboration through external investigation and an alternative explanation for the existence of the memories be considered. The field of professional psychotherapy is divided on false memory syndrome. To question the interpretation of and belief in recovered memories undermines the possibility of the existence of repression, according to some psychotherapists; others see the challenge to recovered memories as coming from a refusal by society to confront a serious problem with child abuse and abuse of women. Yet others contend there are no psychoanalytic theories to support forgetting traumatic events or support their detailed recall after the passage of time.
See also Mnemonic strategies; Serial learning; Serial position function
Bartlett, Frederic C. Remembering: A Study in Experimental and Social Psychology New York: Cambridge University Press, 1995.
Damasio, Antonio. Descartes'Error: Emotion, Reason, and the Human Brain.. New York: G.P. Putnam, 1994.
Loftus, Elizabeth F. and Ketcham, Katherine. The Myth of Repressed Memory: False Memories and Allegations of Sexual Abuse. New York: St. Martin's Press, 1994.
Rubin, David C. Remembering Our Past: Studies in Autobiographical Memory. Cambridge University Press, 1996.
Schacter, Daniel L. Searching for Memory: The Brain, the Mind, and the Past. New York: Basic Books, 1996.
"Memory." Gale Encyclopedia of Psychology. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/memory-1
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If one views memory as the ability to retain and recall past states of consciousness, then psychoanalysis has played a considerable role in its delineation. But in terms of memory theory considered more broadly, its significance is much more modest. Freud approached memory from three perspectives. In terms of neurology, his contributions were original but limited. From the standpoint of psychology, he added to the pre-existing framework. Finally, in creating the psychoanalytic perspective, Freud essentially reworked views that had been extensively discussed in philosophy, literature, and scientific research.
In 1891 Freud's On Aphasia: A Critical Study (1891b) proposed a solution to the problem of memory retrieval and disorders of memory, which was much discussed at the end of the nineteenth century following the discoveries of Paul Broca. Freud did not take sides in the dispute between Broca, who localized language function to a specific cerebral area, and Carl Wernicke, who developed the functional concept of conduction aphasia. Freud's solution, which resembled the one that Henri Bergson adopted five years later in Matter and Memory, could serve as the basis for a dialogue between neurology and philosophy. But the 1891 text is a pre-psychoanalytic work.
Freud's second, psychological perspective finds him apparently subscribing to the theory of memory traces. Already expressed in its major outlines in Plato's Theatetus, this theory was commonplace in the nineteenth century, when the vogue for scientific materialism made it seem self-evident (although spiritualists also accepted it). In this sense Freud is close to his contemporary, Théodule Ribot, but for Freud the theory of memory traces assumed a specific form intended to account for the role the unconscious plays in remembering. This led to Freud's Project for a Scientific Psychology of 1895 (1950c ) and the best expression of the doctrine, in chapter 7 of The Interpretation of Dreams (1900a). The "Mystic Writing Pad" (1925a) represents an attempt to provide the theory of memory traces and process of memory retrieval with a metaphor suitable for psychoanalysis. But in these texts, Freud was concerned to place facts revealed by psychoanalysis within the framework of conventional psychological theory; he made no effort to create a new "theory of memory."
Much more familiar (and often wrongly considered as the specific psychoanalytic contribution to problems of memory) is the third perspective, involving the alleviation of pathological symptoms by recalling forgotten traumata. Freud himself did a great deal to promote this point of view through the significance he attached in numerous of his writings to Josef Breuer's treatment of Anna O. Too common is the impression that the famous formula "hysterics suffer mainly from reminiscences" (Studies on Hysteria, 1895d, p. 7) expresses the most fundamental idea in psychoanalysis.
There is no question that the idea of recollection constitutes an essential part of psychoanalytic therapy, and to think otherwise is to betray Freud in a fundamental way. Serge Viderman's claim in La Construction de l'espace analytique (1970) that the search for lost memories is one of Freud's youthful illusions to be replaced, in analysis, with co-constructions of subjectivity, is simply an attempt to employ non-analytic therapy, proposed in the past by such authors as Karen Horney. Until the end of his life Freud remained attached to this model: trauma / repression / forgetting / symptom / remembering / healing. In 1937, in "Analysis Terminable and Interminable," he went so far as to say that, like hysterics, psychotics also suffer from reminiscences, implying that certain delusional representations were, in fact, the reappearance in consciousness of past experiences unrecognized as such. Between Anna O. and this late text, Freud's entire body of work is sprinkled with thoughts along these lines. In "Remembering, Repeating and Working-Through" (1914g), for example, he resolved the conflict between impossible access to memory and the sterility of repetition through the introduction of what he called "working through" (Durcharbeitung ). Further proof is found in his "A Disturbance of Memory on the Acropolis" (1936a), in which Freud displaces the memory trauma (thinking the Acropolis did not exist) onto another type of fact (fear of surpassing the father). The "search for lost time," the attempt to alleviate repression that has produced a failure of memory and the associated symptom, is one of the major themes of Freudian psychoanalysis. However, reservations are in order regarding its originality and theoretical scope.
Even though Freud often felt that the cure for hysterical symptoms through recollection of repressed traumatic memories could be presented as a revolutionary discovery, such figures as Janet and other late nineteenth-century psychotherapists viewed the idea and even the method as commonplace. The idea can even be traced back much further. For example, in a letter to Pierre Chanut, dated June 6, 1647, René Descartes recounts that his penchant for girls with a squint came to an end with his recollection of a childhood memory. Descartes's interest in such women may not have been a true hysterical symptom, but the link between current behavior and its origin in the past is indicated along with all the characteristics (forgetting, unconsciousness, healing through remembrance) that Freud would later employ. Much earlier, Plato, in the Phaedrus, interpreted the process of falling in love in a similar manner. In short, there is no end to the number of literary, philosophical, and clinical sources for what is often considered the most significant psychoanalytic contribution to the theory of memory.
More plausibly, psychoanalysis lent to a certain type of amnesia and memory retrieval an unanticipated practical (therapeutic) scope. Its importance was practical. Although it constitutes an original theoretical point, it does not amount to a global theory such as those developed by philosophers and psychologists. However, it has a good fit with such theories. It works, for example, within the framework that Henri Bergson described and interpreted in Matter and Memory.
See also: Amnesia; Autohistorization; Character formation; Conscious processes; Day's residues; Deferred action; Dementia; Disavowal; Facilitation; Fantasy, formula of; Forgetting; Historical reality; History and psychoanalysis; Memory; Mnemic trace/memory trace; "Project for a Scientific Psychology, A"; Psychology and psychoanalysis; "Recommendations to Physicians Practicing Psychoanalysis"; Remembering; "Remembering, Repeating and Working-Through"; Reminiscence.
Bergson, Henri. (1896). Matter and memory. New York: Zone Books, 1988.
Freud, Sigmund. (1891b). On aphasia; A critical study. New York: International Universities Press, 1953.
——. (1900a). The interpretation of dreams. Part I, SE,4: 1-338; Part II, SE, 5; 339-625.
——. (1914g). Remembering, repeating and working-through (Further recommendations on the technique of psycho-analysis II). SE, 12: 145-156.
——. (1925a). A note upon the "mystic writing pad." SE, 19: 225-232.
——. (1936a). A disturbance of memory on the Acropolis. SE, 22: 239-248
——. (1937c). Analysis terminable and interminable. SE, 23: 209-253
"Memory." International Dictionary of Psychoanalysis. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/psychology/dictionaries-thesauruses-pictures-and-press-releases/memory
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The term "memory" is used to describe the computer's electronic circuitry that holds data and program instructions. It can be thought of as the computer's workspace and it determines the size and number of programs that can be run at the same time, as well as the amount of data that can be processed. Memory is sometimes referred to as primary storage, primary memory, main storage, main memory, internal storage, or random access memory (RAM). There are four major types of computer memory: random access memory, read only memory, CMOS memory, and virtual memory.
Random Access Memory (RAM)
When most people think of computer memory, random access memory (RAM) is what they mean. RAM is composed of chips. These chips can hold:
- data for processing;
- instructions, or programs, for processing the data;
- data that has been processed and is waiting to be sent to an output, secondary storage, or communications device;
- operating system instructions that control the basic functions of the computer system.
All data and instructions held in RAM are temporary. The contents can and do change as data are processed, programs are run, and instructions are carried out by the computer. RAM is a reusable computer resource.
Most RAM is said to be volatile . This means that when the power to the computer is turned off, or the power goes out, all contents of RAM instantaneously disappear and are permanently lost. Because RAM is temporary and volatile, other forms of more permanent storage were developed. Secondary storage is long term, non-volatile storage of data or programs outside the central processing unit (CPU) and RAM. Some of the more common types of secondary storage include magnetic tape, magnetic disk, and optical disk.
The storage capacity of RAM varies in different types of computers. Capacity is important because it determines how much data can be processed at once and how large and complex a program may be. The computer's operating system manages RAM so that programs run properly. To understand the capacity of RAM, the following terms are used:
- Bit—a binary digit representing the smallest unit of data in the computer system. A bit can be only a 1 or a 0. In the computer, a 0 means that an electronic or magnetic signal is absent, while a 1 signifies its presence;
- Byte—a group of eight bits. A byte represents one character, one digit, or one value. The capacity of the computer's memory, RAM, is expressed in bytes or in multiples of bytes.
Data, instructions, and programs stored in RAM are really stored as bits that represent those data, instructions, and programs. These bits are stored in microscopic electronic parts called capacitors .
Read Only Memory
Read Only Memory (ROM) is a set of chips that contain portions of the operating system that are needed to start the computer. ROM is also known as firmware. ROM cannot be written to or altered by a user. It is nonvolatile memory. ROM chips come from the manufacturer with programs or instructions already stored and the only way to change their contents is to remove them from the computer and replace them with another set. ROM
|COMPUTER GENERATION||MACHINE TYPE AND CAPACITY|
|First Generation (1946 - 1956) Vacuum Tubes||MAINFRAME||2000 bytes (2KB)|
|Second Generation (1957 - 1963) Transistors||MAINFRAME||UP TO 32 KB|
|Third Generation (1964 - 1979) Integrated Circuits||SUPERCOMPUTER|
|MAINFRAME||UP TO 2 MB|
|Fourth Generation (1980 - present) Very Large||SUPERCOMPUTER|
|Scale Integrated Circuits||MAINFRAME||OVER 2 GB|
|MICRO||2 K - OVER 128 MB|
chips can contain frequently used programs, such as computing routines for calculating the square root of numbers.
The most common use for ROM chips is the storage of manufacturer-specific programming such as the Basic Input Output System (BIOS). The BIOS is a critical part of the operating system that tells the computer how to access the disk drives. When the computer is started, RAM is empty and the instructions in the ROM BIOS are used by the CPU to search the disk drives for the main operating system files. The computer then loads these files into RAM and uses them.
There are three variations of ROM.
- PROM, or programmable read only memory. PROM chips are blank chips on which programs can be written using special equipment. PROM chips can be programmed once and are usually used by manufacturers as control devices in their products.
- EPROM, or erasable programmable read only memory. EPROM is similar to PROM, but the program can be erased and a new program written by using special equipment that uses ultraviolet light. EPROM is used for controlling devices such as robots.
- EEPROM, electronic erasable programmable read only memory. EEPROM chips can be reprogrammed using special electric impulses. They do not need to be removed to be changed.
CMOS (pronounced SEE MOSS) stands for "complementary metal oxide semiconductor." It is a specialized memory that contains semi-permanent vital data about the computer system's configuration. Without this data, the computer would not be able to start. CMOS is more permanent than RAM and less permanent than ROM. CMOS requires very little power to retain its contents; the chip is powered by a battery. When a change is needed in the computer system's configuration (i.e., a new hard drive is installed, more RAM is added, or the number of floppy disk drives is changed), CMOS can be updated by running a special utility program available through the operating system.
Virtual memory is a storage method where portions of a program or data are stored on magnetic disk rather than in RAM until needed, giving the illusion that main memory is unlimited. Virtual memory simulates RAM. It allows the computer to run more than one program at a time, manipulate large data files, and run large programs without having sufficient RAM. Virtual storage is slower than RAM, and is nonvolatile.
How Data and Programs Are Stored in Memory
Computer main memory can be thought of as a two-dimensional table where each cell has a unique address. See Figure 1. Each cell can store one byte of data by using eight capacitors to represent the eight bits in a byte.
see also Binary Number System; Integrated Circuits; Microchip; Transistors; Vacuum Tubes.
Charles R. Woratschek
Hutchinson, Sarah E., and Stacey C. Sawyer. Computers, Communications, and Information: A User's Introduction, Comprehensive Version, 7th ed. Boston: Irwin McGraw-Hill, 2000.
Laudon, Kenneth C., and Jane Price Laudon. Essentials of Management Information Systems: Transforming Business and Management, 3rd ed. Upper Saddle River, NJ: Prentice Hall, Inc., 1999.
Long, Larry, and Nancy Long. Computers: Brief Edition, 3rd ed. Upper Saddle River, NJ: Prentice Hall, Inc., 1999.
Parsons, June Jamrich, and Dan Oja. New Perspectives on Computer Concepts, 3rd ed. Cambridge: Course Technology, 1998.
"Memory." Computer Sciences. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/computing/news-wires-white-papers-and-books/memory
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memory (in psychology)
memory, in psychology, the storing of learned information, and the ability to recall that which has been stored. It has been hypothesized that three processes occur in remembering: perception and registering of a stimulus; temporary maintenance of the perception, or short-term memory; and lasting storage of the perception, or long-term memory. Two major recognized types of long-term memory are procedural memory, involving the recall of learned skills, and declarative memory, the remembrance of specific stimuli. For long-term memory to occur, there must be a period of information consolidation.
The process of forgetting was first studied scientifically by Hermann Ebbinghaus, a German experimental psychologist, who performed memory tests with groups of nonsense syllables (disconnected syllables without associative connection). Ebbinghaus showed that the rate of forgetting is greatest at first, gradually diminishing until a relatively constant level of retained information is reached. Theories to explain forgetting include the concept of disuse, which proposes that forgetting occurs because stored information is not used, and that of interference, which suggests that old information interferes with information learned later and new information interferes with previously learned information.
In some instances, memory loss is an organic, physiological process. Retrograde amnesia, i.e., the failure to remember events preceding a head injury, is evidence of interrupted consolidation of memory. In anterograde amnesia, events occurring after brain damage—e.g., in head injury or alcoholism—may be forgotten. Memory loss may also result from brain cell deterioration following a series of strokes, cardiovascular disease, or Alzheimer's disease (see dementia).
Physiologically, learning involves modification of neural pathways. PET scans and related studies have shown certain parts of the brain, such as the frontal lobe of the cerebral cortex and a structure called the hippocampus, to be particularly active in recall. Computer models of brain memory are called neural networks. In a study using genetic manipulation, a mouse with enhanced memory capabilities has been produced.
See M. H. Ashcroft, Human Memory and Cognition (1989, repr. 1994); N. Cowan, Attention and Memory (1995, repr. 1998); J. McConkey, ed. The Anatomy of Memory (1996); D. L. Schacter, Searching for Memory (1996) and The Seven Sins of Memory (2001); J. A. Groegerd, Memory and Remembering (1997); A. Baddeley, Human Memory (rev. ed. 1998); R. Rupp, Committed to Memory (1998).
"memory (in psychology)." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/memory-psychology
"memory (in psychology)." The Columbia Encyclopedia, 6th ed.. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/memory-psychology
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mem·o·ry / ˈmem(ə)rē/ • n. (pl. -ries) 1. a person's power to remember things: I've a great memory for faces my grandmother is losing her memory. ∎ the power of the mind to remember things: the brain regions responsible for memory. ∎ the mind regarded as a store of things remembered: he searched his memory frantically for an answer. ∎ the capacity of a substance to return to a previous state or condition after having been altered or deformed. See also shape memory. 2. something remembered from the past; a recollection: one of my earliest memories is of sitting on his knee | the mind can bury all memory of traumatic abuse. ∎ the remembering or recollection of a dead person, esp. one who was popular or respected: clubs devoted to the memory of Sherlock Holmes. ∎ the length of time over which people continue to remember a person or event: the worst slump in recent memory. 3. the part of a computer in which data or program instructions can be stored for retrieval. ∎ capacity for storing information in this way: the module provides 16Mb of memory. PHRASES: from memory without reading or referring to notes: each child was required to recite a verse from memory. in memory of intended to remind people of, esp. to honor a dead person. take a trip (or walk) down memory lane deliberately recall pleasant or sentimental memories.
"memory." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/memory-1
"memory." The Oxford Pocket Dictionary of Current English. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/memory-1
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- Aethalides herald of the Argonauts; had perfect memory. [Gk. Myth.: Kravitz, 11]
- Balderstone, Thomas knew all of Shakespeare by heart. [Br. Lit.: Sketches by Boz ]
- Eunoe river whose water sparks remembrance of kindnesses. [Ital. Lit.: Purgatory, 33]
- Fahrenheit 451 in a future America where books are prohibited, a group of people memorize texts in order to preserve their content. [Am. Lit.: Bradbury Fahrenheit 451 in Weiss, 289]
- madeleine cookie that awakened the stream of Marcel’s recollections. [Fr. Lit.: Proust Remembrance of Things Past ]
- Memory, Mr. during his stage performance his feats of memory enable him to signal clues to a man trying to thwart England’s enemies. [Eng. Cinema: The 39 Steps ]
- Mneme Boeotian wellspring which whetted the memory. [Gk. Myth.; Wheeler, 713]
- Mnemosyne goddess of memory; mother of Muses. [Gk. Myth.: Espy, 20]
- Munin one of Odin’s ravens; regarded as embodying memory. [Norse Myth.: Leach, 761]
Mercy (See FORGIVENESS .)
"Memory." Allusions--Cultural, Literary, Biblical, and Historical: A Thematic Dictionary. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/memory
"Memory." Allusions--Cultural, Literary, Biblical, and Historical: A Thematic Dictionary. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/memory
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- a loss or lack of memory. —amnesiac , n. —amnesie , adj.
- 1. a reminiscence.
- 2. (cap.) the section of Christian liturgies rehearsing the sacriflee of Christ and ending “Do this in remembrance of me.” —anamnestic , adj.
- the occurrence in consciousness of images not recognized as produced by the memory and its storage of events and scènes. —cryptomnesic , adj.
- déjà vu
- Psychology. the illusion of having previously experienced something actually being encountered for the first time.
- memoria technica
- any mnemonic device or aidememoire, especially a technical device.
- the process or technique of improving, assisting, or developing the memory. Also called mnemotechnics . —mnemonic , adj.
- the belief that every mental impression remains in the memory.
- Psychiatry. a distortion of memory in which fact and fancy are confused.
"Memory." -Ologies and -Isms. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/memory-0
"Memory." -Ologies and -Isms. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/memory-0
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Memory is the ability to remember and to recall previous sensations, ideas, experiences, or information that has been consciously learned.
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It is hard to imagine what it would be like to live without memory. What if the things that people had just seen, learned, or heard simply passed out of their minds after just a few minutes? So many of the activities of daily life, such as reading a book, watching a movie, doing homework, holding a conversation, making friends, and going to the store, would be totally impossible. People, places, and events would always seem brand-new, even if they had been experienced before. Living without memory would mean always having to exist in the present moment with no awareness of the past.
This may sound like a science fiction movie, but it actually happened. In 1953, a 27-year-old man, now known by the initials “H.M.,” underwent brain surgery for his severe epilepsy*, a nervous system disorder that caused him to have daily seizures. The surgeons removed his hippocampi*, which are two parts of the lower brain, and portions of his temporal lobes*, which are the side parts of the cortex*. Doctors believed that these areas were diseased and causing H.M.’s severe symptoms. (Today, most cases of epilepsy can be controlled with medication, although sometimes surgery still is required.)
- * epilepsy
- (EP-i-lep-see) is a disorder of the nervous system characterized by repeated seizures that temporarily affect a person’s awareness, movements, or sensations.
- * hippocampi
- (HIP-o-KAM-pie) are two parts of the lower brain that together look like a small pair of ram’s horns.
- * temporal (TEM-por-al) lobes
- are the side portions of the cortex. They contain the sensory center for hearing and are centers for language function.
- * cortex
- (KOR-teks) is the top outer layer of the brain. It controls the brain’s higher functions, such as thinking, learning, and personality.
H.M. was cured, but with tragic results: He could no longer remember anything for more than a few minutes. He could remember events that happened more than 2 years before the operation, but new experiences or facts were quickly forgotten. In the more than 40 years that psychologists worked with H.M., his situation did not improve. He could remember a set of numbers or a new fact for a short while, but he would forget it as soon as he was distracted or new information was added. In fact, researchers had to reintroduce themselves every time they met with H.M., constantly reminding him where he was and why he was there. H.M. once said, “Every day is alone by itself,” meaning that he could never make sense of today in terms of yesterday. He experienced time in separate chunks that were quickly erased from his mind.
However, H.M. could still learn parts of new motor skills or routines and repeat them at a later time, even though he did not remember that he had learned them. For example, he gradually learned how to draw an image in a mirror, solve puzzles, and mount cigarette lighters on a cardboard display. H.M.’s remarkable case illustrates the fact that there are different types of memory that involve different parts of the brain.
Memory is generally divided into two broad categories: short-term and long-term.
Short-term memory is what a person uses for an activity such as remembering a new phone number after calling directory assistance. The person may repeat the number silently until dialing it, then promptly forget it. If distracted before dialing, the person may have to call directory assistance again. That is because short-term memory is fairly easily disrupted. Think about how students have to study new material in order to learn it, rather than just see it one time. Basically, they are converting the information from unstable short-term memory into more stable long-term memory by attending to it and rehearsing it.
Research has linked memory to the amygdala and to the hippocampus, two structures deep inside the brain. When surgeons removed the hippocampus from a patient known by the initials H.M., hoping to treat his epilepsy, they discovered that H.M.’s epilepsy improved but his short-term memory disappeared. H.M. could remember events that happened many years before, but not events of the previous day or the previous hour. H.M.’s doctors had to reintroduce themselves to him every single day.
People who experience severe head injury demonstrate how easily the process of short-term memory can be interrupted. For example, a car accident victim may not recall what happened just before impact or even during the accident itself. Some athletes who are knocked unconscious during an especially physical play may not remember what happened minutes before they were hit. This is because there was not enough time for experiences to be converted from short-term to long-term memory.
Long-term memory, which is much more permanent and stable, can be further subdivided into two types: implicit and explicit. Implicit memory, or procedural memory, is the ability to repeat automatic tasks or procedures, such as riding a bike, driving a car, typing, or swinging a tennis racket. Of course, these tasks are not automatic at first; just ask any sixteen-year-old who is learning to drive. Over time, though, a person can perform the skill without giving it much thought. Explicit memory is recall for facts or events. This is what comes into play when taking a test, for example, or remembering someone’s name. The patient known as H.M. lost the ability to turn new experiences into explicit memory but retained much of his procedural or implicit memory. Implicit memory appears to be controlled not by the hippocampus but by other parts of the brain.
Thanks to H.M. and other patients who have had diseases affecting the hippocampus, scientists who study the brain now know that this structure and the nearby temporal lobes play a crucial role in turning what people hear, see, and experience into long-term memories. A Canadian neurosurgeon named Wilder Penfield also had a key part in identifying the importance of the temporal lobes in long-term memory. In the 1930s, while performing brain surgery on patients with epilepsy, Dr. Penfield used an electrical probe to stimulate different parts of the brain. Because the brain itself does not feel pain, the patients could remain awake during surgery. Dr. Penfield found that some patients experienced vivid events or scenes from their lives when he stimulated the temporal lobes. The memories were so vivid, in fact, that the patients thought they were actually reliving the experiences. Thus, 20 years before H.M. came on the scene, Dr. Penfield concluded that this part of the brain had a critical role in long-term memory.
Unable to Forget
Writing things down is an important part of the learning process for most people, whether it is to remember phone numbers and addresses, homework assignments, directions, or the teacher’s lecture in class. But what if you had a memory so powerful that, when you encountered new information, you couldn’t make yourself forget it? Such was the case with S., a man with a memory like a trap: whatever he came across, he could remember for life— and without writing down a thing.
S.’s unusual ability was discovered during his days working as a newspaper reporter, when he never took any notes at news briefings. When his boss became concerned, S recited back to him the briefing, word for word. S went on to work with a psychologist intrigued by his ability, and also became a mnemonist, or a person who demonstrates his extraordinary memory to an audience.
S. had a unique way of remembering that allowed him to experience information through several sensations, such as sound, touch, or taste. He envisioned numbers as forms, for example the number 6 as a man with a swollen foot, and the number 7 as a man with a mustache. Numbers also had textures and colors: the number 2 was a gray-white, and the number 8 a milky blue-green. These personal visualizations are what enabled him to absorb and store data with such extraordinary speed and permanence. After years of memorizing lists, tables, and other tests, S. could always recall anything he had ever learned. It seemed his ability was limitless.
In fact S. tried to invent ways to forget what he learned. It seemed that S. did not really have a short term memory, so he did not experience the usual memory decay. Everything he learned was put into long term memory which is a relatively limitless and permanent storage capacity. Did S. even remember how to forget?
Today scientists know that other parts of the brain are important to the memory process as well. The thalamus (THAL-a-mus), a structure in the middle of the brain, relays incoming information from our senses to the cortex. These structures together with the hippocampus coordinate facts with their appropriate time and space context to ensure that an event is remembered as a unique happening. In other words, today’s breakfast is remembered as distinct from other breakfasts in the past.
A person’s emotions affect the process of memory, too. Experiences that make people feel happiness, sadness, or some other strong emotion are more likely to be remembered. For example, most people over the age of 50 can remember exactly where they were and what they were doing when President John F. Kennedy was shot in 1963. Scientists believe that the function of the hippocampus is somehow linked to that of the nearby structures that are involved in controlling a person’s emotional responses.
Where do long-term memories go once formed, and how does a person retrieve them? Scientists believe that the entire cortex is involved in long-term memory, but exactly what happens to make or keep these memories is unclear. What is clear is that memories are not exact “videotapes” of an experience. Rather, memories are constructions that are filtered through a person’s individual mental abilities and past experiences. Thus, two people seeing the same crime, for example, might remember the events somewhat differently. As a result, when people swear to tell the truth in court, it is only the truth that they have constructed from their memory, not literally “the whole truth and nothing but the truth.”
Many researchers believe that short-term memories are the result of ongoing activity by brain cells, while long-term memories actually reflect structural changes in the brain. Basically, long-term memories are thought to be the formation of new connections from cell to cell in the cortex. Eric Kandel, who won the Nobel Prize in Physiology or Medicine in 2000, has found evidence to support this theory in what might seem like the strangest of places: the sea slug.
Neuroscientist Eric Kandel received the Nobel Prize for Medicine in 2000. His research showed that learning and memory affect organisms on a cellular level, permanently changing individual neurons. This may help explain why counseling and therapy, even without medication, can help people change mentally, emotionally, and even physically. AFP/Corbis
Because the sea slug has a very simple nervous system, with large nerve cells distributed up and down its body, it is much easier to study than a human. If the slug is touched, it reacts in self-defense by withdrawing its gill. Dr. Kandel found that, if he repeatedly pricked the slug’s head or tail for a few days, it would withdraw the gill more quickly and sharply. This heightened reaction would occur even when the slug was touched again at a later date. It was almost as if the slug remembered what had happened to it before and reacted accordingly. Dr. Kandel was able to show that there were actually chemical and structural changes in the synapses (SIN-ap-siz), or connections, between the nerve cells that sense touch and the nerve cells that control motion. More neurotransmitters (noor-o-TRANS-mit-erz), or message-carrying chemicals, were released between these nerve cells, and the connections between them were chemically strengthened.
This is a very simple explanation of just one part of Dr. Kandel’s research, but it is enough to show why this work is so important. Now that scientists understand how nerve cells communicate in sea slugs to form memories, they may be able to use this information to better understand how the human brain forms memories.
Greenfield, Susan A. The Human Brain: A Guided Tour. New York: Basic Books, 1997. Dr. Greenfield, a professor who lives in Oxford, England, is well-known for her ability to explain scientific concepts in ways that most people can understand.
Kandel, Eric, and Larry Squire. Memory: From Mind to Molecules. New York: Scientific American Library, 2000. The authors are two of the scientists at the forefront of memory research. Their book explains some of the most important concepts of how memory works and what can go wrong.
Memory Disorders Project at Rutgers University–Newark. This project involves neuroscientists, psychologists, and other researchers at Rutgers University in New Jersey who are studying how the human brain creates and stores memories. The website features easy-to-understand information about memory and memory disorders. http://www.memory.rutgers.edu
Exploratorium, The Museum of Science, Art, and Perception: Memory Exhibition. From 1998 to 1999, this famous museum in San Francisco, California, hosted an exhibition devoted to the subject of memory. An interactive web version includes games and activities that encourage users to test their memory and even improve it. http://www.exploratorium.edu/memory
Neuroscience for Kids. This website by a professor at the University of Washington features kid-friendly information about the brain and nervous system, including the functions of learning and memory. http://faculty.washington.edu/chudler/neurok.html
"Memory." Complete Human Diseases and Conditions. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/memory-0
"Memory." Complete Human Diseases and Conditions. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/memory-0
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"memory." World Encyclopedia. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/memory
"memory." World Encyclopedia. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/memory
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"memory." A Dictionary of Biology. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/memory-1
"memory." A Dictionary of Biology. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/memory-1
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"memory." A Dictionary of Computing. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/memory
"memory." A Dictionary of Computing. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/memory
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See also false memory, a liar ought to have a good memory.
"memory." The Oxford Dictionary of Phrase and Fable. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/memory
"memory." The Oxford Dictionary of Phrase and Fable. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/memory
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"memory." A Dictionary of Ecology. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/memory
"memory." A Dictionary of Ecology. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/memory
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"memory." A Dictionary of Zoology. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/memory-0
"memory." A Dictionary of Zoology. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/memory-0
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memory (in computing)
memory, in computing: see computer.
"memory (in computing)." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/memory-computing
"memory (in computing)." The Columbia Encyclopedia, 6th ed.. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/memory-computing
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"memory." Oxford Dictionary of Rhymes. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/memory-0
"memory." Oxford Dictionary of Rhymes. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/memory-0