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Abstract
This chapter introduces the different types of memory and models for how memory is thought to function. It considers the evidence base for short‐term memory, working memory, the different types of long‐term memory and memory processes. The chapter explores specific memory processes: registration, retention, retrieval, levels of processing and schema theory. It also considers the different modalities for short‐term memory (e.g. verbal and visual STM) and then develops this understanding into a working memory system. The chapter examines the main subdivisions of long‐term memory: declarative (explicit) and non‐declarative (procedural or implicit) memory. Finally, it focuses on the assessment of and treatment options for memory deficits. There are a range of standardised assessment tools for memory, including the Rivermead Behavioural Memory Test‐3, Doors and People, and the Wechsler Memory Test ‐ WMS‐V. Interventions tend to focus on compensatory strategies to aid function.
Working memory can be divided into separate subsystems for verbal and visual information. Although the verbal system has been well characterized, the storage capacity of visual working memory has not yet been established for simple features or for conjunctions of features. The authors demonstrate that it is possible to retain information about only 3-4 colors or orientations in visual working memory at one time. Observers are also able to retain both the color and the orientation of 3-4 objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing many individual features to be retained when distributed across a small number of objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features.
Conducted 10 experiments to evaluate the notion of "depth of processing" in human memory. Undergraduate Ss were asked questions concerning the physical, phonemic, or semantic characteristics of a long series of words; this initial question phase was followed by an unexpected retention test for the words. It was hypothesized that "deeper" (semantic) questions would take longer to answer and be associated with higher retention of the target words. These ideas were confirmed by the 1st 4 experiments. Exps V-X showed (a) it is the qualitative nature of a word's encoding which determines retention, not processing time as such; and (b) retention of words given positive and negative decisions was equalized when the encoding questions were equally salient or congruous for both types of decision. While "depth" (the qualitative nature of the encoding) serves a useful descriptive purpose, results are better described in terms of the degree of elaboration of the encoded trace. Finally, results have implications for an analysis of learning in terms of its constituent encoding operations. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Recent changes in pretheoretical orientation toward problems of human memory have brought with them a concern with retrieval processes, and a number of early versions of theories of retrieval have been constructed. This paper describes and evaluates explanations offered by these theories to account for the effect of extralist cuing, facilitation of recall of list items by non-list items. Experiments designed to test the currently most popular theory of retrieval, the generation-recognition theory, yielded results incompatible not only with generation-recognition models, but most other theories as well: under certain conditions subjects consistently failed to recognize many recallable list words. Several tentative explanations of this phenomenon of recognition failure were subsumed under the encoding specificity principle according to which the memory trace of an event and hence the properties of effective retrieval cue are determined by the specific encoding operations performed by the system on the input stimuli. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This paper briefly reviews the evidence for multistore theories of memory and points out some difficulties with the approach. An alternative framework for human memory research is then outlined in terms of depth or levels of processing. Some current data and arguments are reexamined in the light of this alternative framework and implications for further research considered.
People with neurological disorders often report difficulty with prospective memory (PM), that is, remembering to do things they had intended to do. This paper briefly reviews the literature regarding the neuropsychology of PM function, concluding that from the clinical perspective, PM is best considered in terms of its separable but interacting mnemonic and executive components. Next, the strengths and limitations in the current clinical assessment of PM, including the assessment of component processes, desktop analogues of PM tasks, and naturalistic PM tasks, are outlined. The evidence base for the rehabilitation of PM is then considered, focusing on retraining PM, using retrospective memory strategies, problem-solving training, and finally, electronic memory aids. It is proposed that further research should focus on establishing the predictive validity of PM assessment, and refining promising rehabilitation techniques.
During the past two centuries, the study of learning and memory has been central to three disciplines: first philosophy, then psychology, and now biology. Biological inquiry began in earnest during the latter part of the 20th century, as technological advances made it feasible to move beyond
Tested 2 implications of F. C. Bartlett's (1932) theory of memory: (a) that prose passages are stored in schematic form and (b) that thematic assimilation increases with the passage of time. In 2 experiments a total of 336 college students read brief biographical passages about either a famous or a fictitious person (e.g., Adolph Hitler vs Gerald Martin). Recognition memory for individual sentences was tested after intervals of either 5 min or 1 wk. As expected, passages with a famous main character yielded more false positive errors. In addition, the errors in this condition depended on the thematic relatedness of the recognition foil. The further prediction on thematic assimilation was also upheld-thematic effects were relatively greater at the longer retention interval.
A patient with Korsakoff's syndrome is presented, who showed a selective loss of Autobiographical Memory along with a preserved Semantic Memory. Confabulations were a prominent feature. They only involved Autobiographical Memory and were persistent in time and consistent in content. The implications of these findings for understanding the nature of Autobiographical Memory impairment are discussed.
A 44-year-old woman showed, following an episode of encephalitis, an impoverished knowledge of the meaning and attributes of words and their referents, in spite of intact command of grammatical-syntactic rules and preserved perceptual abilities. There was also a complete loss of the stock of notions she had acquired over her life and constituting the cultural background of a person, in contrast with normal memory for autobiographic events. The case is interpreted as an instance of semantic amnesia. MRI showed damage confined to the antero-medial part of the left temporal lobe.
This article provides a critical review of the empirical literature on the role of depression and elation in biasing mnemonic processing. Two classes of effects—state dependence and mood congruence—are examined. The latter, which involves the enhanced encoding and/or retrieval of material the affective valence of which is congruent with ongoing mood, is the more extensively researched of the two and is thus the focus of much of the present review. Though the support for claims of such a phenomenon is impressive in its size, consistency, and diversity, a number of questions remain. These include whether such effects are linked to mood states per se, and the possible role that such effects may play in the development of persistent depression.
Subjects were asked to walk to targets that were up to 21 m away, either with vision excluded during walking or under normal visual control. Over the entire range, subjects were accurate whether or not vision was available as long as no more than approximately 8 sec elapsed between closing the eyes and reaching the target. If more than 8 sec elapsed, (a) this had no influence on distances up to 5 m, but (b) distances between 6-21 m were severely impaired. The results are interpreted to mean that two mechanisms are involved in guidance. Up to 5 m, motor programs of relatively long duration can be formulated and used to control activity. Over greater distances, subjects internalized information about the environment in a more general form, independently of any particular set of motor instructions, and used this to control activity and formulate new motor programs. Experiments in support of this interpretation are presented.
By repeating words 'in our head', verbal material (such as telephone numbers) can be kept in working memory almost indefinitely. This 'articulatory loop' includes a subvocal rehearsal system and a phonological store. Little is known about neural correlates of this model of verbal short-term memory. We therefore measured regional cerebral blood flow, an index of neuronal activity, in volunteers performing a task engaging both components of the articulatory loop (short-term memory for letters) and a task which engages only the subvocal rehearsal system (rhyming judgement for letters). Stimuli were presented visually and the subjects did not speak. We report here that comparisons of distribution of cerebral blood flow in these conditions localized the phonological store to the left supramarginal gyrus whereas the subvocal rehearsal system was associated with Broca's area. This is, to our knowledge, the first demonstration of the normal anatomy of the components of the 'articulatory loop'.
The concept of working memory is central to theories of human cognition because working memory is essential to such human skills as language comprehension and deductive reasoning. Working memory is thought to be composed of two parts, a set of buffers that temporarily store information in either a phonological or visuospatial form, and a central executive responsible for various computations such as mental arithmetic. Although most data on working memory come from behavioural studies of normal and brain-injured humans, there is evidence about its physiological basis from invasive studies of monkeys. Here we report positron emission tomography (PET) studies of regional cerebral blood flow in normal humans that reveal activation in right-hemisphere prefrontal, occipital, parietal and premotor cortices accompanying spatial working memory processes. These results begin to uncover the circuitry of a working memory system in humans.
Three experiments investigated the role of working memory in various aspects of thinking in chess. Experiment 1 examined the immediate memory for briefly presented chess positions from master games in players from a wide range of abilities, following the imposition of various secondary tasks designed to block separate components of working memory. Suppression of the articulatory loop (by preventing subvocal rehearsal) had no effect on measures of recall, whereas blocking the visuospatial sketchpad (by manipulation of a keypad) and blocking the central executive (by random letter generation) had equivalent disruptive effects, in comparison with a control condition. Experiment 2 investigated the effects of similar secondary tasks on the solution (i.e., move selection) of tactical chess positions, and a similar pattern was found, except that blocking the central executive was much more disruptive than in Experiment 1. Experiment 3 compared performance on two types of primary task, one concerned with solving chess positions as in Experiment 2, and the other a sentence-rearrangement task. The secondary tasks in each case were both designed to block the central executive, but one was verbal (vocal generation of random numbers), while the other was spatial in nature (random generation of keypresses). Performance of the spatial secondary task was affected to a greater extent by the chess primary task than by the verbal primary task, whereas there were no differential effects on these secondary tasks by the verbal primary task. In none of the three experiments were there any differential effects between weak and strong players. These results are interpreted in the context of the working-memory model and previous theories of the nature of cognition in chess.
Functional imaging to date has examined the neural basis of knowledge of spatial layouts of large-scale environments typically in the context of episodic memory with specific spatiotemporal references. Much human behavior, however, takes place in very familiar environments in which knowledge of spatial layouts has entered the domain of general facts often referred to as semantic memory. In this study, positron emission tomography (PET) was used to examine the neural substrates of topographical memory retrieval in licensed London taxi drivers of many years experience while they recalled complex routes around the city. Compared with baseline and other nontopographical memory tasks, this resulted in activation of a network of brain regions, including the right hippocampus. Recall of famous landmarks for which subjects had no knowledge of their location within a spatial framework activated similar regions, except for the right hippocampus. This suggests that the hippocampus is involved in the processing of spatial layouts established over long time courses. The involvement of similar brain areas in routes and landmarks memory indicates that the topographical memory system may be primed to respond to any relevant topographical stimulation; however, the right hippocampus is recruited specifically for navigation in large-scale spatial environments. In contrast, nontopographical semantic memory retrieval involved the left inferior frontal gyrus, with no change in activity in medial temporal regions.
Neuropsychological assessment of older individuals with dementing illnesses has suffered from a lack of appropriately designed test instruments. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was developed for the dual purposes of identifying and characterizing abnormal cognitive decline in the older adult and as a neuropsychological screening battery for younger patients. The entire battery takes less than 30 minutes to administer, and yields scaled scores for five cognitive domains. The current study reports preliminary clinical validity results with the RBANS, comparing very mildly demented patients with a diagnosis of probable Alzheimer's disease (n = 20) to patients with Huntington's disease (n = 20) and normal controls (n = 40). Although the patient groups had essentially identical total scores on the RBANS, they exhibited opposite profiles, differing significantly on four of the five subsections. The AD patients performed most poorly on Language, and Delayed Memory subsections, while the HD patients obtained their lowest scaled scores on the Attention and the Visuospatial/Constructional subsections. These results are consistent with the neuropsychological profiles of these dementing disorders derived from lengthier standardized tests and experimental investigations. In addition, even those patients who performed above the suggested cut-off points on the MMSE and the Dementia Rating Scale scored significantly below their controls on the RBANS. These data suggest that the RBANS is effective at both detecting and characterizing dementia of different etiologies.
Working memory can be divided into separate subsystems for verbal and visual information. Although the verbal system has been well characterized, the storage capacity of visual working memory has not yet been established for simple features or for conjunctions of features. The authors demonstrate that it is possible to retain information about only 3-4 colors or orientations in visual working memory at one time. Observers are also able to retain both the color and the orientation of 3-4 objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing many individual features to be retained when distributed across a small number of objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features.
Alzheimer's disease can be thought of as a multi-faceted neuropsychological disorder, with diverse impairments in cognitive abilities, such as attention, memory, language and executive functioning. Over the last decade cognitive neuropsychology has provided a far richer understanding of these impairments, and this book describes these advances, placing them in their clinical context. The first section deals with background theoretical and clinical issues, such as the extent to which Alzheimer's disease can be considered as a single entity or whether it is more fruitful to explore the neuropsychology of individual patients. It considers the diagnostic aspects of Alzheimer's disease, the natural history of the disease, how it progresses over time and the characteristics of the prodromal phase. A second section, the core of the book, covers major cognitive functions and delineates how impairments can be differentiated from each other. A third portion integrates what is known about cognitive decline with the underlying neurobiological basis, including pathological structural brain abnormality and neuropharmacological changes. The final section explores the clinical implications of the research with an overview of the neuropsychological assessment of this disease, cognitive approaches to management, and neurobiological treatment. As an introduction to this field, The Cognitive Neuropsychology of Alzheimer's Disease brings together the opinion of leading researchers in a book that will provide a useful source of information for neurologists, neuropsychologists, psychiatrists and neuroscientists who wish to broaden their knowledge concerning this debilitating condition.
There is a clear need for brief, but sensitive and specific, cognitive screening instruments as evidenced by the popularity of the Addenbrooke's Cognitive Examination (ACE).
We aimed to validate an improved revision (the ACE-R) which incorporates five sub-domain scores (orientation/attention, memory, verbal fluency, language and visuo-spatial).
Standard tests for evaluating dementia screening tests were applied. A total of 241 subjects participated in this study (Alzheimer's disease=67, frontotemporal dementia=55, dementia of Lewy Bodies=20; mild cognitive impairment-MCI=36; controls=63).
Reliability of the ACE-R was very good (alpha coefficient=0.8). Correlation with the Clinical Dementia Scale was significant (r=-0.321, p<0.001). Two cut-offs were defined (88: sensitivity=0.94, specificity=0.89; 82: sensitivity=0.84, specificity=1.0). Likelihood ratios of dementia were generated for scores between 88 and 82: at a cut-off of 82 the likelihood of dementia is 100:1. A comparison of individual age and education matched groups of MCI, AD and controls placed the MCI group performance between controls and AD and revealed MCI patients to be impaired in areas other than memory (attention/orientation, verbal fluency and language).
The ACE-R accomplishes standards of a valid dementia screening test, sensitive to early cognitive dysfunction.
This book is the magnum opus of one of the most influential cognitive psychologists of the past 50 years. This new volume on the model he created (with Graham Hitch) discusses the developments that have occurred in the past 20 years, and places it within a broader context. Working memory is a temporary storage system that underpins onex' capacity for coherent thought. Some 30 years ago, Baddeley and Hitch proposed a way of thinking about working memory that has proved to be both valuable and influential in its application to practical problems. This book updates the theory, discussing both the evidence in its favour, and alternative approaches. In addition, it discusses the implications of the model for understanding social and emotional behaviour, concluding with an attempt to place working memory in a broader biological and philosophical context. Inside are chapters on the phonological loop, the visuo-spatial sketchpad, the central executive and the episodic buffer. There are also chapters on the relevance to working memory of studies of the recency effect, of work based on individual differences, and of neuroimaging research. The broader implications of the concept of working memory are discussed in the chapters on social psychology, anxiety, depression, consciousness, and on the control of action. Finally, the author discusses the relevance of a concept of working memory to the classic problems of consciousness and free will.
Abstract The topic of multiple forms of memory is considered from a biological point of view. Fact-and-event (declarative, explicit) memory is contrasted with a collection of non conscious (non-declarative, implicit) memory abilities including skills and habits, priming, and simple conditioning. Recent evidence is reviewed indicating that declarative and non declarative forms of memory have different operating characteristics and depend on separate brain systems. A brain-systems framework for understanding memory phenomena is developed in light of lesion studies involving rats, monkeys, and humans, as well as recent studies with normal humans using the divided visual field technique, event-related potentials, and positron emission tomography (PET).
In an earlier paper (Downes et al., 1997), we demonstrated how the beneficial effects of imagery in a face-name association learning task could be enhanced further by the simple expedient of pre-exposing faces for a brief period prior to the introduction of the names to be associated. The present study examines whether the technique of errorless learning, recently applied in neuropsychological rehabilitation, might also benefit from pre-exposure. The rationale for hypothesising such an interaction follows from the speculation raised in our earlier work that the two techniques may be operating at different stages of learning—pre-exposure at registration/consolidation stages and errorless learning at retrieval. Accordingly, a group of brain-injured memory-impaired subjects was given four sets of face-name associations to learn under different experimental conditions. Two of these conditions compared errorless and errorful conditions, and two combined errorless learning with different versions of the pre-exposure technique. The results confirm that, in terms of the number of names learned on the first trial and the number of trials to criterion, errorless learning was significantly superior to errorful learning. Furthermore, both preexposure conditions in combination with errorless learning resulted in a significant enhancement of learning compared to errorless learning alone. Thus, as with imagery, although significant gains in performance are evident when errorless learning is used, further enhancement can be achieved by combining it with preexposure.
This article is an integrative review of empirical studies of cognitive self-efficacy from childhood through old age. Issues of definition and measurement are addressed and the relation of self-efficacy to personal mastery is evaluated. Research on academic achievement in children and adolescents, complex decision-making in young adults, and memory and intellectual functioning in older adults supports a variety of theoretically driven hypotheses regarding the sources and effects of self-efficacy. Percepts of self-efficacy are based on a variety of sources of information, including personal mastery and perceived control beliefs. Self-efficacy has predictable effects on a variety of task engagement variables (e.g. persistence, effort, goal setting, strategy usage, chioce) that mediate the relationship between self-efficacy and performance. Generalisations regarding the applicability of self-efficacy to understanding cognitive development across the life span are discussed in terms of age-relevant domains and it is argued that a life span treatment of self-efficacy development is particularly compelling because both life span theory and self-efficacy theory emphasise domain specificity.
Two experiments are reported in which young and old adults performed in a Brown-Peterson task. In the first experiment young adults recalled with greater accuracy than old adults and the difference between age groups was greater in delayed than in immediate recall. Performance varied inversely with interpolated task difficulty in the delayed recall condition, but this effect did not interact with age. In the second experiment an attempt was made to equate immediate recall performances of old and young adults to determine if age differences in the rate of forgetting are independent of age differences in registration. Each participant was pre-tested to determine the number of stimulus repetitions needed to achieve a minimum of 83% correct in immediate serial recall of 6-letter sequences. The number of repetitions an individual required in pre-testing was then used in a subsequent Brown-Peterson task. No significant age differences in delayed recall were obtained when immediate recall differences were minimized by differential repetition of to-be-remembered sequences. The results of these experiments suggest that age differences in forgetting rates arise from age-related differences in encoding and storage.
Sequences of 6 letters of the alphabet were visually presented for immediate recall to 387 subjects. Errors showed a systematic relationship to original stimuli. This is held to meet a requirement of the decay theory of immediate memory.
The same letter vocabulary was used in a test in which subjects were required to identify the letters spoken against a white noise background. A highly significant correlation was found between letters which confused in the listening test, and letters which confused in recall.
The role of neurological noise in recall is discussed in relation to these results. It is further argued that information theory is inadequate to explain the memory span, since the nature of the stimulus set, which can be defined quantitatively, as well as the information per item, is likely to be a determining factor.
After an initial consideration of psychological experimentation, the author describes a long series of experiments in the fields of perception, imagination, and remembering, using material which approximated that found in everyday life. The work on perceiving utilized chiefly geometrical diagrams; and that on imagination, ink-blots. The results in these two cases revealed the influence of the subjects' attitudes and indicated their tendency to introduce previously learned material. In the experiments on remembering two methods were used, one the method of repeated reproduction by a given subject and the other the method of serial reproduction where the material reproduced by one subject became the learning material for a second subject whose recall constituted the learning material for a third subject, etc. This latter series of experiments showed that proper names and titles are very unstable in recall, that there is a bias toward the concrete, that individualizing aspects of the material (stories) tend to be lost, and that abbreviations and rationalizations occur. Throughout the book emphasis is placed on the social determinants of the manner and matter of recall, a point of view which is supported in the anthropological material cited. "Remembering is not the re-excitation of innumerable fixed, lifeless and fragmentary traces. It is an imaginative reconstruction, or construction, built out of the relation of our attitude towards a whole active mass of organized past reactions or experience, and to a little outstanding detail which commonly appears in image or in language form." (PsycINFO Database Record (c) 2012 APA, all rights reserved)
A study of memory for places was carried out to examine five hypotheses about the use of schemata in memory performance: (a) that schemata determine what objects are encoded into memory; (b) that schemata act as frameworks for episodic information; (c) that schema-based information is integrated with episodic information; (d) that schemata facilitate retrieval; and (e) that schemata influence what is communicated at recall. Subjects were taken into what they thought was a graduate student's office and later were tested for memory of the room with either drawing recall, written recall, or verbal recognition. Memory scores for objects were correlated with schema expectancy and saliency ratings. Schema expectancy was positively correlated with recall and recognition. Expected objects were inferred in recall, supporting the integration hypothesis. Comparison of recall and recognition data supported the retrieval hypothesis. Analysis of the written descriptions supported the communication hypothesis. Saliency was positively correlated with recall and recognition for present objects, but was unrelated to retrieval. Saliency was negatively correlated with recognition for nonpresent objects, suggesting a metacognitive strategy in recognition of high-salient objects.
The Self-Memory System (SMS) is a conceptual framework that emphasizes the interconnectedness of self and memory. Within this framework memory is viewed as the data base of the self. The self is conceived as a complex set of active goals and associated self-images, collectively referred to as the working self. The relationship between the working self and long-term memory is a reciprocal one in which autobiographical knowledge constrains what the self is, has been, and can be, whereas the working self-modulates access to long-term knowledge. Specific proposals concerning the role of episodic memories and autobiographical knowledge in the SMS, their function in defining the self, the neuroanatomical basis of the system, its development, relation to consciousness, and possible evolutionary history are considered with reference to current and new findings as well as to findings from the study of impaired autobiographical remembering.
Neuropsychological rehabilitation of memory performance is still a controversial topic, and rehabilitation studies have not analyzed to which stage of memory processing (encoding, consolidation, or retrieval) enhancement may be attributed. We first examined the efficacy of a computer training program for stroke patients, based on a previous study (Hildebrandt, Clausing, Janssen, & Modden, 2007a) for memory-impaired patients of a rehabilitation unit and compared it with the standard group treatment. In a second randomized controlled experiment, we trained two groups of 15 patients with mild to moderate memory disorders, caused by organic brain lesions, with the same two treatment approaches. We used several standard tests to analyze improvement of memory functions, focusing on separate parameters for encoding, consolidation, and retrieval. We developed for that purpose a new word-list learning test, which allowed assessment of response to novelty and a systematic comparison of free recall after learning of semantically structured and nonstructured word lists. The first treatment experiment showed significant improvement of verbal learning for patients treated with the computer software program. The second experiment showed that memory improvement was based exclusively on retrieval processes, whereas no specific change was found for encoding and consolidation. However, the two groups of the second experiment showed no significant differences for the treatment, although the absolute scores pointed in the same direction as in the first experiment.
An early clinical observation by Claparède suggests that classical conditioning occured in an amnesic patient even though the subject did not acknowledge memory for the conditioning as such. This suggestion is confirmed in two amnesic subjects (one alcoholic Korsakoff patient and one probable encephalitic patient) using the conditioned eye blink. Both subjects showed evidence of conditioning with retention across intervals of 10 min and 24 hr, and with both there was a striking dissociation between their objective performances and their commentaries. Conditioning apparently should be added to the growing list of examples of adequate long-term retention in amnesic subjects, the variety of which makes it difficult to interpret the deficit in terms of a failure of consolidation of particular types of material or of an insensitivity to particular encoding requirements. The theoretical basis of the dissociation between performance and commentary would appear to warrant further development.
This study analyzes the memory deficits shown by an amnesic patient with bilateral frontal damage and a dysexecutive syndrome. He resembles a classic amnesic patient in showing grossly impaired episodic memory for both verbal and nonverbal material, together with normal digit span, and on occasion normal recency in free recall. He differs from the classic amnesic pattern however in showing an impairment in both the speed and accuracy of performance on tests of semantic memory, and in clear evidence for impaired performance on some though not all procedural learning tasks. Finally, his autobiographical memory was poor and subject to substantial confabulation. It is suggested that the pattern of deficits is consistent with a combination of a classic amnesic syndrome with the additional problems associated with the frontal dysexecutive syndrome, rather than exhibiting a qualitatively different form of amnesia.
A SPECIFIC isolated and severe defect of memory, with preservation of other intellectual functions, including span of attention, may occur as the result of localized brain pathology. In amnesic patients the memory defect is so marked that performance on tests of recent memory declines sharply within a matter of minutes1.
Three abacus-derived mental arithmetic experts were given various memory tasks. They had a much larger digit span than the average, but their span for letters of the alphabet or fruit names was not unusual. They could reproduce digits, but not object names, backwards as quickly as forwards; their memory for digits, but not for letters, was to some extent compatible with a preloaded memory for fruit names; their digit memory was disrupted more by concurrent visual-spatial tasks than by aural-verbal tasks while the reverse was true for their memory for letters. In these characteristics their digit memory differed significantly from that of the control subjects who had had negligible experience in abacus operation, while there was no difference in the memory for non-digit materials. After other series had been memorized, the experts could not recall any part of the preceding series, nor could they recognize it, though they could retain completely a near-span digit series for 30 seconds. They seemed to have a 'mental abacus' or specific device to represent visuo-spatially a number comprising many digits just long enough for calculation.
The patient and the author of this case report are the same person. In September 1974 I had a cardiac arrest, and because of anoxia, the arrest resulted in some right-sided brain damage. The brain damage led to some minor physical and perceptual problems, but the most important result was partial loss of past memory and strongly impaired present memory. This report will be concerned with the effects of poor memory on cognition, personality, and interpersonal relationships based on the observations I have made during the period in which my memory was impaired. Of course, the emotional and personality reactions are somewhat related to my past personality, but some may be expected generally when poor memory is present. The effect on cognitive functioning is more likely to be a general finding. I also will describe the course of my rehabilitation over a 2-year-period, and I will make some suggestions about rehabilitation to patients and therapists.
This article describes a process approach to training memory book usage as a compensatory strategy for neurological patients. Clinicians who recommend memory books to patients need to consider the physical, cognitive, social and emotional strengths and weaknesses of the individual as they assist with the design and implementation of such books. Throughout the process, a major focus of this approach is on the need to raise awareness of memory deficits while minimizing patient resistance. By individualizing a memory book, clients tend to view it as a tool which can maximize their independence. Support from the discharge environment may be necessary in some areas to maintain optimum performance.
We propose that one of the major functions of explicit memory is the elimination of learning errors. The hypothesis is explored by means of a stem completion task in which subjects are presented with stems having many potential completions, and in the initial phase are either encouraged to guess, the "errorful" procedure, or are provided with the correct completion, the "errorless" condition. Learning is then tested over a sequence of nine trials. The performance of amnesic subjects who are assumed to have good implicit but bad explicit learning is compared with that of normal elderly subjects, who are assumed to have an intermediate level of explicit learning skill, and young controls who are expected to be high in both implicit and explicit learning capacity. As predicted, errorless learning is beneficial, with the effect being particularly marked for the amnesic group. A detailed analysis of the intrusion errors supports an interpretation of the results in terms of the relative contribution to the three groups of implicit learning, which is assumed to be particularly vulnerable to interference. Implications for the analysis of normal learning, and for the rehabilitation of brain damaged patients are discussed.
In 1974, Baddeley and Hitch proposed a three-component model of working memory. Over the years, this has been successful in giving an integrated account not only of data from normal adults, but also neuropsychological, developmental and neuroimaging data. There are, however, a number of phenomena that are not readily captured by the original model. These are outlined here and a fourth component to the model, the episodic buffer, is proposed. It comprises a limited capacity system that provides temporary storage of information held in a multimodal code, which is capable of binding information from the subsidiary systems, and from long-term memory, into a unitary episodic representation. Conscious awareness is assumed to be the principal mode of retrieval from the buffer. The revised model differs from the old principally in focussing attention on the processes of integrating information, rather than on the isolation of the subsystems. In doing so, it provides a better basis for tackling the more complex aspects of executive control in working memory.