Butters / Cermak Alcoholic Korsakoff's Syndrome

An Information-Processing Approach to Amnesia
1. Auflage 2014
ISBN: 978-1-4832-1686-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 204 Seiten

Alcoholic Korsakoff's Syndrome: An Information-Processing Approach To Amnesia presents an overview of one of the theories of amnesia, namely, the extent to which it represents an information-processing deficit. The book discusses the clinical symptoms, neuropathology, and etiology of the alcoholic Korsakoff's syndrome; the influence of the original memory model on the research in amnesia; and the functional differences among long-term memory, short-term memory, and sensory memory. The text also describes encoding deficits; the depth of encoding and visuoperceptive deficits; as well as alternative theories of amnesia. Sensory capacities and the memory and cognitive disorders of chronic alcoholics are also considered. The book further reviews the differences among various amnesic and dementing populations. Neurologist, neuropsychologists, and students taking related courses will find the book invaluable.

Autoren/Hrsg.

Butters, Nelson

Cermak, Laird S.

Inhaltsverzeichnis

1;Front Cover
;1
2;Alcoholic Korsakoff's Syndrome: An Information-Processing Approach to Amnesia;4
3;Copyrigh Page;5
4;Table of Content;8
5;Dedication
;6
6;Preface;10
7;Acknowledgments;12
8;Chapter 1. Clinical Symptoms, Neuropathology, and Etiology;18
8.1;NEUROPATHOLOGY;28
8.2;ETIOLOGY;31
9;Chapter 2. The Original Memory Model;34
9.1;FUNCTIONAL DIFFERENCES AMONG LONG-TERM MEMORY, SHORT-TERM MEMORY, AND SENSORY MEMORY;35
9.2;SHORT-TERM–LONG-TERM-MEMORY PARADIGMS FREQUENTLY USED IN AMNESIA RESEARCH;45
9.3;PAIRED-ASSOCIATES;45
9.4;SERIAL LEARNING;46
9.5;FREE LEARNING;46
9.6;RECALL;47
9.7;RECOGNITION;47
9.8;RELEARNING;48
10;Chapter 3. Long-Term Memory;50
10.1;PAIRED-ASSOCIATE LEARNING;50
10.2;SERIAL LEARNING;55
10.3;REMOTE MEMORY;60
10.4;SEMANTIC MEMORY;61
10.5;MOTOR MEMORY;64
11;Chapter 4. Short-Term Memory;67
11.1;RECENCY IN SERIAL LEARNING;67
11.2;DISTRACTOR TASK RECALL;70
11.3;RATE OF RETRIEVAL FROM SHORT-TERM MEMORY;79
11.4;SENSORY MEMORY;81
11.5;SHORT-TERM MOTOR MEMORY;83
12;Chapter 5. Encoding Deficits;86
13;Chapter 6. Depth of Encoding and Visuoperceptive Deficits;113
13.1;ANALYSES OF THE ALCOHOLIC KORSAKOFF PATIENT'S DEFICITS ON THE DIGIT-SYMBOL TEST;113
13.2;LIMITED ENCODING AND THE ALCOHOLIC KORSAKOFF PATIENT'S DEFICITS IN FACE PERCEPTION;122
14;Chapter 7. Alternative Theories of Amnesia;128
14.1;CONSOLIDATION;128
14.2;RETRIEVAL-INTERFERENCE THEORY;130
14.3;CONTEXTUAL THEORY;135
14.4;OTHER THEORETICAL APPROACHES;138
14.5;THEORETICAL CONCLUSIONS;139
15;Chapter 8. Are All Amnesics Alike?;141
15.1;MEMORY DISORDERS OF POSTENCEPHALITIC PATIENTS;142
15.2;INDIVIDUAL CASE STUDIES;145
15.3;COMPARISONS OF ALCOHOLIC KORSAKOFF AND DEMENTING PATIENTS;149
16;Chapter 9. Sensory Capacities;158
17;Chapter 10. Memory and Cognitive Disorders of Chronic Alcoholics;174
18;References;187
19;Subject Index;200

Leseproben

2

The Original Memory Model

Publisher Summary

This chapter discusses the historical trends in normal memory and amnesia research at the end of 1960s. Research exploring the functional differences among the three memory systems concentrated largely upon differences in each system’s capacity to retain information and also upon the mechanisms responsible for the loss of information from each of these storage systems. One further area of investigation came specifically from the study of amnesia, namely, the study of the physiological independence of the memory systems. Evidence from each of these areas of concentration supported the division of memory into the three component systems of long-term, short-term, and sensory memory. Most models of compartmentalized memory postulated that the capacity of long-term memory (LTM) was potentially infinite. Short-term memory (STM), on the other hand, was felt to be limited to about 7 plus or minus 2 items of information, although this number could be extended by chunking or some other form of combining items. Physiological evidence for the separation of memory stores has largely centered upon the distinction between STM and LTM, with little or no research being performed on sensory memory. Evidence from studies of amnesic patients has often been cited as being the most substantial support for the classical distinction between LTM and STM.

The model of memory that pervaded most researchers’ early explorations of amnesia was primarily an outgrowth of an already existent model developed and used by researchers in normal memory. It seemed logical to begin the study of the “ultimate” forgetting syndrome using terms and paradigms already developed to describe the normal forgetting process. Many theoretical models existed to depict normal memory, but there were enough commonalities among these models so that a “modal” model could be described (Murdock, 1967). This model had as its cornerstone the notion that two independent storage systems characterized the normal memory process. These storage systems were usually termed “short-term” and “long-term” memory, although “primary” and “secondary” memory terminology was also used extensively. In addition, several theorists postulated the existence of precategorical (sensory) storage mechanisms. The visual form of precategorical storage was termed “iconic storage” (Neisser, 1967); the auditory form was called “echoic storage” (also Neisser, 1967), and occasionally “preacoustic storage” (Crowder & Morton, 1969) when the characteristics of the auditory stimulus became somewhat more well-defined in the individual’s memory system.

In the late 1960s and early 1970s, the characteristics of each of these storehouses of information appeared to be quite well documented, and research in amnesia was paralleling the same sorts of investigations that had been developed by the normal memory theorists. In time, however, the boundaries between these “compartments” became progressively clouded, and the characteristics used to define each system were seen to overlap more and more. As new theories began to emerge to account for these difficulties, research in amnesia began to shift its emphasis. More emphasis came to be placed upon the cognitive analysis performed by the individual patient than upon the characteristics of his inherent (seemingly defective) memory system. Some of the most recent research is acting to further break down the invariant characteristics of memory storage and placing more and more emphasis on the individual’s role in his or her own processing of information for storage and retrieval. These changes in memory and amnesia theorizing will be described in more detail in Chapter 5. However, before such description is possible, the historical trends in normal memory and amnesia research must be documented so that these new approaches can be seen in perspective. Consequently, this chapter shall view memory as it was viewed at the end of the 1960s. In the succeeding three chapters, we will explore how this model influenced research in amnesia which, interestingly enough, in turn supported the model.

FUNCTIONAL DIFFERENCES AMONG LONG-TERM MEMORY, SHORT-TERM MEMORY, AND SENSORY MEMORY

Research exploring the functional differences among the three memory systems concentrated largely upon differences in each system’s “capacity” to retain information, and also upon the mechanisms (i.e., interference or decay) responsible for the loss of information from each of these storage systems. One further area of investigation came specifically from the study of amnesia, namely, the study of the physiological independence of the memory systems. Evidence from each of these areas of concentration supported the division of memory into the three component systems of long-term, short-term, and sensory memory. We shall look first at the research that was concerned with investigating the extent, or limits, of the capacity of each memory system.

Capacity

Most models of compartmentalized memory postulated that the capacity of long-term memory (LTM) was potentially infinite (Atkinson & Shiffrin, 1967; Broadbent, 1958; Waugh & Norman, 1965). Short-term memory (STM), on the other hand, was felt to be limited to about 7 plus or minus 2 items of information (Miller, 1956), although this number could be extended by “chunking” or some other form of combining items. Sensory memory capacity was evaluated using a quite sophisticated procedure introduced by Sperling in 1960. In this procedure, 3–12 letters are presented tachistoscopically for very brief periods of time (50–500 msec). Following presentation, subjects are asked to report as many of the digits as they can possibly recall. Sperling found that the average maximum number of digits that a subject could report was 4.3, regardless of the number of digits in the array. At this time, Sperling questioned whether this finding was due to a perceptual limitation or to the capacity of sensory memory. His conclusion that it was probably the latter was based on evidence from a partial recall procedure he developed. Sperling’s partial recall procedure involved a partial report technique in which subjects were required to report back the digits from one of three rows viewed. Subjects are cued as to which row they must report only after the display has disappeared. Sperling reasoned that if the subjects had perceptual limitations then recall would be all or none, depending on the row they focused on during presentation and the row they were asked to recall. However, if memory load capacity was the minimizing factor, then the subjects should be able to recall most of any row because the memory capacity would never be exceeded. The results showed that subjects could correctly identify 3–4 items from any row if cued immediately after presentation. As we shall see in the next section of this chapter, this ability disappeared rapidly as the interval between presentation and report was increased. However, the fact that recall for any row was present immediately after the display ended favored the memory capacity limitation theory.

The capacity of STM was most elegantly studied by Miller in 1956. Miller felt that seven items is the upper limit on the amount of material an individual can retain in an unanalyzed, uncategorized state. For example, he found that most people can remember approximately seven random numbers after they are presented at a continuous and rather rapid rate (this of course is often called one’s “digit span”). This upper limit seems to hold for randomly presented words, letters, and many other kinds of stimuli. Actually, Miller found the “magic” number seven was not absolute, but that the limit depended on the nature of the material to be remembered and upon the individual. Therefore, he defined the limit of STM as an interval of seven plus or minus two items.

In this important article, Miller also described an experiment in which subjects watched a series of lights go on and off in a random sequence. As expected, he found that the subjects could remember the sequence up to about seven lights, but that they broke down beyond that point. However, he then found that a group of computer technicians were able to reproduce a series of 21 (or even more) such “light-flash” events. They were able to do this by using a binary code to retain one number for a set of 3 lights. Thus, the sequence of 21 lights was really comprised of “seven” numbers, each representing three events. Miller concluded that our short-term capacity can be extended by chunking material into what he called information-rich “bits.” We are still limited by the number of bits we can hold, but each bit can contain more than just a single item.

Long-term capacity has generally been described as being infinite, or at least unmeasurable. This has not been meant to imply that everything, once learned, is somewhere in memory. Rather, it means that the amount that can be placed in long-term memory never reaches a fixed limit. At one time, there was a rather folksy belief in circulation that at some point in life each new fact replaced (by bumping out) an old fact, but this belief has been largely discredited by research in memory since the time of Ebbinghaus. Most...