MEMORY ABNORMALITY

any of the disorders that affect the ability to remember. Disorders of memory must have been known to the ancients and are mentioned in several early medical texts, but it was not until the closing decades of the 19th century that serious attempts were made to analyze them or to seek their explanation in terms of brain disturbances. Of the early attempts, the most influential was that of a French psychologist, Thodule-Armand Ribot, who, in his Diseases of Memory (1881, English translation 1882), endeavoured to account for memory loss as a symptom of progressive brain disease by embracing principles describing the evolution of memory function in the individual, as offered by an English neurologist, John Hughlings Jackson. Ribot wrote: The progressive destruction of memory follows a logical ordera law. It advances progressively from the unstable to the stable. It begins with the most recent recollections, which, being lightly impressed upon the nervous elements, rarely repeated and consequently having no permanent associations, represent organization in its feeblest form. It ends with the sensorial, instinctive memory, which, having become a permanent and integral part of the organism, represents organization in its most highly developed stage. The statement, amounting to Ribot's law of regression (or progressive destruction) of memory, enjoyed a considerable vogue and is not without contemporary influence. The notion has been applied with some success to phenomena as diverse as the breakdown of memory for language in a disorder called aphasia and the gradual return of memory after brain concussion. It also helped to strengthen the belief that the neural basis of memory undergoes progressive strengthening or consolidation as a function of time. Yet students of retrograde amnesia (loss of memory for relatively old events) agree that Ribot's principle admits of many exceptions. In recovery from concussion of the brain, for example, the most recent memories are not always the first to return. It has proved difficult, moreover, to disentangle the effects of passage of time from those of rehearsal or repetition on memory. A Russian psychiatrist, Sergey Sergeyevich Korsakov (Korsakoff), may have been the first to recognize that amnesia need not necessarily be associated with dementia (or loss of the ability to reason), as Ribot and many others had supposed. Korsakov described severe but relatively specific amnesia for recent and current events among alcoholics who showed no obvious evidence of shortcomings in intelligence and judgment. This disturbance, now called the Korsakoff syndrome, has been reported for a variety of brain disorders aside from alcoholism and appears to result from damage in a relatively localized part of the brain. The neurological approach may be combined with evidence of psychopathology to enrich understanding of memory function. Thus, a French neurologist, Pierre Janet, described amnesia sufferers who were apparently very similar to those observed by Korsakov but who gave no evidence of underlying brain disease. Janet also studied people who had lost memory of extensive periods in the past, also without evidence of organic disorder. He was led to regard these amnesias as hysterical, explaining them in terms of dissociation: a selective loss of access to specific memory data that seem to hold some degree of emotional significance. In his experience, reconnection of dissociated memories could as a rule be brought about by suggestion while the sufferer was under hypnosis. Freud regarded hysterical amnesia as arising from a protective activity or defense mechanism against unpleasant recollections; he came to call this sort of forgetting repression, and he later invoked it to account for the typical inability of adults to recollect their earliest years (infantile amnesia). He held that all forms of psychogenic (not demonstrably organic) amnesia eventually could resolve after prolonged sessions of talking (psychotherapy) and that hypnosis was neither essential nor necessarily in the amnesiac's best interest. Nevertheless, hypnosis (sometimes induced with the aid of drugs) has been widely used in the treatment of hysterical amnesia, particularly in time of war when only limited time is available. Additional reading A.R. Luria, The Mind of a Mnemonist (1968, reprinted 1987), is a fascinating account of a memory prodigy studied over many years by an outstanding Soviet psychologist. B. Milner (ed.), Disorders of Memory After Brain Lesions in Man, Neuropsychologia, 6:175291 (1965), a symposium on memory disorders, places major emphasis on psychological aspects. Thodule Armand Ribot, Diseases of Memory (1882, reprinted 1977; originally published in French, 1881), is the classical text on disorders of memory. George A. Talland, Deranged Memory: A Psychonomic Study of the Amnesic Syndrome (1965), is a thorough historical, clinical, and experimental study of memory defect associated with chronic alcoholism, and his Disorders of Memory and Learning (1968) is a popular survey of memory and some of its disorders. C.W.M. Whitty and O.L. Zangwill (eds.), Amnesia, 2nd ed. (1977), considers amnesia from the neurological point of view. David S. Olton, Elkan Gamzu, and Suzanne Corkin (eds.), Memory Dysfunctions: An Integration of Animal and Human Research from Preclinical and Clinical Perspectives (1985), includes discussions on human neuropsychology, animal models of amnesia, memory biochemistry, pharmacological approaches in the treatment of memory disorders, and many other topics. Andrew R. Mayes, Human Organic Memory Disorders (1988), is a highly technical and comprehensive book for psychiatric professionals and students. Takehiko Yanagihara and Ronald C. Petersen (eds.), Memory Disorders: Research and Clinical Practice (1991), an advanced text for memory specialists and students, takes a contemporary approach to the clinical assessment of memory and the study of memory dysfunction, making the connection between specific memory functions and specific neuroanatomical and biochemical structures. The memory loss associated with Alzheimer's disease is discussed in Donna Cohen and Carl Eisdorfer, The Loss of Self (1986), a practical resource for families and caregivers; and Anthony F. Jorm, A Guide to the Understanding of Alzheimer's Disease and Related Disorders (1987), an overview. Oliver Louis Zangwill The Editors of the Encyclopdia Britannica Additional reading Jack A. Adams, Human Memory (1967), provides a well-considered account of memory as viewed from laboratory findings. A somewhat more abbreviated account is John Jung, Verbal Learning (1968). Morris Moscovitch (ed.), Infant Memory: Its Relation to Normal and Pathological Memory in Humans and Other Animals (1984), an advanced book for researchers and clinicians, looks at the essentially preverbal memory systems of human infants and compares and connects them with nonverbal memory systems and with the advanced, verbal memory systems of human adults. Two versions of formal models of memory are given in two essays found in Kenneth W. Spence and Janet Taylor Spence (eds.), The Psychology of Learning and Motivation: one by Gordon Bower, Multicomponent Theory of the Memory Trace, 1:229325 (1967); and the other by R.C. Atkinson and R.M. Shiffrin, Human Memory: A Proposed System and Its Control Processes, 2:89195 (1968). The most comprehensive account of interference in long-term memory is provided by G. Keppel, Retroactive and Proactive Inhibition, in Theodore R. Dixon and David L. Horton (eds.), Verbal Behavior and General Behavior Theory (1968), pp. 172183. A parallel analysis for short-term memory is given by L. Postman, Short-Term Memory and Incidental Learning, in Arthur W. Melton (ed.), Categories of Human Learning (1964), pp. 145201. Gary Lynch, James L. McGaugh, and Norman M. Weinberger (eds.), Neurobiology of Learning and Memory (1984), involves mostly animal studies and may serve as a background resource for delving into more recent research advances. In contrast to works derived largely from laboratory studies, Alan Baddeley, Human Memory: Theory and Practice (1990), harmonizes laboratory studies with actual data from brain-damaged patients and is of value to advanced researchers and undergraduates alike. Two collections of conference papers that discuss memory from the connectionist viewpoint are Geoffrey E. Hinton and James A. Anderson (eds.), Parallel Models of Associative Memory, updated ed. (1989); and R.G.M. Morris (ed.), Parallel Distributed Processing (1989). David E. Rumelhart et al., Parallel Distributed Processing, 2 vol. (1986), is a landmark collection of articles on the connectionist theory of learning and memory. The origins of connectionist theory are traced in H. Christopher Longuet-Higgins, Mental Processes (1987), in the section on memory. Benton J. Underwood The Editors of the Encyclopdia Britannica