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Handbook of dichotic listening: Theory, methods and research
M. BIRCHWOOD, Integruted Approach viii + 403, f12.95.
S. HALLETT. and M. PRESTON, to Reseurch und Treatment (Longman,
Schizophrenia: An Harlow, 1988) pp.
It appears that this book was to be part of the Longman Applied Psychology Series. However, the preface suggests that as the writing progressed it became clear the authors were writing a “state of the art” book which has now been published separately from the series. Can any text book on schizophrenia be “state of the art”? Our increase in knowledge, if not understanding, especially of the biological aspects of schizophrenia, is so rapid that a book such as this, which is in essence an extended review, must be out of date before it is published. For the serious student of schizophrenia, original articles in journals are a must. But let’s not be too niggardly. This is, as far as it goes, an excellent review. Possible aetiological factors, genetic, biochemical, neuroanatomical, social and psychological, are well, if routinely, covered, as are the principal forms of treatment. Perhaps undue emphasis is placed on the importance of behavioural treatments (which I suspect are not very widely used in everyday psychiatric practice in British hospitals), but this is not surprising as the three authors are themselves clinical psychologists. In the last section the authors propose an “integrated model”. The model which tries to explain the development of schizophrenia, I found confusing and unconvincing; the integrated model of treatment is wholly acceptable. In summary, the authors are to be congratulated on their well balanced review. The question must be asked, however, at whom is the book aimed? It is too detailed for the postgraduate student, but contains little new for the serious researcher. Robin G. McCreadie Crichton Royal Hospit&, Dumfries
K. HUGDAHL (Ed.), Handbook of Dichotic Listening: Research (Wiley, Chichester, 1988) pp. 650, E45.00.
Theory,
A4ethod.r und
For over 30 years subjects have been asked to carry out an usual experimental task in which a pair of stimuli, often words, is presented simultaneously, one member of the pair to each ear. Usually the task (dichotic listening) is to report both stimuli, though there are numerous variations. Over a number of trials, performance on one ear often turns out to be superior to performance on the other, the direction and strength of this advantage being related to a host of factors, including the type of stimuli used, the task requirements and
Book reuiews
287
characteristics of the subject population. Increasingly, the main focus of interest has become the use of the technique for investigating brain-behaviour relationships and, in particular, hemisphere specialisation of function. This book attempts to provide a comprehensive and up to date review of current research, theory and applications of the dichotic listening paradigm. All the contributors are actively engaged in some form of dichotic listening work and the majority have a long and distinguished research involvement in it. The book appears to be the first volume of its kind and its appearance will be no doubt be warmly welcomed in view of the now Olympian scale, multidisciplinary character and fragmentation of the dichotic listening literature. In the first chapter Bryden provides a general and historical overview. This useful and lucidly written chapter is important because it so clearly describes the central character in the story which is to follow - Kimura’s “fixed structural model” of hemisphere specialisation - and successfully anticipates the key issues which repeatedly surface in different ways throughout the book. A clear grasp of this model is essential in a story in which, as Sidtis rightly comments, there are many subplots. As originally formulated by Kimura, the model requires that genuinely dichotic stimuli are used in order to achieve suppression of the ipsilateral pathways. The first challenge therefore comes from Bradshaw and Nettleton who argue that, for the great majority of tasks, monoaural presentations are sufficient to produce asymmetries and that is may even be partly the perceived rather than the actual position, or ear of presentation of a sound which creates asymmetry. Many contributors deal at length with the issue of performance variability within subjects which poses another potentially serious problem for the structural model. Some see the solution as essentially methodological. The most vigorous exposition of this line of argument is probably to be found in Wexler’s closely argued chapter which, while leaning rather too heavily on data from split-brain patients, argues that use of appropriate techniques, in this instance “fused” dichotic pairs of carefully selected short words or nonsense sounds, will produce ear advantages which are stable reflections of lateralised functions. The worry is that reliability may have been achieved, to some extent, at the expense of artificiality. In addition, as Speaks reminds us in a chapter on the statistical properties of dichotic listening scores, many other awkward issues remain unresolved, such as those concerning the validity of a method which typically produces a significant ear advantage in only a minority of subjects. According to some models of hemisphere asymmetry, ear advantages result from differences in how a task is processed, not from the type of stimuli used. On this view, variability is not an indication of poor methodology but a phenomenon which one would expect to occur when subjects use different processing strategies. Here, the dangers of circularity loom large since inconsistent asymmetry scores can be conveniently reinterpreted as “strategy ef-
fects”, different asymmetry scores being offered as “proof”. There is ample indirect evidence for such effects in various parts of the book and few contributors can resist the temptation to indulge in post hoc explanations of them. Nowhere is this more apparent than in the final sections concerned with reading disorders and psychopathology where inferences about lateralised processes are made from between group comparisons. Bruder makes heroic efforts to bring a sense of order to the performance of different groups of psychiatric patients. The torch is taken up by Nachshon who, after two misspellings of “schizophrenia”, struggles manfully with the various permutations of left/right hemisphere dysfunction/overactivation/underactivation which might account for the bewildering performance of schizophrenics on dichotic listening tasks. The lack of any clear framework for predicting between group differences is also painfully obvious in the chapters on developmentally based reading and related disorders by Obrzut and by Bakker and Kappers. Such flights of fancy are generally well controlled however and. fortunately, the majority of contributors recognise the circularity involved in such reasoning and attempt to provide some form of independent validation for such claims, though often this is merely correlational. A number of contributions describe research in which attentional strategies have been systematically controlled. Others discuss the use of signal detection theory analyses in separating the decision and sensitivity components of ear performance. It is clear from the Molfese and Adams’ chapter, however, that there is very little to be gained by using auditory evoked response for validation purposes, since the results so far have been disappointingly inconsistent. In one of the outstanding chapters of the book, Peretz and Morais write persuasively about hemisphere related processing strategies in their review of the literature on dichotic musical tasks. They reported findings in which circularity is avoided by using different sets of instructions to create different processing strategies. They conclude that the right but not the left hemisphere’s contribution to musical processing may have a modular basis in the sense envisaged by Fodor (1983). There are also chapters by Clark, Geffen and Geffen on dichotic monitoring, by Eslinger and Damasio on the phenomenon of paradoxical ear extinction in neurological patients and by Sidtis on dichotic listening after commisurotomy. Strauss discusses the evidence that verbal dichotic laterality effects are related to neuroanatomical differences. Hiscock and Decter give a detailed and careful examination of the statistical and methodological problems of using the dichotic listening technique with children. Harshman and Lundy write on the vexed question of the use of dichotic listening to measure “degrees” of lateralisation, their conclusion being that such inferences may be drawn with caution with some types of ear advantage data. Tartter discusses the changes in ear advantages which can be produced by altering the acoustic and phonetic properties of the stimuli. Bryden pops up again to review the
289
Book reviewer
relatively limited research on the lateralisation of affect. One practical lesson which might tentatively be drawn from this chapter is that crying, moaning and shrieking may be marginally more effective if delivered to the recipient’s left ear. A chapter by the editor discusses various forms of dichotic conditioning technique. The chapters vary from the stylish to the stodgy, though the majority are well written. In a book of this length devoted to a single topic some overlap between the contents of each chapter seems inevitable. The coverage seems unduly repetitive, however, in respect of certain general issues such as reliability and measurement, which could have been dealt with once within a single chapter. Absence of British contributors aside, there are no serious omissions though, after 646 pages, one would have welcomed some form of final editorial reflection. More serious is the poor standard of the subject index and the total lack of any author index. The “camera ready” print style is acceptable as far as the ordinary text is concerned but tables of data can be rather difficult to interpret in this format. The book is undoubtedly of great value as a state of the art report. At the end, however, one feels that rather more has been learned about dichotic listening than about what has been learned from using it. The main cause of this dissatisfaction, however, is the inability of current models of dichotic performance to cope adequately with the complexity of the data rather than, for all its faults, the technique itself. It is to be hoped that the central character of future editions will be made of sterner stuff.
The Polytechnic
Andrew Burton of Eust London
Reference Fodor,
J. (1983). The modularity of mind. New York:
J. ZOHAR and (PMA Publishing
MIT Press
R.H. BELMAKER (Eds.), Treating Resistant Corp., New York, 1987) pp. 427, $50.00.
Depression
I was initially reluctant to review this book, as I expected it to consist of a mix of opinionated special pleading and unconvincing case reports. I could not have have been more wrong. The contributors to this volume have made a concerted effort to review critically the efficacy and place of numerous modes of dealing with depressions that resist treatment with antidepressant drugs. Many of the authors are enthusiasts for a particular therapy, but, almost
S. HALLETT. and M. PRESTON, to Reseurch und Treatment (Longman,
Schizophrenia: An Harlow, 1988) pp.
It appears that this book was to be part of the Longman Applied Psychology Series. However, the preface suggests that as the writing progressed it became clear the authors were writing a “state of the art” book which has now been published separately from the series. Can any text book on schizophrenia be “state of the art”? Our increase in knowledge, if not understanding, especially of the biological aspects of schizophrenia, is so rapid that a book such as this, which is in essence an extended review, must be out of date before it is published. For the serious student of schizophrenia, original articles in journals are a must. But let’s not be too niggardly. This is, as far as it goes, an excellent review. Possible aetiological factors, genetic, biochemical, neuroanatomical, social and psychological, are well, if routinely, covered, as are the principal forms of treatment. Perhaps undue emphasis is placed on the importance of behavioural treatments (which I suspect are not very widely used in everyday psychiatric practice in British hospitals), but this is not surprising as the three authors are themselves clinical psychologists. In the last section the authors propose an “integrated model”. The model which tries to explain the development of schizophrenia, I found confusing and unconvincing; the integrated model of treatment is wholly acceptable. In summary, the authors are to be congratulated on their well balanced review. The question must be asked, however, at whom is the book aimed? It is too detailed for the postgraduate student, but contains little new for the serious researcher. Robin G. McCreadie Crichton Royal Hospit&, Dumfries
K. HUGDAHL (Ed.), Handbook of Dichotic Listening: Research (Wiley, Chichester, 1988) pp. 650, E45.00.
Theory,
A4ethod.r und
For over 30 years subjects have been asked to carry out an usual experimental task in which a pair of stimuli, often words, is presented simultaneously, one member of the pair to each ear. Usually the task (dichotic listening) is to report both stimuli, though there are numerous variations. Over a number of trials, performance on one ear often turns out to be superior to performance on the other, the direction and strength of this advantage being related to a host of factors, including the type of stimuli used, the task requirements and
Book reuiews
287
characteristics of the subject population. Increasingly, the main focus of interest has become the use of the technique for investigating brain-behaviour relationships and, in particular, hemisphere specialisation of function. This book attempts to provide a comprehensive and up to date review of current research, theory and applications of the dichotic listening paradigm. All the contributors are actively engaged in some form of dichotic listening work and the majority have a long and distinguished research involvement in it. The book appears to be the first volume of its kind and its appearance will be no doubt be warmly welcomed in view of the now Olympian scale, multidisciplinary character and fragmentation of the dichotic listening literature. In the first chapter Bryden provides a general and historical overview. This useful and lucidly written chapter is important because it so clearly describes the central character in the story which is to follow - Kimura’s “fixed structural model” of hemisphere specialisation - and successfully anticipates the key issues which repeatedly surface in different ways throughout the book. A clear grasp of this model is essential in a story in which, as Sidtis rightly comments, there are many subplots. As originally formulated by Kimura, the model requires that genuinely dichotic stimuli are used in order to achieve suppression of the ipsilateral pathways. The first challenge therefore comes from Bradshaw and Nettleton who argue that, for the great majority of tasks, monoaural presentations are sufficient to produce asymmetries and that is may even be partly the perceived rather than the actual position, or ear of presentation of a sound which creates asymmetry. Many contributors deal at length with the issue of performance variability within subjects which poses another potentially serious problem for the structural model. Some see the solution as essentially methodological. The most vigorous exposition of this line of argument is probably to be found in Wexler’s closely argued chapter which, while leaning rather too heavily on data from split-brain patients, argues that use of appropriate techniques, in this instance “fused” dichotic pairs of carefully selected short words or nonsense sounds, will produce ear advantages which are stable reflections of lateralised functions. The worry is that reliability may have been achieved, to some extent, at the expense of artificiality. In addition, as Speaks reminds us in a chapter on the statistical properties of dichotic listening scores, many other awkward issues remain unresolved, such as those concerning the validity of a method which typically produces a significant ear advantage in only a minority of subjects. According to some models of hemisphere asymmetry, ear advantages result from differences in how a task is processed, not from the type of stimuli used. On this view, variability is not an indication of poor methodology but a phenomenon which one would expect to occur when subjects use different processing strategies. Here, the dangers of circularity loom large since inconsistent asymmetry scores can be conveniently reinterpreted as “strategy ef-
fects”, different asymmetry scores being offered as “proof”. There is ample indirect evidence for such effects in various parts of the book and few contributors can resist the temptation to indulge in post hoc explanations of them. Nowhere is this more apparent than in the final sections concerned with reading disorders and psychopathology where inferences about lateralised processes are made from between group comparisons. Bruder makes heroic efforts to bring a sense of order to the performance of different groups of psychiatric patients. The torch is taken up by Nachshon who, after two misspellings of “schizophrenia”, struggles manfully with the various permutations of left/right hemisphere dysfunction/overactivation/underactivation which might account for the bewildering performance of schizophrenics on dichotic listening tasks. The lack of any clear framework for predicting between group differences is also painfully obvious in the chapters on developmentally based reading and related disorders by Obrzut and by Bakker and Kappers. Such flights of fancy are generally well controlled however and. fortunately, the majority of contributors recognise the circularity involved in such reasoning and attempt to provide some form of independent validation for such claims, though often this is merely correlational. A number of contributions describe research in which attentional strategies have been systematically controlled. Others discuss the use of signal detection theory analyses in separating the decision and sensitivity components of ear performance. It is clear from the Molfese and Adams’ chapter, however, that there is very little to be gained by using auditory evoked response for validation purposes, since the results so far have been disappointingly inconsistent. In one of the outstanding chapters of the book, Peretz and Morais write persuasively about hemisphere related processing strategies in their review of the literature on dichotic musical tasks. They reported findings in which circularity is avoided by using different sets of instructions to create different processing strategies. They conclude that the right but not the left hemisphere’s contribution to musical processing may have a modular basis in the sense envisaged by Fodor (1983). There are also chapters by Clark, Geffen and Geffen on dichotic monitoring, by Eslinger and Damasio on the phenomenon of paradoxical ear extinction in neurological patients and by Sidtis on dichotic listening after commisurotomy. Strauss discusses the evidence that verbal dichotic laterality effects are related to neuroanatomical differences. Hiscock and Decter give a detailed and careful examination of the statistical and methodological problems of using the dichotic listening technique with children. Harshman and Lundy write on the vexed question of the use of dichotic listening to measure “degrees” of lateralisation, their conclusion being that such inferences may be drawn with caution with some types of ear advantage data. Tartter discusses the changes in ear advantages which can be produced by altering the acoustic and phonetic properties of the stimuli. Bryden pops up again to review the
289
Book reviewer
relatively limited research on the lateralisation of affect. One practical lesson which might tentatively be drawn from this chapter is that crying, moaning and shrieking may be marginally more effective if delivered to the recipient’s left ear. A chapter by the editor discusses various forms of dichotic conditioning technique. The chapters vary from the stylish to the stodgy, though the majority are well written. In a book of this length devoted to a single topic some overlap between the contents of each chapter seems inevitable. The coverage seems unduly repetitive, however, in respect of certain general issues such as reliability and measurement, which could have been dealt with once within a single chapter. Absence of British contributors aside, there are no serious omissions though, after 646 pages, one would have welcomed some form of final editorial reflection. More serious is the poor standard of the subject index and the total lack of any author index. The “camera ready” print style is acceptable as far as the ordinary text is concerned but tables of data can be rather difficult to interpret in this format. The book is undoubtedly of great value as a state of the art report. At the end, however, one feels that rather more has been learned about dichotic listening than about what has been learned from using it. The main cause of this dissatisfaction, however, is the inability of current models of dichotic performance to cope adequately with the complexity of the data rather than, for all its faults, the technique itself. It is to be hoped that the central character of future editions will be made of sterner stuff.
The Polytechnic
Andrew Burton of Eust London
Reference Fodor,
J. (1983). The modularity of mind. New York:
J. ZOHAR and (PMA Publishing
MIT Press
R.H. BELMAKER (Eds.), Treating Resistant Corp., New York, 1987) pp. 427, $50.00.
Depression
I was initially reluctant to review this book, as I expected it to consist of a mix of opinionated special pleading and unconvincing case reports. I could not have have been more wrong. The contributors to this volume have made a concerted effort to review critically the efficacy and place of numerous modes of dealing with depressions that resist treatment with antidepressant drugs. Many of the authors are enthusiasts for a particular therapy, but, almost