286 Book recliews

recommends total limb investigations, rather than observing individual joint motor patterns, to identify control strategies. He presents a task-related theory with strong empirical support.

The fourth section contains two chapters on coordination and movement disorder. First, Phillips, Miiller, and Stelmach advocate investigating move- ment disorders because the findings will provide converging evidence in understanding the processes and mechanisms involved in motor coordination. A considerable amount of this excellent chapter centers on patients with Parkinson’s disease and the motor functions of the basal ganglia. The cerebellum and coordination are also extensively discussed.

Speech disorders are the focus of the second chapter. Kent and Adams present interesting information on speech and coordination, procedures for measuring speech impairments, data on specific disorders (e.g., stuttering and dysarthria), and theories of speech control. To fully understand speech disorders and compensations entails an integrated levels of coordination approach (i.e., segmental convergence, auditory-motor linkage, and sensory- motor connections).

This book is highly recommended as a reference for motor control/ learning scholars, graduate students, and advanced undergraduates. It con- tains comprehensive and thorough reviews of movement coordination from both theoretical and empirical perspectives. A majority of the chapters are written as tutorials. The new perspectives in the conceptual approaches section are especially well done.

One minor weakness is the absence of overviews or summaries (e.g., editorial comments) on each of the four topic areas. However, the quality of the diverse approaches and methodologies for studying movement coordina- tion offer wide prospects for future research.

James H. Cauraugh Motor Behavior Laboratory - 2.5 FLG

Exercise and Sport Sciences University of Florida

Gainesville, FL 32611

USA

G.E. Hinton and J.A. Anderson (eds.1, Parallel Models of Associative Mem-

ory. Updated edition. Erlbaum, Hillsdale, NJ, 1989.

Ten years have past since this collection of articles was first published. At that time, parallel models were not widely known in the scientific community and its emphasis on mathematics and neurophysiology of the brain did not

Book reciews 287

help to make this work more accessible to the average experimental psychol- ogist. Since that time, things have dramatically changed. Not only has the area itself been developed considerably in the past decade, the most signifi- cant change has been that this type of modelling approach has gained widespread interest (and not just in the scientific community) and has, under the title of ‘neural nets’ or ‘connectionism’ in fact become something of a fad. However, the majority of the work and the focus of the public interest has been on applications of those models to practical problems and this has led to less attention to its potential as a model for human information processing (most of the ‘neural netters’ only seem to pay lip service to the neurophysiological aspects).

It was therefore a prudent decision to publish an updated edition of this volume in the Cognitive Science Series. However, it is a pity that the original volume is ‘updated’ in only a very limited sense. What the editors have done is add an (interesting) introduction which gives a nice summary of the recent developments in the area (especially in a sociological sense). In addition, each of the chapter authors has provided a brief resume of later develop- ments on that particular topic. Most of these however are too brief to provide much substantial information.

As mentioned above, the most interesting aspect of this new edition is the introduction by Hinton and Anderson. They describe how the emphasis in the field of neural networks has changed from models of memory and thought processes to computational models for applied tasks. It has (espe- cially in the form of ‘backpropagation’) become a method instead of a theory. In this respect, it is enlightening to compare the old introductory chapter by Hinton and Anderson (reprinted also) to the newer one.

Consider as a computational method, neural networks have been quite successful although their exact nature and its relation to conventional tech- niques (especially statistical methods) is often not well understood by many enthusiastic followers. This emphasis on the computational aspects of neural networks has overshadowed (in terms of number of publications) the more psychologically interesting aspects of these models. It would be nice if this new edition would lead a re-emphasis on psychological and neurophysiologi- cal issues.

The various chapters in this volume give many interesting examples of parallel distributed models. These models represent some of the best work that was done in this field prior to the big connectionist boom. For example, one will find chapters on holographic models (Willshaw), Kohonen’s work on associative memory, Anderson’s Brain-State-in-a-Box model, aspects of se- mantic memory (Fahlman, Hinton) and visual memory (Feldman) as well as some chapters of a more technical or programmatic nature (Sejnowski, Geman). The chapter by Anderson and Hinton gives an excellent introduc-

tion to the early history. The chapter by Ratcliff seems to be a bit out of place in this collection since it represents a parallel model in a somewhat different sense: it does not assume a parallel representation but (only) a parallel retrieval process. Nevertheless, for those interested in human mem- ory, the model represents an important approach that has not been given the attention that it deserves.

It is a pity that the various comments that have been written for this updated edition are not only short but also a bit superficial and do not give much helpful information to the (uninitiated) reader. Another point that is quite evident, is that the various models as presented here are quite pro- grammatic. That is, the models deal with possible architectures of human memory but are rarely used to really explain actual data of memory experi- ments. Basic problems such as noise-resistance, incomplete cues, forgetting and interference are not often discussed. Recent work on the so-called ‘catastrophic forgetting’ problem suggests that problems might arise if these models were actually put to test. Nevertheless, they represent an important advancement in the theoretical analysis of human memory because they provide actual mechanisms for one of the key aspects of human memory, namely that it is content-addressable. As such, this volume is a classic and required reading for all those interested in the theoretical analysis of human memory.

Jeroen G.W. Raaijmakers TN0 Institute for Perception

P.O. Box 23

3769 ZG Soesterberg The Netherlunds