Book Review: Cognitive Neuroscience of Emotion, edited by Richard D. Lane, M.D., Ph.D., and Lynn Nadel, Ph.D. New York, Oxford University Press, 2000, 431 pp., $60.00; $35.00 (paper).
Evidence linking specific psychological faculties to localized brain areas has been available for only 150 years, yet distinctions among the features of mental life have been made for thousands of years. Aristotle, for example, divided brain function into cognitive, emotive, and willful processes. This ancient distinction between cognition and emotion is reflected in the structure of the various DSMs of APA, which begin with a section on the disorders of cognition and distinguish them from disorders of mood, and in most training programs, where psychiatrists receive little training in the disorders of cognition and neurologists receive little or no training in the disorders of emotion.
The utility of the distinction between cognition and emotion and questions about its grounding in the brain’s neural substrate are explored in Cognitive Neuroscience of Emotion. This volume is the product of a meeting held at the University of Arizona and is to be commended for presenting a variety of viewpoints on this fascinating question.
Is an alternative view viable? Does research support the view that the distinction between emotion and cognition is artificial? The book addresses these questions by beginning with overviews by Damasio and by Clore and Ortony. They review studies in which techniques used by cognitive scientists have been applied to the study of emotion. Damasio concludes that emotions and feelings should be distinguished and that the failure to make this distinction lies behind the paucity of studies in the brain basis of emotion. The evidence that he offers to support his view is weak, but he does demonstrate the value of studying both emotion and cognition with the same neuropsychological and imaging methods. The distinction between emotion as an externally observable state and feelings as an internal experiential state could be validated if distinct physiological substrates were found for the two. Even if the distinction cannot be supported, it may serve a utilitarian purpose because physiological responses are easier to study. At this point in history, claims that the internal experience of feelings (or emotions) will yield to the methods of neuroscience are similar to the claim that the neural basis of consciousness will be discovered—promises rather than results. Nevertheless, data-based approaches to these issues are the only way to move beyond the realm of rhetoric.
The second section of this book reviews the potential role of the amygdala in the genesis, persistence, and interpretation of emotion. The demonstration that emotional expression is associated with a locus or loci does not prove that the distinction between cognition and emotion is artificial, but these chapters review a wide range of experiments whose results suggest that processes traditionally called “cognitive” are operative in animal behaviors that appear to reflect human emotion. The third section reviews human research more directly. Lesion studies and skin conductance studies support the contention that the amygdala is involved in human emotion, but they also demonstrate the involvement of other brain regions. The hypothesis that the complex mental phenomena we refer to as emotion involve multiple structures, pathways, and molecular mechanisms is supported by much more data than the hypothesis that there is a single “emotion center.” The last section of the book examines the effects of brain lesions on emotional function. Again, there is abundant evidence linking emotional activation to multiple neural pathways. This line of work does not directly address whether cognition and emotion are distinct or entwined brain capacities, but it does provide a set of methods by which neural mechanisms can be dissected.
Although the central question of the book is yet to be answered, this volume demonstrates clearly that the emotion/ cognition interface is an important area of study and that progress is being made along many fronts. The ultimate answer may well be that both views of the emotion/cognition dichotomy are true: these states share some circuitry and molecular mechanisms but also involve distinct loci and mechanisms. A much better understanding of the neural substrates of both emotion and cognition will undoubtedly develop, but new conceptual models of CNS organization and function may be needed before a comprehensive understanding emerges. Readers interested in the even more radical view that our current conception of the term “emotion” needs to be rethought and perhaps even discarded will enjoy Paul Griffiths book, What Emotions Really Are: The Problem of Psychological Categories (1).
1. Griffiths PE: What Emotions Really Are: The Problem of Psychological Categories. Chicago, University of Chicago Press, 1997
PETER V. RABINS, M.D., M.P.H.