Newsstands in the 1980’s have spread the word about differences between the two halves of the brain: The left side is said to be verbal and intellectual, the right spatial, creative, intuitive. Popular books suggest exercises to suppress the left brain’s rigid rationality and thus unleash previously unsuspected abilities in drawing, writing, nonlinear thinking, even mental telepathy. The concept of hemispheric specialization, however, is far from new. In Medicine, Mind, and the Double Brain: A Study in Nineteenth-Century Thought, Anne Harrington recovers the lost history of nineteenth century thought about the existence and nature of differences between the two sides of the brain and persuasively demonstrates the manner in which science—and particularly that science which tells human beings about themselves—is shaped by a society’s values, interests, and intellectual milieu.
The very claim that science, based only on observable reality, is purely objective and value free is, itself, the expression of a set of values. Scientific research grows from practical objectives which are socially determined and, even in its “purest” form, is contextually marked by the values and interests of the cultural climate within which scientists work. These values shape the topics thought worthy of investigation, the questions that are asked (and those that are ignored), the kinds of experiments that can be conducted, the hypotheses that are shaped, the nature of evidence deemed sufficient, the uses to which new discoveries are put, and even the actual content of the observations that are made.
Harrington’s study is thus both a history of science—a careful, detailed work which clearly explains nineteenth century theories and experiments—and an extended essay in conceptual history, which analyzes the context and implications of particular scientific investigations. It impressively demonstrates the strengths contemporary scholarship has gained through crossing the boundaries between traditional academic disciplines. The thesis that ideology shapes science is developed with depth and care, avoiding simplistic complaints—for example, that research has become so expensive that only the government can fund it or that scientists are quintessentially male beings driven by their intensely competitive egos in a race for power and glory, the ultimate aim of which is to conquer nature and all that is natural. Harrington’s sophisticated analysis demonstrates an impressive grasp of psychology, neurology, and several varieties of history (intellectual, political, social); it also makes use of tools drawn from literary criticism to examine the imagery and subtext of scientific writing.
A swift overview of the changing nature of scientific interest in the asymmetrical brain may serve to clarify the concepts. Curiosity about the nature of the brain’s two hemispheres began as a theological problem: Where, in this apparent pair of structures, might it be possible to locate a single, unitary seat of consciousness which could be identified with the soul? A further difficulty arose in the late eighteenth and early nineteenth centuries, as the developing sciences of neurology and phrenology suggested that various parts of the brain were responsible for single, specific functions. Although phrenology bore the germ of a hypothesis that would eventually be refined and verified by physiological experiments, the theory itself did not originate in experimental evidence. It appears to have been primarily a product of the eighteenth century’s predominant intellectual focus on organization and classification: Something so complex as the human mind must also be subdivided, structured, and carefully organized.
Yet, the concept of the brain as a collection of localized functions, without any overriding organ of direction, threatened the religious beliefs of many early nineteenth century scientists. Experiments on birds and rodents were used to reveal that the cerebral lobes apparently controlled sensation and volition, although purely physiological processes could be sustained after they had been surgically removed. Consciousness could therefore be ascribed to that part of the brain which was (happily) most highly developed in the human species. Working with—and beyond—the available evidence, influential physiologists postulated that the two halves of the cerebrum were identical and functioned simultaneously, in synchronized harmony. This conception was theologically appropriate and also satisfied prevailing aesthetic ideas of beauty in symmetry.
In the 1860’s, however, the work of Paul Broca, who examined the brains of deceased persons who had suffered from loss of language facility in their lifetime, compelled attention. A number of physicians and researchers began to compile observations and experiments which...
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