This "living history" of the neuropsychological thinking of Lashley and Hebb provides the reader with useful, instructive and suggestive details on matters of priority, influence and perspective. Orbach's own expert knowledge of neuropsychology serves the reader well as the author assesses contemporary thinking in the brain sciences in light of the issues that so engaged the energies of Lashley and Hebb. But the greater service is bringing to print a number of Lashley's own lectures and essays (chiefly his Vanuxem Lectures) previously available only in special collections. Even the several previously published articles take on renewed importance as a result of Orbach's discussion and critical appraisals of contemporary thought.
2. Just under 400 pages, the volume is divided into two main parts, with Part Two presenting Lashley's Vanuxem Lectures and a number of carefully selected previously published essays. It is in Part One that Orbach discusses matters of theoretical attachment and priority, and the current and longer range implications of Hebb's and Lashley's positions. It is useful to pause to consider this matter of priority.
3. Orbach's Prologue begins with a passage from Lashley's final public lecture, given in 1957 at the University of Rochester; a lecture remarkable for what is never mentioned; viz., Hebb's (1949) by then celebrated and widely discussed "The Organization of Behavior" and its central theoretical concept of "cell assemblies". Orbach is of the view that Lashley had no need to comment on this, for Lashley years earlier had advanced most of the ideas that gave Hebb's work weight and promise: "...non-sensory control of behavor, the central autonomous process, mechanisms of attention, and the importance of Lorente de No's reverberatory circuit" (Orbach, 1998; p. xii). Matters of priority, however, tend to be elusive, especially in scientific realms of inquiry that develop progressively, bit by bit, as it were. One does not deprecate the contributions of Lorente de No or Lashley and Hebb in noting the fairly long and robust pedigree behind each of the central ideas discussed by Orbach. Certainly any historical account, even a quite general one, would include the experimental and technical writings of David Hartley, Robert Whytt, Marshall Hall, Alexander Bain (though see Milner's comments on p. 16), and David Ferrier, not only as important precursors but even as perhaps surprisingly detailed anticipations of the theories under consideration; and this cites only the British contingent.
4. The point here is not one of priority or, alas, pedantry! Rather, in light of the historical persistence and repetition of such notions, and in light of the significant technical progress and enlargement of the data-base taking place over this same span of time, one must ask whether these very notions are, at base, "theoretical" in the fuller scientific sense of the term. This issue is clearly too large for the space reserved here. It is sufficient to point out that neither Orbach nor Lashley and Hebb can be found considering this possibility. At the level of anatomical elaboration and dynamics, the vertebrate nervous system is at once the theoretician's dream and nightmare: It instantiates any pet theory, for it instantiates all of them.
5. In the first chapter ("Setting the Stage"), Orbach rehearses the influence of Lashley's teacher, John B. Watson, on dampening enthusiasm for physiological theorizing: Watson's S-R psychology, which seemed to leave out the brain. Of course, Watson's confidence in his behaviorism was fortified to some extent by Pavlov's research and theory and, though Watson resisted the notion of gremlins digging associational grooves in the brain, he was not indifferent to the relationship between a behavioral and a physiological psychology. By the same token, Lashley was not uncritical in assessing the mechanisitic neurobiology of the same period (Orbach, 1998; p. 133). If there was a more or less official declaration of independence, it would come later, in the final pages of Skinner's Behavior of Organisms (1938), which defends the project of a "purely descriptive" science of behavior that need not await enlightenment from the physiology laboratory. By then, of course, Lashley's overall project was in full swing and could number among its successfully vanquished critics a Skinnerian behaviorism that had yet to be born. Orbach offers Lashley's specific comment on this in a 1952 address excerpted on pp. 111-112. What Lashley understood so fully is that a mechanisitic Pavlovian neuropsychology, like a Skinnerian descriptive behaviorism, becomes ever less credible the more broadly one samples from the rich and various realms of behavior.
6. Lashley and, years later, his student Hebb, would both find in Lorente de No's "reverberatory circuit," the means by which the past could be preserved within the central nervous system. Once established, such circuits give the brain autonomous activities no longer requiring external stimulation. "Mechanism" now gives way to dynamism and to what, in the idiom of a later time, would be seen as a self-organising system. The famous search for the engram would end less in failure than in a perspectival shift: It isn't anywhere, for it is more or less everywhere that duplicated or resonant processes are generated. The search itself may have begun as early as Lashley's sixteenth year when, for 25 cents an hour, he cleaned the basement of the Zoology Department at the University of West Virginia and became transfixed by Golgi series for the frog brain (Orbach, 1998; p. 115). Orbach reminds readers that Lashley's focus on the cerebral cortex was responsible for his skepticism and that he "might well be astonished to learn that Richard Thompson has proposed the cerebellum as the site for memory traces of the classically conditioned response" (p. 24). Yet, so much in Lashley resists place-theories that it is less than certain "traces" would astonish him more if found in cerebellum than, for that matter, in the Islets of Langerhans.
7. In the matter of reverberatory circuits and "field theories", it appears that Lashley remained wedded to the notion that cell-to-cell activity, only after some other mode of integration, may come to comprise a "field" (Orbach, 1998; pp. 29-30). What is missing in the account oddly for an "instinct" theorist is an appreciation of the degree of "pre-wired" cell-to-cell activity (which is to say pre-established "fields") that must already determine (because they are) the cell-to-cell complex influences and dependencies. If there is an important distinction to be made here -- for Lashley was surely a "field" theorist -- it has to do with a system whose "tuning" is in place for there to be resonant circuits. By 1949 Lashley is still tentative on the point, noting only that "evidence is accumulating" in favor of the view that "organization within integrative centers...is entirely different from (a) simple chain conduction" (Orbach, 1999; p. 186). Yet, even here, there seems to be a sensed difference between "organization" and what might be understood as richly rather than simply chained influences. (Thus, if stubbornly, I am inclined to believe that Lashley "thinks cell-to-cell activity is different from, rather than the source of, the field"; Orbach, 1999, p. 29).
8. Regarding his credentials as an instinct theorist, Lashley's scientific and, shame to be told, racist ideas are both given full and fair treatment by Orbach. His constructive writings and teaching on the subject would influence such of his students as Frank Beach; his deplorable prejudices, one hopes, influenced no one. Both he and Hebb left ample room for instinctual processes even at the level of associative learning, but neither filled the room with much beyond granny's furniture, as refinished and wonderfully arranged by Darwin, George Romanes, Conwy Lloyd Morgan, et al. For Hebb, "instinct and intelligence differ in complexity of mechanism" (p. 39), a position at once startling and revealing when taken by someone possessed of so high an intelligence. Nor was Lashley's own understanding of intelligence (Orbach, 1998; p. 78) relevantly different, at least as this understanding would be developed in "Brain Mechanisms and Intelligence" (1929). If Hebb found no more to the matter than a "complexity of mechanism", Lashley was content that "it" was genetically fixed and sampled validly by such chores as maze-learning. These and kindred conclusions from Lashley and from Hebb reveal the source of their (generously bequeathed) confidence in the range and reach of the brain sciences; a range and reach claiming to get hold of emotion, motivation, learning, memory, intelligence, creativity. Such passages could have (and, indeed, did) come from Pierre Cabanis a century and a half earlier; the Cabanis described by Carlyle as one who, "goes through a world of wonder unwonderingly".
9. Especially interesting (for they still defy easy explanation in mechanistic terms) are Lashley's famous studies of recovery of function, of the use of pathways non-functional during learning, etc. This is fully developed in the Vanuxem Lectures with which Part Two of the volume begins. It is here that the concept of equipotentiality grows out of imaginative research which, at the same time, raises doubts about the adequacy of "synaptic resistance" theories of learning and memory. As for the research itself, Lashley appreciated (even if he was not self-consciously guided by) William James's psychologist's fallacy. What one is prepared to say about the powers and achievements of human beings and non-human animals depends crucially on how one goes about sampling these very powers and achievements.
10. Lashley admits that for nearly a decade he and any number of scientists were convinced that dogs and rats were nearly blind, until the right sort of assessments were introduced (Orbach, 1998; pp. 177-178). But if thus awakened from one dogmatic slumber, he seems (along with so many of his colleagues and scientific descendents) to drop off into another. The mammalian nervous system did not evolve under the selection pressures of the Psychology laboratory. Less was it expected to reveal itself clearly only after having been macerated by the scalpel and the anatomical blowpipe. If such a laboratory as recently as 1920 led thoughtful persons to regard dogs and rats as nearly blind, one can only wonder how it continues to shape thinking. If one would come to grips with the complexity and plasticity of adaptive behavior, one wisely goes to where that behavior is shaped and tested daily, hourly, even by the minute. And when one reaches that privileged position of the observer of nature, one is careful to disturb as little as possible, and surely as little of the brain and body as possible. Here the confluence of ethical high-mindedness and scientific aspiration is perhaps most complete. But nowhere in this otherwise fine and instructive volume are such utterly pivotal issues given the attention they should have demanded of Lashley, Hebb and Orbach himself.
11. If that one pivotal question is essentially ignored, it is not because Lashley and Hebb were timid about addressing each and every quaestio vexata. Consider only Lashley's heroic entrance into that enduring fray, the mind/body problem (Orbach, 1998; pp. 327-378). The careful reader will find in these pages as much analytical rigor and substantive use of clinical and experimental findings as any contemporary philosopher or scientist, of materialist persuasion, has offered. In a word, there is a neurophilosophy here rather more informed and informing than current popular ("pop"?) versions. Lashley, of whom it may be said that he had a vocation before the age of careers, had read Haeckel and Huxley, James, Wundt, Titchener and McDougall, Sherrington and Pavlov; he read those who had given definition to the scientific side of the dispute. But he had also read the philosophers, the ethologists, the poets, even Kant! If, in the end, he concluded that "mind has no attributes other than its organization" and that "this particular organization by which alone mind can be defined is the organization of the activities of the brain" (Orbach, 1998; p. 329), he reached this conclusion by default. Alternative theories he judged to be either groundless or weaker or less in concert with the laboratory and the clinic. That he misreads Descartes (e.g., p. 332) seems by now to be an entrance-requirement for the College of Positivistic Cognitive Neuroscience: "I eat, therefore I am", indeed! (p. 333). And he certainly lived long enough for his own reflections (pp. 333-334) on the "privacy of the mental" to derive more rigorous support from Wittgenstein. But against the pardonable lacunae and occasional howler can be projected arguments and understandings at once forceful and original. In an age in which the "brain sciences" are serving up so many volumes best described as "thick but thin", it is gratifying to have one that is "thin but thick".
Hebb, D. O. (1949) The Organization of Behavior: a Neuropsychological Theory. New York: Wiley.
Lashley, K. S. (1929) Brain mechanisms and intelligence: A quantitative study of injuries to the brain. New York: Dover.
Orbach, J. (1998) (Ed.) The Neuropsychological Theories of Lashley and Hebb. University Press of America
Orbach, J. (1999) Precis of: The Neuropsychological Theories of Lashley and Hebb. PSYCOLOQUY 10(23). ftp://ftp.princeton.edu/pub/harnad/Psycoloquy/1999.volume.10/ psyc.99.10.029.lashley-hebb.1.orbach http://www.cogsci.soton.ac.uk/cgi/psyc/newpsy?10.029
Skinner, B. F. 1938. The behavior of organisms. New York: Appleton-Century-Crofts.