A Review Of Steven Lehar's
The World In Your Head: A Gestalt View Of The Mechanism Of Conscious Experience.
Mahwah, New Jersey and London: Lawrence Erlbaum, 2003. 298 pages.
Victor Daniels, Philosophical Psychology
Gestalt psychology, psychophysics, and phenomenology are all alive, well, and engaged in fascinating dialogue in Steven Lehar's The World in Your Head: A Gestalt View of the Mechanism of Conscious Experience. Also vigorously involved in the discussion are neurological and mathematical models of perception. The dialogues among all these that emerge from Lehar's thinking make for an intriguing conversation about how visual perception works.
Like Kurt Goldstein several decades ago, Lehar is exploring the workings of both mind and brain, not just one or the other. He moves artfully back and forth among the phenomena of subjective experience, perceptual models of such experience, and neural processes that underlie what we perceive. He advances novel yet compelling models of perception that are fascinating in their implications.
It is refreshing to encounter a hard-nosed scientific writer who is truly interested in experience itself. Lehar's inclusive epistemology demonstrates that qualitative reports of the world as naively experienced are both a (1) a compelling area of inquiry in its own right; and (2) an invaluable testing ground against which we can assess our neurological and mathematical models to determine whether they are sensible explanations of what they purport to represent. As a basic criterion for evaluating a theory or conceptual model, he uses the question, "Can this model account for the experience that we have as we perceive something?"
A relentlessly holistic emphasis runs through the book. When Lehar examines any individual process or phenomenon, it is not long before he examines its place in the larger whole of our perceiving and thinking. In so doing, Lehar returns to the roots of Gestalt theory in Max Wertheimer's thinking. Fully understood, Gestalt theory is as much a philosophy, and a way of conceptualizing a person's whole way of being-in-the-world, as it is a tool for the examination of specific phenomena in perception or learning. This is demonstrated clearly in Kurt Lewin's application of Gestalt theory to understanding personality dynamics and social phenomena, and Fritz Perls' use of it in developing a truly holistic therapy. Here Lehar both draws on the thinking of Wertheimer, Wolfgang Köhler, and Kurt Koffka, and extends certain important aspects of Kurt Lewin's field theory. And then he offers us a view of the perceptual process that is itself an integrated Gestalt. He may be right or wrong in some of the details, but he has stated his formulations clearly and specifically enough that they are testable, so that the model can be modified in accord with the results.
A primary question addressed by Lehar, is that of, "Do we perceive the world directly or do we form a representation of it with our senses and then perceive that representation? This crucially important paradigmatic dichotomy between naive realism and representationalism, direct versus indirect perception, has been a point of disagreement among phenomenologists, yet one that has been largely glossed-over. Lehar identifies this as a central paradigmatic question. He will not allow us ignore it any longer. Differences on this central issue, he asserts, underlie the more superficial differences between atomists and holists, who often argue at cross-purposes due to lack of consensus on this crucial point.
The central element of Lehar's model hearkens back to the early Gestalt psychologists' demonstrations that even the most direct and immediate experience, such as the perception of a three-dimensional object, is already far removed from the sensory stimulus, so that we do a great deal of perceptual processing without awareness that we have done so. What we "experience", Wertheimer and his colleagues found, is not the event itself, but the result of an initial processing that occurs in the process of sensing the event and representing that sensation in our consciousness. In that sense, phenomenologist Merleau-Ponty's goal of truly attaining a "first opening" on the world that exists before our mind has acted on it in any way is the impossible dream, forever just beyond the reach of our grasping fingertips. "The most direct contact possible" is the most the phenomenologist or anyone else can hope for.
Lehar notes that while the basic properties of visual processing revealed by Wertheimer's Gestalt illusions and laws of perceptual grouping receive obligatory nods in psychology textbooks, there is little real contemplation of what they imply about the nature of our visual processing and its neurological substrate. "Any model that fails to address the Gestalt phenomena of perception," he writes, "is worse than no model at all, for it is a diversion from the real issues of perception." (p. 57)
A central question raised by this assertion is that of whether the brain represents the outside world through an analogical kind of functioning or through a sequential form of neural storage analogous to that of a computer, translating visual stimuli into something like a binary electronic code. That kind of neurological model, he asserts, goes hand-in-hand with naive realism's assumption that we perceive the world "directly." Lehar's studies and models focus most intently on that aspect of conscious experience which cannot be accounted for by either a naive realism or a non-representational neurological model, namely the solid three-dimensional volumetric structure of visuospatial experience.
Lehar argues that outside events are represented in a spatial manner in the cerebral cortex, that in some manner the brain forms an isomorphic representation of the visual stimuli we perceive. That is, the neurological representation of a three-dimensional image in visual experience is actually a pictorial representation of some kind in our physical brain. Most modern researchers take some kind of intermediate position, recognizing that all experience is mediated by the brain, but denying that the brain contains any explicit "pictures."
The kinds of observations and measurements of neural activity that are most typically made in contemporary neuroscience, suggests Lehar, are made because of investigators' commitment to assumptions that underlie the theoretical position of some kind of numerically-coded neural representation and processing system. Advancing the alternative conception of an "object-centered" cortical map of the world, (146-8) Lehar points out that "unlike a neural network model, the output of a perceptual model can be matched directly to psychophysical data, as well as to the subjective experience of perception." (p. 31)
In this discussion as throughout the book, I appreciated the clear presentation of views opposing his own as well as the presentation of his own analyses and models.
I was pleased by the explicit identification of the role of our physical bodies in perception...the whole body, not just the brain. "Perception is embodied by its very nature, for the percept of our body is the only thing that gives an objective measure of scale in the world." (p. 43) There are no disembodied brains in this outlook!
Another central theme is the importancce of developing models of perceptual systems that bring us closer to understanding how perception, and especially visual perception, actually occurs. A fascinating description of the "bounded nature of the perceptual world" examines the phenomenon of perspective, and how it is that form perceptions of parallel lines from stimuli that appear to converge if we contemplate the images that actually fall on our retina.
After a detailed examination of the way we internally represent two-dimensional images that fall on the retina as three dimensional objects in three-dimensional space, the book goes on to examine the process of perceiving objects that are partially concealed from view.
There are also interesting discussions of the phenomenon of apparent motion that was originally identified by Wertheimer, of how we infer depth from texture and motion, and of how we extract shape from shading and motion. There is detailed examination of the perceptual response to many variations of visual stimuli, such as in what happens when you add colored highlights to a monochromatic light source.
Perhaps the piece de resistance of Lehar's conceptual meal is his harmonic resonance theory of perception. It builds on Karl Lashley's (1942) suggestion that "the phenomenon of harmonic resonance, or the representation of spatial structure expressed as patterrns of standing waves in a resonating system" best represents invariances in perception. Lehar provides a thorough scholarly review of the unique properties of harmonic resonance identified by previous investigators in other disciplines such as physics as well as by psychologists, and explains methods for observing them. This review includes a careful appraisal of the neurophysiological and psychophysical evidence that bears on his hypothesis. Lehar follows this with a description of several distinct forms in which harmonic resonance patterns occur, and then goes on to point out that numerous phenomena that have been "explained" by other theories "are actually manifestations of harmonic resonance." He describes several differences between older models of perceptual recognition and shows that the resonance theory accounts for Gestalt properties of perception better than any other that has been advanced.
As I contemplated the harmonic resonance theory, I found myself extending it to such phenomena as "complexes" of thinking, affect, and behavioral tendencies that are related to traumatic past experience, and to opinions, beliefs, and attitudes that persist despite the existence of contradictory information. A group of strong standing waves in the brain would interfere with the formation of waves associated with alternative responses to recollection of the trauma, or with an alternative opinion, belief, or attitude.
After the chapter on harmonic resonance theory, the remaining three chapters are like dessert--not a necessary part of the meal, but delicious.
In a chapter titled "Motor Control and Field Theory," I loved Lehar's use of a backhoe's hydraulic controls to illustrate his field theory of motor control, including posture, gesture, and even driving and navigation. A former commercial pilot, he does not languish in an ivory tower. Like the stonecutter Socrates, who was better known as a philosopher, Lehar's concepts have roots that extend right down into the building trades.
A chapter on "Image Theory of Language and Cognition" mirrors the conceptual leap made by early Gestalt psychology as it moved from the study of perception to the study of learning. From there the book goes on to end with an interesting chapter on the biological components of culture, with special attention to aesthetics and the arts, especially visual art. And lest anyone accuse him of insensitivity to the broader spectrum of experience, he devotes a few pages to a conceptual analysis of spirituality, paranormal phenomena, and psychedelic and mystical experience. He devotes a few pages to left-brained and right-brained thinking, and then describes potential avenues of future investigation. He advances a psycho-aesthetic hypothesis that "the laws of artistic composition. . . can be seen as evidence for the laws of visual structure encoded in the brain." The final pages elaborate on the goal of producing an "artificial mind that works on the same essential principles as our own."
This book delves more deeply into the details of visual perception than anything else I've read. At times I almost felt myself vanishing into Lehar's models, such as, for instance, one in which there is an imagined little man standing inside an archetict's model of a building, like the protagonist in the movie TRON vanishing into the computer.
Lehar is an astute observer of the phenomena of his own visual experience, using these as the grist for an keen conceptual analysis. The pages of his book are informed by numerous interesting examples of what people characteristically do in their perception of their every day world, such as, "people generally gaze ahead while walking, but when they stop, after an interval, they usually begin to look around them at regular intervals, to refresh their mental image of the world around and behind them." (p. 112)
There were plenty of what I, at least, perceived as brilliant little flashes of insight sprinkled throughout the book. After pointing out limitations of a widely held model of perception, he delclares, "I propose that abstraction and reification are complementary functions in perception, for the abstract code defines the pattern or skeleton of the percept to be filled in by reification processes."Along the way, I gleaned some interesting concepts from information theory that were previously unknown to me. The depth and breadth of scholarship is more than impressive, and some of the carefully chosen quotations are wonderful, such as Sherrington's image of the brain as "an enchanted loom where millions of flashing shuttles weave a dissolving pattern. . . ."(Sherrington, 1941, p. 173.)
In an appendix, Lehar provides mathematical proofs of many of the psychophysical assertions in the text, for the benefit of mathematically-minded readers who do not find the verbal exposition sufficiently convincing.
I think it is reasonable to suggest that The World in Your Head is a seminal work that is destined to become a fixture in the conceptual landscape which no one seriously interested in the study of perception can reasonably ignore. It's hypotheses, models, implications, and extensions are likely to influence investigators for decades to come. It is obviously a "must read" for anyone interested in visual perception, and in neurological representations of perceptual phenomena. And it is a paradigm of a multimodal epistemology that takes multiple dimensions of experience, behavior, and neurology into account.
The last line of the acknowledgments refers to "the many years that it took to produce this book." I believe it.