Vision and Mind: Modeling Mental Functions.

Vision and Mind: Modeling Mental Functions Vadim D. Glezer 1995, Lawrence Erlbaum Associates, Publishers 10 Industrial Avenue, Mahwah, NJ 07430 ISBN 0-8058-1668-2 274pp. $59.95

Although this book is not directly related to the giftedness or creativity, it may be of interest for those readers who are interested in understanding the mental functions from the standpoint of vision. The author points out that ninety percent of the information we obtain is transmitted through the eyes, and argues for a close interrelation between vision and thought by citing the plain English that "we say, `I see,' when we mean, `I understand'."

Using a neurophysiological approach to the modeling of mental functioning, the book focuses on vision as the creator of the model of the visual world and discusses the principles of organization of concrete thought in terms of the neural nets of the visual system. Indicating the inadequacy of black box methods used for studying mental processes in other domains (e.g., psychology, linguistics, logic), Glezer takes into account brain structure and the mechanisms that perform certain operations, in its attempt to understand the model of the visual world. While Glezer looks inside the black box (the concrete neural structure) and displays the whole process of the transformation stage by stage, it may not sound very concrete to readers who are not used to sensory physiology.

The book examines the whole process of the transformation and description of visual information (i.e., from the description of visual space to the description of individual objects and the relationships between them), by analyzing the functional organization of the neural structures that gradually form universal categories such as thought and language from "raw" sensory material. Indicating that the module, not the neuron, is the functional unit of the brain utilized for the performance of its highest functions, Glezer discusses the model of functional modules as he defines modules as the functional units of the brain that segment the field of events (the real world, e.g., scenes, concrete images) by separating the events and then describing them.

Glezer distinguishes the visual system into four levels. The information processing at the first level (Chapters 1 and 2) involves the description of the image by the multiplicity of receptive fields (RFs) in the subcortical areas. The neurons of the retina and the lateral geniculate nucleus (LGN) measure the integrated light energy in the central summation zone of the their RFs. The neurons carry out a series of preliminary processing operations such as separating the signal from surrounding noise. The description of the visual field at this level is made on a point-to-point principle, and a foundation is created for the transition to local spectral analysis at the nest level, in the striate cortex.

The receptive fields at the second level of the visual system form a two-dimensional lattice of spatial-frequency filters (Chapters 3 and 4). The fields measure the spatial-frequency and orientation components of pieces of the image. Psychophysical and behavioral investigations revealed a functional order in the neural nets of the visual system: The spatial and spatial-frequency characteristics are in harmonic Pythagorean relation, which points to the model of modules. A module is formed by receptive fields of identical size, but different orientation, projected to the same region of the visual field. For every image, the module of appropriate size and position is selected from the net of modules overlapping the central part of the field of vision.

At the third level of the visual system (Chapters 5 and 6), prestriate neurons produce a local basic description of the image. The modules of the prestriate cortex analyze the images that are organized by texture or are segregated with the aid of binocular parallax or motion parallax. This level is proposed by Glezer based on new, additional findings, and the author stresses that this level is very important because the real object-forms are mostly composed of textures.

The author postulates the double dichotomy of the visual brain at the fourth level (Chapters 7 through 11). The two primary higher division of the visual system--the inferotemporal cortex (ITC) and posterior parietal cortex (PPC)--put the information they have gathered to different uses. Glezer indicates that the important feature of this level is that it contains neurons that learn. Using the experimental results with monkeys and cats, the author reports the different structures found in the right and left hemispheres. For example, in the right ITC, images are described and stored by unifying the elements of the image that have been distinguished by the modules of the striate or prestriate cortex: the structural method. In the left ITC, image recognition is performed using complex discriminant features: the discriminant method. At this level, spatial relationships between images or between parts of a single image are represented, and relationships that entails any logical connection between objects are described. Information about the motivational demands is represented in the PPC.

Indicating that any act of visual perception entails the comparison of new information with the whole organized model of the world stored in the visual cortex, accompanied by the simultaneous supplementation and development of this model, the author concludes that an act of visual perception should be seen as an act of object thinking. In Chapter 12 ("A perceptual model of the world"), the author discusses the neurophysiological correlates of abstract thinking and language, not in terms of concrete neural structures, but of general principles.

The book combined the views of various scientists' and the author's own experimental results to present the model of functional modules. Particularly, the author synthesized three discoveries made in the second half of the 20th century in the neurophysiology of neocortex: the modular construction of neocortex, the orientation selectivity of cells of the visual cortex, and the operation of the cells of visual cortex as spatial-frequency channels. The research evidences provided in the book are extensive: throughout the book, dynamic graphics of the experimental results were presented to help readers understand the intricate schemes, and also mathematical formulae and algorithms to support his arguments (although it took a while to understand them, and some are still not understood). The book did not deal with emotions in its explanation of the mechanisms of visual information processing. It would be fascinating to see how emotions, motor functions, and motivations affect the information processing mechanisms. As mentioned earlier, this book would be excellent reading for anyone interested in understanding of the mental functioning in terms of brain structure and the mechanisms that perform certain operations. As the author claims, this book is written for those interested in the deep brain structures that form the universals of thought and language, including physiologists, psychologists, engineers, linguists, philosophers, mathematicians working on artificial intelligence. From the standpoint of vision, would any differences in the brain structures and operations be found between the various types of gifted population? It would be a challenging research item.

Reviewed by Eunsook Hong, Associate Professor, Department of Educational Psychology, University of Nevada, Las Vegas, and a Contributing Editor of the Roeper Review.