Reading in the Brain

August 17, 2009
The transparent and automatic feat of reading comprehension disguises an intricate biological effort, ably analyzed in this fascinating study. Drawing on scads of brain-imaging studies, case histories of stroke victims and ingenious cognitive psychology experiments, cognitive neuroscientist Dehaene (The Number Sense
) diagrams the neural machinery that translates marks on paper into language, sound and meaning. It's a complex and surprising circuitry, both specific, in that it is housed in parts of the cortex that perform specific processing tasks, and puzzlingly abstract. (The brain, Dehaene hypothesizes, registers words mainly as collections of pairs of letters.) The author proposes reading as an example of “neuronal recycling”—the recruitment of previously evolved neural circuits to accomplish cultural innovations—and uses this idea to explore how ancient scribes shaped writing systems around the brain's potential and limitations. (He likewise attacks modern “whole language” reading pedagogy as an unnatural imposition on a brain attuned to learning by phonics.) This lively, lucid treatise proves once again that Dehaene is one of our most gifted expositors of science; he makes the workings of the mind less mysterious, but no less miraculous. Illus.

September 1, 2009
A neuroscientist explains how the brain deals with reading.

Dehaene (Experimental Cognitive Psychology/Coll'ge de France; The Cognitive Neuroscience of Consciousness, 2002, etc.) begins by pointing out that the brain contains circuitry exquisitely attuned to reading. Humans began to read only 5,000 years ago, so eons of evolution could not have designed it. Since genes haven't evolved to enable us to read, writing systems have adapted to constraints in the human brain. The author describes experiments using dazzling, high-tech devices that image the brain while a subject reads. The retina sends everything we see to the extensive visual areas at the rear of the brain. An instant later, any written word, in any language, lights up a tiny area. Closer examination of this"letterbox area" reveals a smaller section sensitive only to simple lines and curves, an adjacent area that forms these into letters and another that recognizes words. This is the identical area and mechanism which animals use to recognize objects in their environment, so evolution has cleverly recycled existing brain circuits to handle reading. Dehaene stresses that these findings should help teach reading—phonics trump the whole word method, which has no basis in brain physiology—and treat dyslexia, which is rare in"transparent" languages (i.e., where one letter equals one sound) like Italian but epidemic in English where irregular spelling makes it much harder for the brain to decode words.

Dense with ideas and experiments, but richly rewarding for readers willing to put in the effort.

(COPYRIGHT (2009) KIRKUS REVIEWS/NIELSEN BUSINESS MEDIA, INC. ALL RIGHTS RESERVED.)

November 1, 2009
What's behind the invention of reading? Well, for starters, brain plasticity, the evolution of neurocircuits capable of processing visual with audio information, and the expansion of the prefrontal cortex leading to a behavior described as consciousness. The evolutionary infusion of these elements along with a novel hijacking from their evolved use intersects with human culture and incites a revolution: a culture with texts and brains that read those texts. All this drives neuroscientist Dehaene's (experimental cognitive psychology, Coll]ge de France) thesis that the invention of reading has less to do with constructs, such as alphabets, words, and sentence structures, than the mechanics and limits of our brains. Simply, our brains didn't evolve to read, but they are flexible enough to learn new tricks. Dehaene supports his thesis with references to a smorgasbord of research, traversing such subjects as anatomy, reading mechanics, primate evolution, history of linguistics, literacy, dyslexia, and brain symmetry. VERDICT This will appeal to a broad audience interested in the cognitive sciences, reading, and linguistics. Some chapters will attract those who teach reading and languages and parents of children with reading disabilities.Scott Vieira, Johnson Cty. Lib., KS

Copyright 2009 Library Journal, LLC Used with permission.

October 15, 2009
In a work of most benefit to reading teachers, Dehaene, a leading neuroscientist based in France, presents the latest developments in his field that apply to childrens acquisition of the skill. A preview: Dehaene criticizes the so-called whole-language method because, according to his research, the brain doesnt process complete words. The way it really works, well, thats the substance of his text, which is filled with images of high-tech brain scans. Dehaene explains that word processing begins in an area of the cortex he colloquially calls the letterbox. Neuroscientists believe that the letterbox evolved to visually define the outlines of objects, and it found a new application with the invention of writing thousands of years ago. Describing experiments on cognition, Dehaene pulls in sound, and a childs lexical memory, to arrive at an integrated, though by no means experimentally final, theory of how we read. His discussion of reading problems offers encouragement to sufferers and teachers alike as it illuminatingly informs reading teachers of the underlying science of what they are doing.(Reprinted with permission of Booklist, copyright 2009, American Library Association.)