Reading in the Brain Part One

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Stanislas Dehaene has made important contributions to our understanding of how the brain processes mathematics (Number Sense) and reading (Reading in the Brain). This has the potential to develop more effective instruction which will enhance learning. In the words of the author…

  • Part of our visual system, for instance, is not hardwired, but remains open to changes in the environment. Within an otherwise well-structured brain, visual plasticity gave the ancient scribes the opportunity to invent reading.
  • Each word is brought into the central region of our retina, only to be exploded into a myriad of fragments that our brain later pieces back together. It is only because these processes have become automatic and unconscious, thanks to years of practice, that we are under the illusion that reading is simple and effortless.sagitta2
  • Written word processing starts in our eyes. Only the center of the retina, called the fovea, has a fine enough resolution to allow for the recognition of small print. Our gaze must therefore move around the page constantly. Whenever our eyes stop, we only recognize one or two words. Each of them is then split up into fragments by retinal neurons and must be put back together before it can be recognized.
  • In summary, our eyes impose a lot of constraints on the act of reading.
  • Our visual system has learned to treat these groups as bona fide units (ough, for example), to the point where we no longer pay attention to their actual letter content.
  • A written text is not a high-fidelity recording. Its goal is not to reproduce speech as we pronounce it, but rather to code it at a level abstract enough to allow the reader to quickly retrieve its meaning.
  • Reicher’s word superiority effect underlines the redundancy and parallelism of our procedure for visual word recognition. (The time to recognize words does not increase in proportion to word length in accomplished readers.)
  • What we see depends on what we think we are seeing.Street-Optical-Illusions-3D-Pictures-1
  • In less than one-fifth of a second, a time span too brief for conscious perception, it extracts the identity of a letter string regardless of superficial changes in letter size, shape, or position.
  • We recognize the written word using a region that has evolved over time and whose specialty, for the past ten million years of more, has been the visual identification of objects.
  • My radical proposal is that it is only because this preadaptation of the primate inferior temporal cortex exists that we can learn to read. We would not be able to read if our visual system did not spontaneously implement operations close to those indispensable for word recognition, and if it were not endowed with a small dose of plasticity that allows it to learn new shapes. During schooling, a part of this system rewires itself into a reasonably good device for invariant letter and word recognition.
  • As overtrained readers, we no longer have much perspective on how difficult reading really is. We tend to believe that one glance at a word will allow its immediate and global identification in a single step.
  • In young children, however, the process is different. During the first few years of reading acquisition, reading time is strictly related to the number of letters in a word. This word length effect takes years to vanish.images (7)
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