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A Different Perspective on a Scientist's Report
Scientists compared a group of adults who were very poor readers with a group of good readers. They gave each group a series of reading tasks, each one harder than the last. At the same time, they used sophisticated imaging equipment to see what was going on in everyone's brains. They found that as the tasks got harder, the poor readers not only made more mistakes, but they also used their brains in a different way than the good readers.
When they got to the most difficult task, however, the poor readers suddenly improved, and the workings of their brains started to look much more like the better readers.
What made the difference?
The task that gave the poor readers the most trouble was reading pairs of meaningless words and trying to decide whether they rhymed. [The "nonword rhyme" test, which used word pairs like leat / jete.] The readers improved -- and they used their brains more like good readers -- when they were given pairs of real words, and asked to decide whether the words were in a similar category. [The "semantic category judgment" test, which used word pairs like corn / rice.] That is, when asked to think about the meanings of words, the test subjects became better readers.
This looks significant. Thinking about meaning seemed to turn on the part of the brain that was not working when readers thought only about the sounds of the meaningless words. But the scientists who recorded this data didn't seem to notice. Instead, these scientists claimed that they had discovered a "functional disruption," and told the press that dyslexic people have a 'glitch' in their brains.
The scientist who led this study is named Dr. Sally Shaywitz. Her report is called "Functional disruption in the organization of the brain for reading in dyslexia" and was published in the "Proceedings of the National Academy of Sciences" in March 1998. Dr. Shaywitz does not believe, as we do, that dyslexics are picture-thinkers or that their reading problems are related to their visual-spatial thinking abilities. Instead Dr. Shaywitz believes that dyslexia is caused by a brain problem that interferes with the development of "phonologic awareness." That is, she thinks dyslexics do not know how to relate letters to the sounds that make up language, and to put letter/sound combinations together to make words.
When Dr. Shaywitz wanted to study dyslexia, she picked a group of people who were very poor readers, and had particularly bad scores on "nonword reading" on the "Woodcock Reading Mastery Test." Not only were these people bad readers, but their average IQ was 91. Now this is odd, because a person must have average or above-average intelligence to be deemed dyslexic. Poor readers with below-average intelligence are assumed to have generalized learning problems, and are not counted among the dyslexic. So these poor readers were clearly not a representative sample of dyslexic people.
Even stranger, for a comparison group, Dr. Shaywitz selected good readers whose average IQ was 115. This is 24 points higher than the dyslexic group, and is a very big gap when you consider that the whole point of the study was to look at the workings of people's brains. Dr. Shaywitz said that she chose "not to match subjects on IQ" because she wanted to make sure she had really bad readers to study. She does not explain in her report how she determined that the people in the low IQ group were dyslexic.
So this starts to look like a study of readers vs. nonreaders, not dyslexia. If you compare a group of people who have acquired a particular skill with a group who have not acquired the same skill -- testing their ability to apply that very skill -- you would expect to see a different pattern of brain use. Presumably, people use a different part of their brain to puzzle things out than to retrieve things from memory. In this case, poor readers might be more likely to try to sound out the nonsense words letter-by-letter, whereas experienced readers might be more apt to analyze the words by recognizing familiar letter patterns.
To me, this would be like comparing a group of beginners in a dance class with a group of professional dancers as they do the rhumba, and then deciding that the beginners have something wrong with their feet.
Dr. Shaywitz reported that her sample of poor readers had a "functional disruption" in their brains. Compared to the good readers, they did not use some parts of their brains enough and overused others. This happened mostly in the "nonword rhyme" test. Dr. Shaywitz thinks that because the under-used part didn't work right, the dyslexics had to overuse the other part to compensate.
When you think about it, the "nonword rhyme" test is not really fair. In the first place, there are no right answers. For example, they asked whether 'jete' and 'leat' rhyme. But 'jete' looks like the French jeté, pronounced 'zhe-táy,' which definitely does not rhyme with 'leat'.
In our experience, dyslexic people tend to be more creative and might think of more possibilities. So maybe there was something wrong with the question, not with anyone's brains. Maybe the part of the brain that the researchers called overactive was the imagination.
In any case, the under-used part started working better when the subjects moved on to the "semantic category" test. I don't think the researchers expected this to happen, because it isn't mentioned in their report at all. But the bar charts of comparative brain activity show a definite increase in use of the superior temporal gyrus and angular gyrus, which are the brain parts Dr. Shaywitz says are disrupted for dyslexics.
I don't know how Dr. Shaywitz can say there is a "functional disruption" in the brains of her subjects after she saw the brains stop disrupting for the hardest test.
Reading is something that people do to gain meaning from written symbols. The "nonword rhyme" test represents a step along the way to learning to read, a step reflected in rhyming children's books like "The Cat in the Hat." But the "semantic category" test represents the next, culminating step: conceptual understanding of what the words mean. If you can get to where you are going, it really doesn't matter what route you took.
The glitch is in the methods these scientists are using. Our brains are just fine, thank you.
You can read the Sally Shaywitz report, Functional disruption in the organization of the brain for reading in dyslexia here:
