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‘Rise above yourself and grasp the world’ Archimedes – attribution

dyslexia is not one thing, apparently

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Canto: So I’ve been reading Proust and the squid, by Maryanne Wolf, a book I bought back in 2010, when it was published, and apparently read at the time, though I remember very little about it. Did I really read it? I suspect I didn’t finish it. Anyway, it’s subtitled Science and the reading brain, and since we do a lot of reading, mostly still in the old-fashioned way (stuff written on paper), the subject is of obvious interest.

Jacinta: Yes, it’s interesting to reflect that though writing, of various types, came into being four to five thousand years ago, it’s only in the last few centuries that reading has become anything like universally adopted. And our brains have had to adapt to reading…

Canto: Yes, think of reading to ourselves, in a language that’s based on sound. Which not all languages are, if I’m not mistaken. So I imagine that non-phonological languages (is that a meaningful term?) use the brain in a different way…

Jacinta: It’s more complicated than that – for example, there’s a difference between phonetics and phonemics, in which the letter ‘t’ is sounded differently depending on its place within a word and what letters surround it, for example in ‘th’ words, and that phoneme is sounded differently, for example in ‘the’ and in ‘beneath’, if you listen carefully. We generally don’t notice these differences until they’re pointed out to us. And the English language is full of them. Phonemes can be divided into allophones, as they’re called. But getting back to dyslexia…

Canto: Well, first it needs to be made clear that dyslexia has nothing to do with lack of intelligence. Both Einstein and Leonardo da Vinci, the names most often trotted out as examples of genius, were likely dyslexic, or maybe I should say they suffered from some form of dyslexia – because it’s really really complex and multi-faceted, and seems to involve right-left brain differences. The last two chapters of Wolf’s book, ‘Dyslexia’s puzzle and the brain’s design’ and ‘Genes, gifts and dyslexia’, are fiendishly difficult for someone like me, with very little background in neurology, but fascinating, and I think it’ll take several posts to cover not only what’s in the book but the ongoing research since it was written.

Jacinta: Yes that reminds me of Sapolsky’s statement in Behave, that more neurological papers have been published in the 21st century than in all previous centuries combined – and that book was published five years ago.

Canto: Well, it’s not surprising, it’s a burgeoning area of research, looking for neural co-ordinates for various disabilities, proficiencies, tendencies… As well as genetic correlations. And epigenetic too, maybe. Anyway, to begin somewhere, Wolf describes a hypothesis that derives from the thinking of a famous and apparently prophetic 20th century neurologist, Norman Geschwind:

The genes that form the basis for a strengthened right hemisphere could have been highly productive in preliterate societies, but when these same genes are expressed within a literate society, they put structures in the right hemisphere in charge of the precise, time-based functions of reading. These functions would then be performed in the unique ways of the right hemisphere, rather than in the more precise, time-efficient ways of the left hemisphere. In the case of reading, that situation would lead inevitably to difficulties.

M Wolf, Proust & the squid: the story and science of the reading brain, pp205-6

Now, I had no idea that the left hemisphere was more precise and time-efficient than the right…

Jacinta: But this quote doesn’t quite make sense to me. We’re all descended from pre-literate societies after all, so with ‘highly productive right hemispheres’. And then, when literacy came along – what? The right hemisphere took on these ‘precise, time-based functions of reading’ in its ‘unique way’, when it would’ve been better to use the left hemisphere, which is better adapted for the purpose, apparently. Wouldn’t this make us all a bit dyslexic?

Canto: Yes, maybe that’s the point. But there’s also no doubt that the reading brain – which may one day become obsolete in the digital and post-digital world – has transformed our society more or less completely. So having serious reading/writing deficits can be a major problem, perhaps especially for highly intelligent people who might feel the disadvantage more.
So dyslexia, as the word suggests, is a broad and negative term which essentially covers all deficiencies in grasping and producing written text. Wolf presents, inter alia, the definition of The International Dyslexia Association:

Dyslexia is a specific learning disability that is neurological in origin. It is characterised by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.

Note that the only reference to causes here is that it’s ‘neurological in origin’.

Jacinta: Well mention has been made about right and left sides of the brain – does it get any more specific?

Canto: Of course – but as one researcher points out, dyslexia isn’t a reading disorder, as there are no reading centres in the brain. It’s rather a disorder in one or more regions of the brain that have been co-opted for reading and writing. Wolf describes a pyramid of nested connections regarding the disorder. First we observe a behavioural problem, in the act of getting words wrong in reading and writing, or an abnormal slowness and struggle in gaining proficiency in acquiring those skills. Next comes the observation of a pattern of disability, such as seeing/writing/speaking particular letters or phonemes incorrectly. Then there’s the connection between these deficits and neural structures. The next step is homing in on particular neurons and neural circuits, and finally taking this back to the level of particular genes.

Jacinta: But there aren’t any specific genes are there?

Canto: Well, not in the sense of genes for height or eye colour, or even language, which may go back to the earliest Homo sapiens. Literacy is a cultural invention. To quote Wolf:

Across all written languages, reading development involves: a rearrangement of older structures to make new learning circuits; a capacity for specialisation in working groups of neurons within these structures for representing information; and automaticity – the capacity of these neuronal groups and learning circuits to retrieve and connect this information at nearly automatic rates.

M Wolf, Proust and the squid, p 170

Genes aren’t specifically mentioned here – but neurologists are understandably asking whether this ‘rearrangement of older structures’, and possible failures in this rearrangement, have a genetic basis, just as the development of language itself presumably has (though this development too is shrouded in mystery). Wolf goes on to outline four ‘potential basic sources for dyslexia’. I’m going to set them down here because, frankly, I barely understand them. See what you make of them.

  1. a developmental, possibly genetic, flaw in the structures underlying language or vision (e.g. a failure of working groups to learn to specialise within those structures)
  2. a problem achieving automaticity – in retrieving representations within given specialised working groups, or in the connections among structures in the circuits, or both
  3. an impediment in the circuit connections between and among these structures
  4. the rearrangement of a different circuit altogether from the conventional ones used for a particular writing system

Jacinta: Hmmm. I don’t know what she means by ‘working groups’ – of neurons? The fourth one is the only one that I half comprehend. That some forms of dyslexia have harnessed a different circuit which isn’t quite as effective but gets there in the end? Or not?

Canto: Yes, on reflection I half-comprehend the others, and see them as rather connected. For example, failure to achieve automaticity sounds similar to having an impediment in the connections. With some it feels seamless – or doesn’t feel anything at all. I can’t remember ever learning to read or having problems with it, and loved school spelling bees, being very good at them. Anyway, Wolf elaborates on each of these four principles, and I think we should try to follow them in the next blog post. We’ll be better human beings for the process, I’m sure. Because, difficult though it is, I’ve found this to be one of the most intriguing and stimulating books I’ve read for some time.

Jacinta: Okay, let’s go for it.


Maryanne Wolf, Proust & the squid: the story and science of the reading brain, 2010

Click to access memorialminute_geschwind_norman.pdf



Written by stewart henderson

April 11, 2023 at 9:13 pm

Posted in dyslexia

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