Brant, 
Thank you for your  post. While there is limited time for me to write or 
you to read, I shall  nonetheless make some attempt to give my view on the 
points you raise. Although  a long post, this will still be a truncated and 
simplified gallop through a  wealth of complicated issues you raise. We have 
debated before, you and I, and I  remember suggesting you looked in my book on 
my website to be found at the  bottom of all my posts. Chapter eight of 
this book is a longer, fuller and  frankly better exposition of my critical 
views about dyslexia, including my  specific concerns, necessarily rather 
general, about the genetics of it. Chapter  3 also deals with some phonological 
issues.  
I think I detect an  undertone of impatience in your post with my views, on 
the grounds that they are  not mainstream today. So I feel I have to make 
it plain that I enter all such  debates in a spirit of very genuine enquiry 
and base my remarks upon  considerable experience with ABE students and much 
reading and thought. I see my  role as dogged scepticism because I have 
found the dyslexia field to be  credulous, much of the thinking casual and much 
of the research flawed. It has  often seemed to me that science is being 
stretched well beyond reasonable limits  in the field, and unjustifiable 
conclusions often reached thereby. Scepticism is  sacred. It is fundamental to all 
science.  
First, the work of  Tallal and the whole phonological awareness, auditory 
acuity area of the field.  My thinking is made more clear in chapters 3 & 8 
of my book, below, but  there are a few points which can be made briefly 
here.  
One is absolutely  fundamental to the entire field, namely the selection of 
a sample for study. The  question ‘who is dyslexic?’ remains unanswered. 
The old criterion, regarded as  pathognomic, was the IQ-achievement 
criterion. Today, it is no longer regarded  as a valid diagnostic tool – in other 
words people with such a discrepancy  merely reveal that they may have a 
problem with literacy, nothing valid can be  said about the causation of any such 
problem on the basis of the discrepancy and  no diagnosis made. In yet other 
words, the criterion does not identify a  dyslexic. The upshot of all this 
is that practically all studies of ‘dyslexics’,  before the late nineties 
at least, have no scientific validity because they  selected their sample 
solely on the discrepancy criterion. The people they said  were ‘dyslexic’ may 
not have been, so the conclusions they reached about  ‘dyslexics’ are 
invalid.  
Another general  point about the phonological skills debate is the obvious 
one that these are  also cart and horse issues. People do seem to have wide 
differences in their  ability to distinguish and manipulate the sounds of 
language and,  unsurprisingly, their literacy abilities tend to co-vary with 
these phonological  abilities. But most of the work I have read showing these 
correlations, the  reality of which I do not at all dispute, leave me 
wondering whether the  correlations are really causations. It seems to me very 
feasible that they are  probably indicators, among other such potential 
indicators, of many other  influences on literacy acquisition and facility which 
are likely to co-vary,  among these being letter awareness, for example, but 
it also seems to me that  there are also a plethora of ill-defined and 
largely unknown social influences  which must be confounding this area of study 
without being identified or  accounted for. [One reference here might be 
Castles & Coltheart (2004) Cognition 91: 77-111. They conclude  their review of 
the literature by saying that they do not believe it has been  shown that 
phonological awareness has a causative relationship with literacy  
achievement.] 
So I accept that  there may be differences in auditory acuity between 
individuals, but I remain  sceptical as to the degree to which any such 
difference, per se, may or may not make a difference  to literacy facility. It is 
likely to be highly predictive, but may not be  causative, or solely causative, 
or reliably causative. I also consider that  there are many more likely 
reasons for a difference in auditory ability,  especially linguistic auditory 
abilities, than an innate neurological  difference. People have such 
alarmingly varied experiences with language, among  many other things of course, 
from the earliest of ages (see Hart & Risley  (1995), for example) and there 
are so many confounding variables involved, about  which we have no idea. And 
these suggested variables are so much more everyday  and likely than is an 
innate neurological deficit. We medicalise too early, on  too little evidence 
and with too little differential diagnosis. We leap to the  deficit theory 
and fail to consider much else. Good diagnosis demands greater  humility 
than this. 
In short, I have  found the work of Tallal to be unconvincing, for these 
general reasons, among  others. And although I have not read the work of 
Torgesen specifically, I have  read much other work about this much-researched 
aspect of the debate and found  it similarly unconvincing for similar reasons. 
Genetics: This is an  area of the debate which is fiendishly complex. It is 
a discipline which H.  sapiens does not yet understand well applied to an 
organ, the brain, which our  species also does not yet understand well. In 
other words, I feel very strongly  that much of the science is wildly 
over-interpreted – apparent findings being  stretched well beyond what can actually 
be justified on the basis of today’s  understanding. (And on another list we 
have been referred to the Santiago  Declaration 2007 – 
_www.jsmf.org/declaration_ (http://www.jsmf.org/declaration)  - in which leading  
neuroscientists point out that brain science, properly understood, does not  offer good 
evidence-based information to guide education. Quote:  “Neuroscientific 
research, at this stage in its development, does not offer  scientific guidelines 
for policy, practice or parenting.”) We need less  precipitate 
interpretation and more humility, in other words. 
Again, many genetic  studies consistently relied upon, even today, in 
dyslexia literature as  ‘scientific truth’ were carried out using 
discrepancy-diagnosed subjects – ie  these studies are, or should be, thereby invalidated. 
The field, however,  carries right on referring to, and theorising upon, 
such work. 
On this aspect,  several workers from the Colorado group, who do much of 
the world’s research,  have recently stated that they will simply use the 
bottom 10% on the bell curve  of reading ability and consider them ‘dyslexic’, 
there being no agreed consensus  on diagnostic criteria for dyslexia. This 
is, of course, not a valid way of  selecting a sample of ‘dyslexics’ as 
there will be many reasons other than  innate neurological deficit for being in 
that bottom 10% (and membership of that  group will not, anyway, be at all 
consistent). Research based on such poorly  selected samples cannot validly 
theorise about ‘dyslexics’. Twin studies are  also consistently critiqued by 
more informed minds than mine. I am not  adequately qualified (very, very 
few people are!) to examine the genetic  arguments, but I can note that there 
are many who appear to be and who do thus  argue, and sceptical interest 
remains respectable. Please see the section in my  book, chapter eight, for 
fuller debate. 
As for my veterinary  experience and this aspect of the issues, it is 
precisely because I have some  knowledge of biological science, and the practical 
and instantly tested  application thereof, that I am inevitably sceptical. 
Which brings me on to  anatomy. 
The post-mortems you  refer to are, I imagine, those conducted under the 
auspices of Geschwind and  Galaburda, two highly controversial figures. There 
is first the general, but  fundamental, point to make, again, that their 
sample ‘dyslexics’ (only 8 in  number, I think) were ‘diagnosed’ using the 
then gold standard but now  discredited discrepancy criterion. In other words, 
today they would not be  considered a valid sample of ‘dyslexics’ and the 
work would probably not be  published. 
Second, the  conclusions were hotly contested and most writing I read today 
chooses to  overlook this work altogether. Third, the work over-simplifies 
a complex organ.  The ‘abnormalities’ they reported (especially in the 
planum temporale) are quite  probably no more than normal variation (they were 
not even consistent within  their sample) and there is no evidence directly 
linking them, even if they were  genuine abnormalities, to any actual 
behaviour, normal or otherwise. The brain  is, at bottom, simply not amenable to 
such weights-and-measures approaches, it’s  far more subtle than this. The 
apparent results of such rudimentary measurements  are over-interpreted in 
exactly the same way in which brain scans are today.  These methods are much too 
crude and broad-brush for such a subtle, interwoven  and plastic organ as 
the brain. Our understanding of the brain is, in short, too  primitive as yet 
to sustain many of the conclusions people seek to  reach. 
The same arguments  can be deployed in respect of the neuronal migration 
theories (mostly deriving  from Galaburda’s thinking). To say that we do not 
understand the ways in which  the brain comes to be constructed in any 
meaningful detail would be an  understatement; we know in only very broad outline 
how the migration of nervous  tissue affects outcomes in terms of behavour. 
We do not have the detailed  understandings to point at any part of the 
brain, or any aspect of its suspected  developmental history, and claim an 
innate literacy deficit is thereby revealed.  The organ is, apart from anything 
else, nothing like that fixed; we are just  beginning to see how massively 
plastic it is, how flexible in terms of site of  operation and how malleable 
in terms of response to circumstance. If we could  even reliably come to know 
(as we have not yet) that a few thousand neurons  ‘migrate to the incorrect 
location’ it would almost certainly make absolutely no  detectable 
difference to subsequent behavour, especially in respect of such a  wholly learned 
skill as literacy, we must remember, actually is. 
I hope this helps to  show the generality of my view. 

Hugo


at: _http://www.hugokerr.info_ (http://www.hugokerr.info/) 

"We're here to help each other get  through this thing - whatever it might 
be." (Kurt Vonnegut) 
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