Many studies, incidentally, (and see Paracchini et al 2007) speculate on the actual biological effect whichever QTL they claim affects reading ability may have. What actual effect in the brain may the mutation in ‘their’ QTL be having? Many describe an effect on the migration of neurones during the brain’s development. Known neurological syndromes are mentioned in this context, especially lissencephaly, double cortex syndrome and periventricular nodular heteropia. However, these are gross abnormalities detectable, for example, by scanning. They clearly cause many neurological symptoms, frequently, for example, epileptic seizures. They also cause cognitive deficits. It is unsurprising that, in many cases, literacy difficulties may also be seen. In such syndromes there is gross brain damage and multiple deficits, only one of which is ‘dyslexia’. Such gross abnormalities, even when they involve, say, reading difficulty, are not ‘dyslexia’ as we must properly consider it. Such cases are not the classical understanding of ‘dyslexia’ which has to involve an innate literacy difficulty found in people without obviously gross lesion or abnormality. A person suffering from lissencephaly, for example, is to be described as a person suffering from lissencephaly (which may, among many other gross effects, also affect their literacy abilities) but not as a ‘dyslexic’.
The genetic findings, whatever they really are, amount to an admittedly disturbing aspect of the debate, for those who find dyslexia unconvincing in more general terms. I believe I can properly accept and re-assert a ‘general conclusion that a genetic underpinning to ‘dyslexia’ is far from established’ (Steve Ramm, personal communication September 2007). I am not fully qualified to follow detailed genetic argument, and neither, quite probably, are you. We are both required, notwithstanding, to cling fiercely to common sense and scepticism - it is the proper approach to all knowledge.
I believe it is early days yet. Astonishing things, with strange implications, are suggested within this field. Something is being measured by this work (though not always to a high level of significance or very consistently, not always demonstrating much genetic power, not always supported by other research, and seldom carried out in appropriately defined sample populations). What, exactly, is being measured is not at all clear, as is sometimes admitted even by researchers in the field. Whatever it is, it cannot be ‘the gene for dyslexia’, or ‘the gene for spelling’, or ‘the gene for literacy’. And finally, understanding the most appropriate way, or ways, all this work is to be interpreted remains very unclear, to say the least. What (and how much) does any of all this mean? Some are prepared to assert very extraordinary things on the basis of rather small and tentative findings, many are more cautious. (Grigorenko et al (2006 p. 119) say, for example, that ‘… we might be amazed to know how far from understanding the genetic bases of reading we actually are’. Schumacher et al (2007 p. 294) write that ‘to date no specific cognitive processes are known to be influenced by the proposed susceptibility genes”.) Let us remember the wise words of St Augustine: ‘For so it is, Oh Lord my God; I measure it, but what it is that I measure I do not know’.
We should also, because we have our wits still about us, briefly but firmly recall the two issues of carts and horses and affect, both of huge but studiously unrecognised importance. First the unsolved issue of horse and cart in much literacy research – when we discuss the relationship between a skill and an ability, what is cause and what is effect? It is not always clear (to say the least) whether an apparent disability is caused by an apparent skill deficit or whether the apparent deficit is caused by the apparent disability. Put another way, is my skill at orthographic coding, say, the cause of my facility with literacy or has my facility in literacy resulted in a high level of skill in decoding text? Secondly, the consistently unremarked effect of affect on performance: The effect of emotional response and attitude on task performance is often enormous but it is usually unknown, often practically unknowable and almost invariably completely ignored for the purposes of research. Looking the other way is understandable (it makes research and interpretation so much simpler!) but it is also quite unjustified and undoubtedly skews findings and conclusions drastically, often probably fatally. This unconscious researcher bias is only occasionally recognised, as in an interesting article in a special issue of the Journal of Research in Reading given over entirely to reading and genetics (Conlon et al 2006). It remains, otherwise, elephantine but invisible.
This is the ability to locate, separate and distinguish for what they are the sounds in language. (And see the more detailed discussions in chapter three.) Various aspects of the detailed sounds of language are assessed by researchers - syllables, onset, rime, phonemes, consonants, vowel sounds. (Non-word reading or phoneme manipulations are common tests, for example.) The hottest candidate as I write for the ‘core deficit’ in dyslexia is phonological awareness. ‘Dyslexics’ (almost always still IQ/achievement defined) are considered to be less phonologically aware. There is indeed evidence that ‘dyslexics’ (or at least people with poor literacy skills) have relatively poor phonological skills. (Goswami 1997, Snowling 1995, Snowling & Nation 1997 but see also Ellis, McDougall & Monk 1999, Scholes 1998, Thompson 1999) There is also, though, the finding that receiving training in literacy (in an alphabetic language like ours) rapidly improves phonological awareness. This is an important carts and horses issue; it is well aired in Goswami & Bryant 1990 pp. 4-27. (And see Adams 1990, Perfetti & Xhang 1995, Smith 2004, Taft 1991, Thompson 1999.)