Castles, A. 1 & Nation, K. 2
1 Department of Cognitive Science, Macquarie University - Australia
2 University of Oxford, UK
The phonological core deficit hypothesis of dyslexia has dominated research in the field for several decades. In its strongest form, this hypothesis can be seen as reflecting three associated claims: a) that there is only one basic kind of dyslexia, b) that all (or at least the vast majority of) dyslexic children have phonological impairments, and c) that these phonological impairments cause their dyslexia. In this talk, I examine each of these claims in turn and consider evidence both for and against them. I conclude that, although it is clear that many dyslexics perform poorly on tasks designed to tap phonological skills, there is much still to be learned about why this is the case and what the nature of the relationship is between phonological abilities and reading. Evidence from precise and targeted studies is required to untangle the complex pattern of relationships observed.
As noted by Anne Castles, the phonological core deficit hypothesis of dyslexia has dominated research in the field for several decades. Throughout this time, it has also become well-established that learning to read an alphabetic orthography fundamentally changes phonological processing. Although debate continues as to how this might happen, the finding that it does happen has implications for the phonological deficit hypothesis of dyslexia. I will draw on a range of studies to discuss these implications and in doing so, consider the nature of the relationship between phonological skills and learning to read, both in typical development and in children with developmental dyslexia.