Abstract
If you talk to vision researchers, they think it's known that dyslexia results from a visual processing impairment (specific to the magnocellular pathway). If you talk to hearing researchers, they think it's known that dyslexia results from an auditory processing impairment. If you talk to reading researchers, they think it's very hard to reliably detect either visual or auditory processing deficits in dyslexia, and so they focus on its major behavioral characteristic, impaired “phonological awareness,” which interferes with learning spelling-sound correspondences. So, despite the very real advances in understanding reading and its brain bases that have occurred over the past 25 years or so, there is still considerable uncertainty about the cause(s) of dyslexia. I will review some recent research by Lu, Manis, Sperling and myself which suggests that subtle visual processing impairments related to noise exclusion are common in dyslexia (though not specific to the magnocellular channel), and then suggest (speculatively, but consistent with computational models of reading) how they might be causally related to phonological deficits and other aspects of impaired reading.