Brain-behavior relations in reading and dyslexia: implications of Chinese results.

It is ironic that our recent report on the neural correlates of Chinese dyslexia (Siok, Perfetti, Jin, & Tan, 2004) raises a concern by Ziegler (2006) that this report could undermine an agreed-upon conclusion favoring a phonological deficit as the cause of reading disability. Our past research over 20 years in English (Perfetti, 1985) and Chinese (Perfetti, Liu, & Tan, 2005; Pollatsek, Tan, & Rayner, 2000; Tan & Perfetti, 1998) has argued that phonological processes are intrinsic to word reading and universal across writing systems, and we certainly have no reason to minimize the importance of these processes for understanding reading disability. We address Ziegler’s concern by making two observations. (1) The Siok et al. evidence supporting a role for the left middle frontal gyrus (LMFG) instead of the left posterior temporoparietal regions found in alphabetic research does not undermine the consensus on the universality of phonology. Instead this evidence shows that the implementation of phonology depends on language and writing systems, a conclusion also reached through behavioral evidence (Perfetti et al., 2005). (2) The detailed neural basis of dyslexia remains an open question, rather than accepted wisdom. On the first point, Siok et al. did not conclude that phonology plays no role in Chinese reading disability and Ziegler’s critique recognizes this. Indeed, the evidence in favor of a phonological basis for dyslexia in alphabetic writing has accumulated impressively over 20 years, from a time at which the prevailing views emphasized visual problems as the cause of dyslexia. This evidence comes from neurobiological (Brunswick, McCrory, Price, Frith, & Frith, 1999; Eden et al., 2004; Price & Mechelli, 2005; Richards,