Spelling and reading: Using visual sensitivity to explore shared or separate orthographic representations

Do we use the same neurocognitive mechanisms to spell that we do to read? There is a considerable number of conflicting findings, such that evidence has been provided to support common mechanisms for reading and spelling, while other research supports the proposal that reading and spelling utilise unique neurocognitive resources. Sensitivity to visual spatial-frequency doubling (FD) has been demonstrated to correlate with and specifically predict orthographic processing when reading; therefore, if spelling and reading share some elements of orthographic representation, sensitivity to FD should similarly correlate with, and predict, spelling ability by virtue of this shared association. A double dissociation between reading and spelling was found such that sensitivity to the FD task, as mediated by the visual dorsal stream, predicted reading ability but not spelling, while the visual control task predicted spelling but not reading ability, in poor readers/spellers. The results support a dual-orthographic model with separate orthographic representations for reading and spelling.