Sensitivity to orthographic vs. phonological constraints on word recognition: An ERP study with deaf and hearing readers

The role of phonology in word recognition has previously been investigated using a masked lexical decision task and transposed letter (TL) nonwords that were either pronounceable (barve) or unpronounceable (brvae). We used event-related potentials (ERPs) to investigate these effects in skilled deaf readers, who may be more sensitive to orthotactic than phonotactic constraints, which are conflated in English. Twenty deaf and twenty hearing adults completed a masked lexical decision task while ERPs were recorded. The groups were matched in reading skill and IQ, but deaf readers had poorer phonological ability. Deaf readers were faster and more accurate at rejecting TL nonwords than hearing readers. Neither group exhibited an effect of nonword pronounceability in RTs or accuracy. For both groups, the N250 and N400 components were modulated by lexicality (more negative for nonwords). The N250 was not modulated by nonword pronounceability, but pronounceable nonwords elicited a larger amplitude N400 than unpronounceable nonwords. Because pronounceable nonwords are more word-like, they may incite activation that is unresolved when no lexical entry is found, leading to a larger N400 amplitude. Similar N400 pronounceability effects for deaf and hearing readers, despite differences in phonological sensitivity, suggest these TL effects arise from sensitivity to lexical-level orthotactic constraints. Deaf readers may have an advantage in processing TL nonwords because of enhanced early visual attention and/or tight orthographic-to-semantic connections, bypassing the phonologically mediated route to word recognition.