ERP Effects of Word Exposure and Orthographic Knowledge on Lexical Decisions in Spanish

Orthographic knowledge is affected by language processing, which is associated with word exposure. This study used event-related potentials (ERP) to explore this association in Spanish-speaking adults with different levels of orthographic competence (High Spelling Skills: HSS; Low Spelling Skills: LSS) while they performed a lexical decision task on previously exposed words (1 or 5 times). Both groups benefited from the exposure rate, but HSS reached significantly higher correct and faster responses, particularly with repeated words. Word recognition potential (RP) amplitude was higher bilaterally in HSS group, especially with repeated words, while P220 was found to be right-lateralized and sensitive to word exposure. Also, the amplitude of P600 varied as a function of word exposure and positively correlated with reading speed. Results suggest that LSS group is less sensitive to word exposure and fails to automatize strategies to word recognition that affect reading fluency.