N170 visual word specialization on implicit and explicit reading tasks in Spanish speaking adult neoliterates

Adult literacy training is known to be difficult in terms of teaching and maintenance (Abadzi, 2003), perhaps because adults who recently learned to read in their first language have not acquired reading automaticity. This study examines fast word recognition process in neoliterate adults, to evaluate whether they show evidence of perceptual (automatic) distinctions between linguistic (words) and visual (symbol) stimuli. Such a mechanism is thought to be the basis for effortless reading associated with Visual Word Form Area activation that becomes "tuned" to scripts as literacy skills are acquired (McCandliss, Cohen, Dehaene, 2003). High density EEG was recorded from a group of adults who are neoliterate in two reading tasks: (1) a one-back task requiring implicit reading (available only to those who have attained automaticity), and (2) reading verification task, an explicit reading task, in which participants detected mismatches between pairs of visual and auditory words. Results were compared to recordings from a comparison group of adults who learned to read in childhood. Left-lateralized N170 ERP was targeted as an index of automaticity in reading. Participants from the comparison group showed left-lateralized N170 to word stimuli in both the implicit and explicit reading tasks. Conversely, N170 effects were not found on the participants form the study group on either implicit or explicit reading tasks. This suggests that automaticity in reading can be indexed in neoliterate adults using the ERP component N170, and that automaticity had not been acquired by the study group investigated here.