Dimitropoulou, M. 1, 2, 3 , Carreiras, M. 1, 4, 5 & Duñabeitia, J. A. 1
1 Basque Center on Cognition, Brain and Language, BCBL, Donostia, Spain
2 * Project awarded with the 2010 Early Career Stimulus Award, ESCoP
3 Facultad de Psicologia, Universidad de La Laguna, Tenerife, Spain
4 University of the Basque Country, Bilbao, Spain
5 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
Reading acquisition depends on accurate letter identification. Studies testing experienced readers have identified two discrete stages of letter processing: featural decomposition (enabling the discrimination of similar-looking letters; e.g., c-o) and abstract letter identity assignment (enabling the assignment of the same identity to visually dissimilar graphemes; e.g., A-a). By combining behavioral and ERP measures we investigated how processes underlying letter perception are modified by exposure to print during the initial phases of reading. Pre-readers, with knowledge of the letters, and first-graders, with regular exposure to print, performed same/different judgments on letter-pairs. Behavioral results showed that both pre-readers and first-graders tended to judge as identical letter-pairs differing by one-similar looking same-case letter (e.g., za-ze) as well as pairs only differing by an upper and a lowercase version of the same letter (e.g., za-zA). However, the cost for the latter pairs was significantly greater for first-graders than for pre-readers, suggesting that letter identities become automatically activated as a function of increased exposure. ERPs closely mimicked the pattern of behavioral effects, showing larger waveform differences for first-graders than for pre-readers with the latter pairs. These findings support a cognitive shift in letter processing induced by reading experience at the earliest stages of reading acquisition.