Mahé, G. , Zesiger, P. , Cohen, M. & Laganaro, M.
University of Geneva FPSE
The time course of the lexicality effect is debated (i.e., effects at the N170 component or later) and has mostly been investigated using lexical decision tasks, which highlight the difference between words and pseudowords. The aim of the present study was to investigate the time course of the lexicality effect in reading aloud, and to determine the impact on block displays and task instructions. Nineteen French-speaking adults performed two reading aloud tasks. Words and pseudowords were displayed in separated blocks (with specific task instructions for each stimulus type) in study 1 or in mixed blocks (without any specific instructions) in study 2. EEG was recorded continuously using 128 channels and both amplitude waveform and topographic analyses were performed on ERP data. In study 1, a lexicality effect appeared in the P100/N200 time window, suggesting a difference in the visuo-orthographic analysis when stimulus type was predictable. In contrast, in study 2, later lexicality effects were observed (i.e., around 300 ms). Taken together, our findings suggest that the time course of the lexicality effect is highly influenced by stimulus displays and task instructions and warns against experimental bias in investigating this effect in both expert and dyslexic readers.