Duñabeitia, J. A. , Molinaro, N. & Carreiras, M.
Basque Center on Cognition, Brain and Language (BCBL), Donostia, Spain
Recently Duñabeitia, Molinaro and Carreiras (2011, Neuroimage) showed that readers perceive mirror-words as if they were correctly oriented at initial stages of word recognition processes. In order to further examine whether word enantiomorphs (lateral reversals of words in a mirrored style) are processed as canonical word representations during early stages of visual processing, we conducted a masked priming alphabetic decision experiment while recording participants’ electrophysiological brain responses to letter and pseudo-letter strings briefly preceded by correctly oriented and mirrored repetition or control masked primes. Participants were simply asked to identify whether or not the displayed strings were made of existing or invented characters by pressing buttons on a response box. On the one hand, our results showed an N250 masked priming effect for related (normally oriented and mirrored) primes, as compared to the unrelated control conditions (i.e., a mirror priming effect), when the targets were real words made of existing letters. On the other hand, the correctly oriented identical primes elicited a N250 masked repetition priming effect that was significantly different from the effect elicited by mirrored repetition primes (a canonicity effect) for word targets. Besides, effects associated to the mirroring of the letters in the masked primes were observed in the N100 and N/P150 components. These results highlight the ability of the human visual system to tolerate mirror reversals when processing known printed materials.