Tracking hierarchical processing in morphological decomposition with brain potentials

One important debate in psycholinguistics concerns the nature of morphological decomposition processes in visual word recognition (e.g., darkness = {dark} + {-ness}). One theory claims that these processes arise during orthographic analysis and prior to accessing meaning (Rastle & Davis, 2008), and another argues that these processes arise through greater temporal overlap between the activation of orthographic and semantic information (Feldman, O'Connor, & Moscoso del Prado Martín, 2009). This issue has been the subject of intense debate in studies using masked priming but has yet to be resolved unequivocally. The present study takes another approach to resolving this controversy by examining brain potentials as participants made lexical decisions to unprimed morphological (darkness), pseudomorphological (corner), and nonmorphological (brothel) stimuli. Results revealed a difference from ～190 ms between the nonmorphological condition and the other 2 conditions (which showed no differentiation), a likely correlate of morphological processing reliant exclusively on orthography. Only 60-70 ms later was there evidence of the activation of semantic information, when the pseudomorphological condition diverged from the other 2 conditions. These results provide unambiguous support for a hierarchical model of morphological processing whereby decomposition is based initially on orthographic analysis and is only later constrained by semantic information. (PsycINFO Database Record (c) 2012 APA, all rights reserved).