Shared Early Pathways of Word and Pseudoword Processing: Evidence from High-density Electrocorticography

Abstract

UC Berkeley Phonology Lab Annual Report (2012) Shared early pathways of word and pseudoword processing: Evidence from high-density electrocorticography Emily Cibelli ∗ University of California, Berkeley ecibelli@berkeley.edu Introduction In psycholinguistic studies of lexical processing, language users’ responses to real words are often compared to novel pseudoword forms. The goal of these comparisons is to learn something about the architecture of the lexical processing system, by examining or inferring the processing pathways evoked by words, which have full phonological, lexical, grammatical, and semantic representations. These are compared to pseudowords, which are assumed to lack all linguistic information at levels higher than the phonological representation, due to their novel status. However, the precise nature of pseudoword representation is still a subject of inquiry, one that is critical to understanding precisely what is being isolated in the lexical processing system in experiments where words and pseudowords are compared. The present study contributes to this line of research by providing data on the neural processing of words and pseudowords in an auditory listening task. Previous research Theories of pseudoword processing streams In studies of word reading, models of processing have been proposed in which words and pseu- dowords employ different processing pathways, one facilitated by sublexical processes and the other by lexical processes (Coltheart et al. 1993, 2001, see also Marshall and Newcombe 1973). This ar- gument, the dual-route theory, is built upon the observation that readers with different types of dyslexia may or may not be impaired when reading pseudowords, a distinction ascribed to whether or not the sublexical (phonological) level of processing is impaired. Although designed to explain processing with visual presentation of stimuli, this theory has been extended to examine word and pseduworod proccessing in the auditory domain as well (Glosser et al. 1998), making it a more general account of the distinction between novel forms and stored lexical representations. However, on another account, pseudowords and words utilize shared processing pathways, with processing differences attributable to different degrees of engagement of various components of the system. An argument in the connectionist tradition (e.g. Seidenberg and McClelland 1989) argues against the dual-route theory by positing that differences between words and pseudowords reflect differences in how strongly orthography, phonology, and semantics are activated, but not to entirely different Data from this study was collected and made available by the lab of Dr. Edward Chang at UCSF. This study has benefited from suggestions and advice from Edward Chang, Kristofer Bouchard, Nima Mesgarani, Angela Ren, Keith Johnson, Shinae Kang, and Susanne Gahl, and members of the Chang Lab at UCSF and the Phonology Lab at UC Berkeley.