Poster B42, Tuesday, August 20, 2019, 3:15 – 5:00 pm, Restaurant Hall
Reevaluating the dynamics of auditory sentence processing: an ERP study in French
Lauren A. Fromont1,2, Phaedra Royle1,2, Alexandre Herbay2,3, Clara Misirliyan1,3, Karsten Steinhauer2,3;1École d'orthophonie et d'audiologie, Université de Montréal, 2Centre for Research on Brain, Language, and Music (CRBLM), Montréal, 3School of Communication Sciences and Disorders, McGill University
Syntactic categories (SC; noun, verb, etc.) are used to build larger linguistic structures for sentence comprehension, and encounters with unexpected categories create processing difficulties. Serial approaches to sentence processing consider that SC-identification is “ultra-rapid” (reflected by an ELAN, Friederici, 2012) and can block semantic (i.e. meaning) processing (no N400). However, EEG studies supporting this model have serious design issues (Steinhauer & Drury, 2012). While few studies in the visual modality provided empirical evidence against the serial approach (e.g. Fromont, Steinhauer, Royle, submitted), no auditory data has clarified this issue. This experiment is the first auditory study to create pure anomaly conditions, using a balanced design in French to probe mechanisms underlying SC-identification and semantic processing. Thirty-four participants listened to French sentences and judged their acceptability while their EEG was recorded. In correct sentences 1-2, the contexts select for a specific SC: the control verb (+pronoun) in 1. selects a verb (‘to tackle’), and the transitive verb (+determiner) in 2. selects a noun (‘toad’). Since pronouns and determiners are homophonous in French, the context preceding the target is kept constant. We created a 2x2 design that systematically introduced SC anomalies by swapping the 2 target words, and semantic anomalies by swapping introductory sentences (which contained a prime, here ‘hockey’ and ‘swamp’), thus creating “pure” SC violations and semantic anomalies, as well as combined SC+semantic errors. //1. Jeanne joue au hockey avec son copain. Elle ose le plaquer… ‘Jeanne plays hockey with her friend. She dares to-tackle him …’// 2. Jeanne va au marais avec son copain. Elle ôte le crapaud… ‘Jeanne goes to the swamp with her friend. She removes the toad ….'.// ERP data on the N400 time-window revealed main effects of semantic anomalies (p < .001), and SC errors (p = .02). A three-way interaction with anteriority (p = .02) revealed that while both effects were large at posterior sites (p < .001), semantic anomalies elicited larger frontal negativities (p < .001) than SC errors (p = .03). After 800 ms, we observe a small P600 in response to SC errors only (p = .003) but sustained frontal negativities in response to semantic anomalies (p = .006). Our results confirm findings obtained in a previous visual study (Fromont et al, submitted): no ELAN, but an N400 effect for SC-violations. Furthermore, additive N400 effects in both studies show that semantic and SC processing can operate in parallel and may be subserved by distinct processing streams. Later effects in the P600 time-window differ from the visual experiment, in which processes linked to both anomalies competed for the same resources. The present auditory study revealed a P600 only in response to SC errors. This difference could be due to participants being worse at categorizing anomalous sentences as unacceptable in auditory tasks (p = .004), consistent with the P600 being a task-related component. The sustained negativity for semantic anomalies, regardless of syntax, could reflect an increase in working-memory load associated with target-word processing difficulties within spoken discourse (Van Berkum et al, 2003).
Themes: Syntax, Morphology
Method: Electrophysiology (MEG/EEG/ECOG)