Poster E22, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Lexical pre-activation and post-lexical integration accounts of the N400 ERP effect: When words’ syntactic categories interact with semantic relational priming
Alexandre Herbay1,2, Phaedra Royle2,3, Karsten Steinhauer1,2;1McGill University, 2Center for Research on Brain, Language, and Music, 3Université de Montréal
Introduction: Neurocognitive processes underlying the N400 ERP component, typically associated with semantic processing, are still controversial. Several mechanisms have been proposed to account for N400 amplitude reductions associated with semantic priming: (1) automatic spreading activation (ASA), (2) prediction-based priming and (3) post-lexical integration processes in working memory (WM). Recent proposals support (1) and (2) but question (3) (e.g., Lau et al., 2013). However, Steinhauer et al.’s (2017) priming experiment in French showed that related word pairs of a given semantic relationship (e.g., part-whole) showed stronger priming effects when embedded in a list with other prime-target pairs of the same (part-whole) relationship (consistent pair, CON) than a different relationship (e.g., antonyms; inconsistent pair, INC). Moreover, the consistency N400 difference (INC-CON) had a later onset (after 400ms) than the traditional relatedness effect (unrelated word pairs vs. INC) starting at 300ms. The consistency effect is compatible with WM-based post-lexical integration (‘relational priming’) but not with ASA, as semantic networks are arguably not organized according to abstract types of semantic relationships. Alternatively, the short 250 ms Stimulus Onset Asynchrony (SOA) used by these authors may have led to delayed prediction-based priming effects. Methodology: Using a similar experimental design as Steinhauer et al. (2017), but with a longer 450 ms SOA and nine lists of 80 prime-target pairs promoting five distinct semantic relationships (SR; antonyms, synonyms, part-whole, etc.), we hypothesized that N400 consistency effects tied to prediction-based priming (Lau et al., 2013) should now occur earlier (N250 and early N400 effects, respectively reflecting prediction of orthographic and semantic features) and eliminate late-onset effects. In contrast, WM-based post-lexical effects (Steinhauer et al., 2017) should still occur after 400 ms. We also sought to investigate the influence of the words’ syntactic category on semantic relational priming by having three lists for each of our three syntactic categories (SC; adjectives, nouns, verbs). Therefore, in each list, prime-target pairs could be consistent (promoted SC and SR), semantically inconsistent (different SR, SemInc), syntactically inconsistent (different SC, SynInc) or both (different SR and SC, SemSynInc). Results: ERP data from 36 participants were analyzed using mixed-effect linear models. When collapsing all types of inconsistent pairs, N400 relational priming effects still started late (after 390 ms) as in Steinhauer et al. (2017). However, SemInc pairs produced an early fronto-central negativity between 250 and 300 ms (p < 0.05) and a larger N400 between 400 and 450 ms at all sites (p < 0.001). SynInc pairs only produced a larger N400 after 400 ms in posterior regions (p <0.05). Finally, SemSynInc pairs produced a larger N400 between 380 and 500 ms in central and posterior sites (p <0.001). Conclusion: Words’ SC consistency significantly modulated the onset of relational priming effects. Violation of lexical pre-activations in WM for different SRs but consistent SCs (SemInc) elicits an early frontal negativity. In contrast, an inconsistent SC seems to disrupt predictive mechanisms and delays processing: only late integration effects for related pairs are found in SynInc and SemSynInc conditions. Data suggest a combination of prediction and post-lexical effects.
Themes: Meaning: Lexical Semantics, Syntax
Method: Electrophysiology (MEG/EEG/ECOG)