Conceptual Combination in the LATL With and Without Syntactic Composition

Abstract

The relationship between syntactic, semantic, and conceptual processes in language comprehension is a central question to the neurobiology of language. Several studies have suggested that conceptual combination in particular can be localized to the left anterior temporal lobe (LATL), while syntactic processes are more often associated with the posterior temporal lobe or inferior frontal gyrus. However, LATL activity can also correlate with syntactic computations, particularly in narrative comprehension. Here we investigated the degree to which LATL conceptual combination is dependent on syntax, specifically asking whether rapid (∼200 ms) magnetoencephalography effects of conceptual combination in the LATL can occur in the absence of licit syntactic phrase closure and in the absence of a semantically plausible output for the composition. We find that such effects do occur: LATL effects of conceptual combination were observed even when there was no syntactic phrase closure or plausible meaning. But syntactic closure did have an additive effect such that LATL signals were the highest for expressions that composed both conceptually and syntactically. Our findings conform to an account in which LATL conceptual composition is influenced by local syntactic composition but is also able to operate without it.

Non-Local Conceptual Combination

“…Even though the brain is sensitive to local phrase structure in composition (Mollica et al, 2020), we have shown that two lexical items that are part of separate syntactic phrases can engage the LATL in a very similar way to how those two words would if they were part of the same phrase. This extends previous findings from Parrish and Pylkkänen (2022) which showed that the LATL is engaged in conceptual combination for two words that do not syntactically merge (but are otherwise part of the same DP structure). This study furthers our understanding of how conceptual combination fits in to a larger parsing model as well as narrowing down the possibilities of how the mechanism behind conceptual combination operates.…”

“…The copyright holder for this preprint this version posted December 13, 2022. ; https://doi.org/10.1101/2022.12.11.519989 doi: bioRxiv preprint Running head: NON-LOCAL CONCEPTUAL COMBINATION 6 in the syntax (Parrish & Pylkkänen, 2022). The current study tests if such syntax-independent composition can occur across a long distance.…”

“…As regards non-grammatical factors modulating the LATL, it has also shown sensitivity to level of association between the composing words, with high-association pairs ("French cheese") driving LATL activity more than low association pairs ("Korean cheese") (Li and Pylkkänen, 2021). Parrish and Pylkkänen (2022) also showed that plausible modifications lead to a greater increase in LATL activity relative to implausible modifications. This finding was surprising since plausibility cannot be known until a meaning has been constructed.…”

Tracking the behavioral and neural dynamics of semantic representations through negation

“…In parallel to identifying the lexical-semantic representations of adjectives, we showed that negation is significantly decodable at each modifier’s presentation time (reflecting word form encoding and semantic encoding), and its decodability remains sustained throughout the presentation of the adjective, up to ∼700 ms (see Zhang and Pylkkänen, 2018 for a similar result at the sentence level). This pattern was mainly observed in phrases with two modifiers, likely reflecting syntactic and semantic compositional processes (Fedorenko et al, 2016; Pallier et al, 2011; Parrish and Pylkkänen, 2022). These results demonstrate that the lexical-semantic features of adjective and negation are processed in a parallel fashion, as opposed to serially (see Fyshe et al, 2019 for a similar pattern for adjective and noun in the context of adjective-noun phrases).…”

“…Cumulatively, these results suggest that the brain encodes negation every time a "not" is presented and maintains this information up to 720 ms after adjective onset. Further, they show that the duration of negation maintenance is amplified by the presence of a second modifier (i.e., "really"), highlighting combinatoric effects [2,6,50].…”