Neural synchrony reflects closure of jabberwocky noun phrases but not predictable pseudoword sequences

Abstract

Successful language comprehension requires the combination of individual words into larger linguistic units. In the present minimal‐phrase study, we used electroencephalography (EEG) to investigate whether syntactic combination is indexed by changes in neural synchrony, while testing for both token‐based and type‐based effects. To do this, we analysed intertrial phase coherence (ITPC) elicited by reading two item (words or pseudowords) phrases that were either unifiable or nonunifiable. Results indicated that type‐based unifiable phrases elicited increased ITPC relative to all other conditions in the frequency band corresponding to the rate of phrases (0.5 Hz) but not the rate of words (1 Hz). Conversely, we observed a complementary pattern for the N400, which was more sensitive to token‐based effects. These findings provide evidence that the combination of single words into larger syntactic structures may be indexed by the synchronous firing of assemblies of neurons oscillating at the rate of phrases during reading.

Syntactic Constructions Drive Cortical Tracking in the Absence of Lexical Content: An Electrophysiological Investigation of Sentence Processing During Reading

“…In this study we set out to test whether the brain could track purely syntactic units when content words are replaced with pseudowords resulting in a linguistic pattern that would have to be inferred from the syntactic form without recourse to lexical projections. Our results are consistent with our previous findings reported in Rafferty et al (2023). Relative to wordlists that lack syntactic structure, we observed greater MI at phrase boundaries for both English and jabberwocky sentences, both of which adhere to the English caused-motion sentence structure.…”

“…If Coopman’s et al’s interpretation of their results is accurate, their study would provide useful psycholinguistic support in favor of a lexicalist hypothesis. However, there is some recent evidence produced in our lab (Rafferty et al, 2023) that appears to be at odds with the interpretation of the results of Coopmans et al In this study, we used a minimal phrase paradigm to investigate whether individual noun phrases composed of a determiner and a pseudoword were sufficient to elicit neural synchrony given the lack of lexical semantics. This study recorded EEG activity while participants read mixed blocks of syntactically well-formed phrases composed of a determiner and a pseudoword ( the moop ) and a wordlist condition composed of the same pseudoword followed by a determiner ( moop the ).…”

“…Secondly, it is possible that the difference lies in the stimulus presentation modality (i.e., reading versus listening), and this should be tested empirically. Previous research has demonstrated that phrase tracking takes place both with auditory and visual stimuli (Rafferty et al, 2023), but given that there is evidence from Kaufeld et al that participants had difficulty parsing words from the speech stream, it seems that this is at least one important factor when considering the difference in modality. Moreover, the process of phrase tracking while listening as compared to reading must surely overlap on some level, and our findings here may be useful in helping future research isolate overlapping and diverging processes.…”

“…Indeed Coopmans et al suggest that the pattern of differences indicates that phrasal syntax relies on lexically-driven computation of syntax thereby providing support for lexically-based models of syntactic processing (e.g., Hagoort, 2013;Hagoort, 2017;Matchin & Hickok, 2019). This last finding is somewhat at odds with the results of a recent study by Rafferty et al (2023) who used a minimal phrase paradigm to investigate whether individual noun phrases composed of a determiner and a pseudoword were sufficient to elicit neural synchrony given the lack of lexical semantics. This study recorded EEG activity while participants read mixed blocks of syntactically well-formed phrases composed of a determiner and a pseudoword (the moop) and a wordlist condition composed of the same pseudoword followed by a determiner (moop the).…”