Predicting syntactic structure

Multiple dimensions of syntactic structure are resolved earliest in posterior temporal cortex

How we combine minimal linguistic units into larger structures remains an unresolved topic in neuroscience. Language processing involves the abstract construction of 'vertical' and 'horizontal' information simultaneously (e.g., phrase structure, morphological agreement), but previous paradigms have been constrained in isolating only one type of composition and have utilized poor spatiotemporal resolution. Using intracranial recordings, we report multiple experiments designed to separate phrase structure from morphosyntactic agreement. Epilepsy patients (n = 10) were presented with auditory two-word phrases grouped into pseudoword-verb ('trab run') and pronoun-verb either with or without Person agreement ('they run' vs. 'they runs'). Phrase composition and Person violations both resulted in significant increases in broadband high gamma activity approximately 300ms after verb onset in posterior middle temporal gyrus (pMTG) and posterior superior temporal sulcus (pSTS), followed by inferior frontal cortex (IFC) at 500ms. While sites sensitive to only morphosyntactic violations were distributed, those sensitive to both composition types were generally confined to pSTS/pMTG and IFC. These results indicate that posterior temporal cortex shows the earliest sensitivity for hierarchical linguistic structure across multiple dimensions, providing neural resources for distinct windows of composition. This region is comprised of sparsely interwoven heterogeneous constituents that afford cortical search spaces for dissociable syntactic relations.

L2 Arabic learners' processing of Arabic garden-path sentences: a consistent reading pattern

Purpose

The main purpose of this study was to investigate to what extent the L2 Arabic learners' reading process is affected by the incomplete representation of speech (the absence of short vowels and diacritics) while reading ambiguous sentences (garden path sentences).

Method

With a self-paced reading software program, 41 non-native male students, aged from 22 to 26, enrolled in King Saud University, participated in reading 44 sentences (followed by reading comprehension questions) representing three reading conditions, plain, vowelized-discretized, and wrongly-vowelized.

Results

For the reading times data, the analysis revealed that the GP structure had a significant effect on the reading processes of L2 Arabic learners; it took them longer to read the GP sentences than their non-GP counterparts. For the reading comprehension, the analysis did not reveal any significant differences between the means for the percentages of correct responses. For the comparison between the three reading conditions, a significant difference was found: it took the participants on average less time to read the GP sentences when presented plain, and more time with the incorrect representation. However, their reading comprehension was not affected.

Conclusion

In addition to the good-enough model and the nature of Arabic morphology, the reading experience, is a good candidate to start with as an important factor in the interpretation of the ineffectiveness of the GP structure on the reading comprehension process of Arabic readers, in which the segregability of Arabic writing system prepare the readers to emphasize some sensory inputs and ignore others based on their past reading experience.

The Effects of Semantic and Syntactic Prediction on Reading Aloud

Semantic and syntactic prediction effects were investigated in a word naming task using semantic or syntactic contexts that varied between three and six words. Participants were asked to read the contexts silently and name a target word, which was indicated by a color change. Semantic contexts were composed of lists of semantically associated words without any syntactic information. Syntactic contexts were composed of semantically neutral sentences, in which the grammatical category but not the lexical identity of the final word was highly predictable. When the presentation time of the context words was long (1,200 ms), both semantically and syntactically related contexts facilitated reading aloud latencies of target words and syntactically related contexts produced larger priming effects than semantically related contexts in two out of three analyses. When the presentation time was short (200 ms), however, syntactic context effects disappeared, while semantic context effects remained significant. Across the three experiments, longer contexts produced faster response latencies, but longer contexts did not produce larger priming effects. The results are discussed in the context of the extant literature on semantic and syntactic priming and more recent evidence, suggesting that syntactic information constrains single word recognition.

Online neurostimulation of Broca's area does not interfere with syntactic predictions: A combined TMS-EEG approach to basic linguistic combination

Categorical predictions have been proposed as the key mechanism supporting the fast pace of syntactic composition in language. Accordingly, grammar-based expectations are formed-e.g., the determiner "a" triggers the prediction for a noun-and facilitate the analysis of incoming syntactic information, which is then checked against a single or few other word categories. Previous functional neuroimaging studies point towards Broca's area in the left inferior frontal gyrus (IFG) as one fundamental cortical region involved in categorical prediction during incremental language processing. Causal evidence for this hypothesis is however still missing. In this study, we combined Electroencephalography (EEG) and Transcranial Magnetic Stimulation (TMS) to test whether Broca's area is functionally relevant in predictive mechanisms for language. We transiently perturbed Broca's area during the first word in a two-word construction, while simultaneously measuring the Event-Related Potential (ERP) correlates of syntactic composition. We reasoned that if Broca's area is involved in predictive mechanisms for syntax, disruptive TMS during the first word would mitigate the difference in the ERP responses for predicted and unpredicted categories in basic two-word constructions. Contrary to this hypothesis, perturbation of Broca's area at the predictive stage did not affect the ERP correlates of basic composition. The correlation strength between the electrical field induced by TMS and the ERP responses further confirmed this pattern. We discuss the present results considering an alternative account of the role of Broca's area in syntactic composition, namely the bottom-up integration of words into constituents, and of compensatory mechanisms within the language predictive network.

Differential contributions of inferior frontal gyrus subregions to sentence processing guided by intonation

Auditory sentence comprehension involves processing content (semantics), grammar (syntax), and intonation (prosody). The left inferior frontal gyrus (IFG) is involved in sentence comprehension guided by these different cues, with neuroimaging studies preferentially locating syntactic and semantic processing in separate IFG subregions. However, this regional specialisation has not been confirmed with a neurostimulation method. Consequently, the causal role of such a specialisation remains unclear. This study probed the role of the posterior IFG (pIFG) for syntactic processing and the anterior IFG (aIFG) for semantic processing with repetitive transcranial magnetic stimulation (rTMS) in a task that required the interpretation of the sentence's prosodic realisation. Healthy participants performed a sentence completion task with syntactic and semantic decisions, while receiving 10 Hz rTMS over either left aIFG, pIFG, or vertex (control). Initial behavioural analyses showed an inhibitory effect on accuracy without task-specificity. However, electric field simulations revealed differential effects for both subregions. In the aIFG, stronger stimulation led to slower semantic processing, with no effect of pIFG stimulation. In contrast, we found a facilitatory effect on syntactic processing in both aIFG and pIFG, where higher stimulation strength was related to faster responses. Our results provide first evidence for the functional relevance of left aIFG in semantic processing guided by intonation. The stimulation effect on syntactic responses emphasises the importance of the IFG for syntax processing, without supporting the hypothesis of a pIFG-specific involvement. Together, the results support the notion of functionally specialised IFG subregions for diverse but fundamental cues for language processing.

Is the Mind Inherently Predicting? Exploring Forward and Backward Looking in Language Processing

Prediction is one characteristic of the human mind. But what does it mean to say the mind is a "prediction machine" and inherently forward looking as is frequently claimed? In natural languages, many contexts are not easily predictable in a forward fashion. In English, for example, many frequent verbs do not carry unique meaning on their own but instead, rely on another word or words that follow them to become meaningful. Upon reading take a the processor often cannot easily predict walk as the next word. But the system can "look back" and integrate walk more easily when it follows take a (e.g., as opposed to *make|get|have a walk). In the present paper, we provide further evidence for the importance of both forward and backward-looking in language processing. In two self-paced reading tasks and an eye-tracking reading task, we found evidence that adult English native speakers' sensitivity to word forward and backward conditional probability significantly predicted reading times over and above psycholinguistic predictors of reading latencies. We conclude that both forward and backward-looking (prediction and integration) appear to be important characteristics of language processing. Our results thus suggest that it makes just as much sense to call the mind an "integration machine" which is inherently backward 'looking.'

Predictive Processing in Sign Languages: A Systematic Review

The objective of this article was to review existing research to assess the evidence for predictive processing (PP) in sign language, the conditions under which it occurs, and the effects of language mastery (sign language as a first language, sign language as a second language, bimodal bilingualism) on the neural bases of PP. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. We searched peer-reviewed electronic databases (SCOPUS, Web of Science, PubMed, ScienceDirect, and EBSCO host) and gray literature (dissertations in ProQuest). We also searched the reference lists of records selected for the review and forward citations to identify all relevant publications. We searched for records based on five criteria (original work, peer-reviewed, published in English, research topic related to PP or neural entrainment, and human sign language processing). To reduce the risk of bias, the remaining two authors with expertise in sign language processing and a variety of research methods reviewed the results. Disagreements were resolved through extensive discussion. In the final review, 7 records were included, of which 5 were published articles and 2 were dissertations. The reviewed records provide evidence for PP in signing populations, although the underlying mechanism in the visual modality is not clear. The reviewed studies addressed the motor simulation proposals, neural basis of PP, as well as the development of PP. All studies used dynamic sign stimuli. Most of the studies focused on semantic prediction. The question of the mechanism for the interaction between one’s sign language competence (L1 vs. L2 vs. bimodal bilingual) and PP in the manual-visual modality remains unclear, primarily due to the scarcity of participants with varying degrees of language dominance. There is a paucity of evidence for PP in sign languages, especially for frequency-based, phonetic (articulatory), and syntactic prediction. However, studies published to date indicate that Deaf native/native-like L1 signers predict linguistic information during sign language processing, suggesting that PP is an amodal property of language processing.

How do people interpret implausible sentences?

People sometimes interpret implausible sentences nonliterally, for example treating The mother gave the candle the daughter as meaning the daughter receiving the candle. But how do they do so? We contrasted a nonliteral syntactic analysis account, according to which people compute a syntactic analysis appropriate for this nonliteral meaning, with a nonliteral semantic interpretation account, according to which they arrive at this meaning via purely semantic processing. The former but not the latter account postulates that people consider not only a literal-but-implausible double-object (DO) analysis in comprehending The mother gave the candle the daughter, but also a nonliteral-but-plausible prepositional-object (PO) analysis (i.e., including to before the daughter). In three structural priming experiments, participants heard a plausible or implausible DO or PO prime sentence. They then answered a comprehension question first or described a picture of a dative event first. In accord with the nonliteral syntactic analysis account, priming was reduced following implausible sentences than following plausible sentences and following nonliterally interpreted implausible sentences than literally interpreted implausible sentences. The results suggest that comprehenders constructed a nonliteral syntactic analysis, which we argue was predicted early in the sentence.

Can prediction and retrodiction explain whether frequent multi-word phrases are accessed 'precompiled' from memory or compositionally constructed on the fly?

An important debate on the architecture of the language faculty has been the extent to which it relies on a compositional system that constructs larger units from morphemes to words to phrases to utterances on the fly and in real time using grammatical rules; or a system that chunks large preassembled, stored units of language from memory; or some combination of both approaches. Good empirical evidence exists for both 'computed' and 'large stored' forms in language, but little is known about what shapes multi-word storage/ access or compositional processing. Here we explored whether predictive and retrodictive processes are a likely determinant of multi-word storage/ processing. Our results suggest that forward and backward predictability are independently informative in determining the lexical cohesiveness of multi-word phrases. In addition, our results call for a reevaluation of the role of retrodiction in contemporary language processing accounts (cf. Ferreira and Chantavarin, 2018).