Neural correlates of fine-grained meaning distinctions: An fMRI investigation of scalar quantifiers

On the scope of presupposition in discourse reading comprehension

referential relationships can be communicated through presupposition. The presupposition trigger (also) in Jiayan also bought eggs exerts a pragmatic constraint that besides the object, the verb constrains additional and alternative referents. Our study provided a novel set of evidence that the reader preferred larger- over smaller-sized sets for the scope of presupposition in discourse comprehension. The structural hierarchy in smaller-sized sets and the earlier-mentioned structural details in larger-sized sets drove higher preference. Furthermore, readers' difference in their preference reflected their tendency to attend to discourse structural information. These findings are consistent with the multiple constraints hypothesis/the presupposition maximization principle hypothesis, rather than the local bias hypothesis. The present study enlightened the understanding of structural constraints on processing the number and the identity of presupposed referential information in discourse reading comprehension.

Linguistic signs in action: The neuropragmatics of speech acts

What makes human communication exceptional is the ability to grasp speaker's intentions beyond what is said verbally. How the brain processes communicative functions is one of the central concerns of the neurobiology of language and pragmatics. Linguistic-pragmatic theories define these functions as speech acts, and various pragmatic traits characterise them at the levels of propositional content, action sequence structure, related commitments and social aspects. Here I discuss recent neurocognitive studies, which have shown that the use of identical linguistic signs in conveying different communicative functions elicits distinct and ultra-rapid neural responses. Interestingly, cortical areas show differential involvement underlying various pragmatic features related to theory-of-mind, emotion and action for specific speech acts expressed with the same utterances. Drawing on a neurocognitive model, I posit that understanding speech acts involves the expectation of typical partner follow-up actions and that this predictive knowledge is immediately reflected in mind and brain.

Understanding an implicated causality: The brain network for processing concessive relations

Concessive relations, often indicated by conjunction words such as although, are semantically and pragmatically more complex than causal relations (expressed using because), as they involve more semantic features such as implicated meaning and negation. However, it remains unclear how linguistic-level complexity is manifested through different brain activities and functional connectivities. This fMRI study investigated how the neural underpinnings of concessive relations differ from those of causal relations. Pragmatically congruent and incongruent words were embedded in causal as well as concessive sentences. The whole-brain analysis revealed that relative to because-congruent sentences, although-congruent sentences evoked increased activations in a left network including IFG, bilateral MFG, mPFC, pMTG, and TPJ. DCM analysis showed that while the functional connectivity from IFG to MFG was commonly involved in processing concessive and causal relations, functional connectivities from pMTG to IFG and from pMTG to TPJ were involved in processing causal and concessive relations, respectively.

Understanding particularized and generalized conversational implicatures: Is theory-of-mind necessary?

A speaker's intended meaning can be inferred from an utterance with or without reference to its context for particularized implicature (PI) and/or generalized implicature (GI). Although previous studies have separately revealed the neural correlates of PI and GI comprehension, it remains controversial whether they share theory-of-mind (ToM) related inferential processes. Here we address this issue using functional MRI (fMRI) and transcranial direct current stimulation (tDCS). Participants listened to single-turn dialogues where the reply was indirect with either PI or GI or was direct for control conditions (i.e., PIC and GIC). Results showed that PI and GI comprehension shared the multivariate fMRI patterns of language processing; in contrast, the ToM-related pattern was only elicited by PI comprehension, either at the whole-brain level or within dorsal medial prefrontal cortex (dmPFC). Moreover, stimulating right TPJ exclusively affected PI comprehension. These findings suggest that understanding PI, but not GI, requires ToM-related inferential processes.

Gricean Expectations in Online Sentence Comprehension: An ERP Study on the Processing of Scalar Inferences

There is substantial support for the general idea that a formalization of comprehenders' expectations about the likely next word in a sentence helps explaining data related to online sentence processing. While much research has focused on syntactic, semantic, and discourse expectations, the present event-related potentials (ERPs) study investigates neurolinguistic correlates of pragmatic expectations, which arise when comprehenders expect a sentence to conform to Gricean Maxims of Conversation. For predicting brain responses associated with pragmatic processing, we introduce a formal model of such Gricean pragmatic expectations, using an idealized incremental interpreter. We examine whether pragmatic expectancies derived from this model modulate the amplitude of the N400, a component that has been associated with predictive processing. As part of its parameterization, the model distinguishes genuine pragmatic interpreters, who expect maximally informative true utterances, from literal interpreters, who only expect truthfulness. We explore the model's non-trivial predictions for an experimental setup which uses picture-sentence verification with ERPs recorded at several critical positions in sentences containing the scalar implicature trigger some. We find that Gricean expectations indeed affect the N400, largely in line with the predictions of our model, but also discuss discrepancies between model predictions and observations critically.