Contextual modifications of a discursive word ‘however’ and their lexical support

Examination the means of local coherence of the text, namely various auxiliary units, such as conjunctions and conjunctive means, particles, pronouns, hybrid units, etc., remains relevant in studying the text. Same means of textual coherence are classified by the linguists depending on the vector of research. The subject of this article is the discursive word ‘however’. Discursive words are an important part of text studying, and textual coherence in particular. The object of this article is the functionality of the word ‘however’ in the instance of ending narration, as well as the corresponding contextual modification “ending of description / discussion”. The contexts for linguistic analysis that largely contain the word ‘however’ were taken from the Russian National Corpus. Analysis is conducted on the contexts of fiction and popular science styles. The scientific novelty of research consists in examination of the peculiarities of using the word ‘however’ in combination with other words (enough, no more, never mind), as well as the specificity of formation of syntactic constructions with the word ‘however’. The conclusion is made the speaker can end narration, description, discussion due to unwillingness or inexpediency to continue the thought, or due to shifting  onto a new aspect of the given situation.

Does Local Coherence Lead to Targeted Regressions and Illusions of Grammaticality?

Local coherence effects arise when the human sentence processor is temporarily misled by a locally grammatical but globally ungrammatical analysis (The coach smiled at the player tossed a frisbee by the opposing team). It has been suggested that such effects occur either because sentence processing occurs in a bottom-up, self-organized manner rather than under constant grammatical supervision (Tabor et al., 2004), or because local coherence can disrupt processing due to readers maintaining uncertainty about previous input (Levy, 2008b). We report the results of an eye-tracking study in which subjects read German grammatical and ungrammatical sentences that either contained a locally coherent substring or not and gave binary grammaticality judgments. In our data, local coherence affected on-line processing immediately at the point of the manipulation. There was, however, no indication that local coherence led to illusions of grammaticality (a prediction of self-organization), and only weak, inconclusive support for local coherence leading to targeted regressions to critical context words (a prediction of the uncertain-input approach). We discuss implications for self-organized and noisy-channel models of local coherence.

Does local coherence lead to targeted regressions and illusions of grammaticality?

Local coherence effects arise when the human sentence processor is temporarily misled by a locally grammatical but globally ungrammatical analysis ("The coach smiled at THE PLAYER TOSSED A FRISBEE by the opposing team"). It has been suggested that such effects occur either because sentence processing occurs in a bottom-up, self-organized manner rather than being under constant grammatical supervision (Tabor, Galantucci, & Richardson, 2004), or because local coherence can disrupt processing due to readers maintaining uncertainty about previous input (Levy, 2008). We report the results of an eye-tracking study in which subjects read German grammatical and ungrammatical sentences that either contained a locally coherent substring or not and gave binary grammaticality judgments. In our data, local coherence affected on-line processing immediately at the point of the manipulation. There was, however, no indication that local coherence led to illusions of grammaticality (a prediction of self-organization), and only weak, inconclusive support for local coherence leading to targeted regressions to critical context words (a prediction of the uncertain-input approach). We discuss implications for self-organized and noisy-channel models of local coherence.

Enhancing Pointer Network for Sentence Ordering with Pairwise Ordering Predictions

Dominant sentence ordering models use a pointer network decoder to generate ordering sequences in a left-to-right fashion. However, such a decoder only exploits the noisy left-side encoded context, which is insufficient to ensure correct sentence ordering. To address this deficiency, we propose to enhance the pointer network decoder by using two pairwise ordering prediction modules: The FUTURE module predicts the relative orientations of other unordered sentences with respect to the candidate sentence, and the HISTORY module measures the local coherence between several (e.g., 2) previously ordered sentences and the candidate sentence, without the influence of noisy left-side context. Using the pointer mechanism, we then incorporate this dynamically generated information into the decoder as a supplement to the left-side context for better predictions. On several commonly-used datasets, our model significantly outperforms other baselines, achieving the state-of-the-art performance. Further analyses verify that pairwise ordering predictions indeed provide extra useful context as expected, leading to better sentence ordering. We also evaluate our sentence ordering models on a downstream task, multi-document summarization, and the summaries reordered by our model achieve the best coherence scores. Our code is available at https://github.com/DeepLearnXMU/Pairwise.git.

Going off the rails: Impaired coherence in the speech of patients with semantic control deficits

The ability to speak coherently, maintaining focus on the topic at hand, is critical for effective communication and is commonly impaired following brain damage. Recent data suggests that executive processes that regulate access to semantic knowledge (i.e., semantic control) are critical for maintaining coherence during speech. To test this hypothesis, we assessed speech coherence in a case-series of fluent stroke aphasic patients with deficits in semantic control. Patients were asked to speak about a series of topics and their responses were analysed using computational linguistic methods to derive measures of their global coherence (the degree to which they spoke about the topic given) and local coherence (the degree to which they maintained a topic from one moment to the next). Compared with age-matched controls, patients showed severe impairments to global coherence and milder impairments to local coherence, suggesting that semantic control deficits give rise to being “led up the garden path”, i.e., one sentence automatically cueing another, with the topic becoming increasingly less relevant to the original question. Global coherence was strongly correlated with the patients’ performance on tests of semantic control, with poorer ability to maintain top-down global coherence being associated with greater semantic control deficits. Other aspects of speech production were also impaired but were not correlated with semantic control deficits. This is the first study to investigate the impact of semantic control impairments within a naturalistic setting, and indicates patients with these impairments are likely to find maintaining focus in everyday conversation difficult.

Tau deposition is associated with functional isolation of the hippocampus in aging

The tau protein aggregates in aging and Alzheimer disease and may lead to memory loss through disruption of medial temporal lobe (MTL)-dependent memory systems. Here, we investigated tau-mediated mechanisms of hippocampal dysfunction that underlie the expression of episodic memory decline using fMRI measures of hippocampal local coherence (regional homogeneity; ReHo), distant functional connectivity and tau-PET. We show that age and tau pathology are related to higher hippocampal ReHo. Functional disconnection between the hippocampus and other components of the MTL memory system, particularly an anterior-temporal network specialized for object memory, is also associated with higher hippocampal ReHo and greater tau burden in anterior-temporal regions. These associations are not observed in the posteromedial network, specialized for context/spatial information. Higher hippocampal ReHo predicts worse memory performance. These findings suggest that tau pathology plays a role in disconnecting the hippocampus from specific MTL memory systems leading to increased local coherence and memory decline.