Multiple Signals of Coherence Relations

Abstract

In this paper, we investigate the signalling of coherence relations when they are simultaneously indicated by more than one signal. In particular, we examine the co-occurrence of discourse markers and other relational signals when they are used together to mark a single relation. With the goal to identify the source of the usage of multiple signals, we postulate a twofold hypothesis: the co-occurrence of discourse markers and other textual signals can result from the type of the discourse markers themselves, or it can be triggered by the semantics of the relations in question. We conduct a corpus study, examining instances of multiple signals (co-occurrence of discourse markers and other signals) in the RST Signalling Corpus (Das et al., 2015). We analyze discourse markers that appear as part of multiple signals and also relations that frequently employ multiple signals as their indicators. Our observations suggest that the signalling of relations by multiple signals is a complex phenomenon, since the co-occurrence of discourse markers and other textual signals appears to arise from multiple sources.

The role of non-connective discourse cues and their interaction with connectives

“…After having established the overall similarity between two versions of the same coherence relation, one where this relation is explicitly reinforced by cues and one where it is not, we were able to show through a connective insertion task and a forced choice task that the presence of non-connective cues indeed helps participants identify the coherence relation holding between two sentences. Our main hypothesis on the disambiguating role of discourse cues (H1) is thus confirmed and complements recent (mostly corpus-based) studies investigating such linguistic devices (e.g., Das & Taboada 2019;Hoek et al 2019). This result has important implications for psycholinguistic, computational and even acquisitional perspectives, and shifts the attention away from connectives, which had so far been the focus of discourse studies.…”

“…About a third of their data is signalled by two signals or more (dropping to 12.22% for relations signalled by three signals or more). In a later paper, Das and Taboada (2019) focus on these signal clusters (including at least one connective) and suggest that additional signals may serve to specify the type of coherence relation (mononuclear or multinuclear) when the connective does not fully specify it itself, or when it is potentially ambiguous between multiple relations, although the co-occurrence between connectives and other signals is not restricted to these two conditions.…”

“…The first and main hypothesis (H1) thus tests the disambiguation role of nonconnective cues and compares discourse relations conveying the same ideas with and without such reinforcing cues. We expect cues to facilitate disambiguation, as suggested by Das and Taboada (2019). To test the effects of cue presence, we focus on consequence relations vs. contrastive relations.…”

“…There is thus an extensive body of research on the individual roles of connectives and other discourse cues in the marking and processing of coherence relations. By contrast, the interaction between connectives and other cues has only recently started to be systematically investigated from corpus-based (Crible 2020;Hoek et al 2019;Das & Taboada 2019) or experimental methods (Crible & Pickering 2020;Grisot & Blochowiak 2019). These studies point to a multifactorial phenomenon of co-occurrence between connectives and other cues, which is impacted by cognitive factors of complexity and information density.…”

The syntax and semantics of coherence relations

“…However, the method remains inherently subjective: it is the analyst who decides which feature signals the relation. Das and Taboada (2019) further examined the co-occurrence between DMs and signals in the same newspaper corpus, testing whether this co-occurrence was mainly motivated by the type of DM or by the type of relation. They make a number of interesting observations regarding the ambiguity of DMs such as and and their tendency to co-occur with signals, although monosemous DMs such as moreover or for instance also frequently co-occur with signals in their data.…”