Coherence relations in discourse and cognition : comparing approaches, annotations and interpretations

When readers comprehend a discourse, they do not merely interpret each clause or sentence separately; rather, they assign meaning to the text by creating semantic links between the clauses and sentences. These links are known as coherence relations (cf. Hobbs, 1979; Sanders, Spooren & Noordman, 1992). If readers are not able to construct such relations between the clauses and sentences of a text, they will fail to fully understand that text. Discourse coherence is therefore crucial to natural language comprehension in general. Most frameworks that propose inventories of coherence relation types agree on the existence of certain coarse-grained relation types, such as causal relations (relations types belonging to the causal class include Cause or Result relations), and additive relations (e.g., Conjunctions or Specifications). However, researchers often disagree on which finer-grained relation types hold and, as a result, there is no uniform set of relations that the community has agreed on (Hovy & Maier, 1995). Using a combination of corpus-based studies and off-line and on-line experimental methods, the studies reported in this dissertation examine distinctions between types of relations. The studies are based on the argument that coherence relations are cognitive entities, and distinctions of coherence relation types should therefore be validated using observations that speak to both the descriptive adequacy and the cognitive plausibility of the distinctions. Various distinctions between relation types are investigated on several levels, corresponding to the central challenges of the thesis. First, the distinctions that are made in approaches to coherence relations are analysed by comparing the relational classes and assessing the theoretical correspondences between the proposals. An interlingua is developed that can be used to map relational labels from one approach to another, therefore improving the interoperability between the different approaches. Second, practical correspondences between different approaches are studied by evaluating datasets containing coherence relation annotations from multiple approaches. A comparison of the annotations from different approaches on the same data corroborate the interlingua, but also reveal systematic patterns of discrepancies between the frameworks that are caused by different operationalizations. Finally, in the experimental part of the dissertation, readers’ interpretations are investigated to determine whether readers are able to distinguish between specific types of relations that cause the discrepancies between approaches. Results from off-line and online studies provide insight into readers’ interpretations of multi-interpretable relations, individual differences in interpretations, anticipation of discourse structure, and distributional differences between languages on readers’ processing of discourse. In sum, the studies reported in this dissertation contribute to a more detailed understanding of which types of relations comprehenders construct and how these relations are inferred and processed.