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On the Interaction of Relational Coherence and Lexical Cohesion in Expository and Persuasive Text Genres. Gisela Redeker & Markus Egg University of Groningen. Outline. Coherence and cohesion Coherence relations and discourse structure Cohesion (esp. lexical cohesion)
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On the Interaction of Relational Coherence and Lexical Cohesion in Expository and Persuasive Text Genres Gisela Redeker & Markus Egg University of Groningen Gothenburg, 8-13 July 2007
Outline • Coherence and cohesion • Coherence relations and discourse structure • Cohesion (esp. lexical cohesion) • Interaction between coherence and cohesion • Pilot study on local coherence and cohesion • Future work
Coherence and Cohesion Coherence: how a discourse is making sense relations between discourse segments (clauses, sentences, etc.); recursive application yields a hierarchical discourse configuration Cohesion: how discourse elements stick togetherconnectives; referential or lexical relations
Coherence • Three components of coherence (Redeker 2000) • Content relations (additive, causal, temporal, contrastive, etc.) • Pragmatic or intentional relations (evidence, justification, concession, etc.) • Sequential or textual relations (summary, restatement, segment boundary, etc.) • Rhetorical Structure Theory (RST; Mann & Thompson 1988, Taboada & Mann 2006) • Subject-matter relations (= content) • Presentational relations (= intentional and textual)
Coherence Relations and Discourse Structure Example (from Asher & Lascarides 2003): (1) Max experienced a lovely evening last night. (2) He had a fantastic meal. (3) He ate salmon. (4) He devoured lots of cheese. (5) He won a dancing competition. Discourse Structure (RST-analysis):
Cohesion Grammatical cohesion Conjunction (marks transitions between messages) Reference, ellipsis and substitution Lexical cohesion Paradigmatic: • Repetition • Synonymy, antonymy, hyponymy, meronymy Syntagmatic: • Collocation
Cohesion Grammatical cohesion Conjunction (marks transitions between messages) Reference, ellipsis and substitution Lexical cohesion Paradigmatic: • Repetition • Synonymy, antonymy, hyponymy, meronymy Syntagmatic: • Collocation
Discourse structure and cohesion aligned referential chain
Discourse structure and cohesion aligned collocation
Discourse structure and cohesion aligned referential chain meronymy hyponymy collocation
Discourse Structure and Lexical Cohesion: Alignmentand Divergence This example figures prominently in the ongoing discussion on discourse configuration (Danlos 2004, Wolf & Gibson 2005, Egg & Redeker 2006)
Discourse Structure and Lexical Cohesion: Alignmentand Divergence
Cohesion and Discourse Processing • Lexical chains are used for discourse segmen-tation (e.g. Morris & Hirst 1991; Stokes 2005). • Centrality of concepts in cohesive networks reflects importance (Hoey 2005, Tanskanen 2006). • Readers’ paragraphing judgements are highly correlated with breaks in cohesion (e.g. Hoey 2005).
Genre-specific coherence 1 • Encyclopedic text
Genre-specific coherence 2 • Fund-raising letter (Abelen et al. 1993)
Hypothesis Our discourse-analytic experience suggests that the interaction of discourse structure and cohesion is genre sensitive. In particular: Expository and descriptive (i.e., thematically organized) texts will show higher lexical cohesiveness and closer alignment between discourse structure and cohesive structure than persuasive (more intentionally structured) texts.
Test of genre differences Texts labelled informative should have fewer presentational (reader-oriented) RST-relations than texts labelled persuasive.
Local lexical cohesion (average # links per adjacent segment pair) Facts & Events Genres
Local lexical cohesion (average # links per adjacent segment pair) Informative and persuasive texts on cars
Preliminary conclusions Alignment hypothesis supported • Even these simple local counts show that cohesion appears to align with local coherence in informative texts (WSJ, car magazine articles). But: • Indications for a lack of alignment in persuasive texts were only found for the fundraising letters, but not for the car ads.
Future Work Refining the descriptive work • Include non-local cohesive links. • Differentiatetypes of cohesive links. Comparing the two ways of organizing texts • Compute distances between text segments on the basis of cohesive linkage and compare them to distances derived from discourse structure. • Compute and compare the centrality of text segments in cohesive networks and in discourse structure. Testing the cognitive effects • Relate to readers’ judgements of paragraphing and centrality. • Test effects of alignment in processing.