10th International Pragmatics Conference Gothenburg, 8-13 July 2007

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)

• 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 together

connectives; 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

hyponymy

Discourse structure and cohesion aligned

meronymy

Discourse structure and cohesion aligned

collocation

Discourse structure and cohesion aligned

referential chain

hyponymymeronymy

collocation

Discourse Structure and Lexical Cohesion: Alignment and Divergence

1-4

1-2

(1) Schools tried to teach students history of science.

Conjunction(2) At the same time they tried to teach them how to think logically and inductively.

Conjunction

3-4

Volitional-result

(3) Some success has been reached on the first of these aims.

Contrast(4) However, none at all has been reached on the second.

Contrast

This example figures prominently in the ongoing discussion on discourse configuration (Danlos 2004, Wolf & Gibson 2005, Egg & Redeker 2006)

Discourse Structure and Lexical Cohesion: Alignment and Divergence

1-4

1-2

(1) Schools tried to teach students history of science.

Conjunction(2) At the same time they tried to teach them how to think logically and inductively.

Conjunction

3-4

Volitional-result

(3) Some success has been reached on the first of these aims.

Contrast(4) However, none at all has been reached on the second.

Contrast

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.

Pilot study

Informative texts Persuasive texts

Facts & events

Wall Street Journal 358 words

24 RST-relations

Fundraising letters514 words

42 RST-relations

CarsMagazine articles

766 words

58 RST-relations

Advertisements760 words

66 RST-relations

Total1124 words

82 RST-relations

1274 words

108 RST-relations

Test of genre differences

Presentational Relations (%)

Informative Persuasive

Facts & events 8.3 % 42.4 %

Cars 6.9 % 57.1 %

Total 7.3 % 48.1 %

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

0

0.5

1

1.5

2

2.5

WSJ Articles Fundraising Letters

related

unrelated

Local lexical cohesion (average # links per adjacent segment pair)

Informative and persuasive texts on cars

0

0.5

1

1.5

2

2.5

Car Mag. Articles Car Advertisements

related

unrelated

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. – Differentiate types 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.