How thoughts are connected

The question

Thoughts in a conversation do not stand alone. One thought gives the reason for an earlier one, another is contrasted with something said before, and another answers the other person's question.

This page addresses the question, “What kinds of connection can exist between two thoughts?”

The standard: ISO 24617-8 (DR-core)

Relations between sentences or between utterances have long been studied as “discourse relations.” Well-known frameworks include Rhetorical Structure Theory (RST), the Penn Discourse Treebank (PDTB), SDRT, Hobbs's theory of coherence, and the cognitive taxonomy of Sanders et al. However, these frameworks define and group relations differently. Concession, for example, is grouped with contrast in one framework and classified under causal relations in another.

ISO 24617-8 (DR-core) is the international standard that analyzed the commonalities and differences among these frameworks and defined the core relations essential for annotating discourse relations (Prasad & Bunt 2015). It has three main features.

• Content relations onlyIt covers only relations between the situations described, rather than how a speaker presents the content (presentational relations).
• A flat listRelations are not arranged into hierarchical groups. Because different frameworks classify them differently, a flat list serves as better common ground across frameworks.
• Local relations between two elementsRather than the structure of a whole conversation, it describes the relation between two elements, one pair at a time.

DR-core consists of 20 relations, two of which are dependences between utterances (functional dependence and feedback dependence). The second edition of ISO 24617-2, the standard for dialogue acts, handles those two dependences through a separate mechanism and defines 19 relations: the remaining 18 plus Evaluation.

Kinds of connection

AWAI reads connections on two levels: connections between thoughts, and connections between a point and a thought.

Between thoughts — logical relations (19)

These 19 relations, defined in the second edition of ISO 24617-2, describe how the contents of two thoughts relate.

※ marks symmetric relations. In the remaining 13, the two thoughts play different roles (such as reason and result).

Between thoughts — dependence

A thought with a responsive function, such as answering a question or accepting a proposal, connects to the other person's preceding utterance. In ISO 24617-2, a responsive function inherently carries a dependence on an earlier utterance, just as the content of an answer depends on the question (functional dependence).

Between thoughts — latent

A connection between thoughts that are very close in content even though they were never linked in the conversation. It is not added for pairs that already have a logical relation.

Between a point and a thought

A point within a thought can connect directly to another thought: when another thought mentions, answers, or rebuts the point, or when the point itself mentions, answers, or rebuts another thought. Being on a related topic is not enough; a point is judged Connected only when there is a direct response or development. The order of the thoughts does not matter.

A point that connects to no thought remains Unconnected. A point that was raised once and never picked up is still meaningful: it represents what drifted away in the conversation.

A connection is also maintained between a point and a thought very close in content even without a direct response (following the same principle as latent connections between thoughts).

AWAI's interpretation

AWAI incorporates the standard as follows.

• The LLM judges the relation type; semantic closeness determines whether a connection existsFor logical relations, the LLM judges only which relation applies. Whether a line is drawn at all is determined by the semantic closeness of the two thoughts' original wording. This treats “Are they connected?” and “How are they connected?” as separate questions.
• For symmetric relations, the earlier thought is assigned as arg1This directly follows the standard's convention: when both arguments play the same role, the one that occurs first in the discourse is arg1.
• Dependence is determined by ruleIn the standard, dependences are specified by annotators. AWAI determines them by rule: a thought with a responsive function connects to the last thought of the other person's preceding utterance. Which thoughts have a responsive function is determined by the function classification (ISO 24617-2).
• Dependence and logical relations are kept separateJust as the second edition of ISO 24617-2 handles DR-core's dependences through a separate mechanism, AWAI treats dependence as a connection separate from the 19 logical relations.

Connections left unsaid

Connections are read from what was explicitly said, so unstated information is not taken into account. Thoughts connected by reasons understood without being stated, or by assumptions that participants took for granted, may not appear as a line.

References for this page

• ISO 24617-8:2016. Language resource management — Semantic annotation framework (SemAF) — Part 8: Semantic relations in discourse, core annotation schema (DR-core). www.iso.org/standard/60780.htmlNote — what this page draws on:The list of core discourse relations, the starting point for the 19 logical relations on this page. The definition of each relation is taken from ISO 24617-2 Annex E, which imports them from DR-core.
• ISO 24617-2:2020. Language resource management — Semantic annotation framework (SemAF) — Part 2: Dialogue acts. www.iso.org/standard/76443.htmlChecked against the ISO/DIS 24617-2 text published by its authors (2019; the version approved in the international ballot of February 2020): dit.uvt.nlNote — what this page draws on:The 19 relations and their definitions in Annex E.3 (which AWAI provides to the LLM); the convention that, in symmetric relations, the argument occurring first in the discourse is arg1; the principle that a responsive function inherently carries a dependence on an earlier utterance (functional dependence); and the list of responsive functions (§8.3.4).
• Bunt, H., Petukhova, V., Gilmartin, E., Pelachaud, C., Fang, A., Keizer, S. and Prévot, L. (2020). The ISO Standard for Dialogue Act Annotation, Second Edition. Proceedings of LREC 2020, pp. 549–558. aclanthology.org/2020.lrec-1.69Note — what this page draws on:Documents that the second edition defines 19 relations taking DR-core as its point of departure (Table 1 in the appendix); also used to confirm that the 19 relations and their definitions are identical in the draft and the published standard.
• Prasad, R. and Bunt, H. (2015). Semantic Relations in Discourse: The Current State of ISO 24617-8. Proceedings of the 11th Joint ACL-ISO Workshop on Interoperable Semantic Annotation (ISA-11), London. aclanthology.org/W15-0210Note — what this page draws on:DR-core's design principles: comparing existing frameworks such as RST, PDTB, and SDRT; restricting the scope to content relations; maintaining a flat list without groups; treating relations as local, between two elements; and noting that two of its 20 relations are dependences.