A Computational Model of Non-Cooperation in Natural Language Dialogue

A common assumption in the study of conversation is that participants fully cooperate in order to maximise the effectiveness of the exchange and ensure communication flow. This assumption persists even in situations in which the private goals of the participants are at odds: they may act strategically pursuing their agendas, but will still adhere to a number of linguistic norms or conventions which are implicitly accepted by a community of language users. However, in naturally occurring dialogue participants often depart from such norms, for instance, by asking inappropriate questions, by avoiding to provide adequate answers or by volunteering information that is not relevant to the conversation. These are examples of what we call linguistic non-cooperation. This thesis presents a systematic investigation of linguistic non-cooperation in dialogue. Given a specific activity, in a specific cultural context and time, the method proceeds by making explicit which linguistic behaviours are appropriate. This results in a set of rules: the global dialogue game. Non-cooperation is then measured as instances in which the actions of the participants are not in accordance with these rules. The dialogue game is formally defined in terms of discourse obligations. These are actions that participants are expected to perform at a given point in the dialogue based on the dialogue history. In this context, non-cooperation amounts to participants failing to act according to their obligations. We propose a general definition of linguistic non-cooperation and give a specific instance for political interview dialogues. Based on the latter, we present an empirical method which involves a coding scheme for the manual annotation of interview transcripts. The degree to which each participant cooperates is automatically determined by contrasting the annotated transcripts with the rules in the dialogue game for political interviews. The approach is evaluated on a corpus of broadcast political interviews and tested for correlation with human judgement on the same corpus. Further, we describe a model of conversational agents that incorporates the concepts and mechanisms above as part of their dialogue manager. This allows for the generation of conversations in which the agents exhibit varying degrees of cooperation by controlling how often they favour their private goals instead of discharging their discourse obligations

Completions, Coordination, and Alignment in Dialogue

Collaborative completions are among the strongest evidence that dialogue requires coordination even at the sub-sentential level; the study of sentence completions may thus shed light on a number of central issues both at the `macro’ level of dialogue management and at the `micro’ level of the semantic interpretation of utterances. We propose a treatment of collaborative completions in PTT, a theory of interpretation in dialogue that provides some of the necessary ingredients for a formal account of completions at the ‘micro’ level, such a theory of incremental utterance interpretation and an account of grounding. We argue that an account of semantic interpretation in completions can be provided through relatively straightforward generalizations of existing theories of syntax such as Lexical Tree Adjoining Grammar (LTAG) and of semantics such as (Compositional) DRT and SituationSemantics. At the macro level, we provide an intentional account of completions, as well as a preliminary account within Pickering and Garrod’s alignment theory

Modelling non-cooperative dialogue: the role of conversational games and discourse obligations

We describe ongoing research towards modelling dialogue management for conversational agents that can exhibit and cope with non-cooperative behaviour. Empirical studies of conventional dialogue behaviour in the domain of political interviews and a coarse-grained notion of conversational games re used to characterise non-cooperation. We propose an agent architecture that combines conversational games and discourse obligations, and suggest an implementation

Modelling Users, Intentions, and Structure in Spoken Dialog

We outline how utterances in dialogs can be interpreted using a partial first order logic. We exploit the capability of this logic to talk about the truth status of formulae to define a notion of coherence between utterances and explain how this coherence relation can serve for the construction of AND/OR trees that represent the segmentation of the dialog. In a BDI model we formalize basic assumptions about dialog and cooperative behaviour of participants. These assumptions provide a basis for inferring speech acts from coherence relations between utterances and attitudes of dialog participants. Speech acts prove to be useful for determining dialog segments defined on the notion of completing expectations of dialog participants. Finally, we sketch how explicit segmentation signalled by cue phrases and performatives is covered by our dialog model.Comment: 17 page

Perspectives on dialogue: Introduction to this special issue

We briefly summarize the papers in this volume, draw attention to the variety of perspectives that they bring to the subject of dialogue, identify a number of common themes, and conclude with a discussion of directions for further research

Modelling dialogue: Challenges and Approaches

Schlangen D. Modelling dialogue: Challenges and Approaches. Künstliche Intelligenz. 2005;3/05:23-28

Agreement and Disputes in Dialogue

In this paper we define agreement in terms of shared public commitments, and implicit agreement is conditioned on the semantics of the relational speech acts (e.g., Narration, Ex-planation) that each agent performs. We pro-vide a consistent interpretation of disputes, and updating a logical form with the current utterance always involves extending it and not revising it, even if the current utterance denies earlier content.

Uncommon ground: the distribution of dialogue contexts

PhDContext in dialogue is at once regarded as a set of resources enabling successful interpretation and is altered by such interpretations. A key problem for models of dialogue, then, is to specify how the shared context evolves. However, these models have been developed mainly to account for the way context is built up through direct interaction between pairs of participants. In multi-party dialogue, patterns of direct interaction between participants are often more unevenly distributed. This thesis explores the effects of this characteristic on the development of shared contexts. A corpus analysis of ellipsis shows that side-participants can reach the same level of grounding as speaker and addressee. Such dialogues result in collective contexts that are not reducible to their component dyadic interactions. It is proposed that this is characteristic of dialogues in which a subgroup of the participants are organised into a party, who act as a unified aggregate to carry the conversation forward. Accordingly, the contextual increments arising from a dialogue move from one party member can affect the party as a whole. Grounding, like turn-taking, can therefore operate between parties rather than individuals. An experimental test of this idea is presented which provides evidence for the practical reality of parties. Two further experiments explore the impact of party membership on the accessibility of context. The results indicate that participants who, for a stretch of talk, fall inside and outside of the interacting parties, effect divergent contextual increments. This is evidence for the emergence of distinct dialogue contexts in the same conversation. Finally, it is argued that these findings present significant challenges for how formal models of dialogue deal with individual contributions. In particular, they point to the need for such models to index the resulting contextual increments to specific subsets of the participant