Formalising Hinting in Tutorial Dialogues

The formalisation of the hinting process in Tutorial Dialogues is undertaken in order to simulate the Socratic teaching method. An adaptation of the BE&E annotation scheme for Dialogue Moves, based on the theory of social obligations, is sketched, and a taxonomy of hints and a selection algorithm is suggested based on data from the BE&E corpus. Both the algorithm and the tutor’s reasoning are formalised in the context of the information state theory of dialogue management developed on the trindi project. The algorithm is characterised using update rules which take into account the student model, and the tutor’s reasoning process is described in terms of context accommodation. 1 Theoretical Background 1.1 Information State Update The formalisation of the hinting process uses the Information State (IS) approach, in which dialogue is seen in terms of the information that each participant has at every point in the interaction. The formal account thus accords with the proposals put forward on the trindi project1 (Bohlin et al. (1999), Larsson et al. (1999)). The IS representation consists of fields containing different kinds of information about the dialogue. This information is updated after each new utterance using update rules of various types. The latter include details of how each field, or information attribute, in the IS should be updated, if at all.2 The background Telematics Applications Programme, Language Engineering Project LE4-8314. Figure 2 contains an IS with relevant fields, and a commented instance of an update rule can be found in example (4) below. theories that inform the IS update formalisation assumed here are the obligation-driven approaches discussed in Matheson et al. (2000) and Traum and Allen (1994), and Context Accommodation as described in Cooper et al. (2000), Kreutel and Matheson (2000), and Larsson et al. (2000). 1.2 Discourse Obligations The theory of obligations introduces the notion of discourse and social obligation as a way of analysing some of the social aspects of interactions and provides an explanation for behaviour that other theories do not predict. It is an augmentation to the representation of the intentions of dialogue participants that attempts to capture the natural flow of conversation. There are different genres of obligation-based research, as evidenced by the above references. Treating tutorial dialogues in terms of obligations is an intuitive way of analysing and predicting some specific kinds of dialogue behaviour that do not seem to follow the rules of everyday discourse. For example, applying the Shared Plans theory (see Rich and Sidner (1998)) to tutorial dialogues would soon prove problematic since the tutor does not follow the principle of co-operativity which is central to the theory. A prerequisite for achieving goals, according to Shared Plans, is that the dialogue participants should be as clear as they can about their beliefs and plans, when the one thing that the tutor avoids doing in the hinting process is exactly that. For example, SharedPlans do not explain why the tutor in utterance T[2] in example 1 below does not just tell the student what a sine-wave is, which she could easily do. According to the obligation-driven framework, on the other hand, intentions are necessary but not the only driving force behind an utterance. For example, only if one considers it the student’s obligation to address the tutor’s questions and follow her directives can one interpret the total lack of overt signals from the student that he intends to cooperate, such signals being normally central to collaboration. In the context of the overall obligations the tutor knows what the student’s intentions are, and will be able to interpret his actions correctly because the tutorial dialogue genre will not permit any other behaviour, since it is the student’s obligation to follow the tutor’s directives. 2 Obligations and Dialogue Moves 2.1 Dialogue Moves in the BE&E