Would I Lie to You? Modelling Misrepresentation and Context in Dialogue

WOULD I LIE TO YOU? MODELLING MISREPRESENTATION AND CONTEXT IN DIALOGUE Carl Gutwin Alberta Research Council 1 6815 8th Street N. E. Calgary, Alberta T2E 7H7, Canada Internet: gutwin@ skyler.arc.ab.ca Gordon McCalla ARIES Laboratory, University of Saskatchewan 2 Saskatoon, Saskatchewan S7N 0W0, Canada ABSTRACT In this paper we discuss a mechanism for modifying context in a tutorial dialogue. The context mechanism imposes a pedagogically motivated misrepresentation (PMM) on a dialogue to achieve instructional goals. In the paper, we outline several types of PMMs and detail a particular PMM in a sample dialogue situation. While the notion of PMMs are specifically oriented towards tutorial dialogue, misrepresentation has interesting implications for context in dialogue situations generally, and also suggests that Grice's maxim of quality needs to be modified. 1. INTRODUCTION Most of the time, truth is a wonderful thing. However, this research studies situations where not saying what you believe to be the truth can be the best course of action. Intentional misrepresentation of a speaker's knowledge appears to be a common and highly pragmatic process used in many different kinds of dialogue, especially tutorial dialogue. We use imperfect or incomplete representations in response to constraints and demands imposed by the situation: for example, many models of the real world are extremely complex, and misrepresentations are often used as useful, comprehensible approximations of complicated systems. People use idealized Newtonian mechanics, the wave (or particle) theory of light, and rules of default reasoning stating that birds fly, penguins are birds, and penguins don't fly. Some systems which cannot be simplified are purposefully ignored: for example, higher order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 This research was completed while C. Gutwin was a graduate student at the University of Saskatchewan. All correspondence should be sent to the first author. 2 Visiting scientist, Learning Research & Development Centre, University of Pittsburgh, 1991-92 differential equations are left out of engineering classes because of their complexity. Simplified and imperfect representations are often found in tutoring discourse. Misrepresentation as a pedagogic strategy holds promise for extending the capabilities of intelligent tutoring systems (ITSs), but the concept also affects computational dialogue research: it builds on the idea of discourse focus and context, extends work on adapting to the user with multiple representations of knowledge, and challenges Grice's maxims of conversation. 2. MOTIVATION AND BACKGROUND Misrepresentations are alterations to a perceived reality. When they have sincere pedagogic purposes, we name them Pedagogically Motivated Misrepresentations, or PMMs. PMMs can reduce the complexity of the dialogue and of the concepts to be learned, provide focus in a busy environment, or facilitate the communication of essential …

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