Empirical Verification of Meaning-Game-based Generalization of Centering Theory with Large Japanese Corpus

Proceedings of PACLIC 19, the 19th Asia-Pacific Conference on Language, Information and Computation. Empirical Verification of Meaning-Game-based Generalization of Centering Theory with Large Japanese Corpus Shun SHIRAMATSU† Kazunori KOMATANI† Takashi MIYATA†† {siramatu, komatani}@kuis.kyoto-u.ac.jp miyata.t@aist.go.jp Koiti HASIDA†††, †† Hiroshi G. OKUNO† hasida.k@aist.go.jp okuno@kuis.kyoto-u.ac.jp †Graduate School of Informatics, Kyoto University Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan ††CREST, Japan Science and Technology Agency (JST) Akihabara Dai-Building, Soto- Kanda 1-18-13, Chiyoda-ku, Tokyo 101-0021, Japan †††ITRI, National Institute of Advanced Industrial Science and Technology (AIST) Akihabara Dai-Building, Soto- Kanda 1-18-13, Chiyoda-ku, Tokyo 101-0021, Japan ^ Abstract Centering theory (Grosz et al., 1995) tries to explain relations among attention, anaphora, and cohesion. It has two theoretical limitations. The first is the lack of a principle behind these discourse phenomena. The second is that the salience of discourse entities has not been quantitatively defined, although it plays a critical role in this theory. Hasida et al. (1995, 1996) propose the meaning game as a more principled model of intentional communication based on game theory, and claim that it can derive centering theory. This claim, however, has not yet been verified on the basis of substantial linguistic data. In this paper, we formulate salience as a measurable quantity in terms of a reference probability. We also formulate preferences subsuming centering theory under this quantitative formulation of salience. The preferences are derived from the meaning game and entail more general predictions than those of conventional centering theory. These formulations overcome the above limitations of centering theory. By following them, we empirically verify our generalization with a large Japanese corpus. The experimental results show that there is positive correlation between the salience (reference probability) of an entity and the simplicity (utility) of a noun phrase which refers to the entity. They also indicate correspondence between the values of expected utility and the ranking of the transition states. These results indicate that our generalization is appropriate. 1. Introduction Principled and quantitative modeling of discourse is important for analyzing and generating discourse. Centering theory (CT) is a model of discourse structures. It explains the relations among attention, anaphora, and cohesion (Iida, 1997). However, CT has had two theoretical limitations. The first is the lack of a general principle behind the discourse phenomena. Although some studies on CT have focused on analyzing surficial linguistic features without general principles, we consider that the principle of discourse phenomena must be addressed based on measurable quantities. The second is that “salience”, which plays a critical role in CT, cannot be verified based on large linguistic data because it is not formulated as a measurable quantity, but as heuristic rules. We have investigated the general principle of CT. We adopted the meaning game (MG) (Hasida et al., 1995, 1996) framework because it gives a more principled explanation of the discourse phenomena than CT does. MG is a model of intentional communication (e.g., anaphora) based on game theory. Game players in game theory correspond to interlocutors in MG, and they decide their intentions and interpretations at the Pareto-optimum. Although …

Content truncated to 500 words