Modeling Norms of Turn-Taking in Multi-Party Conversation

Proceedings of the 48th Annual Meeting of the Association for Computational Linguistics, pages 999–1008, Uppsala, Sweden, 11-16 July 2010. c⃝2010 Association for Computational Linguistics Modeling Norms of Turn-Taking in Multi-Party Conversation Kornel Laskowski Carnegie Mellon University Pittsburgh PA, USA kornel@cs.cmu.edu Abstract Substantial research effort has been in- vested in recent decades into the com- putational study and automatic process- ing of multi-party conversation. While most aspects of conversational speech have benefited from a wide availabil- ity of analytic, computationally tractable techniques, only qualitative assessments are available for characterizing multi-party turn-taking. The current paper attempts to address this deficiency by first proposing a framework for computing turn-taking model perplexity, and then by evaluat- ing several multi-participant modeling ap- proaches. Experiments show that direct multi-participant models do not general- ize to held out data, and likely never will, for practical reasons. In contrast, the Extended-Degree-of-Overlap model rep- resents a suitable candidate for future work in this area, and is shown to success- fully predict the distribution of speech in time and across participants in previously unseen conversations. 1 Introduction Substantial research effort has been invested in recent decades into the computational study and automatic processing of multi-party conversation. Whereas sociolinguists might argue that multi- party settings provide for the most natural form of conversation, and that dialogue and monologue are merely degenerate cases (Jaffe and Feldstein, 1970), computational approaches have found it most expedient to leverage past successes; these often involved at most one speaker. Consequently, even in multi-party settings, automatic systems generally continue to treat participants indepen- dently, fusing information across participants rel- atively late in processing. This state of affairs has resulted in the near- exclusion from computational consideration and from semantic analysis of a phenomenon which occurs at the lowest level of speech exchange, namely the relative timing of the deployment of speech in arbitrary multi-party groups. This phe- nomenon, the implicit taking of turns at talk (Sacks et al., 1974), is important because unless participants adhere to its general rules, a conver- sation would simply not take place. It is there- fore somewhat surprising that while most other aspects of speech enjoy a large base of computa- tional methodologies for their study, there are few quantitative techniques for assessing the flow of turn-taking in general multi-party conversation. The current work attempts to address this prob- lem by proposing a simple framework, which, at least conceptually, borrows quite heavily from the standard language modeling paradigm. First, it de- fines the perplexity of a vector-valued Markov pro- cess whose multi-participant states are a concate- nation of the binary states of individual speakers. Second, it presents some obvious evidence regard- ing the unsuitability of models defined directly over this space, under various assumptions of in- dependence, for the inference of conversation- independent norms of turn-taking. Finally, it demonstrates that the extended-degree-of-overlap model of (Laskowski and Schultz, 2007), which models participants in an alternate space, achieves by far the best likelihood estimates for previ- ously unseen conversations. This appears to be because …

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