Grounding Conversations with Improvised Dialogues

Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 2398–2413 July 5 - 10, 2020. c⃝2020 Association for Computational Linguistics 2398 Grounding Conversations with Improvised Dialogues Hyundong Cho and Jonathan May Information Sciences Institute University of Southern California {jcho, jonmay}@isi.edu Abstract Effective dialogue involves grounding, the pro- cess of establishing mutual knowledge that is essential for communication between people. Modern dialogue systems are not explicitly trained to build common ground, and therefore overlook this important aspect of communica- tion. Improvisational theater (improv) intrinsi- cally contains a high proportion of dialogue fo- cused on building common ground, and makes use of the yes-and principle, a strong ground- ing speech act, to establish coherence and an actionable objective reality. We collect a cor- pus of more than 26,000 yes-and turns, tran- scribing them from improv dialogues and ex- tracting them from larger, but more sparsely populated movie script dialogue corpora, via a bootstrapped classifier. We fine-tune chit-chat dialogue systems with our corpus to encourage more grounded, relevant conversation and con- firm these findings with human evaluations. 1 Introduction For humans, dialogue is fundamentally a collabora- tive, cooperative process by which partners coordi- nate via turns or acts to jointly construct a common world state (Bohm and Nichol, 2004). Without coordination, partners may establish different or conflicting world states, leading to solipsism in the best case and conflict in the worst. Clark and Schae- fer (1989), describe five dimensions of grounding, by which partners cooperate to establish common ground, or a shared world state. The dimension of “initiation of next relevant contribution” is the most effective of these in expressing understanding of an ongoing dialogue, and yet is the least observed in dialogue systems. Improvisational theater (improv) is a form of theater in which most or all of what is performed is unscripted, created spontaneously by the actors in real time. Because the performance is not scripted and there is typically little to no scenery or other es- Figure 1: Explicit (top) and implicit (bottom) examples of yes-ands in the SPOLIN corpus. The text high- lighted in light blue reflects acceptance of the con- text established in the prompt (“yes”) and the text high- lighted in orange initiates a new relevant contribution to the dialogue (“and”). tablished environment,1 there is no objective reality that can naturally ground the scene. Hence, actors must mainly rely on dialogue in order to build a co- herent scene and progressively establish a common world view. This necessitates accelerated use of the “initiation of next relevant contribution,” which in improv is known as the yes-and principle. The yes-and principle is a rule-of-thumb that suggests that a participant should accept the reality of what the other participant has said (“yes”) and expand or refine that reality with additional information (“and”). Since actors consciously abide by this principle during improv performances, there is a high proportion of these turns embedded in improv dialogue, which helps ensure scenes are coherent and interesting. 1except for, on occasion, external …

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