Building common ground: Quantifying the interplay of mechanisms that promote understanding in conversations
Humans readily engage in idle chat, heated discussions, and negotiate tough joint decisions without ever having to think twice about the different mechanisms they use to keep the conversation grounded in mutual understanding. However, current attempts at identifying and assessing the grounding mechanisms that make this possible are fragmented across disciplines and investigate single mechanisms within single contexts. We present a comprehensive conceptual framework to investigate and quantify conversational grounding mechanisms, and how they adjust to contextual demands. In three corpus studies, we systematically test the role of three grounding mechanisms, backchannels, repair, and interactive alignment. Contrasting affiliative (AC) and task-oriented (TOC) conversations between and within participants, we find that grounding mechanisms adaptively adjust to the increased need for precision in the latter: Across Study 1 and Study 2, we show that low-precision mechanisms such as backchannels are more frequent in AC, while more costly but higher-precision mechanisms, such as specific repairs, are more frequent in TOC. Further, TOC involve higher complementarity of contributions in terms of the content and perspective: lower semantic alignment, and less frequent (but richer) lexical and syntactic alignment. Crucially, in Study 3, these variations in the use of grounding mechanisms are shown to be adaptive: pairs of interlocutors that show stronger linguistic complementarity perform better across the two tasks. By combining motivated comparisons of several conversational contexts, and theoretically informed computational analyses of empirical and experimental data, the present work lays the foundations for a comprehensive conceptual framework of grounding mechanisms in conversation.