On Incrementality in Dialogue: Evidence from Compound Contributions

Spoken contributions in dialogue often continue or complete earlier contributions by either the same or a different speaker. These compound contributions (CCs) thus provide a natural context for investigations of incremental processing in dialogue.We present a corpus study which confirms that CCs are a key dialogue phenomenon: almost 20% of contributions fit our general definition of CCs, with nearly 3% being the cross-person case most often studied. The results suggest that processing is word-by-word incremental, as splits can occur within syntactic ‘constituents’; however, some systematic differences between same- and cross-person cases indicate important dialogue-specific pragmatic effects. An experimental study then investigates these effects by artificially introducing CCs into multi-party text dialogue. Results suggest that CCs affect people’s expectations about who will speak next and whether other participants have formed a coalition or ‘party’.Together, these studies suggest that CCs require an incremental processing mechanism that can provide a resource for constructing linguistic constituents that span multiple contributions and multiple participants. They also suggest the need to model higher-level dialogue units that have consequences for the organization of turn-taking and for the development of a shared context.