Investigating Proactivity in Task-Oriented Dialogues

This paper investigates proactivity, a characteristic phenomenon of collaborative human-human
interaction, where a participant in the dialogue offers the addressee some useful and not explicitly
requested information. More precisely, a proactive behaviour is: (i) self-prompted and not simply
reactive, that is, the speaker does not act merely in response to the requests the other participant
has made; (ii) somehow effective for the achievement of the dialogue goal, since the speaker has a
long-term, goal-directed behaviour that predicts future states and needs. Proactivity has been poorly
investigated from a theoretical point of view, and there is a general need of empirical data for both
quantitative and qualitative research. The paper provides an extensive analysis of proactivity in several
human-human task-oriented dialogic corpora, selected with different characteristics, including
chat exchanges and telephone calls, collection modalities such as natural setting andWizard of Oz,
and two languages, Italian and English. The main result is the D-Pro Corpus, a new resource manually
annotated at the utterance level with proactivity and dialogue acts, which allows to investigate
proactivity in the context of task-oriented dialogues. There are several findings from our empirical
investigation of proactivity: (i) we find that about 20% of turns in our corpus are proactive turns,
showing that this is a very diffused and relevant phenomenon; (ii) we confirm the non-reactive
nature of proactivity, highlighting the presence of a pattern where a turn in the dialogue triggers
a reaction in a following turn and a proactive utterance is then added to the turn; (iii) we show
that only a limited number of dialogue acts are actually involved in expressing proactivity, and
we discuss the theoretical implications of this finding; (iv) we empirically confirm that proactivity
has a crucial role in recovering from goal-failure situations, contributing to the effectiveness of the
whole dialogue; (v) we support the intuition of a non-uniform distribution of proactive utterances
throughout the dialogue. Our empirical findings and the D-Pro Corpus provide relevant insights for
deeper theoretical investigations, as well as crucial resources for improving proactivity in current
task-oriented dialogue systems.