“I’ve got to go”. Analyses of closing sequences in human-robot conversations

Based on a corpus of videotaped human-robot interactions, we offer a multimodal study of phases of final disengagement following a conversation analysis approach. Doing closing sequences implies that the robot is capable of completing interactional sequences, and we describe how human participants appear to be particularly sensitive to situations in which robots may appear to show understanding of their prior actions. We then analyse the phases of disengagement and show that their form may vary, ranging from “mechanical” closing statements (exit, instruction) to the pre-closing sequences characteristic of ordinary human interactions. With regard to the latter, we show that it is also relevant to distinguish between forms in which human participants are in a hurry to finish and those in which humans give the robot an opportunity to respond. This allows us to reveal two different dimensions of these closing statement formulas in human-robot interactions: that of interactional tact (the extent to which the robot is treated like a partner) and the relatively collaborative nature of sequence-based disengagement.