System-initiated digressive proposals in automated human-computer telephone dialogues: the use of contrasting politeness strategies

System-initiated digressive proposals may be used to introduce new and unexpected information into automated telephone services. These digressions may be viewed as particularly pronounced forms of unsolicited interruptions as they contain information not directly related to the caller's intended activity. In human-human conversation, interruptions are considered to be speech acts which intrinsically threaten both the positive and negative face wants of the addressee and conversants adopt specific verbal strategies to mitigate the negative impact of their interruptions. A question therefore arises whether the introduction of face-redressive expressions, based on human-human conversational strategies, into the design of system-initiated proposals in automated services can mitigate the negative impact of the interruptions. A usability experiment was conducted to examine the effectiveness of three contrasting politeness strategies for system-initiated digressions in a mass-market telephone banking dialogue using speech recognition technology. Participants (N=111) experienced these proposals while using the automated service to perform banking tasks. Results indicated that all these system-initiated digressions-irrespective of politeness strategy employed-had a negative impact on the user attitudes towards the service. This paper reports these results and explores participants' perceptions of the politeness styles and registers employed in the system-initiated proposals.