In this paper we propose a research framework to explore the possibilities that state-of-the-art embodied conversational agents (ECAs) technology can offer to overcome typical robustness problems in spoken language dialogue systems (SLDSs), such as error detection and recovery, changes of turn and clarification requests, that occur in many human-machine dialogue situations in real applications. Our goal is to study the effects of nonverbal communication throughout the dialogue, and find out to what extent ECAs can help overcome user frustration in critical situations. In particular, we have created a gestural repertoire that we will test and continue to refine and expand, to fit as closely as possible the users’ expectations and intuitions, and to favour a more efficient and pleasant dialogue flow for the users. We also describe the test environment we have designed, simulating a realistic mobile application, as well as the evaluation methodology for the assessment, in forthcoming tests, of the potential benefits of adding nonverbal communication in complex dialogue situations. 1.

Abstract. With research revealing the importance of trust as a deciding factor for users to visit a website, designing websites that users find credible becomes important. Adding onscreen characters in various forms (e.g. photographs of a person) to represent the source of information is a simple and popular way to to increase the credibility of a website. However, despite its popularity, empirical studies have reported mixed results. This paper presents three experiments that explored the causes of this contradiction. In our experiments, the credibility of the source (as resulting from a photograph of a person) was found to be topic dependent. It was also found to positively correlate with and account for some 30 % of the variability in the credibility of a website. These findings perhaps can explain the inconsistency of many previous studies. Finally, our study suggested that adding a user-selected photograph increases the credibility of the website, while the opposite occurs when adding a photograph that is lowly credible with respect to the topic of the website’s content. 1 1