Evaluating ECAs - What and how?

Embodied conversational agents (ECAs) are synthetic characters which can converse with the user (or with other ECAs) by some natural modalities of human-human communication [2]. ECAs have become increasingly popular, as the promising new interface for several traditional computer applications or as the basis for applications in entirely new domains. Much research has been going on to endow ECAs with own behavioral, personality and emotional models, to enable ECAs to act more or less autonomously. The embodiment of the ECAs poses also challenging research tasks, to define which modalities to use to convey some information, how to generate good-quality output in the single modalities (speech, facial-, handand body gestures) and how to co-ordinate them. Often ECAs are meant to be involved in conversation with the user, when the maintenance of the discourse is an additional task.