Look who's talking: appearance of embodied conversational agents in eHealth

As we live longer and more people develop chronic diseases, the demand for care increases. The focus of our health care has to shift from curing acute complaints to (secondary) prevention of com¬plaints via long-term care and coaching. A solution widely investigated to offer this long-term care and coaching is eHealth. But, for eHealth applications to be effective, use of the applications is crucial. In that sense, engagement with an eHealth application is necessary; those who are more engaged are significantly less likely to stop using it. To engage users in long-term care and coaching, Embodied Conversational Agents (ECAs) can be used. As humans, we immediately form ideas about such ECAs based on their appearance when we interact with them for the first time, similar to what we do when interacting with another human for the first time. Then, when we have a positive first impression of another human, we tend to interact more with that human. This might also apply to our interaction with ECAs. Therefore, ECAs could stimulate users to start or continue interacting with the underlying eHealth application (at first glance or after short interaction respectively) to eventually reach long-term interaction. By researching how an ECA’s appearance should be designed to trigger positive impressions in these different phases of interaction, we can stimulate users to continue to next phase and eventually reach long-term engagement. The main aim of this thesis was: How to design the appearance of an ECA in eHealth to promote user engagement? The sub objectives of this thesis were: 1) How to design the appearance of an ECA in eHealth for positive impressions at first glance?, 2) How to design the appearance of an ECA in eHealth for positive impressions after short interaction? and 3) How to design the appearance of an ECA in eHealth for positive impressions after long-term interaction?