Challenges for Virtual Humans in Human Computing

The vision of Ambient Intelligence (AmI) presumes a plethora of embedded services and devices that all endeavor to support humans in their daily activities as unobtrusively as possible. Hardware gets distributed throughout the environment, occupying even the fabric of our clothing. The environment is equipped with a diversity of sensors, the information of which can be accessed from all over the AmI network. Individual services are distributed over hardware, share sensors with other services and are generally detached from the traditional single access-point computer (see also the paper of Pantic et al in this volume [51]). ‘Unobtrusive support’ means that where possible the user should be freed from the necessity of entering into an explicit dialog with all these services and devices. The environment shifts towards the use of implicit interaction, that is, “interactions that may occur without the behest or awareness of the user��? [36]. However, not all interactions between user and environment will be implicit. It may not be possible, or it may not be desirable, e.g. because the user does not want to feel a loss of control over certain aspects of his environment. So how does the user achieve the necessary explicit interaction? Will (s)he address every query for information to the specific device or service that ultimately provides the information? Will (s)he give commands to the heating system, the blinds and the room lighting separately? Will each service and each device carry its own interaction interface? Clearly not. Interfaces will come to be developed that abstract from individual services and devices and offer the user access to certain combined functionalities of the system. The interfaces should support the mixture of explicit and implicit, and reactive and proactive, interaction required for a successful AmI environment. Finally, AmI environments are inherently multiuser, so the interface needs to be able to understand and engage in addressed multi party interaction [48]. We argue that Virtual Humans (VHs) are eminently suited to fulfill the role of such interfaces. An AmI environment can serve various purposes. It can be a home environment, an office environment, a public space or it can be used in an educational setting. Virtual humans can be available, among others, as friend, exercise adviser, health care specialist, butler, conversation partner or tutor. Sometimes they know things better than you do, sometimes they have more control over parts of the AmI environment than you have and sometimes they persuade you to do things differently. You may not always like all aspects of the virtual humans that cohabit your house. Maybe the virtual tutor that is available to monitor your children’s homework sometimes takes decisions that are not liked by your children at all. Your virtual friend is not very interesting if it always agrees with your opinions. A health care agent has to be strict. A virtual human that acts as a conversational partner for your grandmother may have some peculiar behavior sometimes (like a dog or cat has; remember the Tamagotchi). As in collaborative virtual environments we can have remote participation in activities in AmI environments. Virtual humans can then represent family members (with all their characteristics, including weaknesses) that are abroad and that nevertheless take part in family activities. Transformation of communicative behavior of virtual humans that represent real humans can be useful too [4]. Summarizing, in the AmI environments we foresee that virtual humans can play human-like roles and need human-like properties, including (semi-) autonomous behavior, personalities, individual characteristics and peculiarities. However, the vast majority of existing, implemented applications of Virtual Humans are focused around one clear task, such as selling tickets, learning a skill, answering questions or booking flights and hotels, and are accessed in a clearly explicit manner. There, one can take it as a given that the attention of the user is on the system and the user is primarily engaged with the interaction. In an AmI environment this is no longer true. A dialog with a Virtual Human may be altogether secondary to several other activities of the user. A dialog with a Virtual Human may also be about many different issues, pertaining to different aspects of the environment, in parallel. This has a lot of impact on many aspects of a Virtual Human. In the rest of this paper we will examine a (not necessarily exhaustive) number of aspects to Virtual Humans that we feel as most relevant to their introduction in a complex AmI environment. Some of these aspects relate to the embedding of the Human / Virtual Human interaction in ongoing daily activities: issues of synchronization, turn taking and control. Other points touch upon the fictional/real polemic: how realistic should VHs be? Should a VH interface exhibit ‘socially inspired’ behaviour? Should a VH exhibit also the imperfections and shortcomings so characteristic of human communication? Some of the points will be illustrated with examples from our recent work on Virtual Humans, summarized in Section 4.