Caught Between Real and Virtual Worlds

While agreement was breaking out at this workshop, so too were some concerns. As most HCI practitioners would agree the distinction between design and evaluation in HCI is often blurred, indeed design and evaluation have been described as the different sides of the same coin. The design of the DISCOVER system proved to be no different. As we elicited requirements and undertook early design we kept an eye on evaluation, ultimately as a sanity check. The use of the prototype, described above, had given us clear usability requirements. The affinity diagram had given us detailed requirements of the design, content and substance of the DISCOVER collaborative virtual environment but concerns as to the issue of evaluation (and with it validation) began to emerge.

Design Tensions: No Magic, Thanks

For many collaborative tasks in virtual environments, the goal is to achieve a particular state of affairs within the virtual world, for example agreeing the layout of an office, as in Hindmarsh et al. (1998). For others, the activity within the CVE is part of a larger collaborative process, but the way collaboration works within the CVE need not exactly replicate real world interaction. In contrast, the DISCOVER environment must support the acquisition of real world skills. In short, skills acquired in the DISCOVER CVE must be transferable to the real world of the ship. This presents a significant constraint: ideally, interaction and collaboration must not be artificially harder or take longer than in the real world, but neither must they be artificially easier or executed faster. Thus the design of DISCOVER should treat with caution "magical" devices such as birds' eye views of the state of environment, Star Trek-like transporting, or visible rubber banding between an avatar and its current focus of attention.

Accordingly, much research which has addressed the problems of ensuring that the users of such environments are aware of their surroundings and of other users cannot be employed directly. Consider, for example, the problems with recognizing other avatars. To maintain realism, avatars cannot be simply labelled. There may also be the presence of dense smoke, and perhaps the need for the avatars to wear vision obscuring breathing apparatus. All of this means that recognizing one's colleagues (as avatars), mediated in the real situation by such characteristics as gait, stance and minor variations in standard issue clothing, becomes far more difficult.

Thus there is a fundamental tension between exploiting the technology to the full to produce a state-of-the-art virtual training environment and creating one which is faithful to the behaviour and constraints of a real ship. This, of course, is not merely a design issue but also presents a corresponding evaluation challenge.