Design models for computer-human interfaces

Computer-human interface design has been recognized as a distinct field for only a little more than a decade, but the design of interfaces to control mechanical devices has a much longer history. The interface-design models used in these mechanical systems play similar roles in computer systems, despite the obvious differences between the two types of systems. There are many ways to control a given mechanism. Whether consciously or unconsciously, every interface designer chooses a model that forms the basis for how the mechanism is controlled. Two principal approaches are the engineering model and the user-task model. There is no best way to design a user interface, however. Interface designers must be aware that a user interface can be based on any of several models, that each model has its advantages, and that their job is to choose the approach most suitable for the project at hand. We examine the models underlying computer-human interface designs by considering a wide variety of systems, including many from areas outside of computing. These noncomputer examples can be instructive because they are simpler and thus clearer. They also provide some helpful detachment and perspective for those of us who are immersed in computers.