Interface: an evolving concept

o the words that we use shape our outlook and affect our behavior? Undoubtedly they do. In fields that change as quickly as ours, we should step back once in a while and ask: Have our terminology and habits of speech kept up with the changes, or do they perpetuate an outmoded perspective that holds us back? This is an article on "the user in-terface" to a computer and "the computer interface" to one or more users. It also addresses "a user's in-terface" (or "a group's interface") to a computer and "a computer's inter-face" to a user or users. After noting the further distinction of users' interfaces to their work, the work that a computer is to support, it concludes with a discussion of the concepts of "the designer" and designers' "mod-els of users." The goal[ is not to split semantic hairs. "At a certain stage in the development of ,every science a degree of vagueness is what best consists with fertility," wrote William James [17], and the field of human-computer interaction has not yet advanced beyond that stage. The goal is to show that the way we use these words conceals important changes in our field. The term "user interface" came into use when system development was very different than it is now. At that time, the term served a useful purpose. Most of us now feel quite comfortable with it, although we may not use it consistently. This article details the possibilities for confusion and misdirection in our use of this and related terms in the changing environments of computer design and use. Perpetuating the current usage can reinforce and bind us to an obsolete perspective, and this may subtly and indirectly inhibit the adoption of new areas of research and new approaches to development. The term "user interface" originated in the engineering environment in the late 1970s. Virtually everyone who interacted directly with computers had been engineers and prograinmers, but a new kind of user was emerging: the nonpro-gramming user. These users often reacted more negatively to difficulties in dealing with a machine. Easier forms of interaction were needed, new interfaces-attention flowed to "the user interface." In the next section, the word "user," which was helpful in early engineering environments, is shown to be problematic in today's broader context. Then the term "interface" is explored, noting that a user's interface to a computer does not match or …