Searching for unity among diversity: exploring the `interface' concept

Despite widespread interest in the human-computer interaction (HCI) field, there remains much debate as to appropriate conceptual frameworks for the field, and even confusion surrounding the meaning of basic terms in the field. HCI is seen by many as focusing on the design of interfaces to computer systems, yet exactly what is implied by this focus on 'interfaces' is unclear. In this paper we show how a better understanding of what is meant by the interface is possible via the concept of abstraction levels. We show how this levels approach can clarify some ambiguities, and also how it can be related to different phases in the evolution of the human-computer interaction field itself. In this context, we are able to account for the recent interest in activity theory as a possible alternative framework for HCI work, while stressing the need for HCI research and design to consider each of the separate, but related, levels.