Philip Barker and Paul van Schaik
University of Teesside
Borough Road,
Middlesbrough
TS1 3BA

Icons are now widely used in many different contexts for the purpose of communication and knowledge representation. One very important area where their use has become quite commonplace is in the design and development of human- computer interfaces. Graphical user interfaces, for example, usually embed a range of different iconic forms. When embedded within such interfaces they act as stimuli that trigger a wide range of mental processes within users of those interfaces. Of course, as well as being used as agents for the purpose of communication, they can also be used ‘in the head’ in order to facilitate the storage of various forms of knowledge. This paper therefore discusses the role of icons from a knowledge representation perspective and outlines some findings from a teach-back experiment that we have recently conducted.

The paper commences with a broad introduction to the nature of icons and their role as agents for the communication and storage of knowledge. This is followed by a section which outlines the basic characteristics of declarative and procedural knowledge and the ways in which these are stored using various types of cognitive structure. We then compare textual and pictorial mental representations of knowledge and thereby establish a framework for the following discussion on the role of iconic representation in mental models. As the thrust of the paper deals with the cognitive aspects of icons, we next present a brief review of the relevant psychological literature relating to ‘icons in the mind’ and then go on to describe a case study that we have been undertaking. This involves the use of teach-back experiments in order to study people’s mental models of word-processing systems. The results of the experiments are discussed and some conclusions pertaining to end-user interface design are presented.