Metaphors in User Interface Development: Methods and Requirements for Effective Support

Metaphors can provide paths through the jungle of functionality. Let us take the metaphor included in the previous sentence to outline the general components of a metaphor. A metaphor is a rhetorical device (rhetoric: techniques for communicating messages) to describe an object or event, real or imagined, using concepts that cannot be applied to the object or event in an conventional way (Indurkhya 1992). The object being described is called the target (other terms sometimes used are topic, object and tenor), and the concepts that cannot be applied conventionally are called the source (vehicle). There exists a metaphorical mapping between these two domains which is a cognitive process of combining the target and source. In our initial sentence the target is the complexity of software systems, the source is the jungle where it is usually not easy for the untrained to find the right way. The essence of a metaphor is understanding and experiencing one kind of thing in terms of another (Lakoff & Johnson 1980). In visual user interfaces the concepts of the source are presented in a visual form. So given an appropriate mapping the user may not be aware of the existence of an explicit metaphor. It is the challenge for the designer to select the right metaphor source with appropriate mappings to the target visualized with appropriate visual elements.