Assess The Relevance Of Metaphors To Human

– Computer Interaction From The Perspective Of The Design Essay, Research Paper

System metaphors appear to be attracting more and more attention and you often hear the term banded about in journals and conference proceedings. The aim of this essay is to examine the potential usefulness of metaphors to the users and designers of systems, concentrating, in particular, on the human-computer interface. It will hopefully be established whether system metaphors are phenomena worthy of serious thought or whether it is simply an empty term with no more than intuitive appeal which will be passed over and forgotten with time. The basic idea behind a metaphor is to understand a new concept in terms of one which is already familiar and understood. A well known metaphor is that of Rutherford’s comparison of the hydrogen atom to the solar system. Lakoff and Johnson (1980) see language to be structured metaphorically and claim that this reflects the structure of thought processes in general: Metaphor is pervasive in everyday life, not just in language but in thought and action (Lakoff & Johnson 1980, p3) Many teachers have used metaphor and analogy to facilitate their pupils learning and indeed analogy seems to be a central aspect of learning. Metaphors can be distinguished from models by the partial nature of the correspondence between the old and new concept. What is then the relevance of metaphor to human-computer interaction. A significant interest in HCI is controlling system complexity. This affects the learnability and ease of use of a system and consequently its acceptance by users. If a system is not accepted by users then in many ways it is a failure. There are different approaches to reducing system complexity and improving learnability and usability: firstly the number of actions the user has to execute and the number of processes and concepts to be remembered can be reduced; alternatively, instead of reducing the initial complexity designers could increase the initial familiarity of a system by using interface actions, procedures and concepts which make use of specific existing knowledge and experience that users have of other domains. This is the broadened meaning of the term metaphor which is employed in HCI research. Metaphors can be of use for both the user and the designer, since what is good for the one is frequently good for the other. The user’s behaviour at the interface is often believed to be shaped by the mental model thet he or she has of a system and task. The knowledge that it represents enables an expert user to predict and understand a complex system. Metaphors can be regarded as short-cuts along the path to acquiring a comprehensive mental model. They can be used to lend a familiar air to unfamiliar circumstances which might otherwise prove confusing. Gentner (1980) speculates that the difference between experts and novices can be explained in terms of analogies: …the expert has an abstract global model with broad scope, while the novice has a pastiche of rich, only locally useful models…naive models of science appear more like expressive analogies than do expert models There is evidence that even when not provided with a metaphor users spontaeously create them anyway as part of the understanding process (Carroll & Thomas 1982). It would be useful if designers could anticipate likely metaphors in order to guide users towards useful ways of thinking about a system and prevent them from selecting inappropriate metaphors which would perhaps hinder learning. As Carroll, Mack & Kellog (1987) point out “the use of interface metaphors is pervasive and growing in interface design”, however it is not clear to what extent designers are aware that they are using metaphors. At present it seems to be a rather intuitive and haphazard process. A metaphor which has appeal for a designer may not necessarly convey the correct concepts to a user and may have broader implications which are not superficially evident. These and many other factors seem to imply that user interface designers should learn all they can about what metaphors are, how they have effect and how they can be incorporated into user interface and system design in a systematic manner. “”"”"”"”"”"”"”"”"”"”"”"”" This next section aims to present some of the main metaphors which are presently used, as well as discussing more experimental metaphors. The metaphor of a typewriter is frequently used to help people master word processing systems. Much useful knowledge about keyboards and the act of typing itself can be applied to word processing, reducing the complexity of the system and making it easier to learn. Whiteboard and Chalkboard are both systems which exploit prior knowledge about the very same real-world objects as well as attributes of these objects such as a common work space for cooperative groups, and freeform text and graphics. Other frequently used metaphors include document and business forms, but perhaps the best known metaphor is that of the desktop, a complex composite metaphor. Commercial examples of this metaphor include the Xerox Star system as well as Apple’s Lisa and Macintosh systems. This metaphor is intended to enable users to manipulate familiar office objects in familiar ways and exploits people’s ability to use the space around them for organising and storing things. For example, a document folder can be retrieved from a fil