Metaphor in User Interface Design

This is a collection of references and other material about the use (and mis-use) of metaphor in user interface design, which I collected while preparing a presentation for James Landay's Research Topics in Human-Computer Interaction class.

The interesting thing about the topic "Metaphor in User Interface Design" is that there is some disagreement about what exactly that means. The "desktop metaphor" developed and promoted by Apple has come up for a lot of criticism, I think because it attempts to over-extend the metaphor. Some writers, such as Alan Cooper and even Alan Kay, roundly criticise the use of metaphor as a tool for designing user interfaces. Alan Kay, for example, states that "metaphor is a poor metaphor for what needs to be done."

Other writers, such as Neale and Carroll, and Aaron Marcus, take the concept of metaphor very seriously, in some cases appearing to propose it as a fundamental method for designing user interfaces. Texts on user interface design ask questions like "Is the metaphor extensible?" and "Is the metaphor easily understood?" Compared to what we understand about metaphor as a linguistic device, these kinds of questions seem very strange.

I found the book by Lakoff and Johnson, Metaphors We Live By, invaluable in helping me understand what "metaphor" actually means. Until reading it, my understanding of metaphor was basically wrong (perhaps this is an argument for including courses in English in engineering and computer science degree curricula, but that's another story...). In the class discussion, one person pointed out that Lakoff and Johnson's view of metaphor is by no means universally accepted -- but still, I found it provided an invaluable grounding to allow me to place the other, user-interface specific, writings about metaphor into context.

My assessment, based on the readings referenced below, is that the use of metaphor in user interface design is used in two ways. First, as a way of providing user's with a mental model. The paper by Halskov Madsen says that users will construct metaphors to explain the operation of a computer system, whether you explicitly give them one or not -- in this light, designing metaphor into a user interface (provided the right metaphors are chosen) is invaluable in making the metaphor explicit. However, this approach to metaphor often uses a dumbed-down kind of metaphor (compared to the meaning of metaphor as revealed by L&J), in which metaphor is exploited to provide "instant" understanding (just add a user and mix!), without exploiting the richness of association and understanding that is fundamental to the use of metaphor in language.

Second, metaphor is used in a very literal way -- for example, an electronic address book is made to look and function rather like a physical one. This usage tends to focus on literal representations, and invariable becomes the target for criticism. This approach is extended to what one might call "metaphoric literals" -- Marcus, for example, proposes the rather ridiculous user interface in which files are selected by lassooing cattle.

Of course, user interfaces are not natural language, so my remarks about the poverty of user interface metaphors compared to language need to be taken with a grain of salt. Nonetheless, linguistic metaphor has a richness that visual metaphors have not, for the most part, been able to tap. If is is true that we, by our nature, understand and structure abstract concepts in metaphorical ways, then there are some exciting challenges for HCI researchers here.