Composite Interface Metaphors 1 A componential model for understanding the effects of composite interface metaphors on web-based task performance and learning

Composite Interface Metaphors 2 Two experiments describe how a composite metaphor interface (CMI) for performing website tasks can be developed using an iterative and theory-based design approach. The CMI consisted of two semantically unrelated metaphors: the library metaphor and the travel metaphor. A new componential model for predicting the effectiveness of CMIs is described and used for deriving and testing specific hypotheses. Results show that an improved version of the CMI resulted in better declarative knowledge about metaphor-interface mappings than a non-metaphorical control interface (even before the interface was first used), and in less mental effort, as measured by clicking behavior. It also resulted in faster performance of web-based tasks, but only if differences in pre-existing declarative knowledge were taken into account. The discussion addresses i.a. the question how mismatches between interface functions and the metaphor they belong to (confusions) can be measured and used for improving the quality of the CMI. 1.1 Background For years, metaphors have been used to facilitate user tasks on the World Wide Web. The most popular ones are implicit, or embedded, analogies, and are used as a way to control the complexity of the user interface of a web browser or web site. This is done by designing the actions, underlying concepts, and appearance of the (new) web site or browser on the basis of actions, concepts, and appearances the user is already familiar with: " … metaphors can facilitate active learning by providing clues for abductive and adductive inferences through which learners construct procedural knowledge of the computer " This type of metaphor is also called interface metaphor. Examples of interface metaphors for the World Wide Web are the book metaphor and the tab (folder) metaphor. Interface metaphors are, in turn, an example of what are sometimes also called " cognitive " metaphors: mechanisms of the human mind allowing us to use what we know about our physical and social experience to provide understanding of other and less familiar subjects (Lakoff & Johnson, 1980). Despite their popularity, systematic knowledge about how to design good interface metaphors is scarce. Some authors even doubt whether metaphorical interfaces should be more neutrally, one could say there is disagreement about various issues, such as what the relative strength is of single and composite interface metaphors, what the long-term effects are of using interface metaphors, and whether or not the two single metaphors making up a composite metaphor …