A pedagogical role for conceptual models in user interface design

Conventional user-interface design concentrates on reducing the user's cognitive load with respect to the task they are using the computer to accomplish. In contrast, this thesis identifies a number of pedagogical roles in which the user interface can help challenge the student intellectually. Based on Perkins' (1986) constructivist theory of "knowledge-as-design", this analysis suggests that a particular kind of software feature--called an undetermined feature--may be beneficial in engaging users in constructive thinking. Specifically, it may provide extensibility--the ability for users to construct their own understanding through re-interpretation of screen elements. A hypertext environment was developed which incorporates undetermined features, without introducing any difficulties in operation of the program. In an empirical study, subjects used iconic anchors to construct links within a hypertext document. A treatment group made use of undetermined anchor symbols to create their own link semantics, while a control group used predetermined link semantics. While the linking task itself reduced the number of facts recalled from the document, the treatment group's retention of recalled facts was improved significantly, by about twenty percent after a one week latency period. Analysis of video protocols from a separate study showed that treatment subjects spent more time considering the textual material as a whole rather than as separate components. Additional work is needed to encourage students to explore more alternatives in their semantic designs. Long-term studies, additional software, and instructional support are areas that could help reveal the full potential of an extensible user interface.