Testing the Boundaries of Two User-Centered Design Principles: Metaphors and Memory Load

This experiment examined how varying implementations of two user-centered design principles affected the usability of a computer program. Drawing from human-computer interaction, as well as cognitive psychology, the following principles were implemented and tested: maximizing use of the user's expectations and stereotypes and minimizing the user's memory load. Nine interfaces were created using Hypercard' s datebook program. On each interface, the graphics and text were manipulated according to the design principle and the related cognitive psychology research. A total of 108 people participated. Of the five hypotheses, only one was supported by the data. The data suggest that for less complicated programs and tasks, strict adherence to design principles may not be required.