The Rhetoric of Universal Interaction Design

A digital UI design brief is a rhetorical artifact that should serve the user goal, whatever the interaction mode. The designer task is to map every aspect of interaction design, from graphic and text content to visible and textual feedback, to keep the user goal foremost in every interaction a device may support: default view, high-contrast mode, whatever the text or viewport scale. The multimodality of digital devices poses a difficulty for user-centered designers: how to convey to system-centered developers the complexity of human-device interactions. This task is made simpler by mapping design artifacts into modal overlays that show each interaction mode as a distinct layer.