Effects of Prompt Style when Navigating through Structured Data

This study examines how the structure of information presented via a speech interface interacts with the choice of a prompting strategy. Participants (N = 60) performed a series of searches with a telephone-based, voice-activated, tree-structured search engine in a 3 (prompt type: multiple choices listed up-front, open-ended prompts with a multiple-choice fallback, or open-ended prompts without any fallback) by 2 (broad vs. deep tree) between-participants experiment. There were significant interactions between the prompt type and tree structure for perceived ease of use and perceived usefulness, as well as for the participants’ sense of control, sense of success, and liking of the system. In general, up-front prompts were most desirable for deep trees, while the other two strategies were more desirable for broad trees. Implications for prompt design are presented.