Psychology models of attention have several objectives: an important one is to explain the limitations of human performance in multi-tasking situations where people must "split" their attention between several activities. In this project, we are adapting a psychological theory of attention called Multiple Resource Theory (Kahneman 1973; Wickens 1980), in order to investigate multi-tasking performance when a mobile computing activity must compete for the user's attention with other demands from the user's cognitive environment. Our long-term goals are:

1. modeling how competing demands for a user's attention that arise in mobile computing contexts can lead to less efficient performance of typical mobile computing tasks,
2. discovering how user interface (UI) designs for mobile devices or applications can mitigate (or exacerbate) this effect, and
3. translating that understanding into useful guidelines for mobile UI and application designers.

    This talk will be a progress report on the project, describing a detailed model of attention in multi-tasking environments and an experiment we conducted to evaluate the effect of changes in the user interface on dual-task performance.