Exploiting spatial memory to design efficient command interfaces.

A common goal for user interface designers is to design efficient UIs that facilitate high levels of performance. In point-and-click interfaces, spatial memory has been shown to play an important role in reaching this level of performance, since it allows users to make quick decisions about item locations rather than resorting to slow visual search. However, spatial memory is rarely exploited by modern applications. Hierarchical menus force users through laborious action sequences to access commands, while window content is frequently elided and reshuffled in response to changing window geometries. In order to inform the design of UIs that better support spatial memory, we are studying the human and interface factors that affect the growth and resilience of spatial knowledge, and producing a series of exemplar interfaces that exploit users' spatial memory to rapidly achieve high levels of performance. A new command selection technique called CommandMaps demonstrates that when users have spatial memory of an interface, target acquisition can be vastly improved by removing control hierarchies. StencilMaps builds on the CommandMap technique, highlighting salient commands to accelerate novice visual search. Our ongoing research investigates the robustness of spatial memory and the role of 'effortful' learning in the development of spatial automaticity.