Hierarchical menu design: Breadth, depth, and task complexity

In this research a relationship between an hierarchical menu's depth and the perceived complexity of a task involving menu retrieval was proposed and validated. 12 subjects were asked to use six different hierarchical menus of varying breadth and depth. The dependent variables were response time and accuracy. The independent variables were depth and breadth of the hierarchy. Subsequent to experimentation, the subjects were asked to complete a questionnaire on users' perceptions of the complexity of the different menu structures. As depth increased, perceived complexity of the menus increased significantly. These phenomena are linked to an existing theory of task complexity. We suggest that the cognitive component influencing users' perceptions of task complexity was short-term memory load.