Three different instruction formats were examined respecting their usefulness for the navigation through hierarchical menus in mobile phones. 56 middle-aged adults had to solve four mobile phone tasks twice consecutively. Before completing the first trial, they were supported by instruction formats which contained different spatial knowledge types [28]. The first form was a procedural step-by-step instruction delivering landmark and route knowledge. The second instruction consisted of a visualized menu tree, in which the menu path to be taken was marked. By this, mainly survey knowledge but also route information was provided. The third instruction format also used the visualized menu tree. However, in addition to the menu path which had to be taken, also functions' labels were given, conveying landmark, route and survey knowledge. Further, a condition was examined in which no help was given. Dependent variables were navigation effectiveness and efficiency. Overall, the step-by-st...