Age-related learning effects in working with layered interfaces

Many adults complain that domestic products of today are more difficult to use than earlier products. Learning problems may have arisen because of (1) the increasing complexity of interfaces over the past years or (2) age-related cognitive changes. The organization of objects on an interface plays a key role in the user's understanding and recall of executable sequences of actions. Up until the eighties, objects on domestic products were organized in the breadth (single-layer). Later, a large expansion offunctionality on appliances made it infeasible to organize all objects on the same layer. Now objects are organized in depth (multi-layered) to hide less relevant functionality. Disadvantages of this solution are the reduction of status feedback on the device and the visual disconnection between a control and its function. Therefore, it can be assumed that it is easier to learn to use a device composed of a singlelayer interface than one composed of a multi-layered interface. It is assumed that older adults encounter even more difficulties than younger adults with multi-layered interfaces, due to age-related inefficiency of information processing and encoding. The learning behaviour of three age-groups was compared using a simulation of a single-layer and a two-layered videophone interface, with a counterbalanced block design. Younger people were found to encounter fewer interaction problems than older persons, and each of the three age-groups showed different learning progress. In general, the single-layer interface was found to be easier to use than the two-layered interface.