Design and evaluation of online multimedia maintenance manuals

In two experiments younger (18-25 years) and older (60-70 years) participants performed an information retrieval task in which they searched for the answers to questions in a hierarchical menu structure. Participants' movement speed, spatial ability, spatial memory, working memory capacity and reasoning speed were measured. Results showed older participants to be slower than younger participants on overall latencies on the information retrieval task. This slowing increases with each consecutive step in the menu structure. Regression analysis showed that movement speed, reasoning speed and spatial ability predicted the overall latencies accurately. Modelling the consecutive steps showed that latencies on the first selection are predicted by movement speed and reasoning speed. Memory and spatial measures are predictors for latencies on steps further into the menu structure only. This finding is consistent with increased slowing of older participants for later selections and suggests that deep menu structures are less suited for older users