Assessing age-related performance decrements in user interface tasks

As the computer and internet generations age, there is an increasing need to develop appropriate interfaces for the elderly that can accommodate age-related changes in manual dexterity, visual acuity, and cognitive abilities. Assessment of age effects is typically a necessary first step in designing age-appropriate interfaces, but assessment of age related effects may be complicated by a bias towards accuracy in the elderly or by other differences in how the tradeoff between speed and accuracy is handled by different people. In this paper, we attempt to investigate the effects of aging on performance difference in interacting with computer interfaces. An experiment was conducted to examine age related effects in a steering task. In order to assess the impact of a possible speed-accuracy tradeoff, performance was observed under three different instructional sets i.e., accuracy (A), neutral (N), and speed (S) when steering on a circular track. Experimental results showed that the elderly group performed significantly less accurately for all three instruction sets. The younger subjects were more influenced by instructions to perform faster, or with more accuracy. Cluster analysis of the empirical data individually for both the old and younger participants showed that variability among subjects was much greater in older users than younger users. Implications for user interface design for older users, and for the evaluation of age effects in HCI generally, are discussed.