Optimization of Touch Active Area Size Based on Click Position Bias in Older Adults’ Touchscreen Interaction

Changes in both physiological structure and psychological factors occur in older adults, leading to a decline in fine motor control and inferior performance compared to young adults during touchscreen interactions. It is crucial to understand the behavioral patterns of older adults’ touchscreen clicks and subsequently optimize the touch active area size based on click position bias. An experimental prototype was developed using Android Studio, and 25 participants aged 65 and above (9 males, and 16 females) were recruited for touchscreen tasks. Several key findings emerged from the study. Firstly, older adults exhibited significant deviations when clicking targets near the left and right edges of the screen. The leftward deviation was predominantly downward, while the rightward deviation was upward. Secondly, to achieve an 80% accuracy rate for older users, recommended touch active area sizes were determined as follows: 2.3 cm for the left 25% of the screen, 1.1 cm for the central 50%, 1.7 cm for the right 25%, and 2.1 cm for the entire screen. These findings could contribute to enhancing the design of touch interfaces, providing reference parameters for touch active area sizes to achieve optimal click accuracy in different screen areas.