Abstract
The present study aims to establish a guideline for designing of GUI (e.g., software-keyboards) for touch-screens, so as to reduce the "digital divide" in our society. As a first step to this goal, we examined the aging effect and sexual difference on the dynamical properties of pointing movements on a touch-screen. The major results are as follows: 1. Pitts' law (MT=α log_2 D/S+β) did not necessarily hold when the subjects repeated pointing movements between two targets locations on the screen (D is the distance between the targets, S is the size of the target). Rather, the increase in the movement time (MT) was linearly related to the the index of difficulty (ID=D/S), this is, MT=α D/S+β. 2. Coefficient α and intercept β were not significantly different between the movements in left-right direction and in depth direction. 3. No sexual difference was found in the magnitude of α and β. 4. The intercept β linearly correlated to the subjects' ages while the coefficient α took almost the same value irrespective of the ages.
