Abstract
Four experiments were carried out to investigate the use of computer-based pointing devices by six, eight and ten year old children. Three groups ( N = 45) used three devices (mouse, joystick, trackball) for a discrete and a continuous pointing task. Two target shapes were used: square and rectangular. A factorial analysis of variance with repeated-measures design was employed. The dependent variables were movement time (MT) and processing rate and the independent variables were age, device, target depth and trial. Results showed that there was a significant age and device difference for both tasks. Target depth appeared to affect strongly movement time in a linear fashion for the square targets while weaker support was found for Fitts' law for the continuous task/rectangular target condition. The discrete task/rectangular target condition showed no effect of target depth and offered no support for Fitts' law. A comparison of target shape for both tasks indicated that the prediction of movement time was not restricted to the effect of the index of difficulty given a relative definition of the pointing movement. For the continuous task, the definition of target depth as the size of the target measured from the movement initiation point was found to be reasonable. With respect to children's processing rate, surprisingly low rates were recorded.