Cursor trajectory analysis

Target acquisition is greatly helped by tactual feedback. To create non-disturbing tactual feedback-effects in human-computer interaction. Ihe user' s goal has to be predicted, so that the tactual feedback can help the user toward Ihe target and away from non-targets. In this paper we describe an experiment in which we explore cursor movements with an amplitude of 250 pixels, in eight different directions and with three different control devices (a mechanical mouse, an optical mouse, and an oplical trackball). The aim of this exploration was to find characteristics of the cursor path that could be used to creale a prediction algorithm. The focus was on the mean curvature and variability of the paths. It can be concluded that, on average, cursor paths are rather straight in all eight directions and with all three devices. The variability of the paths depends on three factors: (1) direction (the variability is higher in oblique directions than in horizontal and vertical directions); (2) friction of the control device (the variability is higher when a low friction device is used than when a higher friction device is used - the optical trackball having a lower friction than the two mice); and (3) the user. The amount of variability is used to estimate the maximum target resolution at which an algorithm can predict the user's target with a certain probability.