A human motor behavior model for distal pointing tasks

• Published in: International journal of human-computer studies Vol. 68; no. 10; pp. 603 - 615
• Main Authors: Kopper, Regis, Bowman, Doug A., Silva, Mara G., McMahan, Ryan P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.10.2010; Elsevier
• Subjects: Applied sciences; Computer science; control theory; systems; Computer systems and distributed systems. User interface; Distal pointing; Exact sciences and technology; Fitts’ law; HCI models of human motor behavior; Software; Fitts’ law; Distal pointing; HCI models of human motor behavior; Correlation coefficient; User interface; Input output equipment; Motor control; Behavior model; Modeling; Fitts' law
• ISSN: 1071-5819; 1095-9300
• DOI: 10.1016/j.ijhcs.2010.05.001

Models of human motor behavior are well known as an aid in the design of user interfaces (UIs). Most current models apply primarily to desktop interaction, but with the development of non-desktop UIs, new types of motor behaviors need to be modeled. Distal pointing—pointing directly at a target that is remotely situated with respect to the input device—is such a motor behavior. A model of distal pointing would be particularly useful in the comparison of different interaction techniques, because the performance of such techniques is highly dependent on user strategy, making controlled studies difficult to perform. Inspired by Fitts’ law, we studied four possible models and concluded that movement time for a distal pointing task is best described as a function of the angular amplitude of movement and the angular size of the target. Contrary to Fitts’ law, our model shows that the angular size has a much larger effect on movement time than the angular amplitude and that the growth in the difficulty of the tasks is quadratic, rather than linear. We estimated the model's parameters experimentally with a correlation coefficient of 96%.