Target-directed movements at a comfortable pace: movement duration and Fitts's law.

Although many studies have supported P. M. Fitts's (1954) law as a description of the speed-accuracy trade-off for speeded movements, there has been a lack of research regarding movement duration for target-directed movements made at any other pace. In the present study, the duration of movements made at a naturally selected comfortable pace and a quick pace differed from Fitts's law in a way that was similar to the predictions of participants in previous studies of naive motor decisions and imagined movements (S. J. Young, J. Pratt, & T. Chau, 2008; S. J. Young, J. Pratt, & T. Chau, 2009). These results show that movements of various speeds have predictable patterns of movement duration. The results also suggest that individuals adjust more than the implicit target size when changing their desired movement speed.