A pointing movement is executed faster when a subject is allowed to stop at the first target than when the subject has to proceed to a second target ("one-target advantage"). Our hypothesis was that this is because the impact at the target helps to stop the finger when the finger does not have to proceed to a second target. This hypothesis would predict that the horizontal force at contact with the first target should be larger when there is only one-target. Modelling smooth movements with larger forces at contact using a minimum-jerk model, shows that the peak velocity is slightly higher and it occurs later during the movement when there is only one target. Although the one-target advantage was present in our experiment, the horizontal force at contact in the one-target condition was not larger than in the two-target condition. The time of the maximum velocity did not differ, but the maximum velocity was higher in the one-target condition. Thus our hypothesis is rejected, favouring a non-mechanical explanation of the one-target advantage.

Impact force, Motor control, One-target advantage
dx.doi.org/10.1016/S0167-9457(03)00050-2, hdl.handle.net/1765/61421
Human Movement Science
Department of Neuroscience

Biegstraaten, M, Smeets, J.B.J, & Brenner, E. (2003). Impact forces cannot explain the one-target advantage in rapid aimed hand movements. Human Movement Science, 22(3), 365–376. doi:10.1016/S0167-9457(03)00050-2