UMR 7287 Institut des Sciences du Mouvement E.J. Marey, CNRS and Aix-Marseille Université, Marseille, France.
PLoS One. 2012;7(7):e41190. doi: 10.1371/journal.pone.0041190. Epub 2012 Jul 18.
The lawful continuous linear relation between movement time and task difficulty (i.e., index of difficulty; ID) in a goal-directed rapid aiming task (Fitts' law) has been recently challenged in reciprocal performance. Specifically, a discontinuity was observed at critical ID and was attributed to a transition between two distinct dynamic regimes that occurs with increasing difficulty. In the present paper, we show that such a discontinuity is also present in discrete aiming when ID is manipulated via target width (experiment 1) but not via target distance (experiment 2). Fitts' law's discontinuity appears, therefore, to be a suitable indicator of the underlying functional adaptations of the neuro-muscular-skeletal system to task properties/requirements, independently of reciprocal or discrete nature of the task. These findings open new perspectives to the study of dynamic regimes involved in discrete aiming and sensori-motor mechanisms underlying the speed-accuracy trade-off.
在目标导向快速瞄准任务中，运动时间与任务难度（即难度指数；ID）之间存在合法的连续线性关系（菲茨定律），但最近在反向表现中受到了挑战。具体来说，在临界 ID 处观察到不连续性，并归因于随着难度增加而发生的两个不同动态范围之间的转变。在本文中，我们表明，当通过目标宽度（实验 1）而不是目标距离（实验 2）来操纵 ID 时，离散瞄准也存在这种不连续性。因此，菲茨定律的不连续性似乎是神经肌肉骨骼系统对任务特性/要求进行功能适应的合适指标，与任务的反向或离散性质无关。这些发现为离散瞄准中涉及的动态范围以及速度准确性权衡的感觉运动机制的研究开辟了新的视角。
