Bohan Michael, Longstaff Mitchell G, Van Gemmert Arend W A, Rand Miya K, Stelmach George E
Motor Control Laboratory at Arizona State University, Tempe, AZ 85287, USA.
Motor Control. 2003 Jul;7(3):278-89. doi: 10.1123/mcj.7.3.278.
This study examined the impact of target geometry on the trajectories of rapid pointing movements. Participants performed a graphic point-to-point task using a pen on a digitizer tablet with targets and real time trajectories displayed on a computer screen. Circular- and elliptical-shaped targets were used in order to systematically vary the accuracy constraints along two dimensions. Consistent with Fitts Law, movement time increased as target difficulty increased. Analysis of movement kinematics revealed different patterns for targets constrained by height (H) and width (W). When W was the constraining factor, movements of greater precision were characterized by a lower peak velocity and a longer deceleration phase, with trajectories that were aimed relatively farther away from the center of the target and were more variable across trials. This indicates an emphasis on reactive, sensory-based control. When H was the constraining factor, however, movements of greater precision were characterized by a longer acceleration phase, a lower peak velocity, and a longer deceleration phase. The initial trajectory was aimed closer to the center of the target, and the trajectory path across trials was more constrained. This suggests a greater reliance on both predictive and reactive control.
本研究考察了目标几何形状对快速指向运动轨迹的影响。参与者使用一支笔在数位绘图板上执行一项图形点对点任务，目标以及实时轨迹显示在电脑屏幕上。使用圆形和椭圆形目标，以便在两个维度上系统地改变精度约束。与菲茨定律一致，随着目标难度增加，运动时间也增加。对运动运动学的分析揭示了受高度（H）和宽度（W）约束的目标的不同模式。当W是约束因素时，精度更高的运动的特征是峰值速度较低和减速阶段较长，轨迹相对更远离目标中心，并且在各次试验中变化更大。这表明强调基于反应性的、基于感觉的控制。然而，当H是约束因素时，精度更高的运动的特征是加速阶段更长、峰值速度更低和减速阶段更长。初始轨迹更靠近目标中心，并且各次试验中的轨迹路径受到更多约束。这表明对预测性控制和反应性控制的更大依赖。
