Bulloch Melissa C, Prime Steven L, Marotta Jonathan J
Perception and Action Lab, Department of Psychology, University of Manitoba, Winnipeg, MB, R3T-2N2, Canada.
Department of Psychology, University of Saskatchewan, Saskatoon, SK, Canada.
Exp Brain Res. 2015 Dec;233(12):3413-23. doi: 10.1007/s00221-015-4413-7. Epub 2015 Aug 20.
Grasping moving objects involves both spatial and temporal predictions. The hand is aimed at a location where it will meet the object, rather than the position at which the object is seen when the reach is initiated. Previous eye-hand coordination research from our laboratory, utilizing stationary objects, has shown that participants' initial gaze tends to be directed towards the eventual location of the index finger when making a precision grasp. This experiment examined how the speed and direction of a computer-generated block's movement affect gaze and selection of grasp points. Results showed that when the target first appeared, participants anticipated the target's eventual movement by fixating well ahead of its leading edge in the direction of eventual motion. Once target movement began, participants shifted their fixation to the leading edge of the target. Upon reach initiation, participants then fixated towards the top edge of the target. As seen in our previous work with stationary objects, final fixations tended towards the final index finger contact point on the target. Moreover, gaze and kinematic analyses revealed that it was direction that most influenced fixation locations and grasp points. Interestingly, participants fixated further ahead of the target's leading edge when the direction of motion was leftward, particularly at the slower speed-possibly the result of mechanical constraints of intercepting leftward-moving targets with one's right hand.
抓取移动物体涉及空间和时间预测。手瞄准的是它将与物体相遇的位置，而不是开始伸手时物体所在的位置。我们实验室之前利用静止物体进行的眼手协调研究表明，参与者在进行精确抓握时，最初的目光往往会指向食指的最终位置。本实验研究了计算机生成方块的移动速度和方向如何影响注视以及抓握点的选择。结果表明，当目标首次出现时，参与者会通过在目标最终运动方向上领先边缘的前方进行注视来预测目标的最终运动。一旦目标开始移动，参与者将注视点转移到目标的领先边缘。在伸手开始时，参与者随后将注视点转向目标的顶部边缘。正如我们之前对静止物体的研究中所看到的，最终的注视点倾向于目标上食指的最终接触点。此外，注视和运动学分析表明，对注视位置和抓握点影响最大的是方向。有趣的是，当运动方向向左时，参与者在目标领先边缘前方的注视距离更远，尤其是在速度较慢时——这可能是用右手拦截向左移动目标的机械限制的结果。
