Summers Jeffery J, Maeder Sabrina, Hiraga Cynthia Y, Alexander James R M
Human Motor Control Laboratory, School of Psychology, University of Tasmania, Private Bag 30, Hobart, Tasmania 7001, Australia.
Hum Mov Sci. 2008 Oct;27(5):823-37. doi: 10.1016/j.humov.2007.11.003. Epub 2008 Jan 28.
It has been suggested that the temporal control of rhythmic unimanual movements is different between tasks requiring continuous (e.g., circle drawing) and discontinuous movements (e.g., finger tapping). Specifically, for continuous movements temporal regularities are an emergent property, whereas for tasks that involve discontinuities timing is an explicit part of the action goal. The present experiment further investigated the control of continuous and discontinuous movements by comparing the coordination dynamics and attentional demands of bimanual continuous circle drawing with bimanual intermittent circle drawing. The intermittent task required participants to insert a 400ms pause between each cycle while circling. Using dual-task methodology, 15 right-handed participants performed the two circle drawing tasks, while vocally responding to randomly presented auditory probes. The circle drawing tasks were performed in symmetrical and asymmetrical coordination modes and at movement frequencies of 1Hz and 1.7Hz. Intermittent circle drawing exhibited superior spatial and temporal accuracy and stability than continuous circle drawing supporting the hypothesis that the two tasks have different underlying control processes. In terms of attentional cost, probe RT was significantly slower during the intermittent circle drawing task than the continuous circle drawing task across both coordination modes and movement frequencies. Of interest was the finding that in the intermittent circling task reaction time (RT) to probes presented during the pause between cycles did not differ from the RT to probes occurring during the circling movement. The differences in attentional demands between the intermittent and continuous circle drawing tasks may reflect the operation of explicit event timing and implicit emergent timing processes, respectively.
有人认为，在需要连续动作（如画圈）和非连续动作（如手指敲击）的任务中，有节奏的单手动作的时间控制是不同的。具体而言，对于连续动作，时间规律是一种涌现属性，而对于涉及不连续性的任务，时间安排是动作目标的一个明确部分。本实验通过比较双手连续画圈和双手间歇画圈的协调动力学和注意力需求，进一步研究了连续和非连续动作的控制。间歇任务要求参与者在画圈的每个周期之间插入400毫秒的停顿。使用双任务方法，15名右利手参与者执行这两项画圈任务，同时对随机呈现的听觉探针进行口头回应。画圈任务以对称和不对称协调模式以及1Hz和1.7Hz的运动频率进行。间歇画圈比连续画圈表现出更高的空间和时间准确性及稳定性，支持了这两项任务具有不同潜在控制过程的假设。在注意力成本方面，在两种协调模式和运动频率下，间歇画圈任务期间的探针反应时间（RT）均显著慢于连续画圈任务。有趣的是，发现在间歇画圈任务中，对周期之间停顿期间呈现的探针的反应时间与对画圈运动期间出现的探针的反应时间没有差异。间歇画圈任务和连续画圈任务在注意力需求上的差异可能分别反映了明确事件计时和隐现计时过程的运作。
