Wijnants M L, Cox R F A, Hasselman F, Bosman A M T, Van Orden G
Behavioural Science Institute, Radboud University Nijmegen Nijmegen, Netherlands.
Front Physiol. 2012 May 23;3:116. doi: 10.3389/fphys.2012.00116. eCollection 2012.
This study investigates human performance in a cyclic Fitts task at three different scales of observation, either in the presence (difficult condition) or in the absence (easy condition) of a speed-accuracy trade-off. At the fastest scale, the harmonicity of the back and forth movements, which reflects the dissipation of mechanical energy, was measured within the timeframe of single trials. At an intermediate scale, speed and accuracy measures were determined over a trial. The slowest scale pertains to the temporal structure of movement variability, which evolves over multiple trials. In the difficult condition, reliable correlations across each of the measures corroborated a coupling of nested scales of performance. Participants who predominantly emphasized the speed-side of the trade-off (despite the instruction to be both fast and accurate) produced more harmonic movements and clearer 1/f scaling in the produced movement time series, but were less accurate and produced more random variability in the produced movement amplitudes (vice versa for more accurate participants). This implied that speed-accuracy trade-off was accompanied by a trade-off between temporal and spatial streams of 1/f scaling, as confirmed by entropy measures. In the easy condition, however, no trade-offs nor couplings among scales of performance were observed. Together, these results suggest that 1/f scaling is more than just a byproduct of cognition. These findings rather support the claim that interaction-dominant dynamics constitute a coordinative basis for goal-directed behavior.
本研究在三种不同的观察尺度下，对循环菲茨任务中的人类表现进行了调查，观察是在存在速度-准确性权衡（困难条件）或不存在速度-准确性权衡（容易条件）的情况下进行的。在最快的尺度下，在单次试验的时间范围内测量来回运动的谐波性，该谐波性反映了机械能的耗散。在中间尺度下，在一次试验中确定速度和准确性指标。最慢的尺度涉及运动变异性的时间结构，其在多次试验中演变。在困难条件下，各项指标之间可靠的相关性证实了嵌套性能尺度之间的耦合。主要强调权衡中速度方面的参与者（尽管被要求既要快速又要准确）产生了更谐波性的运动，并且在产生的运动时间序列中1/f标度更清晰，但准确性较低，并且在产生的运动幅度中产生了更多的随机变异性（对于更准确的参与者则相反）。这意味着速度-准确性权衡伴随着1/f标度的时间和空间流之间的权衡，这一点通过熵测量得到了证实。然而，在容易条件下，未观察到性能尺度之间的权衡或耦合。总之，这些结果表明1/f标度不仅仅是认知的副产品。这些发现更支持这样的观点，即交互主导动力学构成了目标导向行为的协调基础。
