Bonnet Cédrick T, Szaffarczyk Sébastien
a SCALab, Laboratoire de Neurosciences Fonctionnelles et Pathologies, CNRS UMR 9193 , University of Lille 2 , France.
J Mot Behav. 2017 Sep-Oct;49(5):494-504. doi: 10.1080/00222895.2016.1241749. Epub 2016 Dec 29.
In studies of postural control, a control task is often used to understand significant effects obtained with experimental manipulations. This task should be the easiest task and (therefore) engage the lowest behavioral variability and cognitive workload. Since 1983, the stationary-gaze task is considered as the most relevant control task. Instead, the authors expected that free looking at small targets (white paper or images; visual angle: 12°) could be an easier task. To verify this assumption, 16 young individuals performed stationary-gaze, white-panel, and free-viewing 12° tasks in steady and relaxed stances. The stationary-gaze task led to significantly higher cognitive workload (mean score in the National Aeronotics and Space Administration Task Load Index questionnaire), higher interindividual body (head, neck, and lower back) linear variability, and higher interindividual body angular variability-not systematically yet-than both other tasks. There was more cognitive workload in steady than relaxed stances. The authors also tested if a free-viewing 24° task could lead to greater angular displacement, and hence greater body sway, than could the other tasks in relaxed stance. Unexpectedly, the participants mostly moved their eyes and not their body in this task. In the discussion, the authors explain why the stationary-gaze task may not be an ideal control task and how to choose this neutral task.
在姿势控制研究中，常常使用控制任务来理解实验操作所产生的显著效果。该任务应是最简单的任务，（因此）具有最低的行为变异性和认知负荷。自1983年以来，固定注视任务被认为是最相关的控制任务。相反，作者预计自由注视小目标（白皮书或图像；视角：12°）可能是一项更简单的任务。为了验证这一假设，16名年轻人在稳定和放松的姿势下分别执行了固定注视、白色面板和自由观看12°任务。固定注视任务导致认知负荷显著更高（美国国家航空航天局任务负荷指数问卷中的平均得分），个体间身体（头部、颈部和下背部）的线性变异性更高，以及个体间身体角度变异性更高——尚未呈现系统性——高于其他两项任务。稳定姿势下的认知负荷比放松姿势下更高。作者还测试了在放松姿势下，自由观看24°任务是否会比其他任务导致更大的角位移，进而导致更大的身体摆动。出乎意料的是，在这项任务中参与者大多是移动眼睛而非身体。在讨论中，作者解释了为什么固定注视任务可能不是理想的控制任务以及如何选择这个中性任务。
