VARIABILITY AND STABILITY IN SKILL ACQUISITION

描述(申请人提供)：知觉运动的获得和适应是日常生活的基础。在技能习得和控制的研究中，稳定性和变异性的概念发挥了核心作用，尽管它们有不同的定义和严格程度。最常见的是，绩效的提高与某些任务参数的可变性降低有关。反过来，这种变异性的降低被解读为稳定性的提高。这种相反的关系掩盖了经验性可变性可以代表许多不同的方面，从明显的“缺乏控制”--被视为目标导向型任务中的错误或不稳定--到更有益的方面，如参数之间的补偿性差异，以及对新任务的探索。变异性的异常水平是功能障碍行为的特征，表现为震颤、过度运动或刻板印象，即没有波动。我们方法中的一个基本假设是，一定程度的“噪声”是生物系统的基本表达。因此，稳定性也大于某些性能参数的不变性。具体地说，动态稳定性被定义为对扰动的抵抗力，它可以独立于变化性而被量化。该项目考察了两个任务中的技能获得，以区分我们对人类行动中的可变性和稳定性的理解。在Skittle，一种前馈控制下的面向目标的投掷动作，我们开发了一种方法，将可变性分解为三个独立的组成部分：容忍、协变和噪声，每个分量都捕获对成功行为的单独贡献。在6个实验中，我们测试了变异性的不同组成部分如何在学习的不同阶段做出贡献，以及随机噪音如何成为找到成功解决方案的一种手段。第二项任务是有节奏地弹跳球，这是一种连续的感知引导技能。以前的建模工作得出了动态稳定性能的标准，我们表明受试者使用这种“被动”稳定性。六个实验考察了技能习得如何表现为对动态稳定性的日益依赖。我们将分析性能的可变性，以测试不同的组件如何影响稳定性的这种变化。对知觉-运动任务的习得和控制有了更深入的了解，将有助于运动障碍的诊断和康复方法的发展。

DESCRIPTION (provided by applicant): The acquisition and adaptation of perceptual-motor is fundamental to everyday life. In the inquiry of skill acquisition and control the concepts of stability and variability have played a central role, albeit with different definitions and levels of rigor. Most commonly, improvement of performance has been associated with a decrease in variability of some task parameters. This reduced variability, in turn, has been interpreted as an increase in stability. This inverse relationship obscures that empirical variability can be indicative of many different facets, ranging from the obvious "lack of control", seen as errors or inconstancy in target-oriented tasks, to more beneficial aspects, such as compensatory variation between parameters, and exploration of new tasks. Abnormal levels of variability are characteristic for dysfunctional behavior, as evidenced in tremor, excessive movements, or stereotypy, the absence of fluctuations. A fundamental assumption in our approach is that a certain irreducible level of "noise" is a basic expression of biological systems. Hence, also stability is more than invariance of some performance parameter. Specifically, dynamical stability is defined as resistance to perturbations, which can be quantified independently from variability. The project examines skill acquisition in two tasks to differentiate our understanding of variability and stability in human action. In skittles, a target-oriented throwing action under feedforward control, we develop a method to decompose variability into three independent components: tolerance, covariation, and noise, each capturing a separate contribution to successful behavior. In 6 experiments we test how different components of variability contribute in different stages of learning, and how stochastic noise can be a means to find successful solutions. The second task is the continuous perceptually-guided skill of rhythmically bouncing a ball. Previous modeling work derived criteria for dynamically stable performance and we showed that subjects used this "passive" stability. Six experiments examine how skill acquisition is characterized by an increasing reliance on dynamical stability. Performance variability will be analyzed to test how different components contribute to this change in stability. Obtaining a deeper understanding of acquisition and the control of perceptual-motor tasks will advance knowledge for diagnosis of movement disorders as well as to develop methods of rehabilitation.