VARIABILITY AND STABILITY IN SKILL ACQUISITION

描述（由申请人提供）：感知运动的获得和适应是日常生活的基础。在技能获得和控制的调查中，稳定性和可变性的概念发挥了核心作用，尽管有不同的定义和严格程度。最常见的是，性能的改善与某些任务参数的可变性降低有关。这种降低的可变性反过来被解释为稳定性的增加。这种相反的关系掩盖了经验的可变性可以指示许多不同的方面，从明显的“缺乏控制”，被视为错误或不稳定的目标导向的任务，更有益的方面，如补偿参数之间的变化，探索新的任务。异常水平的变异性是功能失调行为的特征，如震颤、过度运动或刻板，即没有波动。在我们的方法中的一个基本假设是，一定的不可约水平的“噪音”是生物系统的基本表达。因此，稳定性也不仅仅是一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，它可以独立于可变性来量化。该项目研究了两项任务中的技能获取，以区分我们对人类行为的可变性和稳定性的理解。在九柱戏，一个面向目标的投掷动作前馈控制下，我们开发了一种方法来分解成三个独立的组件：公差，协变和噪音，每个捕获一个单独的贡献成功的行为的可变性。在6个实验中，我们测试了可变性的不同组成部分如何在不同的学习阶段做出贡献，以及随机噪声如何成为找到成功解决方案的一种手段。第二个任务是有节奏地拍球的持续感知指导技能。以前的建模工作得出的标准动态稳定的性能，我们表明，主题使用这种“被动”的稳定性。六个实验研究技能获取的特点是越来越依赖于动态稳定性。将对性能变异性进行分析，以检测不同组分对稳定性变化的影响。获得更深入的理解和控制的知觉运动任务将推进知识的诊断运动障碍，以及开发康复的方法。

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.