Dynamics of Action and Perception in a Rhythmic Task

所有的人类行为都需要行为人与环境之间的持续互动。这种互动需要微妙程度的协调，通常是在极其复杂的条件下，而我们才刚刚开始了解如何实现这种协调。在国家科学基金会的资助下，斯特纳德博士将考察知觉-运动任务的表现，在这个任务中，参与者和环境的复杂协调被提炼成适合研究的范式。这项任务是用球拍有节奏地弹球。在这项任务中，表演者必须不断地协调球拍的移动和球的移动，球的运动轨迹又由表演者决定。这项任务的好处是，由此产生的球拍系统遵循众所周知的物理原理。此外，由于它是一个可定义的非线性动力系统，它表现出稳定性和分叉等特征。通过操纵球拍，演员成为这个动力系统的一部分，并可以利用它的性质。系统的一些区域提供了具有“被动稳定性”的有节奏的解，其中扰动收敛回吸引子而不需要校正控制。其他制度则需要行为人的积极控制。主动控制机制的建立、维持和调整依赖于感知信息的多个来源。这项研究的主要目的之一是更好地理解这两种一般的协调机制。这项研究还将建立国内和国际合作，高级调查人员和研究生都将参与其中。

All human behavior entails the continuous interaction between the actor and the environment. This interaction requires an exquisite degree of coordination, often under extremely complex conditions, and we are only just beginning to understand how such coordination is achieved. With funding from the National Science Foundation, Dr. Sternad will examine the performance of a perceptual-motor task in which the complex coordination of actor and environment is distilled in a paradigm suitable for research. The task is the rhythmic bouncing of a ball with a racket. In this task, the actor must continuously coordinate the movements of the racket with the movements of the ball, whose trajectories are in turn determined by the actor. This advantage of this task is that the resulting ball-racket system obeys well-understood physical principles. Moreover, by virtue of being a definable nonlinear dynamical system, it displays characteristic features such as stability and bifurcations. By manipulating the racket, the actor becomes part of this dynamical system and can exploit its properties. Some regimes of the system offer rhythmic solutions with "passive stability", where perturbations converge back onto the attractor without requiring corrective control. Other regimes require active control on the part of actor. Establishing, maintaining, and tuning the regimes of active control rely upon multiple sources of perceptual information. One of the primary aims of this research is to better understand these two general regimes of coordination. The research will also establish national and international collaborations in which both senior investigators and graduate students will participate.