Dynamics of Action and Perception in a Rhythmic Task

人类的所有行为都需要演员和环境之间的持续互动。这种相互作用需要高度的协调，而且往往是在极其复杂的条件下进行的，我们才刚刚开始了解如何实现这种协调。Sternad将研究感知运动任务的表现，其中演员和环境的复杂协调在适合研究的范式中被提炼出来。 这项任务是用球拍有节奏地拍球。在这项任务中，演员必须不断协调球拍的运动与球的运动，其轨迹反过来又由演员决定。这项任务的优点是，所得到的球-球拍系统遵守众所周知的物理原理。 此外，由于是一个可定义的非线性动力系统，它显示的特点，如稳定性和分叉。通过操纵球拍，演员成为这个动力系统的一部分，并可以利用它的属性。系统的某些制度提供了具有“被动稳定性”的节奏解决方案，其中扰动收敛回吸引子而无需校正控制。其他制度要求行为者进行主动控制。建立，维持和调整的制度，主动控制依赖于多个来源的感知信息。本研究的主要目的之一是更好地了解这两个一般制度的协调。该研究还将建立国家和国际合作，高级研究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.