Todorov E, Shadmehr R, Bizzi E
a Massachusetts Institute of Technology.
b Johns Hopkins University.
J Mot Behav. 1997 Jun;29(2):147-58. doi: 10.1080/00222899709600829.
One can use a number of techniques (e.g., from videotaping to computer enhancement of the environment) to augment the feedback that a subject usually receives during training on a motor task. Although some forms of augmented feedback have been shown to enhance performance on isolated isometric tasks during training, when the feedback has been removed subjects have sometimes not been able to perform as well in the "real-world" task as controls. Indeed, for realistic, nonisometric motor tasks, improved skill acquisition because of augmented feedback has not been demonstrated. In the present experiments, subjects (Experiment 1, N = 42; Experiment 2, N = 21) performed with a system that was designed for teaching a difficult multijoint movement in a table tennis environment. The system was a fairly realistic computer animation of the environment and included paddles for the teacher and subject, as well as a virtual ball. Each subject attempted to learn a difficult shot by matching the pattern of movements of the expert teacher. Augmented feedback focused the attention of the subject on a minimum set of movement details that were most relevant to the task; feedback was presented in a form that required the least perceptual processing. Effectiveness of training was determined by measuring their performance in the real task. Subjects who received the virtual environment training performed significantly better than subjects who received a comparable amount of real-task practice or coaching. Kinematic analysis indicated that practice with the expert's trajectory served as a basis for performance on the real-world task and that the movements executed after training were subject-specific modifications of the expert's trajectory. Practice with this trajectory alone was not sufficient for transfer to the real task, however: When a critical component of the virtual environment was removed, subjects showed no transfer to the real task.
人们可以使用多种技术（例如，从录像到计算机对环境的增强）来增加受试者在运动任务训练期间通常所获得的反馈。尽管某些形式的增强反馈已被证明可在训练期间提高孤立等长任务的表现，但当去除反馈后，受试者有时在“现实世界”任务中的表现不如对照组。实际上，对于现实的、非等长的运动任务，尚未证明增强反馈能改善技能习得。在本实验中，受试者（实验1，N = 42；实验2，N = 21）使用一个为在乒乓球环境中教授困难的多关节运动而设计的系统进行操作。该系统是对环境相当逼真的计算机动画，包括教师和受试者的球拍以及一个虚拟球。每个受试者试图通过匹配专家教师的运动模式来学习一个困难的击球动作。增强反馈将受试者的注意力集中在与任务最相关的最少一组运动细节上；反馈以需要最少感知处理的形式呈现。通过测量他们在实际任务中的表现来确定训练的有效性。接受虚拟环境训练的受试者的表现明显优于接受等量实际任务练习或指导的受试者。运动学分析表明，与专家轨迹的练习是在现实世界任务中表现的基础，并且训练后执行的动作是专家轨迹的特定于受试者的修改。然而，仅使用此轨迹进行练习不足以转移到实际任务：当虚拟环境的一个关键组件被移除时，受试者没有表现出向实际任务的转移。
