Collaborative Research: Coordination of Multi-Digit Forces During Grasping

大脑是如何与人体一起控制行为的？这个问题包含了许多对行为科学和认知科学至关重要的深层次问题。它们中的一些本质上更具哲理性(比如著名的笛卡尔二元论的心灵/身体问题)，而另一些则更机械。行为控制最普遍的机械问题之一通常被称为“自由度”问题。问题是，行动目标往往可以通过许多不同的行动路径来实现。为了说明这一点，想象一下拿起一杯咖啡的动作。健康的成年人认为这一行为是理所当然的，很容易，但从人类大脑和身体的角度来看，有很大的问题需要解决。问题是，躯干、手臂和手指有大量不同的轨迹，可能都足以完成举起杯子的任务。这个系统是如何如此高效、毫不费力地在众多可能性中做出选择的？在美国国家科学基金会的支持下，桑泰罗博士和戈登博士将对人类抓取行为进行一系列实验，以更好地理解行为控制的本质。实验将集中在手指的协调性上，以响应施加在手指上的力，同时保持握住物体并不让其滑动或倾斜的目标。先前的研究表明，抓握行为在一定程度上受到简化手指控制的倾向的支配，这有助于缓解自由度问题。然而，也有理由相信这种倾向本身就是一个复杂的现象，因为什么是简单的可能取决于抓取任务的特殊性。本合作研究项目的主要目的是研究抓取控制的任务依赖性。抓握是一项简单的实验室任务，用来更广泛地研究人类行为的显著灵活性和适应性。在这项研究项目中获得的知识也可能有助于开发更灵巧的机器人操作器，以及能够处理脆弱或危险物体的远程操作机械。

How does the brain work with the human body to control behavior? This question holds many deep issues that are central to the behavioral and cognitive sciences. Some of them are more philosophical in nature (like the famous mind/body problem of Cartesian dualism), while others are more mechanical. One of the most general mechanical issues with behavioral control is often referred to as the "degrees of freedom" problem. The problem is that action goals may very often be reached by many different paths of action. To illustrate, imagine the act of picking up a cup of coffee. Healthy adults take this act for granted as trivially easy, but from the perspective of the human brain and body, there is non-trivial problem to be solved. The problem is that there is a vast number of distinct trajectories of the torso, arms, and fingers that may all suffice to accomplish the task of lifting the cup. How does the system choose among the vast array of possibilities so efficiently and effortlessly?With support of the National Science Foundation, Dr. Santello and Dr. Gordon will conduct a series of experiments on human grasp behaviors to better understand the nature of behavioral control. The experiments will focus on the coordination of the fingers in response to the forces that are imposed upon them while maintaining the goal of holding an object and not allowing it to slip or tilt. Prior research suggests that grasping behaviors are governed in part by a tendency to simplify the control of the fingers, which helps to alleviate the degrees of freedom problem. However, there is also reason to believe that this tendency is itself a complex phenomenon because what is simple may depend on the particularities of the grasping task. The primary aim of this collaborative research project is to investigate the task-dependency of grasp control. Grasping serves as a simple laboratory task for more generally investigating the remarkably flexible and adaptive nature of human behavior. The knowledge to be gained in this research project may also inform the development of more dexterous robotic manipulators, as well as remotely operated machinery that is capable of handling fragile or dangerous objects.