ABSTRACT
This article is concerned with the principles that describe the behavior in some of the human’s simplest movements, discovered and refined over the past 50 years or so. Such actions might involve one-directional hand movements to a target, where the action is brief and usually rapidly done. The principles discussed here are those that define the relationships among various manipulable or measurable features in these actions, such as the movement’s duration, the distance moved, the loads applied, the type of load (friction, mass, etc.), and the accuracy demands in achieving a target. Understanding these simple actions is probably fundamental for understanding more complex actions, assuming that more complex actions are in some sense “built” out of simpler ones. We can conceptualize these principles of simple movement as analogous to the laws of Newtonian physics (e.g. the relations among force, velocity, time, etc.) in movements of a mass, which form the cornerstone for understanding more complex mechanical devices (e.g. automobiles).
