The haptic nervous system allows one to know about nearby objects and surfaces by means of contact with the body. Without having to look at an object, a person can get an impression of some of its properties by holding it and wielding it. This research conceptualizes the haptic subsystem in wielding as a measurement instrument which capitalizes smartly on lawful regularities, such as the constant pattern of the resistances of an object to rotations in different directions. The experiments will examine the haptic perception of object length, angular separation of components, orientations, and shape. They will do so for conditions where one object or two are held in the hand. People in the experiments will respond by adjusting (visible) movable surfaces or pointers to quantify the perceived properties. The experiments will attempt to identify the mechanical variables that relate uniquely to the perceived geometric properties of the hand-held objects, and to show that wielding must be done in a definite though complex way in order for a particular property to be perceived. Identifying these hand-related capabilities and their physical basis will help the design of sensory and motor prostheses, robotic limbs, and clever tools. Understanding the form and function of haptic perceptual instruments will advance the theory of special purposes cognitive mechanisms.
