Can shape be perceived by dynamic touch?

Abstract

The possibility that some aspects of the shapes of solid objects can be perceived through dynamic touch, even when the objects are not touched, but simply wielded with a handle, was investigated in four experiments. Wooden solids were constructed of three sizes and five shapes: hemisphere, cylinder, parallelepiped, cone, and pyramid. Experiments 1 and 2 involved comparisons (judgments of same or different) between and among wielded objects of the same mass. In Experiments 3 and 4, subjects were required to wield an object and to select a match from a visible arrangement of objects of the five shapes; the wielded objects were of two sizes, each different from that of the visible objects. The success of subjects at these tasks, and the patternings of errors, are seen to involve the characteristic moment of inertia profiles of each shape, and a ratio of the object's resistances to rotation around orthogonal axes is shown to be a strong predictor of performance in the identification experiments. The results are discussed with reference to dynamic touch and to the notion of shape invariants that do not reduce to aspects of object surface.Existing research on nonvisual perception of object shape (e.g., J.

Perceiving the width and height of a hand-held object by dynamic touch.

“…Mathematically speaking, shape is a geometrical structure invariant over isometrics (i.e., orientation and position) and homotheities (i.e., scalings; Koenderink, 1990). Burton, Turvey, and Solomon (1990) suggested a definition of tangible shapetangible, that is, in the manner of dynamic touch-in terms of the largest and smallest elements of I k . The ratio 7i/7 3 would be independent of coordinate system and unaffected by scale.…”

Transfer of Calibration Between Length and Sweet-Spot Perception by Dynamic Touch

“…This paradigm is convenient for several reasons. First, using the dynamic touch system, one is capable of perceiving several properties of the hand-held object: length (e.g., Solomon & Turvey, 1988), heaviness (e.g., Amazeen & Turvey, 1996), center of percussion (e.g., Carello, Thuot, Anderson, & Turvey, 1999;Carello, Thuot, & Turvey, 2000), shape (Burton, Turvey, & Solomon, 1990), and width and height (e.g., Turvey, Burton, Amazeen, Butwill, & Carello, 1998). Second, dynamic touch needs to be calibrated.…”

Eigenvectors of the inertia tensor and perceiving the orientation of a hand-held object by dynamic touch

“…Moments of inertia constitute the relevant independent quantity in perceiving by wielding the lengths of rods or rod segments that cannot be seen rather than other potentially relevant quantities such as mass, center of mass, center of oscillation, average torque, and average kinetic energy Pagano & Turvey, in press;Solomon & Turvey, 1988;Solomon, Turvey, & Burton, 1989a, 1989bTurvey, Solomon, & Burton, 1989). Moments of inertia also seem to underlie the perception of the shapes of wielded objects hidden from view (Burton, Turvey, & Solomon, 1990). Moments and products of inertia together have been found to affect the perceived orientation, with respect to the hand, of occluded objects consisting of a stem and a branch perpendicular to the stem (Turvey, Burton, Pagano, Solomon, & Runeson, 1992).…”