In the absence of vision, environmental properties must still be perceived in order that activity can be guided effectively. How are properties such as size, shape, distance, orientation, and so on revealed in the tissue deformations that ac company wielding an object with the hand or exploring with a hand-held object such as a cane? How are muscular forces and reactive forces, both of which are time-dependent, coupled? The inertia tensor, a time-invariant quantity, has been shown to underlie perception of a variety of properties by dynamic touch. Experiments involving tensor manipulations reveal which properties ought to be perceivable by touch, which ought to be confused, and how the relevant information compares to that available to vision and hearing.

In addition to the perception of properties of hand-held objects, recent research has focused upon awareness of one's own body. The eigenvectors of the inertia tensor, rather than joint angles or gravitational torque, have been shown to underly the perception of limb orientation. Research currently being conducted and planned for the future will examine how multijoint movement trajectories are affected by manip ulations of the arm's mass distribution.

Faculty: Claudia Carello, Jeff Kinsella-Shaw, Claire Michaels, Michael Turvey

CESPA Fellows: Paula Fitzpatrick

Graduate Students: Steve Harrison, Robert Isenhower

Amazeen, E., & Turvey, M. T. (1996). Weight perception and the haptic size-weight illusion are functions of the inertia tensor. Journal of Experimental Psychology: Human Perception and Performance, 22, 213-232.

Carello, C., Santana, M-V., & Burton, G. (1996). Sele ctive attention by dynamic touch. Perception & Psychophysics, 58, 1177-1190.

Garrett, S., Pagano, C., Austin, G., & Turvey, M. T. (1998). Spatial and physical frames of reference in positioning a limb. Perception & Psychophysics, 60, 1206-1215.

Turvey, M. T. (1996). Dynamic touch. American Psychologist, 51, 1134-1152.

Turvey, M. T. (1998). Dynamics of effortful touch and interlimb coordination. Journal of Biomechanics, 31, 873-882.

Carello, C., Thuot, S., Anderson, K. L., & Turvey, M. T. (1999). Perceiving the sweet spot. Perception.

Cooper, M., Carello, C., & Turvey, M. T. (2000). Perceptual independence of whole length, partial length, and hand position in wielding a rod. Journal of Experimental Psychology: Human Perception and Performance, 26.