Dynamic Touch in Varying Media and for Proprioception

Abstract

The perception of actively manipulated objects via muscle sensitivity has been referred to as ‘dynamic touch.’ Recent research has indicated that the perception of various properties of occluded objects by dynamic touch is a function of the object's resistances to angular rotation, as quantified by the inertia tensor. Additional findings have generalized this hypothesis to the proprioception of occluded limbs. It is suggested that the mechanisms supporting the perception of intact limbs, prosthetic devices, and hand held tools and implements via dynamic touch may be one and the same—the detection of movement-produced physical invariants such as the inertia tensor. Research will also be presented showing that the kinesthetic perception of the length of occluded objects remains unchanged when wielding occurs in air or water. This demonstrates that the constancy of perception can be derived from the invariant nature of physical stimulation available to the perceiver, as Gibson (1966) hypothesized. Implications of this work for the design of hand-held tools and attachments to the body are discussed.