Perceptual independence of whole length, partial length, and hand position in wielding a rod.

Previous investigations of dynamic touch have shown that, in wielding an occluded rod, the nonvisible perceptions of total rod length, hand position, and fractional rod length above or below the hand are different functions of the eigenvalues and eigenvectors of the inertia tensor. The implication that the 3 perceptions are independent covariants of the inertia tensor of a wielded object was tested with the complete identification experimental procedure using the statistical prescriptions of F. G. Ashby and J. T. Townsend (1986). The confirmed independence is discussed in the context of the generalized psychological or perception-information hypothesis.