Berkeleian Principles in Ecological Realism: An Ontological Analysis

Three experiments are reported, which examined the relation between the percep- tion of the distance reachable with a hand-held rod that can be wielded but not seen and the rod's resistance to having its rotational speed changed by application of a torque. In these experiments, subjects wielded any given rod about an axis intermediate between its endpoints. The subject's task was to adjust a visible, movable surface to coincide with where he or she could reach with the given rod if allowed to hold it at its proximal end. Two experiments considered the effects of wielding a rod at different orientations to the pull of gravity. Rods were wielded either within a plane roughly perpendicular to the ground or within a plane roughly parallel to the ground. Plane of wielding did not affect the patterning of perceived reachable distances as a function of the various conditions, which included variations in the positioning of grasp and the positioning of a mass affixed to the rods. The patterning of the moments of inertia associated with the various conditions determined the patterning of perceived reachable distances. The third experiment restricted wielding to a plane roughly parallel to the ground and varied how the rods were grasped, either overhand or underhand. The variation in grasp amounted to a variation in the neuromuscular patterning associated with the wielding of any given rod. Perceived reachable distances proved to be indifferent to the overhand versus underhand contrast.