VISUALLY PERCEIVED LOCATION IS AN INVARIANT IN THE CONTROL OF ACTION

We provide experimental evidence that perceived location is an invaria nt in the control of action, by showing that different actions are dir ected toward a single visually specified location in space (correspond ing to the putative perceived location) and that this single location, although specified by a fixed physical target, varies with the availa bility of information about the distance of that target. Observers in two conditions varying in the availability of egocentric distance cues viewed targets at 1.5, 3.1, or 6.0 m and then attempted to walk to th e target with eyes closed using one of three paths; the path was not s pecified until after vision was occluded. The observers stopped at abo ut the same location regardless of the path taken, providing evidence that action was being controlled by some invariant, ostensibly visuall y perceived location. That it was indeed perceived location was indica ted by the manipulation of information about target distance-the traje ctories in the full-cues condition converged near the physical target locations, whereas those in the reduced-cues condition converged at lo cations consistent with the usual perceptual errors found when distanc e cues are impoverished.