Visually perceived location is an invariant in the control of action.
We provide experimental evidence that perceived location is an invariant in the control of action, by showing that different actions are directed toward a single visually specified location in space (corresponding to the putative perceived location) and that this single location, although specified by a fixed physical target, varies with the availability 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 the target with eyes closed using one of three paths; the path was not specified until after vision was occluded. The observers stopped at about the same location regardless of the path taken, providing evidence that action was being controlled by some invariant, ostensibly visually perceived location. That it was indeed perceived location was indicated by the manipulation of information about target distance--the trajectories in the full-cues condition converged near the physical target locations, whereas those in the reduced-cues condition converged at locations consistent with the usual perceptual errors found when distance cues are impoverished.
Philbeck
J W
JW
Department of Psychology, University of California, Santa Barbara 93106-9660, USA. philbeck@psych.ucsb.edu
Loomis
J M
JM
Beall
A C
AC
D000328:Adult; D003674:Defense Mechanisms; D004215:Distance Perception; D005260:Female; D006801:Humans; D008124:Locomotion; D008297:Male; D008875:Middle Aged; D009949:Orientation; D010364:Pattern Recognition, Visual; D011597:Psychomotor Performance; D012683:Sensory Deprivation