COMPARISON OF OCULOMOTOR AND MOTION PARALLAX CUES OF EGOCENTRIC DISTANCE

Using the head motion procedure, the apparent distance of a point of light in an otherwise dark visual field was measured under conditions in which oculomotor cues (accommodation, convergence) and absolute motion parallax were varied together and separately. It was concluded that absolute motion parallax is almost as effective a cue to distance as are oculomotor cues from monocular observation, but is not as effective as oculomotor cues from binocular observation. Evidence was also presented that the null adjustment method, used in conjunction with the head motion procedure, provides an unbiased measure of apparent distance. © 1979.