Eye elevation and visual space in monocular regard.

Abstract

liighly junior high school studenls made monocular comparisons of standard and variable apertures through collimating lenses in a dark room. Placement of paired targets was varied in a vertical arc with 10 combinations of elevations at 10°, 30°, 50°, 70°, and 90° to the horizontal. When the standard was the lower target, size and distance discriminations were both distorted (p < .001) in a comparable illusory direction (lower target seen as larger and nearer). No illusion was obtained for size or distance discriminations when the standard target was in the upper position.

The anisotropy of perceived distance: The eyes story

“…He showed that the eye position shift affected perceived size and distance in binocular vision, in such a way, that, when the gaze was shifted towards the zenith, stimuli were being perceived as smaller and further. Also, the effect of the eye position shift was larger on perceived distance than on perceived size (Thor et al, 1970). All these findings show the importance of the kinesthetic information from eye muscles for perceived size and the Moon illusion.…”

Apparent size as a function of vertical gaze direction: New tests of an old hypothesis.

“…Even with large stimulus distances, which increase the size illusion (Schur, 1926; van de Geer & Zwaan, 1964), it became not even approximately as large as the normal moon illusion. Although Kaufman and Rock (1962) rejected a potential role for the angle of regard in the normal moon illusion, the size illusion under darkroom conditions or homogeneous-field conditions appears to be a fairly stable although small phenomenon (Baird, Gulick, & Smith; Hermans, 1954; Leibowitz & Hartmann, 1959; Thor, Winters, & Hoats, 1969, 1970).…”

“…There are at least two more objections to the more specific vergence-effort hypothesis. First, the size illusion has been found when the target stimuli were in monocular view (e.g., Schur, 1926; Thor et al, 1970), although it was also found to be smaller than with binocular view (van de Geer & Zwaan, 1964). When targets are viewed monocularly, vergence effort should play no role.…”

The moon illusion: Kaufman and Rock's (1962) apparent‐distance theory reconsidered1

“…In many experiments on the effect of eye elevation on apparent size, only negligible or limited effects were reported. Most of them, however, were conducted only under monocular viewing conditions (e.g., Gruber, King, & Link, 1963; Hermans, 1954; Thor, Winters, & Hoats, 1970). If they had adopted binocular ones, a larger effect of eye elevation would have been observed.…”