2 experiments were conducted to determine the generality of the finding by Stavrianos (1945) that judged slant of plane rectangular figures varies directly with size. In Experiment I, equal-slant contours were obtained from 54 undergraduate Ss for 14 rectangles whose lengths varied in equal log steps from 1.0 to 42.2 cm. with a reference stimulus of 7.5 cm. In Experiment II, 72 Ss were tested o...

We investigate temporal aspects of binocular slant perception in the presence and absence of a visual reference. Subjects judge slant induced by large-field stereograms of which one half-image is either horizontally scaled or sheared relative to the other half-image. Each stimulus is presented for different observation periods ranging from 0.1 to 19.2 sec. We quantitatively corroborate earlier ...

What do infants learn when they learn to sit upright? We tested behavioral flexibility in learning to sit-the ability to adapt posture to changes in the environment-in 6- to 9-month-old infants sitting on forward and backward slopes. Infants began with slant at 0°; then slant increased in 2° increments until infants lost balance. Infants kept balance on impressively steep slopes, especially in ...

Weighted averaging is said to be optimal when the weights assigned to the cues minimize the variance of the final estimate. Since the variance of this optimal percept only depends on the variances of the individual cues, irrespective of their values, judgments about a cue conflict stimulus should have the same variance as ones about a cue consistent stimulus. We tested this counter-intuitive pr...

Slant is the degree to which a surface recedes or slopes away from the observer about the horizontal axis. The perception of surface slant may be derived from static monocular cues, including linear perspective and foreshortening, applied to single shapes or to multi-element textures. It is still unclear the extent to which color vision can use these cues to determine slant in the absence of ac...

Consider a stereoscopic display simulating two rectangular patches, the lower frontoparallel and the upper slanted around the vertical axis. When the two patches are amodally completed and appear as the unoccluded parts of a smooth surface partially hidden by a foreground frontoparallel surface, either real or illusory, their relative slant is underestimated with respect to a baseline condition...

Observers viewed large dichoptic patterns undergoing smooth temporal modulations or step changes in simulated slant or inclination under various conditions of disparity-perspective cue conflict and concordance. After presentation of each test surface, subjects adjusted a comparison surface to match the perceived slant or inclination of the test surface. Addition of conflicting perspective to di...