Some conditions sufficient for accurate monocular perceptions of moving surface slants.

Abstract

246 Ss monocularly judged from 1 to 9 different slants of a surface whose edges were occluded from view. In a reference experiment surface texture was irregular, unfamiliar, and continuously moving, viewed through a 69[degree] aperture. Then the mean regression coefficient for 16 Ss'' slant judgments over 9 physical slants was .96, a coefficient of 1.0 signifying an identity relation. Doubling and halving velocity, substituting regular or different irregular textures, changing amount of exposure to the displays did not significantly alter the results[long dash]the coefficients varying from .85 to 1.12. Absence of motion, a texture of l/2-in. squares, and changing field of view over a series of 4 physical slants alone produced different results. Dependence of slant on shape judgments was also tested. Shape judgments varied positively with retinal shapes rather than with slant judgments. Individual data were evaluated.