DEPTH INTERACTIONS BETWEEN INCLINED AND SLANTED SURFACES IN VERTICAL AND HORIZONTAL ORIENTATIONS

Depth interactions between a frontal test surface and an adjacent indu ction surface were measured as a function of the type of disparity in the induction surface and of the vertical/horizontal orientation of th e boundary between the surfaces. The types of disparity were 4 degrees horizontal-shear disparity, 4 degrees vertical-shear disparity, and 4 degrees rotation disparity; 4% horizontal-size disparity, 4% vertical -size disparity, and 4% overall-size disparity. Depth contrast in a fr ontal surface was produced by surfaces containing horizontal-size disp arity but not by those containing horizontal-shear disparity. Vertical -shear and vertical-size disparities produced induced effects in both the induction and the test surface, which is here explained in terms o f deformation-disparity processing. Effects of rotation disparity on t he test surface can be accounted for in terms of cyclovergence, deform ation disparity, and perhaps also depth contrast. The fact that horizo ntal-size disparity produced more depth contrast than horizontal-shear disparity is due to an anisotropy of disparity processing rather than the relative orientation of the surfaces. Ground surfaces appeared mo re slanted than ceiling surfaces. Surfaces containing horizontal dispa rities produced a sharp boundary with the test surface because horizon tal disparities are processed locally. Surfaces with vertical disparit ies produced a gradual boundary with the test surface because vertical disparities are processed over a wider area.