Perceiving the Orientation-In-Depth of Triangular Surfaces: Static-Monocular, Moving-Monocular, and Static-Binocular Viewing

Abstract

Although data from simulations suggest that motion information and binocular information each elicit veridical depth perception, data from real stimuli, such as trapezoidal surfaces, are equivocal; the discrepancy might be explained by the complexity of nonveridical pictorial information in the latter. In the present study, observers judged the orientations-in-depth of triangular surfaces about a vertical axis: Pictorial information resided only in the visual lengths of surfaces, so it was predicted that motion and binocularity would be fully effective. Viewing conditions were static-monocular (SM), moving-monocular (MM), and static-binocular (SB). SM judgments were largely frontal, reflecting the equidistance tendency that applies in impoverished conditions. SB judgments were broadly veridical, as predicted. However, MM judgments were only partly influenced by motion information; the equidistance tendency and visual length also contributed--the latter in contrast to SM. It is concluded that motion information is only weakly effective, no matter what the complexity of pictorial information. Instead, motion may be valuable in enhancing pictorial information.

The Framing Effect with Rectangular and Trapezoidal Surfaces: Actual and Pictorial Surface Slant, Frame Orientation, and Viewing Condition

“…It is possible that the framing effect is diminished during more informative viewing. This would be consistent with a link between the framing effect and the specific-distance and equidistance tendencies: the two latter phenomena are known to be strongest in the most restricted viewing conditions (Foley 1977;Gogel 1956;Reinhardt-Rutland 1996a, 1996b. In the present experiment, observers viewed monocularly while making side-to-side head motions of 30 cm extent to introduce the depth cue of motion parallax.…”

“…Impoverished viewing conditions and competition in depth information are pertinent to the present experiments. The equidistance and specific-distance tendencies are at their most potent when viewing is stationary-monocular; like the framing effect in the present experiment 3, the equidistance and specific-distance tendencies are weakened by more informative viewing conditions (Foley 1977;Gogel 1956;Reinhardt-Rutland 1996a, 1996b. The equidistance tendency is also at its most potent when pictorial depth information competes with actual depth, as is demonstrated in judging the separation-indepth of discrete objects in which the pictorial depth cue of visual size is manipulated (Eriksson 1972); this is consistent with each of the present experiments.…”

“…That the framing effect elicits results that compare with those of the equidistance and specific-distance tendencies (Foley 1977;Gogel 1956Gogel , 1965Gogel , 1969Reinhardt-Rutland 1996a, 1996b argues that the various phenomena are related öa general frontal-plane tendency can be invoked. The various phenomena can be understood as reflecting the high experimental demands in depth perception entailed by impoverished scene and viewing conditions, by competition in depth information, and by choice of procedure.…”

“…Eby and Braunstein (1995) have identified a framing effect: the perceived slant of the surface is reduced by the presence of the frame. Eby and Braunstein's surfaces were triangular, butöin contrast to Reinhardt-Rutland (1996a, 1996b öthey conveyed appreciable pictorial information: surfaces were patterned with equally spaced horizontal or vertical stripes, and the visual angle of the bottom edge of the surface depended on surface orientation. Viewing was stationary-monocular, with the frameörectangular in form and in a frontal plane övisible on half the trials.…”