Verbal Judgments of a Surface's Orientation-In-Depth in Degrees of Angle: Equidistance Tendency, Motion Ineffectiveness, and Automaticity

1999

Perception

The perceived slant of a surface relative to the frontal plane can be reduced when the surface is viewed through a frame between the observer and the surface. Aspects of this framing effect were investigated in three experiments in which observers judged the orientations-in-depth of rectangular and trapezoidal surfaces which were matched for pictorial depth. In experiments 1 and 2, viewing was stationary-monocular. In experiment 1, a frontal rectangular frame was present or absent during viewing. The perceived slants of the surfaces were reduced in the presence of the frame; the reduction for the trapezoidal surface was greater, suggesting that conflict in stimulus information contributes to the phenomenon. In experiment 2, the rectangular frame was either frontal or slanted; in a third condition, a frame was trapezoidal and frontal. The conditions all elicited similar results, suggesting that the framing effect is not explained by pictorial perception of the display, or by assimilation of the surface orientation to the frame orientation. In experiment 3, viewing was moving-monocular to introduce motion parallax; the framing effect was reduced, being appreciable only for a trapezoidal surface. The results are related to other phenomena in which depth perception of points in space tends towards a frontal plane; this frontal-plane tendency is attributed to heavy experimental demands, mainly concerning impoverished, conflicting, and distracting information.

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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

1999

Perception

Depth Judgments of Triangular Surfaces during Moving Monocular Viewing

1996

Perception

When an observer judges the orientation in depth of a trapezoidal surface, the pictorial information of the surface is often more influential than motion information. Motion information might be more effective if pictorial information is simplified: this prompts the present study. Surfaces were triangular and pictorial information resided only in the visual lengths of the surfaces. In experiment 1, monocular observers viewed during head motions of 0 to 30 cm extent. Static judgments were somewhat dependent on visual length and tended to be frontal. Contrary to predictions, moving judgments were similarly affected: only 30 cm motion elicited near-veridical perception, as in previous studies with trapezoidal surfaces, although visual length had a residual effect. Experiment 2 involved investigation of whether visual length requires prior exposure to triangular surfaces to be effective; this was found not to be the case, which argues that observers rely on internal models of triangular surfaces. Depth perception appears to balance rapidity of processing against accuracy, in a way suggesting that 'direct' approaches are incomplete. Finally, it is argued that depth-from-motion simulations-influential in assertions that motion information is fully effective-depend on pictorial information.

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

The Journal of General Psychology

1996

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.