Perceiving Surface Orientation: Pictorial Information Based on Rectangularity Can Be Overriden during Observer Motion

Abstract

Although the observer's motion can elicit perception of relative depth, it is less successful in doing so when competing pictorial information is available. However, the evidence for this may be affected by limited extents of motion and by equidistance tendencies. Results obtained when monocular observers judged the orientation-in-depth of trapezoidal and of rectangular surfaces, during lateral head motion of extents 0 cm to 30 cm, are described. When the motion extent was less than 30 cm, trapezoidal surfaces were misperceived because they were interpreted as rectangular; this pictorial information was overriden only when the motion extent was 30 cm. The results may reflect the sequential nature of motion information and the redundancy of information in normal viewing: pictorial information may take precedence when motion is limited, but motion information can be indefinitely augmented. Comments are directed to: (i) the use of Ames 'distorted rooms' in this area of research, and (ii) the 'ecological' interpretation of pictorial information.

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

“…A judgment in minutes of analog time, used in earlier studies by Reinhardt-Rutland (1990, 1993b, is more automatic than a judgment in degrees of angle, used in the present study, a fact consistent with the assertion that the equidistance tendency is a product of information processing not directly concerned with sensory input. By extrapolation, it can be concluded that the nonautomaticity of verbal judgments of distance contributes to the equidistance tendency concerning discrete objects (Eriksson, I972c, 1974;Foley, 1977;Gogel, 1969;Gogel & Teitz, 1973), a result with clear implications for several studies in which the equidistance tendency was not explicitly isolated (Eriksson, 1972a(Eriksson, , 1972bGehringer & Engel, 1986;Hell, 1978;Hell & Freeman, 1977).…”

“…Again in contrast with the present study, Reinhardt-Rutland (1990) reported no evidence for the equidistance tendency, because pictorial orientation had no significant effect on difference scores; he found similar results for monocular data considered alone and binocular data considered alone. Additionally, the equidistance tendency was not reported by Reinhardt-Rutland (1993b). Although 15-cm motion was not employed in that study, 20-cm motion had a significant effect on difference scores.…”

“…Because, as in previous studies (Reinhardt-Rutland, 1990, 1993b, pictorial and true orientations balanced, analysis of variance of the raw data would not be easy to interpret. To overcome this problem, I computed difference scores for pairs of stimuli matched in pictorial orientation.…”

“…The equidistance tendency has a greater effect in monocular viewing than it does in binocular viewing (Foley, 1977;Gogel, 1956), and it affects nonveridical pictorial information more than it does veridical pictorial information (Eriksson, 1972c). Despite the attenuated display conditions in his experiments with surfaces (no background pattern was present), Reinhardt-Rutland (1990, 1993b reported no significant evidence for the equidistance tendency in any viewing condition. Attenuation of depth information may trigger the equidistance tendency, but it cannot otherwise explain the phenomenon.…”

Where's the Floor?

“…Under natural circumstances, cues that were not available in our rather sparse, static displays are also likely to play a role in the selection of a support surface. For example, when an observer is moving, motion parallax plays a role in defining the perceived orientation of a surface (Reinhardt-Rutland, 1993;Louw et al, 2007). However, this is likely to be a small factor.…”