Subjective Towers: Depth Relationships in Multilevel Subjective Contours

The perceived depth associated with subjective contours was studied with a three-level subjective contour configuration. An analysis of subjects' size judgments showed significant size-constancy scaling consistent with the prediction that subjects would perceive the various subjective surfaces as superimposed upon one another in depth. Direct depth estimations, however, showed only weak depth effects, easily reversed by conflicting depth cues, and observed with real, as well as subjective contours. The discrepant results point to the possibility of different functional depth cues for the two tasks. The order of tasks, indicative of priming, further suggested that depth processing may be secondary to pattern recognition rather than being causal in the formation of subjective contours.

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The Site of Size Constancy

Perception ◽

10.1068/p010111 ◽

1972 ◽

Vol 1 (1) ◽

pp. 111-119 ◽

Cited By ~ 17

Author(s):

C Blakemore ◽

E T Garner ◽

J A Sweet

Keyword(s):

Visual Cortex ◽

Spatial Frequency ◽

Neural Mechanism ◽

Angular Width ◽

Size Constancy ◽

Depth Cues ◽

Black And White ◽

Maximum Elevation ◽

Constancy Scaling ◽

High Contrast Grating

Under appropriate conditions, with good depth cues, the perception of the bar width or spatial frequency of a pattern of black and white stripes (a grating) shows excellent size constancy. Two gratings at different distances look similar in spatial frequency when the actual width, not the angular width, of their stripes is the same. Adaptation to a high-contrast grating causes a rise in the threshold contrast for detecting gratings of similar orientation and spatial frequency. This aftereffect transfers from one eye to the other, so it probably depends on binocular orientation-selective neurones in the visual cortex. With the adapting grating at three times the distance of the test grating the maximum elevation of threshold occurs for exactly the same angular spatial frequency as that of the adapting pattern. Therefore the neural mechanism for size-constancy scaling probably occurs after the visual cortex, perhaps in the inferotemporal cortex.

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Nonsymbolic-Magnitude Deficit in Adults With Developmental Dyscalculia: Evidence of Impaired Size Discrimination but Intact Size Constancy

Psychological Science ◽

10.1177/0956797621995204 ◽

2021 ◽

pp. 095679762199520

Author(s):

Nirit Fooks ◽

Bat-Sheva Hadad ◽

Orly Rubinsten

Keyword(s):

Size Constancy ◽

Size Discrimination ◽

Depth Cues ◽

Developmental Dyscalculia ◽

Core Deficit ◽

Depth Ordering

Although researchers have debated whether a core deficit of nonsymbolic representation of magnitude underlies developmental dyscalculia (DD), research has mostly focused on numerosity processing. We probed the possibility of a general magnitude deficit in individuals with DD and asked whether sensitivity to size varied in contexts of depth ordering and size constancy. We measured full psychometric functions in size-discrimination tasks in 12 participants with DD and 13 control participants. Results showed that although people with DD exhibited veridical perceived magnitude, their sensitivity to size was clearly impaired. In contrast, when objects were embedded in depth cues allowing size-constancy computations, participants with DD demonstrated typical sensitivity to size. These results demonstrate a deficit in the perceptual resolutions of magnitude in DD. At the same time, the finding of an intact size constancy suggests that when magnitude perception is facilitated by implicit mandatory computations of size constancy, this deficit is no longer evident.

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Susceptibility to the Müller-Lyer Illusion and its Relationship to Differences in Size Constancy

Quarterly Journal of Experimental Psychology ◽

10.1080/14640746608400008 ◽

1966 ◽

Vol 18 (1) ◽

pp. 63-72 ◽

Cited By ~ 6

Author(s):

Vernon Hamilton

Keyword(s):

Individual Differences ◽

Size Constancy ◽

Direct Test ◽

Perceptual Inference ◽

Lyer Illusion ◽

Perceptual Style ◽

Constancy Scaling

The hypothesis that susceptibility to the Müller-Lyer illusion is the result of normal constancy scaling, misapplied, was submitted to direct test. No significant correlations between illusion error and size constancy estimates were obtained. Also invalidated were hypotheses that under-constancy is correlated with non-susceptibility to the illusion, and that over-constancy is correlated with greater illusion error. The results suggest that an approach to the explanation of illusion effects by means of analysing individual differences in size constancy, in intelligence and preferred “perceptual style,” might be fruitful. Some tentative suggestions are made concerning the role of perceptual inference, abstraction and analysing.

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Size Constancy Scaling and the Apparent Thickness of the Shaft in the Mueller-Lyer Illusion

The Journal of General Psychology ◽

10.1080/00221309.1977.9920844 ◽

1977 ◽

Vol 97 (2) ◽

pp. 307-308 ◽

Cited By ~ 3

Author(s):

Gene Lester

Keyword(s):

Size Constancy ◽

Lyer Illusion ◽

Apparent Thickness ◽

Constancy Scaling

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The Ponzo Illusion: Inadequacy of Apparent Depth Explanations

Perceptual and Motor Skills ◽

10.2466/pms.1969.28.2.423 ◽

1969 ◽

Vol 28 (2) ◽

pp. 423-433

Author(s):

Robert L. Houck ◽

Roy B. Mefferd ◽

Betty A. Wieland

Keyword(s):

Ponzo Illusion ◽

Apparent Distance ◽

Apparent Size ◽

Vertical Line ◽

Apparent Depth ◽

Size Constancy ◽

Constancy Scaling ◽

Distance Relationship

Os viewing the Ponzo figure reported a series of sudden changes in its phenomenal organization and orientation. In none of these was the vertical line nearer the vertex of the figure reported to be smaller than the vertical line nearer the open end, i.e., the illusion occurred with all percepts except a rare one of a flat stimulus. In two of the most frequent and persistent percepts, the illusion could be explained on the basis of apparent size-apparent distance relationship among the elements. This was also the case with Gregory's theory of misapplied size-constancy scaling. However, with other percepts neither of these explanations was tenable.

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The Ponzo Illusion in Virtual Environments: Correctly Applied Size Constancy?

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/154193129604001106 ◽

1996 ◽

Vol 40 (11) ◽

pp. 551-554

Author(s):

Robert A. King ◽

Greg E. Fujawa ◽

Kelly G. Elliott

Keyword(s):

Effect Size ◽

Rating Scale ◽

Linear Trend ◽

Relative Size ◽

Ponzo Illusion ◽

Linear Perspective ◽

Size Constancy ◽

Relative Height ◽

Significant Linear Trend ◽

Depth Cues

The perceived size of a stimulus can be greatly influenced by the surrounding depth cues. The effect size of the Ponzo Illusion was tested in a virtual environment with many depth cues (MC) and few depth cues (FC) conditions. The effect of size and the depth cues on the perceived proximal size of the stimulus was measured. Methods. A modified Wheatstone stereoscope was used to present the stimuli on a monitor positioned 80 cm from the subjects. The subjects used a 6AFC confidence rating scale to indicate whether the first or second of two sequentially presented stimuli had a greater proximal extent. The ‘many cues’ (MC) condition included texture, relative height, foreshortening, linear perspective, relative brightness, and relative size. The few cues condition consisted of linear perspective, relative height, and relative size. Stimulus size (proximal extent) was varied independently from all other depth cues. Results. Both depth cue context and proximal size were found to have a significant effect on the perceived proximal size for FC conditions. However, for MC conditions only the depth cues, and not proximal size, had an effect on perceived proximal size. The effect size for both depth cues and proximal size had a significant linear trend. But proximal size had a larger trend that was significantly related to the size constancy function.

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Depth cues and constancy scaling in the horizontal-vertical illusion: The bisection error.

Canadian Journal of Psychology/Revue Canadienne de Psychologie ◽

10.1037/h0082021 ◽

1975 ◽

Vol 29 (1) ◽

pp. 59-65 ◽

Cited By ~ 35

Author(s):

Joan S. Girgus ◽

Stanley Coren

Keyword(s):

Depth Cues ◽

Constancy Scaling

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Subjective Contour: Apparent Depth or Simultaneous Brightness Contrast?

Perceptual and Motor Skills ◽

10.2466/pms.1974.38.3c.1047 ◽

1974 ◽

Vol 38 (3_suppl) ◽

pp. 1047-1053 ◽

Cited By ~ 75

Author(s):

Willard L. Brigner ◽

M. Brooks Gallagher

Keyword(s):

Subjective Contour ◽

Brightness Contrast ◽

Apparent Depth ◽

Two Dimensional ◽

Prior Work ◽

Depth Cues ◽

Simultaneous Brightness Contrast

The perceptibility of subjective contour in a two-dimensional configuration is shown to vary systematically with the magnitude of simultaneous brightness contrast. Since prior work had suggested depth cues as the basis for subjective contour, depth cues were maintained in all configurations. However, depth cues failed to sustain the perception of subjective contour with a reduction in simultaneous brightness contrast.

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A Size Illusion Based upon a Minimal Interposition Cue

Perception ◽

10.1068/p040251 ◽

1975 ◽

Vol 4 (3) ◽

pp. 251-254 ◽

Cited By ~ 4

Author(s):

Stanley Coren ◽

Joan S Girgus

Keyword(s):

Two Dimensional ◽

Dimensional Array ◽

Depth Cues ◽

Constancy Scaling

It has often been suggested that many visual geometric illusions are caused by inappropriate constancy scaling triggered by depth cues implicit in the two-dimensional array. A new size illusion based upon a minimal interposition cue is presented, which seems to support this contention. Asymmetries in the results suggest that the major component of the illusion is overestimation of apparently more distant targets rather than underestimation of apparently closer targets.

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