The Psychophysics of Form: Reversible-Perspective Drawings of Spatial Objects

Hochberg, Julian; Brooks,

doi:10.2307/1420172

Cited by 165 publications

(106 citation statements)

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“…This phenomenological observation has been a subject of a number of psychophysical experiments. These experiments showed that shape perception involves solving an optimization problem with the objective function containing measures of simplicity or compactness of the 3-D interpretation (Attneave & Frost, 1969;Hochberg & Brooks, 1960;Perkins, 1972;Pizlo & Scheessele, 1998). These simplicity and compactness constraints allowed a unique perceptual interpretation to be obtained from a single image.…”

Section: Discussionmentioning

confidence: 99%

Shape constancy from novel views

Pizlo

Stevenson

1999

Perception & Psychophysics

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Prior experiments on shape constancy from novel views are inconclusive: Some show that shapes of objects can be recognized reliably from novel views, whereas others show just the opposite. Our analysis of prior results suggests that shape constancy from novel views is reliable when the object has properties that constrain its shape: The object has volumetric primitives, it has surfaces, it is symmetrical, it is composed of geons, its contours are planar, and its images provide useful topological information about its three-dimensional structure. To test the role of some of these constraints, we performed a set of experiments. Solid shapes (polyhedra) were shown on a computer monitor by means of kinetic depth effect. Experiment 1 showed that shape constancy can be reliably achieved when a polyhedron is represented by its contours (most of the constraints are present), but not when it is represented by vertices or by a polygonal line connecting the vertices in a random order (all the constraints are absent). Experiments 2 and 3 tested the role of individual constraints. Results ofthese experiments show that shape constancy from novel views is reliable when the object has planar contours and when the shapes of the contours together with topological information about the relations among the contours constrain the possible interpretations of the shape. Symmetry of the object and the topological stability of its image also contribute to shape constancy.Shape constancy refers to the fact that the percept ofthe shape of a given object remains constant despite changes in the shape of the retinal image. The retinal image may change because of changes in the orientation of the object relative to the observer (see Pizlo, 1994, for a review of prior research on shape constancy). Consider an example of shape constancy. When you walk around your car, your retinal image of the car changes. Yet, your percept of the shape of the car is constant. One can argue that achieving shape constancy in the case of your car may represent a rather trivial accomplishment: After all, you have seen your car from almost all viewing directions, and, therefore, the constancy of the percept of the car's shape may simply involve matching ofthe current view with all previously seen views. To prevent the observer from matching familiar views (or images), one should use unfamiliar objects and test shape constancy from unfamiliar (novel) views. There have been a number of studies performed during the last decade that tested whether shape constancy can be reliably achieved from novel views. We will first briefly review the most representative results.Rock and DiVita (1987) used three-dimensional (3-0) wire objects as stimuli. Viewing was binocular with a This study was presented at the annual meetings of the Association for Research in Vision and Ophthalmology in 1997 and 1998. The authors thank the anonymous reviewers for their comments and suggestions, Moses Chan, Jan-Yuen Chen, Corrinne Lim, and Grant Wei who served as subjects, Filip J. Pizlo for his...

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Section: Discussionmentioning

confidence: 99%

Shape constancy from novel views

Pizlo

Stevenson

1999

Perception & Psychophysics

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“…Studies of the interpretation of visual form also indicate that the construction of 3-D space might be demanding. The 3-D interpretation of drawings can be effortful, and its ease is affected by cues such as shading (Hemenway and Palmer, 1978), and the number of line segments or angles in the 2-D rendition of the space (Attneave and Frost, 1969;Hochberg and Brooks, 1960). Such studies suggest that the perceptual interpretation of 3-D space requires more computation and maintenance than 2-D interpretations (Rock, 1983;Roth and Kosslyn, 1988).…”

Section: Academic Pressmentioning

confidence: 99%

Collaborative Activity between Parietal and Dorso-Lateral Prefrontal Cortex in Dynamic Spatial Working Memory Revealed by fMRI

2000

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Functional MRI was used to determine how the constituents of the cortical network subserving dynamic spatial working memory respond to two types of increases in task complexity. Participants mentally maintained the most recent location of either one or three objects as the three objects moved discretely in either a two-or three-dimensional array. Cortical activation in the dorsolateral prefrontal (DLPFC) and the parietal cortex increased as a function of the number of object locations to be maintained and the dimensionality of the display. An analysis of the response characteristics of the individual voxels showed that a large proportion were activated only when both the variables imposed the higher level of demand. A smaller proportion were activated specifically in response to increases in task demand associated with each of the independent variables. A second experiment revealed the same effect of dimensionality in the parietal cortex when the movement of objects was signaled auditorily rather than visually, indicating that the additional representational demands induced by 3-D space are independent of input modality. The comodulation of activation in the prefrontal and parietal areas by the amount of computational demand suggests that the collaboration between areas is a basic feature underlying much of the functionality of spatial working memory. © 2000 Academic Press Dealing with dynamic spatial activity is a ubiquitous element of human behavior. Behaviors as general as navigating in a new city, to as specialized as monitoring airplanes in an air traffic control center, often require the maintenance of spatial representations of varying dimensionality, and the updating of the locations of objects as they move in that space. The underlying space may be two-dimensional, as in the case of navigating in a city in which the constraints are largely specified by relations on a two-dimensional map. Alternatively, the space may be a more demanding threedimensional one, as in the case of air traffic control, which adds the dimension of altitude. The demands imposed by keeping track of the locations of objects may also vary from tracking a single object to tracking multiple objects. Mentally updating the locations of targets, maintaining active representations of those locations and of the space, and coordinating these computations are all component processes in spatial working memory. Demands on the spatial working memory system could be imposed by each of these components and through their interplay during a task.A shared facet of several imaging studies of spatial working memory is that they have used maintenance tasks to identify cortical regions involved in memory for spatial location Courtney et al., 1996;Jonides et al., 1993;Smith et al., 1995). However, maintaining information regarding location is only one of several component processes in spatial working memory. Simple maintenance tasks may not necessarily engage the full range of capabilities of the system and consequently may not sufficiently reveal patte...

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“…Consider the four projections of a cube in Figure 1. Hochberg and Brooks (1960) devised 17 different measures of simplicity to be applied to such drawings. The relative simplicity of the bidimensional shapes to one another and the relation of the measured simplicity of these shapes to that of the tridimensional cube vary depending upon the measure adopted.…”

Section: Choice Of Simplicity Metricmentioning

confidence: 99%

“…Although Hochberg and Brooks (1960) conveniently make our point for us by supplying alternative metrics, the point can be made with regard to any metric of simplicity. Thus, in the recent application of coding theory by Buffart et al (1981) in assessing the simplicity of figural completions, it is clear that metrics other than those used by the authors could be proposed.…”

Section: Choice Of Simplicity Metricmentioning

confidence: 99%