Skewed symmetry: A nonaccidental property used to perceive visual forms.

Wagemans, Johan

doi:10.1037/0096-1523.19.2.364

Cited by 87 publications

(88 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, when a symmetrical pattern is tilted relative to the frontal plane, its features in the image projected to the retinae are no longer symmetrical. Nonetheless, the detection advantage seems to be robust even in these cases of skewed symmetry although it is clearest if symmetry is present in several axes Wagemans, 1993). However, not all symmetries are equal.…”

Section: Symmetrymentioning

confidence: 99%

Traditional and New Principles of Perceptual Grouping

Brooks

2014

Oxford Handbooks Online

View full text Add to dashboard Cite

Perceptual grouping refers to the process of determining which regions and parts of the visual scene belong together as parts of higher order perceptual units such as objects or patterns. In the early 20 th century, Gestalt psychologists identified a set of classic grouping principles which specified how some image features lead to grouping between elements given that all other factors were held constant. Modern vision scientists have expanded this list to cover a wide range of image features but have also expanded the importance of learning and other non-image factors. Unlike early Gestalt accounts which were based largely on visual demonstrations, modern theories are often explicitly quantitative and involve detailed models of how various image features modulate grouping. Work has also been done to understand the rules by which different grouping principles integrate to form a final percept. This chapter gives an overview of the classic principles, modern developments in understanding them, and new principles and the evidence for them. There is also discussion of some of the larger theoretical issues about grouping such as at what stage of visual processing it occurs and what types of neural mechanisms may implement grouping principles.

show abstract

Section: Symmetrymentioning

confidence: 99%

Traditional and New Principles of Perceptual Grouping

Brooks

2014

Oxford Handbooks Online

View full text Add to dashboard Cite

show abstract

“…, 1992, but this result may be partly due to the particular experimental conditions (dot patterns with affine skewing). Casual observations with polygons (Stevens, 1980), as well as a few experimental results (Wagemans, 1993), suggest that polygons (which are more representative for object contours than dot patterns) may be less affected by skewing. Surface contours embedded in 3-D objects may even be less affected, as seems to be implied by our recent finding that the skewed symmetry of top and side surfaces of cubes affects the perceived global object structure (Van Lier & Wagemans, in press).…”

Section: Evolutionary Considerations •mentioning

confidence: 99%

Toward a better approach to goodness: Comments on Van der Helm and Leeuwenberg (1996).

Wagemans

1999

Psychological Review

Self Cite

View full text Add to dashboard Cite

Some resularities are more salient to the visual system than others. P. A. van der Helm and E. L. J. Leeuwenberg (1996) have proposed a new approach that quantifies the goodness of a pattern's regularity as the number of holographic identities constituting the regulartiy, relative to the total amount of information needed to describe the pattern. This holographic approach to goodness was compared with previous approaches and was presented in relation to metatheoretical issues. Tnese 3 aspects are discussed further here. First, the theory is shown to contain implausible assumptions and unfortunate gaps with respect to the required processing. Second, Van der Helm and Lseuwenberg's critique on preceding theories is refuted. Third, some metatheorerical issues need to be qualified or at least clarified. Together, these concerns suggest that a better approach to goodness might result from a synthesis of the most useful aspects of diverse theories of goodness. I would like to acknowledge the useful discussions with Rob Van Lier, who acted as the perfect sounding board for my view on structural information theory. I am also grateful to Julian Hochberg, Stephen Palmer, and Peter van der Helm, and two anonymous reviewers for their comments on a draft. This article was written with support from Grants G.

show abstract

“…Also, if the point pattern happened to have two points close together or three points almost collinear, this property was easy to verify for the other pattern: If it was also present, participants tended to respond same; if it was not, they tended to respond different (likewise for parallel configurations). Convexity, proximity, coUinearity, and parallelism are referred to as qualitative invariants (or nonaccidental properties; see Biederman, 1987;Lowe, 1987;Wagemans, 1992Wagemans, , 1993to distinguish them from the numerical invariants discussed in the preceding section. This notion may be clarified by considering the properties of convexity/concavity, parallelism, and collinearity in turn.…”

Section: Qualitatively Invariant and Quasi-lnvariant Propertiesmentioning

confidence: 99%

Minimal information to determine affine shape equivalence.

Wagemans¹,

Gool²,

Troy³

et al. 2000

Journal of Experimental Psychology: Human Perception and Perfor

Self Cite

View full text Add to dashboard Cite

Participants judged the affine equivalence of 2 simultaneously presented 4-point patterns. Performance level (d') varied between 1.5 and 2.7, depending on the information available for solving the correspondence problem (insufficient in Experiment 1a, superfluous in Experiment 1b, and minimal in Experiments 1c, 2a, 2b) and on the exposure time (unlimited in Experiments 1 and 2a and 500 ms in Experiment 2b), but it did not vary much with the complexity of the affine transformation (rotation and slant in Experiment 1 and same plus tilt in Experiment 2). Performance in Experiment 3 was lower with 3-point patterns than with 4-point patterns, whereas blocking the trials according to the affine transformation parameters had little effect. Determining affine shape equivalence with minimal-information displays is based on a fast assessment of qualitatively or quasi-invariant properties such as convexity/ concavity, parallelism, and collinearity.

show abstract

Skewed symmetry: A nonaccidental property used to perceive visual forms.

Cited by 87 publications

References 67 publications

Traditional and New Principles of Perceptual Grouping

Traditional and New Principles of Perceptual Grouping

Toward a better approach to goodness: Comments on Van der Helm and Leeuwenberg (1996).

Minimal information to determine affine shape equivalence.

Contact Info

Product

Resources

About