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Special Issue "Visual Symmetry"

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A special issue of Symmetry (ISSN 2073-8994).

Deadline for manuscript submissions: closed (31 October 2014)

Special Issue Editor

Guest Editor
Dr. Yuka Sasaki

Brown University, Department of Cognitive, Linguistic & Psychological Sciences, Box 1821, 190 Thayer Street Providence, RI 02912, USA
Interests: unconscious brain activity; visual/motor skill learning during wakefulness and sleep; non-invasive neuroimaging techniques including functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG)

Special Issue Information

Dear Colleagues,

Humans have appreciated and created symmetric objects in all ages and cultures. Why does symmetry attract us so much? In this special issue of Symmetry, we focus on visual symmetry. We call for papers to gather behavioral and neuroimaging evidence for visual symmetry to attract, influence and bias humans and animals preference, and decision-making, in hope to deepen understanding of our appreciation of symmetry.

Dr. Yuka Sasaki
Guest Editor

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 800 CHF (Swiss Francs).


Keywords

  • vision
  • perception
  • decision-making
  • electroencephalogram (EEG)
  • magnetic resonance imaging (MRI)
  • magnetoencephalography (MEG)

Published Papers (6 papers)

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Research

Jump to: Review

Open AccessArticle Can the Comparisons of Feature Locations Explain the Difficulty in Discriminating Mirror-Reflected Pairs of Geometrical Figures from Disoriented Identical Pairs?
Symmetry 2015, 7(1), 89-104; doi:10.3390/sym7010089
Received: 24 October 2014 / Accepted: 9 January 2015 / Published: 23 January 2015
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Abstract
The present experiment investigates whether patterns of shifts of feature locations could affect the same/different decisions of simultaneously presented pairs of geometrical figures. A shift of locations was defined as the angular distance from the location of a feature in one figure [...] Read more.
The present experiment investigates whether patterns of shifts of feature locations could affect the same/different decisions of simultaneously presented pairs of geometrical figures. A shift of locations was defined as the angular distance from the location of a feature in one figure to the location of the same feature in another figure. It was hypothesized that the difficulty in discriminating mirror-reflected (or axisymmetric) pairs from disoriented identical pairs was caused by complex shifting patterns inherent in axisymmetric pairs. According to the shifts of the locations of the four structural features, five pair types were prepared. They could be ordered from completely identical to completely different in their shifts: identical 0/4 pairs, non-identical 1/4 pairs, non-identical 2/4 pairs = axisymmetric 2/4 pairs and non-identical 4/4 pairs. The latencies for non-identical pairs decreased with the increase of difference in the shifts of feature locations, indicating that serial, self-terminating comparisons of the shifts were applied to the discrimination of non-identical pairs from identical pairs. However, the longer latencies in axisymmetric 2/4 pairs than in non-identical 2/4 pairs suggested that the difficulty for axisymmetric pairs was not caused by the complex shifting patterns, and the difficulty was not satisfactorily explained by the comparisons of feature locations. Full article
(This article belongs to the Special Issue Visual Symmetry)
Open AccessArticle Gestalt Algebra—A Proposal for the Formalization of Gestalt Perception and Rendering
Symmetry 2014, 6(3), 566-577; doi:10.3390/sym6030566
Received: 14 February 2014 / Revised: 17 June 2014 / Accepted: 19 June 2014 / Published: 7 July 2014
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Abstract
Gestalt Algebra gives a formal structure suitable for describing complex patterns in the image plain. This can be useful for recognizing hidden structure in images. The work at hand refers to the laws of perceptual psychology. A manifold called the Gestalt Domain [...] Read more.
Gestalt Algebra gives a formal structure suitable for describing complex patterns in the image plain. This can be useful for recognizing hidden structure in images. The work at hand refers to the laws of perceptual psychology. A manifold called the Gestalt Domain is defined. Next to the position in 2D it also contains an orientation and a scale component. Algebraic operations on it are given for mirror symmetry as well as organization into rows. Additionally the Gestalt Domain contains an assessment component, and all the meaning of the operations implementing the Gestalt-laws is realized in the functions giving this component. The operation for mirror symmetry is binary, combining two parts into one aggregate as usual in standard algebra. The operation for organization into rows, however, combines n parts into an aggregate, where n may well be more than two. This is algebra in its more general sense. For recognition, primitives are extracted from digital raster images by Lowe’s Scale Invariant Feature Transform (SIFT). Lowe’s key-point descriptors can also be utilized. Experiments are reported with a set of images put forth for the Computer Vision and Pattern Recognition Workshops (CVPR) 2013 symmetry contest. Full article
(This article belongs to the Special Issue Visual Symmetry)
Figures

Open AccessArticle Domain Specificity in Human Symmetry Preferences: Symmetry is Most Pleasant When Looking at Human Faces
Symmetry 2014, 6(2), 222-233; doi:10.3390/sym6020222
Received: 21 February 2014 / Revised: 24 March 2014 / Accepted: 26 March 2014 / Published: 17 April 2014
Cited by 2 | PDF Full-text (3443 KB) | HTML Full-text | XML Full-text
Abstract
Visual symmetry has been found to be preferred to asymmetry in a variety of domains and across species. A number of theories propose to explain why symmetry is preferred. In this article, I compare a perceptual bias view, in which symmetry is [...] Read more.
Visual symmetry has been found to be preferred to asymmetry in a variety of domains and across species. A number of theories propose to explain why symmetry is preferred. In this article, I compare a perceptual bias view, in which symmetry is preferred due to factors inherit to the visual system, and an evolutionary advantage view, in which symmetry is preferred due to selection pressures on partner preference. Preferences for symmetry in three stimulus types were determined by having symmetric and asymmetric versions of the same images rated for pleasantness: human female faces, macaque monkey faces, and abstract art. It was found that preferences for symmetry were strongest for human female faces and weakest for art. This finding builds on previous research suggesting that symmetry preferences for human faces are different from symmetry preferences in other domains and that simple perceptual bias explanations do not wholly explain human visual face symmetry preferences. While consistent with an evolutionary advantage view, these data are also potentially explainable via a perceptual bias view which accounts for experience of stimuli. The interplay between these two views is discussed in the context of the current study. Full article
(This article belongs to the Special Issue Visual Symmetry)
Figures

Open AccessArticle Peripheral Contour Grouping and Saccade Targeting: The Role of Mirror Symmetry
Symmetry 2014, 6(1), 1-22; doi:10.3390/sym6010001
Received: 26 September 2013 / Revised: 30 December 2013 / Accepted: 30 December 2013 / Published: 2 January 2014
Cited by 3 | PDF Full-text (558 KB) | HTML Full-text | XML Full-text
Abstract
Integrating shape contours in the visual periphery is vital to our ability to locate objects and thus make targeted saccadic eye movements to efficiently explore our surroundings. We tested whether global shape symmetry facilitates peripheral contour integration and saccade targeting in three [...] Read more.
Integrating shape contours in the visual periphery is vital to our ability to locate objects and thus make targeted saccadic eye movements to efficiently explore our surroundings. We tested whether global shape symmetry facilitates peripheral contour integration and saccade targeting in three experiments, in which observers responded to a successful peripheral contour detection by making a saccade towards the target shape. The target contours were horizontally (Experiment 1) or vertically (Experiments 2 and 3) mirror symmetric. Observers responded by making a horizontal (Experiments 1 and 2) or vertical (Experiment 3) eye movement. Based on an analysis of the saccadic latency and accuracy, we conclude that the figure-ground cue of global mirror symmetry in the periphery has little effect on contour integration or on the speed and precision with which saccades are targeted towards objects. The role of mirror symmetry may be more apparent under natural viewing conditions with multiple objects competing for attention, where symmetric regions in the visual field can pre-attentively signal the presence of objects, and thus attract eye movements. Full article
(This article belongs to the Special Issue Visual Symmetry)

Review

Jump to: Research

Open AccessReview Brain Activity in Response to Visual Symmetry
Symmetry 2014, 6(4), 975-996; doi:10.3390/sym6040975
Received: 11 October 2014 / Revised: 22 November 2014 / Accepted: 26 November 2014 / Published: 2 December 2014
Cited by 3 | PDF Full-text (25941 KB) | HTML Full-text | XML Full-text
Abstract
A number of studies have explored visual symmetry processing by measuring event related potentials and neural oscillatory activity. There is a sustained posterior negativity (SPN) related to the presence of symmetry. There is also functional magnetic resonance imaging (MRI) activity in extrastriate [...] Read more.
A number of studies have explored visual symmetry processing by measuring event related potentials and neural oscillatory activity. There is a sustained posterior negativity (SPN) related to the presence of symmetry. There is also functional magnetic resonance imaging (MRI) activity in extrastriate visual areas and in the lateral occipital complex. We summarise the evidence by answering six questions. (1) Is there an automatic and sustained response to symmetry in visual areas? Answer: Yes, and this suggests automatic processing of symmetry. (2) Which brain areas are involved in symmetry perception? Answer: There is an extended network from extrastriate areas to higher areas. (3) Is reflection special? Answer: Reflection is the optimal stimulus for a more general regularity-sensitive network. (4) Is the response to symmetry independent of view angle? Answer: When people classify patterns as symmetrical or random, the response to symmetry is view-invariant. When people attend to other dimensions, the network responds to residual regularity in the image. (5) How are brain rhythms in the two hemispheres altered during symmetry perception? Answer: Symmetry processing (rather than presence) produces more alpha desynchronization in the right posterior regions. Finally, (6) does symmetry processing produce positive affect? Answer: Not in the strongest sense, but behavioural measures reveal implicit positive evaluation of abstract symmetry. Full article
(This article belongs to the Special Issue Visual Symmetry)
Open AccessReview Symmetry Detection in Visual Impairment: Behavioral Evidence and Neural Correlates
Symmetry 2014, 6(2), 427-443; doi:10.3390/sym6020427
Received: 19 February 2014 / Revised: 13 May 2014 / Accepted: 14 May 2014 / Published: 26 May 2014
Cited by 1 | PDF Full-text (604 KB) | HTML Full-text | XML Full-text
Abstract
Bilateral symmetry is an extremely salient feature for the human visual system. An interesting issue is whether the perceptual salience of symmetry is rooted in normal visual development. In this review, we discuss empirical work on visual and tactile symmetry detection in [...] Read more.
Bilateral symmetry is an extremely salient feature for the human visual system. An interesting issue is whether the perceptual salience of symmetry is rooted in normal visual development. In this review, we discuss empirical work on visual and tactile symmetry detection in normally sighted and visually impaired individuals. On the one hand, available evidence suggests that efficient visual symmetry detection may need normal binocular vision development. On the other hand, converging evidence suggests that symmetry can develop as a principle of haptic perceptual organization in individuals lacking visual experience. Certain features of visual symmetry detection, however, such as the higher salience of the patterns containing a vertical axis of symmetry, do not systematically apply to the haptic modality. The neural correlates (revealed with neuroimaging) associated with visual and haptic symmetry detection are also discussed. Full article
(This article belongs to the Special Issue Visual Symmetry)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Why Are Flowers Beautiful? The Perceptual Meaning of Radial Symmetry of Shape and Color
Author:
Baingio Pinna
Affiliation: Department of Humanities and Social Sciences, University of Sassari, Italy
Abstract:
What is the perceptual e biological meaning of radial symmetry of shape and color in flowers? To answer this question The starting point aimed to answer this question is found within a “to show list” that involve to use of symmetrical shapes and colors in all kinds of living organism according to the following list—to show the whole; to show a part; to show some parts more clearly than others; to show something that would be otherwise invisible; to show parts that are not natural parts; to show fragments; to show in order to hide; to show to break and split, etc. The answer to the question “why are flowers beautiful?” was extracted from this list in terms of perceptual organization and through psychophysical experiments.
Keywords: color vision; evolution; adaptation; camouflage; filling-in; perceptual organization; watercolor illusion

Title: The Beauty of the Square. Symmetry vs. Asymmetry, Simplicity vs. Complexity
Authors:
Baingio Pinna and Katia Deiana
Affiliation: Department of Humanities and Social Sciences, University of Sassari, Italy
Abstract:
The Gestalt approach to object perception is based on two phenomenal dynamics: figure-ground segregation and grouping. This approach is here reconsidered in the light of a special limiting shape, the square, that is a pure human product, an extraordinary creation of the human brain, not present in nature unlike other singular shapes, e.g., the circle. The iris and the pupil, the full moon and the sun are circles. The square is something more. It is the measure of all things, both shapes and spaces. As such, the square is the reference shape and the human elementary component of all the possible shapes. The rectangle is a square with elongated sides; the triangle is half of a square and so on. Every object and space either regular or irregular is measured in squares (m2) or in cubes (m3). By moving around the gaze and focusing the attention on the shapes, one can easily notice that almost everything has a square shape. Most of the human artifacts are made up of squares or its variations. The main purpose of this work is to answer through psychophysical experiments the following questions: Why is the square so important? What does make the square so basic and important in human artifacts?
Keywords:
shape perception; color perception; perceptual organization; vision and art; visual illusions

Title: Symmetric Flows: Synthesis, Visualization, Perception, and Analysis
Authors:
Zhanping Liu and Robert J. Moorhead II
Type:
Article
Abstract:
This paper presents parameterized synthesis and numerical visualization of symmetric flows as well as their significant value to both explicit data generation and implicit task design in support of unbiased flow visualization user studies. The use of a wide variety of symmetric flows (about the x-axis, y-axis, and center) with similar topological complexity, combined with geometrically symmetric yet topologically asymmetric flows, requires local+global visual perception and thorough pattern analysis of each flow. Thus, synthetic symmetric flows help conduct objective evaluation on the effectiveness of different visualization techniques, including sparse geometry-based methods (e.g., arrow plots and evenly-spaced streamlines) and dense texture-based approaches (e.g., variants of line integral convolution or LIC) coupled with color maps. Synthesis, application, and visualization of symmetric flows allow for comprehensive investigation of visual perception, mental reconstruction, and pattern analysis as we seek novel techniques to visualize unknown large complex flows resulting from real-world phenomena and from numerical simulations in oceanography, meteorology (e.g., tornados and hurricanes), and computational fluid dynamics (CFD), etc., to achieve efficient scientific discovery and informed decision making.
Keywords:
symmetry; flow synthesis; flow visualization; flow topology; critical point; streamlines; LIC; user study

Title: Brain Activity in Response to Visual Symmetry
Authors: Marco Bertamini and Alexis D. J. Makin
Type:
Review
Abstract:
Recent studies on visual symmetry processing have analysed event related potentials, oscillatory activity, functional MRI and TMS. There is an automatic neural response in a specific but extended network. Activity in this network is largest for reflection but present for other regularities. Activity is present for slanted symmetry, but slant compensation is not automatic. The interaction with figure-ground processing is still unclear. The right hemisphere is specialised for symmetry because it shows more alpha desynchronization. Finally, symmetry processing does not produce an automatic positive affective response. We believe these results provide new insights into old questions about symmetry perception.

Type: Article
Title:
Why Are Mirror-Reflected Pairs of Figures Difficult to Discriminate from Rotated to be the Same Pairs?
Author:
Fumio Kanbe
Abstract: The same/different decisions of simultaneously presented, mutually isomorphic pairs of random lined figures were used to investigate why mirror-reflected (or axisymmetric) pairs are difficult to discriminate from rotated to be the same pairs. Easily disrupted, serial, self-terminating comparisons of locational shifts in polar coordinates between the two figures of a pair were hypothesized. Five types of pairs were prepared for the experiment according to the patterns of shifts of the locations of four arbitrary chosen graph invariant: Identical pairs where all shifts were constant, Non-identical (1/4) pairs where one shift was different from the other three shifts, Non-identical (2/4) pairs where two shifts were different from the other two shifts, Non-identical (4/4) pairs where all four shifts were different from each other, and Axisymmetric (2/4) pairs where two shifts were different from the other two shifts between two mutually axisymmetric figures.  The results indicated (tentatively: Kanbe) that the hypothesis could not fully explain the extremely long latencies obtained in Axisymmetirc (2/4) pairs.

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