Contour symmetry detection: the influence of axis orientation and number of objects

Friedenberg, Jay; Bertamini, Marco

doi:10.1016/s0001-6918(00)00051-2

Cited by 28 publications

(32 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, when figure/ground segmentation assigned the contours to separate objects, subjects showed decreased performance in detecting symmetry with increasing complexity of the contours. Bertamini, Friedenberg, and Kubovy (1997) and Friedenberg and Bertamini (2000) obtained similar results comparing symmetry and repetition in contour patterns that defined multiple objects or single objects. They found a ''one object'' preference for symmetry and a ''multiple object'' preference for repetition.…”

Section: Introductionmentioning

confidence: 61%

Effects of asynchrony on symmetry perception

Vloed

Csathó

Helm

2005

Psychological Research

View full text Add to dashboard Cite

The effect of temporal image segmentation on symmetry perception was investigated by means of stimuli composed of one part surrounding another. The two parts could be presented synchronously or with a temporal offset (20-100 ms), and each part could be either symmetrical or random. The task was to discriminate completely symmetrical (S) stimuli (in Experiment 1) or completely random (R) stimuli (in Experiment 2) from partially symmetrical (PS) stimuli in which one part was symmetrical and the other random. The R stimuli showed an asynchrony effect but the S stimuli did not. Furthermore, in both experiments, the PS stimuli showed an asynchrony effect when the symmetrical part was presented last but not when the symmetrical part was presented first (independent of whether it was the surrounded part or the surrounding part). Both results suggest that symmetry is strong enough to override this kind of temporal image segmentation.

show abstract

Section: Introductionmentioning

confidence: 61%

Effects of asynchrony on symmetry perception

Vloed

Csathó

Helm

2005

Psychological Research

View full text Add to dashboard Cite

show abstract

“…It has often been observed (at least as far back as Mach; see Baylis & Driver, 1994 that humans are more sensitive to symmetry within a pattern than to repetition. This observation has been confirmed in many experiments (e.g., Bertamini, Friedenberg, & Kubovy, 1997;Bruce & Morgan, 1975;Corballis & Roldan, 1974;Friedenberg & Bertamini, 2000). More recently, Baylis and Driver (1994) have argued that whereas symmetry within a shape can be detected in parallel, repetition seems to involve a serial process.…”

mentioning

confidence: 63%

Early computation of part structure: Evidence from visual search

Singh

2002

Perception & Psychophysics

View full text Add to dashboard Cite

The visual system represents object shapes in terms of intermediate-level parts. The minima rule proposes that the visual system uses negative minima of curvature to define boundaries between parts. We used visual search to test whether part structures consistent with the minima rule are computed preattentively-or at least, rapidly and early in visual processing. The results of Experiments 1 and 2 showed that whereas the search for a non-minima-segmentedshape is fast and efficient among minimasegmented shapes, the reverse search is slow and inefficient. This asymmetry is expected if parsing at negative minima occurs obligatorily. The results of Experiments 3 and 4 showed that although both minima-and non-minima-segmentedshapes pop out among unsegmented shapes, the search for minimasegmented shapes is significantly slower. Together, these results demonstrate that the visual system segments shapes into parts, using negative minima of curvature, and that it does so rapidly in early stages of visual processing.

show abstract

“…This effect was bilateral, implying more activation of both left and right posterior regions during horizontal trials. Previous symmetry perception research has shown that vertical orientations are detected faster (Friedenberg & Bertamini, ; Julesz, ). However, it is not clear whether the vertical advantage survives when axis orientation can be anticipated (Wenderoth, ; Wenderoth & Welsh, ).…”

Section: Discussionmentioning

confidence: 96%

Right‐lateralized alpha desynchronization during regularity discrimination: Hemispheric specialization or directed spatial attention?

2014

Self Cite

View full text Add to dashboard Cite

When actively classifying abstract patterns according to their regularity, alpha desynchronization (ERD) becomes right lateralized over posterior brain areas. This could reflect temporary enhancement of contralateral visual inputs and specifically a shift of attention to the left, or right hemisphere specialization for regularity discrimination. This study tested these competing hypotheses. Twenty-four participants discriminated between dot patterns containing a reflection or a translation. The direction of the transformation, which matched one half onto the other half, was either vertical or horizontal. The strategy of shifting attention to one side of the patterns would not produce lateralized ERD in the horizontal condition. However, right-lateralized ERD was found in all conditions, regardless of orientation. We conclude that right hemisphere networks that incorporate the early posterior regions are specialized for regularity discrimination.

show abstract

Contour symmetry detection: the influence of axis orientation and number of objects

Cited by 28 publications

References 19 publications

Effects of asynchrony on symmetry perception

Effects of asynchrony on symmetry perception

Early computation of part structure: Evidence from visual search

Right‐lateralized alpha desynchronization during regularity discrimination: Hemispheric specialization or directed spatial attention?

Contact Info

Product

Resources

About