Orientation Misperceptions Induced by Contrast Polarity: Comment on “Contrast Polarities Determine the Direction of Café Wall Tilts” by Akiyoshi Kitaoka, Baingio Pinna, and Gavin Brelstaff (2004)

Perception ◽  
10.1068/p5268 ◽  
2006 ◽  
Vol 35 (3) ◽  
pp. 401-409 ◽  
Author(s):  
Sergio Roncato
Keyword(s):  
Contrast Polarity

scholarly journals Differential roles of contrast polarity reveal two streams of second-order visual processing

2007 ◽  
Vol 47 (15) ◽  
pp. 2047-2054 ◽  
Author(s):  
Isamu Motoyoshi ◽  
Frederick A.A. Kingdom
Keyword(s):  
Visual Processing ◽  
Second Order ◽  
Contrast Polarity

scholarly journals Surface and motion integration determined by luminance contrast polarity

2004 ◽  
Vol 4 (8) ◽  
pp. 888-888
Author(s):  
Y. Su ◽  
T. Leng ◽  
Z. J. He
Keyword(s):  
Luminance Contrast ◽  
Contrast Polarity ◽  
Motion Integration

scholarly journals Asymmetries in contrast polarity processing in young human infants

10.1167/1.2.5 ◽  
2001 ◽  
Vol 1 (2) ◽  
pp. 5 ◽  
Author(s):  
James L. Dannemiller ◽  
Benjamin R. Stephens
Keyword(s):  
Human Infants ◽  
Contrast Polarity

scholarly journals Polarity Inversion Catalysis by the 1,4-Addition of N-Heterocyclic Carbenes

2020 ◽  
Vol 73 (1) ◽  
pp. 1 ◽  
Author(s):  
Xuan B. Nguyen ◽  
Yuji Nakano ◽  
David W. Lupton
Keyword(s):  
Catalytic Reaction ◽  
Heterocyclic Carbenes ◽  
Lewis Base ◽  
Coupling Reactions ◽  
Polarity Inversion ◽  
Contrast Polarity ◽  
Base Catalysts ◽  
Selection For ◽  
Lewis Base Catalysts ◽  
Comprehensive Coverage

Polarity inversion is the hallmark of N-heterocyclic carbene (NHC) organocatalysis, with the generation and reaction of acyl anion equivalents known for more than 70 years. In contrast, polarity inversion through 1,4-addition of NHCs to conjugate acceptors was first applied in a catalytic reaction in 2006. This sub-field of NHC-organocatalysis has developed steadily over the subsequent years, enabling novel coupling reactions, enantioselective cycloisomerizations, polymerizations, and other reactions. In this review, this emerging area of NHC-organocatalysis is discussed with comprehensive coverage. In addition, notes regarding the use of other Lewis base catalysts for related reactions, and comments regarding NHC selection for this type of catalysis, are provided.

Brightness induction: Unequal spatial integration with increments and decrements

2004 ◽  
Vol 21 (3) ◽  
pp. 353-357 ◽  
Author(s):  
SANG WOOK HONG ◽  
STEVEN K. SHEVELL
Keyword(s):  
Matching Task ◽  
Spatial Integration ◽  
Contrast Polarity ◽  
Spatial Range ◽  
Neural Integration

Modern theories of brightness induction include an influence from regions that do not share a border with the target. This study tested whether the spatial range of neural integration is the same with incremental versus decremental contrast edges in relatively remote parts of the background. Using an asymmetric matching task, observers set the brightness of a comparison ring, within its own uniform surround, to match the brightness of a test ring within a contiguous surround and a noncontiguous background. The measurements showed that the area of integration depended on the incremental versus decremental contrast polarity at the edge between the surround and background. This implies that brightness induction from an inhomogeneous background must consider the polarity of contrast edges within the whole scene.

Contrast polarity affects verification of addition and subtraction problems via conceptual mapping

2020 ◽  
pp. 174702182095659
Author(s):  
Mia Šetić Beg ◽  
Dragan Glavaš ◽  
Dražen Domijan
Keyword(s):  
Mental Arithmetic ◽  
Arithmetic Operation ◽  
Negative Contrast ◽  
Single Digit ◽  
Contrast Polarity ◽  
Similar Relation ◽  
Perceptual Representations ◽  
Addition And Subtraction ◽  
Written Word ◽  
Open Question

The extent to which processing of abstract numerical concepts depends on perceptual representations is still an open question. In four experiments, we examined the association between contrast polarity and mental arithmetic, as well as its possible source. Undergraduate psychology students verified the correctness of single-digit arithmetic problems such as 2 + 5 = 7 or 9 − 6 = 5. Problems appeared either in white or black on a grey background, thus creating positive or negative contrast polarity, respectively. When the correct response was Yes (No), participants were faster (slower) in verifying positive than negative addition problems and in verifying negative than positive subtraction problems. Experiment 2 confirmed that the same result also held for written word problems (e.g., SEVEN + SIX = THIRTEEN). However, Experiment 3 found that the effect of contrast polarity observed in Experiments 1 and 2 disappeared in a blocked design where arithmetic operation was a between-participant factor. In addition, Experiment 4 revealed that the effect of contrast polarity does not generalise to multiplication and division. Overall, available evidence suggests that participants spontaneously associate the abstract relation between addition and subtraction (more-less) with a similar relation between contrast polarities (bright-dark).

scholarly journals The Limiting Case of Amodal Completion: The Phenomenal Salience and the Role of Contrast Polarity

2019 ◽  
Vol 9 (6) ◽  
pp. 149 ◽  
Author(s):  
Pinna ◽  
Conti
Keyword(s):  
Perceptual Organization ◽  
Amodal Completion ◽  
Main Question ◽  
Good Continuation ◽  
Contrast Polarity ◽  
Visual Phenomenon ◽  
Continuous Object ◽  
Limiting Case ◽  
Visual Properties

In this work, we demonstrated unique and relevant visual properties imparted by contrast polarity in perceptual organization and in eliciting amodal completion, which is the vivid completion of a single continuous object of the visible parts of an occluded shape despite portions of its boundary contours not actually being seen. T-junction, good continuation, and closure are considered the main principles involved according to relevant explanations of amodal completion based on the simplicity–Prägnanz principle, Helmholtz’s likelihood, and Bayesian inference. The main interest of these approaches is to explain how the occluded object is completed, what is the amodal shape, and how contours of partially visible fragments are relatable behind an occluder. Different from these perspectives, amodal completion was considered here as a visual phenomenon and not as a process, i.e., the final outcome of perceptual processes and grouping principles. Therefore, the main question we addressed through our stimuli was “What is the role of shape formation and perceptual organization in inducing amodal completion?” To answer this question, novel stimuli, similar to limiting cases and instantiae crucis, were studied through Gestalt experimental phenomenology. The results demonstrated the domination of the contrast polarity against good continuation, T-junctions, and regularity. Moreover, the limiting conditions explored revealed a new kind of junction next to the T- and Y-junctions, respectively responsible for amodal completion and tessellation. We called them I-junctions. The results were theoretically discussed in relation to the previous approaches and in the light of the phenomenal salience imparted by contrast polarity.

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