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Journal of Vision

Carolin Hübner, Alexander C Schütz
Humans achieve a stable and homogeneous representation of their visual environment, although visual processing varies across the visual field. Here we investigated the circumstances under which peripheral and foveal information is integrated for numerosity estimation across saccades. We asked our participants to judge the number of black and white dots on a screen. Information was presented either in the periphery before a saccade, in the fovea after a saccade, or in both areas consecutively to measure transsaccadic integration...
November 1, 2017: Journal of Vision
Wonmo Jung, Isabelle Bülthoff, Regine G M Armann
The brain can only attend to a fraction of all the information that is entering the visual system at any given moment. One way of overcoming the so-called bottleneck of selective attention (e.g., J. M. Wolfe, Võ, Evans, & Greene, 2011) is to make use of redundant visual information and extract summarized statistical information of the whole visual scene. Such ensemble representation occurs for low-level features of textures or simple objects, but it has also been reported for complex high-level properties...
November 1, 2017: Journal of Vision
Sang Wook Hong, Frank Tong
Perceptual filling-in exemplifies the constructive nature of visual processing. Color, a prominent surface property of visual objects, can appear to spread to neighboring areas that lack any color. We investigated cortical responses to a color filling-in illusion that effectively dissociates perceived color from the retinal input (van Lier, Vergeer, & Anstis, 2009). Observers adapted to a star-shaped stimulus with alternating red- and cyan-colored points to elicit a complementary afterimage. By presenting an achromatic outline that enclosed one of the two afterimage colors, perceptual filling-in of that color was induced in the unadapted central region...
November 1, 2017: Journal of Vision
Timothy G Shepard, Safiya I Lahlaf, Rhea T Eskew
Six linear chromatic mechanisms are sufficient to account for the pattern of threshold elevations produced by chromatic noise masking in the (L,M) plane of cone space (Shepard, Swanson, McCarthy, & Eskew, 2016). Here, we report results of asymmetric color matching of the threshold-level tests from that detection study and use those matches to test the detection model. We assume the mechanisms are univariant labeled lines (Rushton, 1972; Watson & Robson, 1981), implying that the chromaticities of physically different stimuli that are detected by a single mechanism should all be the same-they are postreceptoral metamers-but the chromaticities of two stimuli detected by different mechanisms should be different...
November 1, 2017: Journal of Vision
Gerald Westheimer
The oblique effect-poorer performance when contours are in oblique meridians-is here extended from the discrimination of line-orientation to the tilt illusion and to the detection and contextual induction of curvature. The distinction is made between a contour's susceptibility to contextual perturbation and its capacity to induce such perturbation, for which the oblique effect is only about one half. That the cardinal/oblique superiority is retained for the orientation of illusory borders and for the implicit orientation of shapes lacking explicit rectilinear delineation has implications for its neural substrate...
November 1, 2017: Journal of Vision
Andrew Stockman, G Bruce Henning, Andrew T Rider
The mean hue of flickering waveforms comprising only the first two harmonics depends on their temporal alignment. We evaluate explanatory models of this hue-shift effect using previous data obtained using L- and M-cone-isolating stimuli together with chromatic sensitivity and hue discrimination data. The key questions concerned what type of nonlinearity produced the hue shifts, and where the nonlinearities lay with respect to the early band-pass and late low-pass temporal filters in the chromatic pathways. We developed two plausible models: (a) a slew-rate limited nonlinearity that follows both early and late filters, and (b) a half-wave rectifying nonlinearity-consistent with the splitting of the visual input into ON- and OFF-channels-that lies between the early and late filters followed by a compressive nonlinearity that lies after the late filter...
November 1, 2017: Journal of Vision
Michele Fornaciai, Joonkoo Park
Numerosity perception involves a complex cascade of processing stages comprising an early sensory representation stage followed by a later stage providing a conceptual representation of numerical magnitude. While much recent work has focused on understanding how nonnumerical spatial features (e.g., density, area) influence numerosity perception in this processing cascade, little is known about how the spatiotemporal properties of the stimuli affect numerosity processing. Whether numerosity information is integrated over space and time in the processing cascade is an important question as it can provide insights into how the system dedicated for numerosity interacts with other perceptual systems...
November 1, 2017: Journal of Vision
Yvonne Norgett, John Siderov
Foveal vision in strabismic amblyopia can show increased levels of crowding, akin to typical peripheral vision. Target-flanker similarity and visual-acuity test configuration may cause the magnitude of crowding to vary in strabismic amblyopia. We used custom-designed visual acuity tests to investigate crowding in observers with strabismic amblyopia. LogMAR was measured monocularly in both eyes of 11 adults with strabismic or mixed strabismic/anisometropic amblyopia using custom-designed letter tests. The tests used single-letter and linear formats with either bar or letter flankers to introduce crowding...
November 1, 2017: Journal of Vision
Jian Ding, Dennis M Levi
We develop and test a new two-dimensional model for binocular combination of the two eyes' luminance profiles. For first-order stimuli, the model assumes that one eye's luminance profile first goes through a luminance compressor, receives gain-control and gain-enhancement from the other eye, and then linearly combines the other eye's output profile. For second-order stimuli, rectification is added in the signal path of the model before the binocular combination site. Both the total contrast and luminance energies, weighted sums over both the space and spatial-frequency domains, were used in the interocular gain-control, while only the total contrast energy was used in the interocular gain-enhancement...
November 1, 2017: Journal of Vision
Lars O M Rothkegel, Hans A Trukenbrod, Heiko H Schütt, Felix A Wichmann, Ralf Engbert
When watching the image of a natural scene on a computer screen, observers initially move their eyes toward the center of the image-a reliable experimental finding termed central fixation bias. This systematic tendency in eye guidance likely masks attentional selection driven by image properties and top-down cognitive processes. Here, we show that the central fixation bias can be reduced by delaying the initial saccade relative to image onset. In four scene-viewing experiments we manipulated observers' initial gaze position and delayed their first saccade by a specific time interval relative to the onset of an image...
November 1, 2017: Journal of Vision
Sven Ohl, Clara Kuper, Martin Rolfs
Saccadic eye movements cause a rapid sweep of the visual image across the retina and bring the saccade's target into high-acuity foveal vision. Even before saccade onset, visual processing is selectively prioritized at the saccade target. To determine how this presaccadic attention shift exerts its influence on visual selection, we compare the dynamics of perceptual tuning curves before movement onset at the saccade target and in the opposite hemifield. Participants monitored a 30-Hz sequence of randomly oriented gratings for a target orientation...
November 1, 2017: Journal of Vision
Xiangyong Yuan, Xilei Zhang, Yi Jiang
In the classic tilt illusion, the perceived orientation of a center patch is shifted away from its oriented context. Additionally, a stronger illusion effect is yielded when the center patch is simultaneously rather than asynchronously presented with a constant context for a shorter duration. However, little is known about the temporal characteristic of the tilt illusion in a reverse situation in which a constant center patch is presented throughout while the contexts change. Therefore, we continuously alternated two opposite-oriented contexts and manipulated alternate speeds to examine how the tilt illusion would build up as a function of dynamic contextual alternation...
November 1, 2017: Journal of Vision
Rosa Lafer-Sousa, Bevil R Conway
We present a full analysis of data from our preliminary report (Lafer-Sousa, Hermann, & Conway, 2015) and test whether #TheDress image is multistable. A multistable image must give rise to more than one mutually exclusive percept, typically within single individuals. Clustering algorithms of color-matching data showed that the dress was seen categorically, as white/gold (W/G) or blue/black (B/K), with a blue/brown transition state. Multinomial regression predicted categorical labels. Consistent with our prior hypothesis, W/G observers inferred a cool illuminant, whereas B/K observers inferred a warm illuminant; moreover, subjects could use skin color alone to infer the illuminant...
October 1, 2017: Journal of Vision
Michelle P S To, Mazviita Chirimuuta, David J Tolhurst
We consider the role of nonlinear inhibition in physiologically realistic multineuronal models of V1 to predict the dipper functions from contrast discrimination experiments with sinusoidal gratings of different geometries. The dip in dipper functions has been attributed to an expansive transducer function, which itself is attributed to two nonlinear inhibitory mechanisms: contrast normalization and surround suppression. We ran five contrast discrimination experiments, with targets and masks of different sizes and configurations: small Gabor target/small mask, small target/large mask, large target/large mask, small target/in-phase annular mask, and small target/out-of-phase annular mask...
October 1, 2017: Journal of Vision
Benjamin Balas
Although adults' ability to recognize materials from complex natural images has been well characterized, we still know very little about the development of material perception. When do children exhibit adult-like abilities to categorize materials? What visual features do they use to do so as a function of age and material category? In the present study, we attempted to address both of these issues in two experiments that we administered to school-age children (5-10 years old) and adults. In both tasks, we asked our participants to categorize natural materials (metal, stone, water, and wood) using original images of these materials as well as synthetic images made with the Portilla-Simoncelli algorithm...
October 1, 2017: Journal of Vision
W Drew Bromfield, Jason M Gold
People can reliably infer the actions, intentions, and mental states of fellow humans from body movements (Blake & Shiffrar, 2007). Previous research on such biological-motion perception has suggested that the movements of the feet may play a particularly important role in making certain judgments about locomotion (Chang & Troje, 2009; Troje & Westhoff, 2006). One account of this effect is that the human visual system may have evolved specialized processes that are efficient for extracting information carried by the feet (Troje & Westhoff, 2006)...
October 1, 2017: Journal of Vision
Zheng Ma, Scott N J Watamaniuk, Stephen J Heinen
When small objects move in a scene, we keep them foveated with smooth pursuit eye movements. Although large objects such as people and animals are common, it is nonetheless unknown how we pursue them since they cannot be foveated. It might be that the brain calculates an object's centroid, and then centers the eyes on it during pursuit as a foveation mechanism might. Alternatively, the brain merely matches the velocity by motion integration. We test these alternatives with an illusory motion stimulus that translates at a speed different from its retinal motion...
October 1, 2017: Journal of Vision
Hugh Riddell, Markus Lappe
When we move through the world, a pattern of expanding optic flow is generated on the retina. In completely rigid environments, this pattern signals one's direction of heading and is an important source of information for navigation. When we walk towards an oncoming person, the optic environment is not rigid, as the motion vectors generated by the other person represent a composite of that person's movement, his or her limb motion, and the observer's self-motion. Though this biological motion obfuscates the optic flow pattern, it also provides cues about the movement of other actors in the environment...
October 1, 2017: Journal of Vision
Brian Vohnsen, Alessandra Carmichael, Najnin Sharmin, Salihah Qaysi, Denise Valente
The integrated Stiles-Crawford function is commonly used as apodization model for vision through the natural eye pupil. However, this method does not account for possible effects related to the retinal thickness, the large length-to-diameter aspect ratio of the photoreceptors, or the use of nonMaxwellian illumination. Here, we introduce a geometrical optics model to calculate the fraction of overlap between light at the retina and the photoreceptor outer segments where absorption triggers vision. The model, which does not account for photoreceptor waveguiding, is discussed for both Maxwellian and nonMaxwellian illumination...
October 1, 2017: Journal of Vision
Shuntaro C Aoki, Hiroshi M Shiozaki, Ichiro Fujita
Binocular disparity is represented by interocular cross-correlation of visual images in the striate and some extrastriate cortices. This correlation-based representation produces reversed depth perception in a binocularly anticorrelated random-dot stereogram (aRDS) when it is accompanied by an adjacent correlated RDS (cRDS). Removal of the cRDS or spatial separation between the aRDS and cRDS abolishes reversed depth perception. However, how an immediate plane supports reversed depth perception is unclear. One possible explanation is that the correlation-based representation generates reversed depth based on the relative disparity between the aRDS and cRDS rather than the absolute disparity of the aRDS...
October 1, 2017: Journal of Vision
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