scholarly journals Visual crowding is a combination of an increase of positional uncertainty, source confusion, and featural averaging

2016 ◽  
Author(s):  
William J Harrison ◽  
Peter J Bex
Keyword(s):  
Peripheral Vision ◽  
Positional Uncertainty ◽  
Show Evidence ◽  
Source Confusion ◽  
Trial Basis ◽  
Visual Crowding ◽  
Line Positions ◽  
Method Of Adjustment ◽  
Uncertainty Source ◽  
Multiple Error

Although we perceive a richly detailed visual world, our ability to identify individual objects is severely limited in clutter, particularly in peripheral vision. Models of such crowding have generally been driven by the phenomenological misidentifications of crowded targets: using stimuli that do not easily combine to form a unique symbol (e.g. letters or objects), observers typically confuse the source of objects and report either the target or a distractor, but when continuous features are used (e.g. orientated gratings or line positions) observers report a feature somewhere between the target and distractor. To reconcile these accounts, we develop a hybrid method of adjustment that allows detailed analysis of these multiple error categories. Observers reported the orientation of a target, under several distractor conditions, by adjusting an identical foveal target. We apply new modelling to quantify whether perceptual reports show evidence of positional uncertainty, source confusion, and featural averaging on a trial-by-trial basis. Our results show that observers make a large proportion of source-confusion errors. However, our study also reveals the distribution of perceptual reports that underlie performance in this crowding task more generally: aggregate errors cannot be neatly labelled because they are heterogeneous and their structure depends on target-distractor distance.

scholarly journals A summary-statistic representation in peripheral vision explains visual crowding

2009 ◽  
Vol 9 (12) ◽  
pp. 13-13 ◽  
Author(s):  
B. Balas ◽  
L. Nakano ◽  
R. Rosenholtz
Keyword(s):  
Peripheral Vision ◽  
Summary Statistic ◽  
Visual Crowding

scholarly journals The role of Peripheral Vision in the Flashed Face Distortion Effect

Perception ◽  
2018 ◽  
Vol 48 (1) ◽  
pp. 93-101
Author(s):  
Jamie Bowden ◽  
David Whitaker ◽  
Matt J. Dunn
Keyword(s):  
Visual Acuity ◽  
Analogue Scale ◽  
Peripheral Vision ◽  
Crowding Effect ◽  
Visual Periphery ◽  
Peripheral Location ◽  
Distortion Effect ◽  
Optical Defocus ◽  
Visual Crowding

The flashed face distortion effect is a phenomenon whereby images of faces, presented at 4–5 Hz in the visual periphery, appear distorted. It has been hypothesized that the effect is driven by cortical, rather than retinal, components. Here, we investigated the role of peripheral viewing on the effect. Normally sighted participants viewed the stimulus peripherally, centrally, and centrally with a blurring lens (to match visual acuity in the peripheral location). Participants rated the level of distortion using a Visual Analogue Scale. Although optical defocus did have a significant effect on distortion ratings, peripheral viewing had a much greater effect, despite matched visual acuity. We suggest three potential mechanisms for this finding: increased positional uncertainty in the periphery, reduced deployment of attention to the visual periphery, or the visual crowding effect.

The effects of visual crowding, text size, and positional uncertainty on text legibility at a glance

2018 ◽  
Vol 70 ◽  
pp. 240-246 ◽  
Author(s):  
Jonathan Dobres ◽  
Benjamin Wolfe ◽  
Nadine Chahine ◽  
Bryan Reimer
Keyword(s):  
Positional Uncertainty ◽  
Visual Crowding ◽  
Text Legibility

scholarly journals Dissociable effects of visual crowding on the perception of color and motion

2020 ◽  
Vol 117 (14) ◽  
pp. 8196-8202 ◽  
Author(s):  
John A. Greenwood ◽  
Michael J. Parsons
Keyword(s):  
Deleterious Effect ◽  
Peripheral Vision ◽  
The Other ◽  
Correct Recognition ◽  
Visual Features ◽  
Double Dissociation ◽  
Multiple Processes ◽  
Specific Manner ◽  
Visual Crowding ◽  
Selective Mechanism

Our ability to recognize objects in peripheral vision is fundamentally limited by crowding, the deleterious effect of clutter that disrupts the recognition of features ranging from orientation and color to motion and depth. Previous research is equivocal on whether this reflects a singular process that disrupts all features simultaneously or multiple processes that affect each independently. We examined crowding for motion and color, two features that allow a strong test of feature independence. “Cowhide” stimuli were presented 15° in peripheral vision, either in isolation or surrounded by flankers to give crowding. Observers reported either the target direction (clockwise/counterclockwise from upward) or its hue (blue/purple). We first established that both features show systematic crowded errors (biased predominantly toward the flanker identities) and selectivity for target–flanker similarity (with reduced crowding for dissimilar target/flanker elements). The multiplicity of crowding was then tested with observers identifying both features. Here, a singular object-selective mechanism predicts that when crowding is weak for one feature and strong for the other that crowding should be all-or-none for both. In contrast, when crowding was weak for color and strong for motion, errors were reduced for color but remained for motion, and vice versa with weak motion and strong color crowding. This double dissociation reveals that crowding disrupts certain combinations of visual features in a feature-specific manner, ruling out a singular object-selective mechanism. Thus, the ability to recognize one aspect of a cluttered scene, like color, offers no guarantees for the correct recognition of other aspects, like motion.

scholarly journals Jumpy and Jerky: When Peripheral Vision Faces Reverse-Phi

i-Perception ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 204166952093910
Author(s):  
Jean Lorenceau ◽  
Patrick Cavanagh
Keyword(s):  
Apparent Motion ◽  
Peripheral Vision ◽  
Reversal Rate ◽  
Motion Processing ◽  
Central Vision ◽  
Positional Uncertainty ◽  
Motion Energy ◽  
Motion Speed ◽  
Over Time

When an annulus in fast apparent motion reverses its contrast over time, the foveal and peripheral percepts are strikingly different. In central vision, the annulus appears to follow the same path as an annulus without flicker, whereas in the periphery, the stimulus seems to randomly jump across the screen. The illusion strength depends on motion speed and reversal rate. Our observations suggest that it results from a balance between conflicting phi and reverse-phi motion, positional uncertainty, and attention. In addition to illustrating the differences between central and peripheral motion processing, this illusion shows that both discrete positional sampling and motion energy combine to generate motion percepts, although with eccentricity dependent weights that are themselves affected by attention.

scholarly journals Crowding changes appearance systematically in peripheral, amblyopic, and developing vision

2021 ◽  
Author(s):  
A.V. Kalpadakis-Smith ◽  
V.K. Tailor ◽  
A.H. Dahlmann-Noor ◽  
J.A. Greenwood
Keyword(s):  
Peripheral Vision ◽  
Underlying Mechanism ◽  
Reference Stimulus ◽  
Disruptive Effect ◽  
Typically Developing ◽  
Foveal Vision ◽  
Typically Developing Children ◽  
Strabismic Amblyopia ◽  
Adults And Children ◽  
Visual Crowding

AbstractVisual crowding is the disruptive effect of clutter on object recognition. Although most prominent in adult peripheral vision, crowding also disrupts foveal vision in typically-developing children and those with strabismic amblyopia. Do these crowding effects share the same mechanism? Here we exploit observations that crowded errors in peripheral vision are not random: target objects appear either averaged with the flankers (assimilation), or replaced by them (substitution). If amblyopic and developmental crowding share the same mechanism then their errors should be similarly systematic. We tested foveal vision in children aged 3-9 years with typical vision or strabismic amblyopia, and peripheral vision in adults. The perceptual effects of crowding were measured by requiring observers to adjust a reference stimulus to match the perceived orientation of a target ‘Vac-Man’ element. When the target was surrounded by flankers that differed by ±30°, adults and children reported orientations between the target and flankers (assimilation). Errors were reduced with ±90° differences, but primarily matched the flanker orientation (substitution) when they did occur. A population pooling model of crowding successfully simulated this pattern of errors in all three groups. We conclude that the perceptual effects of amblyopic and developing crowding are systematic and resemble the near periphery in adults, suggesting a common underlying mechanism.

scholarly journals Investigating Visual Crowding of Objects in Complex Real-World Scenes

i-Perception ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 204166952199415
Author(s):  
Ryan V. Ringer ◽  
Allison M. Coy ◽  
Adam M. Larson ◽  
Lester C. Loschky
Keyword(s):  
Object Recognition ◽  
Real World ◽  
Target Location ◽  
Peripheral Vision ◽  
Retinal Eccentricity ◽  
Choice Response ◽  
Natural Scenes ◽  
Found Object ◽  
Visual Crowding ◽  
Effect Experiment

Visual crowding, the impairment of object recognition in peripheral vision due to flanking objects, has generally been studied using simple stimuli on blank backgrounds. While crowding is widely assumed to occur in natural scenes, it has not been shown rigorously yet. Given that scene contexts can facilitate object recognition, crowding effects may be dampened in real-world scenes. Therefore, this study investigated crowding using objects in computer-generated real-world scenes. In two experiments, target objects were presented with four flanker objects placed uniformly around the target. Previous research indicates that crowding occurs when the distance between the target and flanker is approximately less than half the retinal eccentricity of the target. In each image, the spacing between the target and flanker objects was varied considerably above or below the standard (0.5) threshold to either suppress or facilitate the crowding effect. Experiment 1 cued the target location and then briefly flashed the scene image before participants could move their eyes. Participants then selected the target object’s category from a 15-alternative forced choice response set (including all objects shown in the scene). Experiment 2 used eye tracking to ensure participants were centrally fixating at the beginning of each trial and showed the image for the duration of the participant’s fixation. Both experiments found object recognition accuracy decreased with smaller spacing between targets and flanker objects. Thus, this study rigorously shows crowding of objects in semantically consistent real-world scenes.

scholarly journals Influence of Multiple Types of Proximity on the Degree of Visual Crowding Effects Within a Single Gap Detection Task

i-Perception ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 204166951983726 ◽  
Author(s):  
Daisuke Hayashi ◽  
Madoka Ohnishi
Keyword(s):  
Target Location ◽  
Peripheral Vision ◽  
Function Analysis ◽  
Semantic Category ◽  
Detection Task ◽  
Spatial Distance ◽  
Gap Detection ◽  
Single Task ◽  
Different Types ◽  
Visual Crowding

The visual system cannot recognize an object (target) in peripheral vision when presented with neighboring similar stimuli (flanker). This object recognition disability is known as crowding. Studies have shown that various types of proximity, such as spatial distance or semantic category, affect the degree of crowding. However, thus far, these effects have mostly been studied separately. Hence, their underlying similarities and differences are still unknown. In this study, we developed a novel gap detection task and tested whether the effect of three different types of proximity in crowding (the relative position between target gap and nearest flanker edge, the flanker location compared with the target location, and the semantic category of the target) can be measured within a single task. A psychometric function analysis revealed that two of the assumed types of proximity affected the degree of crowding within a single task.

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