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L-Miao L, Reynvoet B, Sayim B. The radial-tangential anisotropy of numerosity perception. J Vis 2024; 24:15. [PMID: 39046720 PMCID: PMC11271808 DOI: 10.1167/jov.24.7.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 06/17/2024] [Indexed: 07/25/2024] Open
Abstract
Humans can estimate the number of visually presented items without counting. In most studies on numerosity perception, items are uniformly distributed across displays, with identical distributions in central and eccentric parts. However, the neural and perceptual representation of the human visual field differs between the fovea and the periphery. For example, in peripheral vision, there are strong asymmetries with regard to perceptual interferences between visual items. In particular, items arranged radially usually interfere more strongly with each other than items arranged tangentially (the radial-tangential anisotropy). This has been shown for crowding (the deleterious effect of clutter on target identification) and redundancy masking (the reduction of the number of perceived items in repeating patterns). In the present study, we tested how the radial-tangential anisotropy of peripheral vision impacts numerosity perception. In four experiments, we presented displays with varying numbers of discs that were predominantly arranged radially or tangentially, forming strong and weak interference conditions, respectively. Participants were asked to report the number of discs. We found that radial displays were reported as less numerous than tangential displays for all radial and tangential manipulations: weak (Experiment 1), strong (Experiment 2), and when using displays with mixed contrast polarity discs (Experiments 3 and 4). We propose that numerosity perception exhibits a significant radial-tangential anisotropy, resulting from local spatial interactions between items.
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Affiliation(s)
- Li L-Miao
- Université de Lille, CNRS, UMR 9193-SCALab-Sciences Cognitives et Sciences Affectives, Lille, France
- Faculty of Psychology and Educational Sciences, KU Leuven Kulak, Kortrijk, Belgium
- https://miaoli-psy.github.io/
| | - Bert Reynvoet
- Faculty of Psychology and Educational Sciences, KU Leuven Kulak, Kortrijk, Belgium
- Brain and Cognition, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
- https://www.kuleuven.be/wieiswie/nl/person/00047096
| | - Bilge Sayim
- Université de Lille, CNRS, UMR 9193-SCALab-Sciences Cognitives et Sciences Affectives, Lille, France
- https://www.appearancelab.org/bilge
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2
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Purokayastha S, Roberts M, Carrasco M. Do microsaccades vary with discriminability around the visual field? J Vis 2024; 24:11. [PMID: 38869372 PMCID: PMC11178122 DOI: 10.1167/jov.24.6.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 04/19/2024] [Indexed: 06/14/2024] Open
Abstract
Microsaccades-tiny fixational eye movements-improve discriminability in high-acuity tasks in the foveola. To investigate whether they help compensate for low discriminability at the perifovea, we examined microsaccade characteristics relative to the adult visual performance field, which is characterized by two perceptual asymmetries: horizontal-vertical anisotropy (better discrimination along the horizontal than vertical meridian) and vertical meridian asymmetry (better discrimination along the lower than upper vertical meridian). We investigated whether and to what extent microsaccade directionality varies when stimuli are at isoeccentric locations along the cardinals under conditions of heterogeneous discriminability (Experiment 1) and homogeneous discriminability, equated by adjusting stimulus contrast (Experiment 2). Participants performed a two-alternative forced-choice orientation discrimination task. In both experiments, performance was better on trials without microsaccades between ready signal onset and stimulus offset than on trials with microsaccades. Across the trial sequence, the microsaccade rate and directional pattern were similar across locations. Our results indicate that microsaccades were similar regardless of stimulus discriminability and target location, except during the response period-once the stimuli were no longer present and target location no longer uncertain-when microsaccades were biased toward the target location. Thus, this study reveals that microsaccades do not flexibly adapt as a function of varying discriminability in a basic visual task around the visual field.
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Affiliation(s)
| | - Mariel Roberts
- Department of Psychology, New York University, New York, NY, USA
| | - Marisa Carrasco
- Department of Psychology, New York University, New York, NY, USA
- Center for Neural Science, New York University, New York, NY, USA
- Carrasco Lab, New York University, New York, NY, USA
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3
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Tanriverdi D, Cornelissen FW. Rapid assessment of peripheral visual crowding. Front Neurosci 2024; 18:1332701. [PMID: 38629049 PMCID: PMC11019380 DOI: 10.3389/fnins.2024.1332701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/12/2024] [Indexed: 04/19/2024] Open
Abstract
Visual crowding, the phenomenon in which the ability to distinguish objects is hindered in cluttered environments, has critical implications for various ophthalmic and neurological disorders. Traditional methods for assessing crowding involve time-consuming and attention-demanding psychophysical tasks, making routine examination challenging. This study sought to compare trial-based Alternative Forced-Choice (AFC) paradigms using either manual or eye movement responses and a continuous serial search paradigm employing eye movement responses to evaluate their efficiency in rapidly assessing peripheral crowding. In all paradigms, we manipulated the orientation of a central Gabor patch, which could be presented alone or surrounded by six Gabor patches. We measured participants' target orientation discrimination thresholds using adaptive psychophysics to assess crowding magnitude. Depending on the paradigm, participants either made saccadic eye movements to the target location or responded manually by pressing a key or moving a mouse. We compared these paradigms in terms of crowding magnitude, assessment time, and paradigm demand. Our results indicate that employing eye movement-based paradigms for assessing peripheral visual crowding yields results faster compared to paradigms that necessitate manual responses. Furthermore, when considering similar levels of confidence in the threshold measurements, both a novel serial search paradigm and an eye movement-based 6AFC paradigm proved to be the most efficient in assessing crowding magnitude. Additionally, crowding estimates obtained through either the continuous serial search or the 6AFC paradigms were consistently higher than those obtained using the 2AFC paradigms. Lastly, participants did not report a clear difference between paradigms in terms of their perceived demand. In conclusion, both the continuous serial search and the 6AFC eye movement response paradigms enable a fast assessment of visual crowding. These approaches may potentially facilitate future routine crowding assessment. However, the usability of these paradigms in specific patient populations and specific purposes should be assessed.
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Affiliation(s)
- Dilce Tanriverdi
- Laboratory for Experimental Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
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4
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Veríssimo IS, Nudelman Z, Olivers CNL. Does crowding predict conjunction search? An individual differences approach. Vision Res 2024; 216:108342. [PMID: 38198971 DOI: 10.1016/j.visres.2023.108342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 11/27/2023] [Accepted: 12/07/2023] [Indexed: 01/12/2024]
Abstract
Searching for objects in the visual environment is an integral part of human behavior. Most of the information used during such visual search comes from the periphery of our vision, and understanding the basic mechanisms of search therefore requires taking into account the inherent limitations of peripheral vision. Our previous work using an individual differences approach has shown that one of the major factors limiting peripheral vision (crowding) is predictive of single feature search, as reflected in response time and eye movement measures. Here we extended this work, by testing the relationship between crowding and visual search in a conjunction-search paradigm. Given that conjunction search involves more fine-grained discrimination and more serial behavior, we predicted it would be strongly affected by crowding. We tested sixty participants with regard to their sensitivity to both orientation and color-based crowding (as measured by critical spacing) and their efficiency in searching for a color/orientation conjunction (as indicated by manual response times and eye movements). While the correlations between the different crowding tasks were high, the correlations between the different crowding measures and search performance were relatively modest, and no higher than those previously observed for single-feature search. Instead, observers showed very strong color selectivity during search. The results suggest that conjunction search behavior relies more on top-down guidance (here by color) and is therefore relatively less determined by individual differences in sensory limitations as caused by crowding.
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Affiliation(s)
- Inês S Veríssimo
- Department of Experimental and Applied Psychology, Cognitive Psychology Section, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; Institute for Brain and Behavior, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
| | - Zachary Nudelman
- Department of Experimental and Applied Psychology, Cognitive Psychology Section, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Christian N L Olivers
- Department of Experimental and Applied Psychology, Cognitive Psychology Section, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
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5
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Bondarko VM, Chikhman VN, Danilova MV, Solnushkin SD. Foveal crowding for large and small Landolt Cs: Similarity and Attention. Vision Res 2024; 215:108346. [PMID: 38171199 DOI: 10.1016/j.visres.2023.108346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 12/05/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
We compare the recognition of foveal crowded Landolt Cs of two sizes: brief (40 ms), large, low-contrast Cs and high-contrast (1 sec) tests at the resolution limit of the visual system. In different series, the test Landolt C was surrounded by two identical distractors located symmetrically along the horizontal or by a single distractor. The distractors were Landolt Cs or rings. At the resolution limit, the critical spacing was similar in the two series and did not depend on the type of distractor. The result supports the hypothesis that crowding at the resolution limit occurs when both the test and the distractors fall into the same smallest receptive field responsible for the target recognition. For large stimuli, at almost all separations distractors of the same shape caused greater impairment than did rings, and recognition errors were non-random. The critical spacing was equal to 0.5 test diameters only in the presence of one distracting Landolt C. This result suggests that attention is involved: When one distractor is added, involuntary attention, which is directed to the centre of gravity of the stimulus, can lead to confusion of features that are present in both tests and distractors and thus to non-random errors.
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Affiliation(s)
- V M Bondarko
- IP Pavlov Institute of Physiology, Laboratory of Visual Physiology, Nab.Makarova 6, St. Petersburg 199034, Russia
| | - V N Chikhman
- IP Pavlov Institute of Physiology, Laboratory of Information Technologies and Mathematical Modelling, Nab.Makarova 6, St. Petersburg 199034, Russia
| | - M V Danilova
- IP Pavlov Institute of Physiology, Laboratory of Visual Physiology, Nab.Makarova 6, St. Petersburg 199034, Russia.
| | - S D Solnushkin
- IP Pavlov Institute of Physiology, Laboratory of Information Technologies and Mathematical Modelling, Nab.Makarova 6, St. Petersburg 199034, Russia
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6
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Purokayastha S, Roberts M, Carrasco M. Do microsaccades vary with discriminability around the visual field? BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.11.575288. [PMID: 38260406 PMCID: PMC10802594 DOI: 10.1101/2024.01.11.575288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Microsaccades-tiny fixational eye movements- improve discriminability in high acuity tasks in the foveola. To investigate whether they help compensate for low discriminability at perifovea, we examined MS characteristics relative to the adult visual performance field, which is characterized by two perceptual asymmetries: Horizontal-Vertical Anisotropy (better discrimination along the horizontal than vertical meridian), and Vertical Meridian Asymmetry (better discrimination along the lower- than upper-vertical meridian). We investigated whether and to what extent microsaccade directionality varies when stimuli are at isoeccentric locations along the cardinals under conditions of heterogeneous discriminability (Experiment 1) and homogeneous discriminability, equated by adjusting stimulus contrast (Experiment 2). Participants performed a two-alternative forced-choice orientation discrimination task. In both experiments, performance was better on trials without microsaccades between ready signal onset and stimulus offset than on trials with microsaccades. Across the trial sequence the microsaccade rate and directional pattern were similar across locations. Our results indicate that microsaccades were similar regardless of stimulus discriminability and target location, except during the response period-once the stimuli were no longer present and target location no longer uncertain-when microsaccades were biased toward the target location. Thus, this study reveals that microsaccades do not flexibly adapt as a function of varying discriminability in a basic visual task around the visual field.
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Affiliation(s)
| | - Mariel Roberts
- Department of Psychology, New York University, New York, USA
| | - Marisa Carrasco
- Department of Psychology, New York University, New York, USA
- Center for Neural Science, New York University, New York, USA
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7
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Kim T, Pasupathy A. Neural correlates of crowding in macaque area V4. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562617. [PMID: 37905025 PMCID: PMC10614871 DOI: 10.1101/2023.10.16.562617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Visual crowding refers to the phenomenon where a target object that is easily identifiable in isolation becomes difficult to recognize when surrounded by other stimuli (distractors). Extensive psychophysical studies support two alternative possibilities for the underlying mechanisms. One hypothesis suggests that crowding results from the loss of visual information due to pooled encoding of multiple nearby stimuli in the mid-level processing stages along the ventral visual pathway. Alternatively, crowding may arise from limited resolution in decoding object information during recognition and the encoded information may remain inaccessible unless it is salient. To rigorously test these alternatives, we studied the responses of single neurons in macaque area V4, an intermediate stage of the ventral, object-processing pathway, to parametrically designed crowded displays and their texture-statistics matched metameric counterparts. Our investigations reveal striking parallels between how crowding parameters, e.g., number, distance, and position of distractors, influence human psychophysical performance and V4 shape selectivity. Importantly, we found that enhancing the salience of a target stimulus could reverse crowding effects even in highly cluttered scenes and such reversals could be protracted reflecting a dynamical process. Overall, we conclude that a pooled encoding of nearby stimuli cannot explain the observed responses and we propose an alternative model where V4 neurons preferentially encode salient stimuli in crowded displays.
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Affiliation(s)
- Taekjun Kim
- Department of Biological Structure, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
| | - Anitha Pasupathy
- Department of Biological Structure, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
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Huang Y, Liu Z, Wang M, Gao L, Wu Y, Hu J, Zhang Z, Yan FF, Deng D, Huang CB, Yu M. Cortical Reorganization After Optical Alignment in Strabismic Patients Outside of Critical Period. Invest Ophthalmol Vis Sci 2023; 64:5. [PMID: 37535007 PMCID: PMC10408769 DOI: 10.1167/iovs.64.11.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 07/17/2023] [Indexed: 08/04/2023] Open
Abstract
PURPOSE To measure visual crowding, an essential bottleneck on object recognition and reliable psychophysical index of cortex organization, in older children and adults with horizontal concomitant strabismus before and after strabismus surgery. METHODS Using real-time eye tracking to ensure gaze-contingent display, we examined the peripheral visual crowding effects in older children and adults with horizontal concomitant strabismus but without amblyopia before and after strabismus surgery. Patients were asked to discriminate the orientation of the central tumbling E target letter with flankers arranged along the radial or tangential axis in the nasal or temporal hemifield at different eccentricities (5° or 10°). The critical spacing value, which is the minimum space between the target and the flankers required for correct discrimination, was obtained for comparisons before and after strabismus surgery. RESULTS Twelve individuals with exotropia (6 males, 21.75 ± 7.29 years, mean ± SD) and 15 individuals with esotropia (6 males, 24.13 ± 5.96 years) participated in this study. We found that strabismic individuals showed significantly larger critical spacing with nasotemporal asymmetry along the radial axis that related to the strabismus pattern, with exotropes exhibiting stronger temporal field crowding and esotropes exhibiting stronger nasal field crowding before surgical alignment. After surgery, the critical spacing was reduced and rebalanced between the nasal and temporal hemifields. Furthermore, the postoperative recovery of stereopsis was associated with the extent of nasotemporal balance of critical spacing. CONCLUSIONS We find that optical realignment (i.e., strabismus surgery) can normalize the enlarged visual crowding effects, a reliable psychophysical index of cortical organization, in the peripheral visual field of older children and adults with strabismus and rebalance the nasotemporal asymmetry of crowding, promoting the recovery of postoperative stereopsis. Our results indicated a potential of experience-dependent cortical organization after axial alignment even for individuals who are out of the critical period of visual development, illuminating the capacity and limitations of optics on sensory plasticity and emphasizing the importance of ocular correction for clinical practice.
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Affiliation(s)
- Yiru Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Zitian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Mingqin Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Le Gao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Yanyan Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Jingyi Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Zhenyu Zhang
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences (CAS), Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Fang-Fang Yan
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences (CAS), Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Daming Deng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Chang-Bing Huang
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences (CAS), Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
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9
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Chen YR, Zhang YW, Zhang JY. The impact of training on the inner-outer asymmetry in crowding. J Vis 2023; 23:3. [PMID: 37526622 PMCID: PMC10399601 DOI: 10.1167/jov.23.8.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 06/18/2023] [Indexed: 08/02/2023] Open
Abstract
Inner-outer asymmetry, where the outer flanker induces stronger crowding than the inner flanker, is a hallmark property of visual crowding. It is unclear the contribution of inner-outer asymmetry to the pattern of crowding errors (biased predominantly toward the flanker identities) and the role of training on crowding errors. In a typical radial crowding display, 20 observers were asked to report the orientation of a target Gabor (7.5° eccentricity) flanked by either an inner or outer Gabor along the horizontal meridian. The results showed that outer flanker conditions induced stronger crowding, accompanied by assimilative errors to the outer flanker for similar target/flanker elements. In contrast, the inner flanker condition exhibited weaker crowding, with no significant patterns of crowding errors. A population coding model showed that the flanker weights in the outer flanker condition were significantly higher than those in the inner flanker condition. Nine observers continued to train the outer flanker condition for four sessions. Training reduced inner-outer asymmetry and reduced flanker weights to the outer flanker. The learning effects were retained over 4 to 6 months. Individual differences in the appearance of crowding errors, the strength of inner-outer asymmetry, and the training effects were evident. Nevertheless, our findings indicate that different crowding mechanisms may be responsible for the asymmetric crowding effects induced by inner and outer flankers, with the outer flankers dominating the appearance more than the inner ones. Training reduces inner-outer asymmetry by reducing target/flanker confusion, and learning is persistent over months, suggesting that perceptual learning has the potential to improve visual performance by promoting neural plasticity.
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Affiliation(s)
- Yan-Ru Chen
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Yu-Wei Zhang
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Jun-Yun Zhang
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
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10
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Kurzawski JW, Burchell A, Thapa D, Winawer J, Majaj NJ, Pelli DG. The Bouma law accounts for crowding in 50 observers. J Vis 2023; 23:6. [PMID: 37540179 PMCID: PMC10408772 DOI: 10.1167/jov.23.8.6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/16/2023] [Indexed: 08/05/2023] Open
Abstract
Crowding is the failure to recognize an object due to surrounding clutter. Our visual crowding survey measured 13 crowding distances (or "critical spacings") twice in each of 50 observers. The survey includes three eccentricities (0, 5, and 10 deg), four cardinal meridians, two orientations (radial and tangential), and two fonts (Sloan and Pelli). The survey also tested foveal acuity, twice. Remarkably, fitting a two-parameter model-the well-known Bouma law, where crowding distance grows linearly with eccentricity-explains 82% of the variance for all 13 × 50 measured log crowding distances, cross-validated. An enhanced Bouma law, with factors for meridian, crowding orientation, target kind, and observer, explains 94% of the variance, again cross-validated. These additional factors reveal several asymmetries, consistent with previous reports, which can be expressed as crowding-distance ratios: 0.62 horizontal:vertical, 0.79 lower:upper, 0.78 right:left, 0.55 tangential:radial, and 0.78 Sloan-font:Pelli-font. Across our observers, peripheral crowding is independent of foveal crowding and acuity. Evaluation of the Bouma factor, b (the slope of the Bouma law), as a biomarker of visual health would be easier if there were a way to compare results across crowding studies that use different methods. We define a standardized Bouma factor b' that corrects for differences from Bouma's 25 choice alternatives, 75% threshold criterion, and linearly symmetric flanker placement. For radial crowding on the right meridian, the standardized Bouma factor b' is 0.24 for this study, 0.35 for Bouma (1970), and 0.30 for the geometric mean across five representative modern studies, including this one, showing good agreement across labs, including Bouma's. Simulations, confirmed by data, show that peeking can skew estimates of crowding (e.g., greatly decreasing the mean or doubling the SD of log b). Using gaze tracking to prevent peeking, individual differences are robust, as evidenced by the much larger 0.08 SD of log b across observers than the mere 0.03 test-retest SD of log b measured in half an hour. The ease of measurement of crowding enhances its promise as a biomarker for dyslexia and visual health.
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Affiliation(s)
- Jan W Kurzawski
- Department of Psychology, New York University, New York, NY, USA
| | - Augustin Burchell
- Cognitive Science & Computer Science, Swarthmore College, Swarthmore, PA, USA
| | - Darshan Thapa
- Center for Neural Science, New York University, New York, NY, USA
| | - Jonathan Winawer
- Department of Psychology, New York University, New York, NY, USA
- Center for Neural Science, New York University, New York, NY, USA
| | - Najib J Majaj
- Center for Neural Science, New York University, New York, NY, USA
| | - Denis G Pelli
- Department of Psychology, New York University, New York, NY, USA
- Center for Neural Science, New York University, New York, NY, USA
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11
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Haseeb Z, Wolfe B, Kosovicheva A. Spatial variability in localization biases predicts crowding performance. J Vis 2023; 23:9. [PMID: 37432845 DOI: 10.1167/jov.23.7.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023] Open
Abstract
Visual processing varies substantially across individuals, and prior work has shown significant individual differences in fundamental processes such as spatial localization. For example, when asked to report the location of a briefly flashed target in the periphery, different observers systematically misperceive its location in an idiosyncratic manner, showing different patterns of reproduction error across visual field locations. In this study, we tested whether these individual differences may propagate to other stages of visual processing, affecting the strength of visual crowding, which depends on the spacing between objects in the periphery. We, therefore, investigated the relationship between observers' idiosyncratic biases in localization and the strength of crowding to determine whether these spatial biases limit peripheral object recognition. To examine this relationship, we measured the strength of crowding at 12 locations at 8° eccentricity, in addition to the perceived spacing between pairs of Gaussian patches at these same locations. These measurements show an association between variability in crowding strength and perceived spacing at the same visual field locations: at locations where a participant experienced stronger crowding, their perceived spacing was smaller, and vice versa. We demonstrate that spatial heterogeneity in perceived spacing affects observers' ability to recognize objects in the periphery. Our results support the idea that variability in both spatial sensitivity and bias contribute to variability in the strength of crowding and bolster the account that variability in spatial coding may propagate across multiple stages of visual processing.
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Affiliation(s)
- Zainab Haseeb
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, Canada
- https://applylab.org/
| | - Benjamin Wolfe
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, Canada
- https://applylab.org/
| | - Anna Kosovicheva
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, Canada
- https://applylab.org/
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12
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Himmelberg MM, Winawer J, Carrasco M. Polar angle asymmetries in visual perception and neural architecture. Trends Neurosci 2023; 46:445-458. [PMID: 37031051 PMCID: PMC10192146 DOI: 10.1016/j.tins.2023.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 04/10/2023]
Abstract
Human visual performance changes with visual field location. It is best at the center of gaze and declines with eccentricity, and also varies markedly with polar angle. These perceptual polar angle asymmetries are linked to asymmetries in the organization of the visual system. We review and integrate research quantifying how performance changes with visual field location and how this relates to neural organization at multiple stages of the visual system. We first briefly review how performance varies with eccentricity and the neural foundations of this effect. We then focus on perceptual polar angle asymmetries and their neural foundations. Characterizing perceptual and neural variations across and around the visual field contributes to our understanding of how the brain translates visual signals into neural representations which form the basis of visual perception.
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Affiliation(s)
- Marc M Himmelberg
- Department of Psychology, New York University, New York, NY 10003, USA; Center for Neural Science, New York University, New York, NY 10003, USA.
| | - Jonathan Winawer
- Department of Psychology, New York University, New York, NY 10003, USA; Center for Neural Science, New York University, New York, NY 10003, USA
| | - Marisa Carrasco
- Department of Psychology, New York University, New York, NY 10003, USA; Center for Neural Science, New York University, New York, NY 10003, USA.
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13
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Gong M, Liu T, Liu X, Huangfu B, Geng F. Attention relieves visual crowding: Dissociable effects of peripheral and central cues. J Vis 2023; 23:9. [PMID: 37163245 PMCID: PMC10179668 DOI: 10.1167/jov.23.5.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
Visual crowding can be reduced when attention is directed to the target by peripheral cues. However, it is unclear whether central cues relieve visual crowding to the same extent as peripheral cues. In this study, we combined the Posner cueing task and the crowding task to investigate the effect of exogenous and endogenous attention on crowding. In Experiment 1, five different stimulus-onset asychronies (SOAs) between the cue and the target and a predictive validity of 100% were adopted. Both attentional cues were shown to significantly reduce the effect of visual crowding, but the peripheral cue was more effective than the central cue. Furthermore, peripheral cues started to relieve visual crowding at the shortest SOA (100 ms), whereas central cues worked only at later SOAs (275 ms or above). When the predictive validity of the cue was decreased to 70% in Experiment 2, similar results to Experiment 1 were found, but the valid cue was less effective in reducing crowding than that in Experiment 1. In Experiment 3, when the predictive validity was decreased to 50%, a valid peripheral cue improved performance but a valid central cue did not, suggesting that endogenous attention but not exogenous attention can be voluntarily controlled when the cues are not predictive of the target's location. These findings collectively suggest that both peripheral and central cues can alleviate crowding, but they differ in terms of strength, time dynamics, and flexibility of voluntary control.
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Affiliation(s)
- Mingliang Gong
- School of Psychology, Jiangxi Normal University, Nanchang, China
| | - Tingyu Liu
- School of Psychology, Jiangxi Normal University, Nanchang, China
| | - Xi Liu
- School of Psychology, Jiangxi Normal University, Nanchang, China
| | - Bingzhe Huangfu
- School of Psychology, Jiangxi Normal University, Nanchang, China
| | - Fulei Geng
- School of Psychology, Jiangxi Normal University, Nanchang, China
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14
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Jigo M, Tavdy D, Himmelberg MM, Carrasco M. Cortical magnification eliminates differences in contrast sensitivity across but not around the visual field. eLife 2023; 12:e84205. [PMID: 36961485 PMCID: PMC10089656 DOI: 10.7554/elife.84205] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 03/16/2023] [Indexed: 03/25/2023] Open
Abstract
Human visual performance changes dramatically both across (eccentricity) and around (polar angle) the visual field. Performance is better at the fovea, decreases with eccentricity, and is better along the horizontal than vertical meridian and along the lower than the upper vertical meridian. However, all neurophysiological and virtually all behavioral studies of cortical magnification have investigated eccentricity effects without considering polar angle. Most performance differences due to eccentricity are eliminated when stimulus size is cortically magnified (M-scaled) to equate the size of its cortical representation in primary visual cortex (V1). But does cortical magnification underlie performance differences around the visual field? Here, to assess contrast sensitivity, human adult observers performed an orientation discrimination task with constant stimulus size at different locations as well as when stimulus size was M-scaled according to stimulus eccentricity and polar angle location. We found that although M-scaling stimulus size eliminates differences across eccentricity, it does not eliminate differences around the polar angle. This finding indicates that limits in contrast sensitivity across eccentricity and around polar angle of the visual field are mediated by different anatomical and computational constraints.
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Affiliation(s)
- Michael Jigo
- Department of Psychology, New York UniversityNew YorkUnited States
| | - Daniel Tavdy
- Department of Psychology, New York UniversityNew YorkUnited States
| | - Marc M Himmelberg
- Department of Psychology, New York UniversityNew YorkUnited States
- Center for Neural Science, New York UniversityNew YorkUnited States
| | - Marisa Carrasco
- Department of Psychology, New York UniversityNew YorkUnited States
- Center for Neural Science, New York UniversityNew YorkUnited States
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15
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Huang Y, Liu Z, Chen Z, Zhan Z, Gao L, Hu J, Wu Y, Yan FF, Deng D, Huang CB, Yu M. Visual Crowding Reveals Field- and Axis-Specific Cortical Miswiring After Long-Term Axial Misalignment in Strabismic Patients Without Amblyopia. Invest Ophthalmol Vis Sci 2023; 64:10. [PMID: 36652265 PMCID: PMC9855284 DOI: 10.1167/iovs.64.1.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Purpose Inspired by physiological and neuroimaging findings that revealed squint-induced modification of cortical volume and visual receptive field in early visual areas, we hypothesized that strabismic eyes without amblyopia manifest an increase in critical spacing of visual crowding, an essential bottleneck on object recognition and reliable psychophysical index of cortical organization. Methods We used real-time eye tracking to ensure gaze-contingent display and examined visual crowding in patients with horizontal concomitant strabismus (both esotropia and exotropia) but without amblyopia and age-matched normal controls. Results Nineteen patients with exotropia (12 men, mean ± SD = 22.89 ± 7.82 years), 21 patients with esotropia (10 men, mean ± SD = 23.48 ± 6.95 years), and 14 age-matched normal controls (7 men, mean ± SD = 23.07 ± 1.07 years) participated in this study. We found that patients with strabismus without amblyopia showed significantly larger critical spacing with nasotemporal asymmetry in only the radial axis that related to the strabismus pattern, with exotropia exhibiting stronger temporal hemifield crowding and esotropia exhibiting stronger nasal hemifield crowding, in both the deviated and fixating eyes. Moreover, the magnitude of crowding change was related to the duration and degree of strabismic deviation. Conclusions Using visual crowding as a psychophysical index of cortical organization, our study demonstrated significantly greater peripheral visual crowding with nasotemporal asymmetry in only the radial axis in patients with strabismus without amblyopia, indicating the existence of hemifield- and axis-specific miswiring of cortical processing in object recognition induced by long-term adaptation to ocular misalignment.
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Affiliation(s)
- Yiru Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Zitian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Zidong Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Zongyi Zhan
- Shenzhen Eye Hospital, Shenzhen Eye Institute, Shenzhen Eye Hospital affiliated to Jinan University, Shenzhen, China,School of Optometry, Shenzhen University, Shenzhen, China
| | - Le Gao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Jingyi Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Yanyan Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Fang-Fang Yan
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences (CAS), Beijing, China,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Daming Deng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
| | - Chang-Bing Huang
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences (CAS), Beijing, China,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, Guangdong, China
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16
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Biles MK, Maniglia M, Yadav IS, Vice JE, Visscher KM. Training With Simulated Scotoma Leads to Behavioral Improvements Through at Least Two Distinct Mechanisms. Invest Ophthalmol Vis Sci 2023; 64:14. [PMID: 36656567 PMCID: PMC9872837 DOI: 10.1167/iovs.64.1.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/22/2022] [Indexed: 01/20/2023] Open
Abstract
Purpose Individuals with central vision loss due to macular degeneration (MD) often spontaneously develop a preferred retinal locus (PRL) outside the area of retinal damage, which they use instead of the fovea. Those who develop a stable PRL are more successful at coping with their vision loss. However, it is unclear whether improvements in visual performance at the PRL are specific to that retinal location or are also observed in other parts of the retina. Perceptual learning literature suggests that the retinal specificity of these effects provides insight about the mechanisms involved. Better understanding of these mechanisms is necessary for the next generation of interventions and improved patient outcomes. Methods To address this, we trained participants with healthy vision to develop a trained retinal locus (TRL), analogous to the PRL in patients. We trained 24 participants on a visual search task using a gaze-contingent display to simulate a central scotoma. Results Results showed retinotopically specific improvements in visual crowding only at the TRL; however, visual acuity improved in both the TRL and in an untrained retinal locus. Conclusions These results suggest that training with an artificial scotoma involves multiple mechanistic levels, some location-specific and some not, and that simulated scotoma training paradigms likely influence multiple mechanisms simultaneously. Eye movement analysis suggests that the non-retinotopic learning effects may be related to improvements in the capability to maintain a stable gaze during stimulus presentation. This work suggests that effective interventions promoting peripheral viewing may influence multiple mechanisms simultaneously.
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Affiliation(s)
- Mandy K. Biles
- Department of Psychology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Marcello Maniglia
- Department of Psychology, The University of California at Riverside, Riverside, California, United States
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Ishant S. Yadav
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jason E. Vice
- School of Optometry, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
| | - Kristina M. Visscher
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
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17
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Kewan-Khalayly B, Yashar A. The role of spatial attention in crowding and feature binding. J Vis 2022; 22:6. [PMID: 36479947 PMCID: PMC9742967 DOI: 10.1167/jov.22.13.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 10/19/2022] [Indexed: 12/13/2022] Open
Abstract
Crowding refers to the failure to identify a peripheral object due to nearby objects (flankers). A hallmark of crowding is inner-outer asymmetry; that is, the outer flanker (more peripheral) produces stronger interference than the inner one. Here, by manipulating attention, we tested the predictions of two competing accounts: the attentional account, which predicts a positive attentional effect on the inner-outer asymmetry (i.e., attention to the outer flanker will increase asymmetry) and the receptive field size account, which predicts a negative attentional effect. In Experiment 1, observers estimated a Gabor target orientation. A peripheral pre-cue drew attention to one of three locations: target, inner flanker, or outer flanker. Probabilistic mixture modeling demonstrated asymmetry by showing that observers often misreported the outer-flanker orientation as the target. Interestingly, the outer cue led to a higher misreport rate of the outer flanker, and the inner cue led to a lower misreport rate of the outer flanker. Experiment 2 tested the effect of crowding and attention on incoherent object reports (i.e., binding errors, reporting the tilt of one presented item with the color of another item). In each trial, observers estimated both the tilt and color of the target. Attention merely increased coherent target reports, but not coherent flanker reports. The results suggest that the locus of spatial attention plays an essential role in crowding, as well as inner-outer asymmetry, and demonstrate that crowding and feature binding are closely related. However, our findings are inconsistent with the view that covert attention automatically binds features together.
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Affiliation(s)
- Bahiyya Kewan-Khalayly
- Department of Special Education, Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, University of Haifa, Haifa, Israel
| | - Amit Yashar
- Department of Special Education, Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, University of Haifa, Haifa, Israel
- https://yasharlab.com
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18
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Abstract
A small number of objects can be rapidly and accurately enumerated, whereas a larger number of objects can only be approximately enumerated. These subitizing and estimation abilities, respectively, are both spatial processes relying on extracting information across spatial locations. Nevertheless, whether and how these processes vary across visual field locations remains unknown. Here, we examined if enumeration displays asymmetries around the visual field. Experiment 1 tested small number (1–6) enumeration at cardinal and non-cardinal peripheral locations while manipulating the spacing among the objects. Experiment 2 examined enumeration at cardinal locations in more detail while minimising crowding. Both experiments demonstrated a Horizontal-Vertical Asymmetry (HVA) where performance was better along the horizontal axis relative to the vertical. Experiment 1 found that this effect was modulated by spacing with stronger asymmetry at closer spacing. Experiment 2 revealed further asymmetries: a Vertical Meridian Asymmetry (VMA) with better enumeration on the lower vertical meridian than on the upper and a Horizontal Meridian Asymmetry (HMA) with better enumeration along the left horizontal meridian than along the right. All three asymmetries were evident for both subitizing and estimation. HVA and VMA have been observed in a range of visual tasks, indicating that they might be inherited from early visual constraints. However, HMA is observed primarily in mid-level tasks, often involving attention. These results suggest that while enumeration processes can be argued to inherit low-level visual constraints, the findings are, parsimoniously, consistent with visual attention playing a role in both subitizing and estimation.
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19
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Kewan-Khalayly B, Migó M, Yashar A. Transient attention equally reduces visual crowding in radial and tangential axes. J Vis 2022; 22:3. [PMID: 35921089 PMCID: PMC9360535 DOI: 10.1167/jov.22.9.3] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Crowding refers to the failure to identify a peripheral object due to its proximity to other objects (flankers). This phenomenon can lead to reading and object recognition impairments and is associated with macular degeneration, amblyopia, and dyslexia. Crucially, the maximal target–flanker spacing required for the crowding interference (critical spacing) increases with eccentricity. This spacing is also larger when target and flankers appear along the horizontal meridian (radial arrangement) than when the flankers appear above and below the target (tangential arrangement). This phenomenon is known as radial–tangential anisotropy. Previous studies have demonstrated that transient attention can reduce crowding interference; however, it is still unclear whether and how attention interacts with radial–tangential anisotropy. To address this issue, we manipulated transient attention by using a cue at either the target (valid) or the fixation (neutral) location, in both radial and tangential target–flanker arrangements. Results showed that critical spacing was larger in the radial than in the tangential arrangement and that cueing the target location improved performance and reduced the critical spacing for both radial and tangential arrangements to the same extent. Together, our findings suggest that transient spatial attention plays an essential role in crowding but not in radial–tangential anisotropy.
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Affiliation(s)
| | - Marta Migó
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,
| | - Amit Yashar
- Department of Special Education, University of Haifa, Haifa, Israel.,The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, University of Haifa, Haifa, Israel., https://yasharlab.com
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20
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Yildirim FZ, Sayim B. High confidence and low accuracy in redundancy masking. Conscious Cogn 2022; 102:103349. [DOI: 10.1016/j.concog.2022.103349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 02/19/2022] [Accepted: 04/25/2022] [Indexed: 11/03/2022]
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21
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Lin Z, Gong M, Li X. On the relation between crowding and ensemble perception: Examining the role of attention. Psych J 2022; 11:804-813. [PMID: 35557502 DOI: 10.1002/pchj.559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/10/2022] [Indexed: 11/06/2022]
Abstract
Ensemble perception of a crowd of stimuli is very accurate, even when individual stimuli are invisible due to crowding. The ability of high-precision ensemble perception can be an evolved compensatory mechanism for the limited attentional resolution caused by crowding. Thus the relationship of crowding and ensemble coding is like two sides of the same coin wherein attention may play a critical factor for their coexistence. The present study investigated whether crowding and ensemble coding were similarly modulated by attention, which can promote our understanding of their relation. Experiment 1 showed that diverting attention away from the target harmed the performance in both crowding and ensemble perception tasks regardless of stimulus density, but crowding was more severely harmed. Experiment 2 showed that directing attention toward the target bar enhanced the performance of crowding regardless of stimulus density. Ensemble perception of high-density bars was also enhanced but to a lesser extent, while ensemble perception of low-density bars was harmed. Together, our results indicate that crowding is strongly modulated by attention, whereas ensemble perception is only moderately modulated by attention, which conforms to the adaptive view.
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Affiliation(s)
- Zhen Lin
- School of Psychology, Jiangxi Normal University, Nanchang, China
| | - Mingliang Gong
- School of Psychology, Jiangxi Normal University, Nanchang, China
| | - Xiang Li
- School of Psychology, Jiangxi Normal University, Nanchang, China
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22
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Kalpadakis-Smith AV, Tailor VK, Dahlmann-Noor AH, Greenwood JA. Crowding changes appearance systematically in peripheral, amblyopic, and developing vision. J Vis 2022; 22:3. [PMID: 35506917 PMCID: PMC9078053 DOI: 10.1167/jov.22.6.3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Visual 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 to 8 years with typical vision or strabismic amblyopia and peripheral vision in typical 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°, all three groups (adults and children with typical or amblyopic vision) 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.
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Affiliation(s)
| | - Vijay K Tailor
- Experimental Psychology, University College London, London, UK.,NIHR Biomedical Research Centre @ Moorfields Eye Hospital, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,
| | - Annegret H Dahlmann-Noor
- NIHR Biomedical Research Centre @ Moorfields Eye Hospital, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,
| | - John A Greenwood
- Experimental Psychology, University College London, London, UK., http://eccentricvision.com
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23
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Koornneef A, Kraal A. Does BeeLine Reader’s gradient-coloured font improve the readability of digital texts for beginning readers? COMPUTERS IN HUMAN BEHAVIOR REPORTS 2022. [DOI: 10.1016/j.chbr.2022.100197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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24
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Abstract
Redundancy masking is the reduction of the perceived number of items in repeating patterns. It shares a number of characteristics with crowding, the impairment of target identification in visual clutter. Crowding strongly depends on the location of the target in the visual field. For example, it is stronger in the upper compared to the lower visual field and is usually weakest on the horizontal meridian. This pattern of visual field asymmetries is common in spatial vision, as revealed by tasks measuring, for example, spatial resolution and contrast sensitivity. Here, to characterize redundancy masking and reveal its similarities to and differences from other spatial tasks, we investigated whether redundancy masking shows the same typical visual field asymmetries. Observers were presented with three to six radially arranged lines at 10° eccentricity at one of eight locations around fixation and were asked to report the number of lines. We found asymmetries that differed pronouncedly from those found in crowding. Redundancy masking did not differ between upper and lower visual fields. Importantly, redundancy masking was stronger on the horizontal meridian than on the vertical meridian, the opposite of what is usually found in crowding. These results show that redundancy masking diverges from crowding in regard to visual field asymmetries, suggesting different underlying mechanisms of redundancy masking and crowding. We suggest that the observed atypical visual field asymmetries in redundancy masking are due to the superior extraction of regularity and a more pronounced compression of visual space on the horizontal compared to the vertical meridian.
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Affiliation(s)
| | - Daniel R Coates
- Institute of Psychology, University of Bern, Bern, Switzerland.,College of Optometry, University of Houston, Houston, TX, USA.,
| | - Bilge Sayim
- Institute of Psychology, University of Bern, Bern, Switzerland.,Sciences Cognitives et Sciences Affectives (SCALab), CNRS, UMR 9193, University of Lille, Lille, France.,
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25
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Smith DT. A horizontal–vertical anisotropy in spatial short-term memory. VISUAL COGNITION 2022. [DOI: 10.1080/13506285.2022.2042446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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26
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Attentional demand induced by visual crowding modulates the anger superiority effect. Atten Percept Psychophys 2022; 84:442-449. [PMID: 35013992 DOI: 10.3758/s13414-021-02408-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2021] [Indexed: 11/08/2022]
Abstract
Previous research on emotional bias in face perception has shown inconsistent findings, proposing either angry or happy faces to be detected more efficiently. A recent study showed that the anger superiority effect (ASE), which showed in the high attentional demand condition, vanished in the low attentional demand condition. The authors thus proposed an attentional demands modulation hypothesis to interpret the inconsistent findings. The present study tested this hypothesis in a visual crowding task in which participants were instructed to determine whether the target face was happy or angry. Attentional demands were manipulated by changing the strength of crowding, including presenting stimuli in different configurations (Experiment 1), and setting different target-flanker separations and presenting stimuli in different eccentricities (Experiment 2). Experiment 1 showed an ASE when the stimulus configuration incurred a high attentional demand. Intriguingly, the ASE became weaker and then disappeared as the attentional demand became lower. Experiment 2 replicated this finding and showed that the ASE decreased as the target-flanker separation became larger. Together, these results suggest that the emergence and magnitude of ASE is modulated by attentional demands, which supports the attentional demands modulation hypothesis.
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27
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Theiss JD, Bowen JD, Silver MA. Spatial Attention Enhances Crowded Stimulus Encoding Across Modeled Receptive Fields by Increasing Redundancy of Feature Representations. Neural Comput 2021; 34:190-218. [PMID: 34710898 PMCID: PMC8693207 DOI: 10.1162/neco_a_01447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 07/01/2021] [Indexed: 11/04/2022]
Abstract
Any visual system, biological or artificial, must make a trade-off between the number of units used to represent the visual environment and the spatial resolution of the sampling array. Humans and some other animals are able to allocate attention to spatial locations to reconfigure the sampling array of receptive fields (RFs), thereby enhancing the spatial resolution of representations without changing the overall number of sampling units. Here, we examine how representations of visual features in a fully convolutional neural network interact and interfere with each other in an eccentricity-dependent RF pooling array and how these interactions are influenced by dynamic changes in spatial resolution across the array. We study these feature interactions within the framework of visual crowding, a well-characterized perceptual phenomenon in which target objects in the visual periphery that are easily identified in isolation are much more difficult to identify when flanked by similar nearby objects. By separately simulating effects of spatial attention on RF size and on the density of the pooling array, we demonstrate that the increase in RF density due to attention is more beneficial than changes in RF size for enhancing target classification for crowded stimuli. Furthermore, by varying target/flanker spacing, as well as the spatial extent of attention, we find that feature redundancy across RFs has more influence on target classification than the fidelity of the feature representations themselves. Based on these findings, we propose a candidate mechanism by which spatial attention relieves visual crowding through enhanced feature redundancy that is mostly due to increased RF density.
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Affiliation(s)
| | - Joel D Bowen
- University of California, Berkeley, CA 94720, U.S.A.
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28
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Tailor VK, Theodorou M, Dahlmann-Noor AH, Dekker TM, Greenwood JA. Eye movements elevate crowding in idiopathic infantile nystagmus syndrome. J Vis 2021; 21:9. [PMID: 34935877 PMCID: PMC8709927 DOI: 10.1167/jov.21.13.9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Idiopathic infantile nystagmus syndrome is a disorder characterised by involuntary eye movements, which leads to decreased acuity and visual function. One such function is visual crowding – a process whereby objects that are easily recognised in isolation become impaired by nearby flankers. Crowding typically occurs in the peripheral visual field, although elevations in foveal vision have been reported in congenital nystagmus, similar to those found with amblyopia. Here, we examine whether elevated foveal crowding with nystagmus is driven by similar mechanisms to those of amblyopia – long-term neural changes associated with a sensory deficit – or by the momentary displacement of the stimulus through nystagmus eye movements. A Landolt-C orientation identification task was used to measure threshold gap sizes with and without either horizontally or vertically placed Landolt-C flankers. We assume that a sensory deficit should give equivalent crowding in these two dimensions, whereas an origin in eye movements should give stronger crowding with horizontal flankers given the predominantly horizontal eye movements of nystagmus. We observe elevations in nystagmic crowding that are above crowding in typical vision but below that of amblyopia. Consistent with an origin in eye movements, elevations were stronger with horizontal than vertical flankers in nystagmus, but not in typical or amblyopic vision. We further demonstrate the same horizontal elongation in typical vision with stimulus movement that simulates nystagmus. Consequently, we propose that the origin of nystagmic crowding lies in the eye movements, either through image smear of the target and flanker elements or through relocation of the stimulus into the peripheral retina.
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Affiliation(s)
- Vijay K Tailor
- Experimental Psychology, University College London, London, UK.,NIHR Biomedical Research Centre @ Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK., https://eccentricvision.com
| | - Maria Theodorou
- NIHR Biomedical Research Centre @ Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,
| | - Annegret H Dahlmann-Noor
- NIHR Biomedical Research Centre @ Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,
| | - Tessa M Dekker
- Experimental Psychology, University College London, London, UK.,NIHR Biomedical Research Centre @ Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK., https://www.ucl.ac.uk/~ucjttb1/
| | - John A Greenwood
- Experimental Psychology, University College London, London, UK., https://eccentricvision.com
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Lee RJ, Reuther J, Chakravarthi R, Martinovic J. Emergence of crowding: The role of contrast and orientation salience. J Vis 2021; 21:20. [PMID: 34709355 PMCID: PMC8556554 DOI: 10.1167/jov.21.11.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 09/22/2021] [Indexed: 11/27/2022] Open
Abstract
Crowding causes difficulties in judging attributes of an object surrounded by other objects. We investigated crowding for stimuli that isolated either S-cone or luminance mechanisms or combined them. By targeting different retinogeniculate mechanisms with contrast-matched stimuli, we aim to determine the earliest site at which crowding emerges. Discrimination was measured in an orientation judgment task where Gabor targets were presented parafoveally among flankers. In the first experiment, we assessed flanked and unflanked orientation discrimination thresholds for pure S-cone and achromatic stimuli and their combinations. In the second experiment, to capture individual differences, we measured unflanked detection and orientation sensitivity, along with performance under flanker interference for stimuli containing luminance only or combined with S-cone contrast. We confirmed that orientation sensitivity was lower for unflanked S-cone stimuli. When flanked, the pattern of results for S-cone stimuli was the same as for achromatic stimuli with comparable (i.e. low) contrast levels. We also found that flanker interference exhibited a genuine signature of crowding only when orientation discrimination threshold was reliably surpassed. Crowding, therefore, emerges at a stage that operates on signals representing task-relevant featural (here, orientation) information. Because luminance and S-cone mechanisms have very different spatial tuning properties, it is most parsimonious to conclude that crowding takes place at a neural processing stage after they have been combined.
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Affiliation(s)
| | - Josephine Reuther
- School of Psychology, University of Aberdeen, Aberdeen, Scotland, UK
| | | | - Jasna Martinovic
- Department of Psychology, School of Philosophy, Psychology and Language Sciences, University of Edinburgh & School of Psychology, University of Aberdeen, Aberdeen, Scotland, UK
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30
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Chakravarthi R, Rubruck J, Kipling N, Clarke ADF. Characterizing the in-out asymmetry in visual crowding. J Vis 2021; 21:10. [PMID: 34668932 PMCID: PMC8602924 DOI: 10.1167/jov.21.11.10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 09/18/2021] [Indexed: 11/24/2022] Open
Abstract
An object's processing is impaired by the presence of nearby clutter. Several distinct mechanisms, such as masking and visual crowding, are thought to contribute to such flanker-induced interference. It is therefore important to determine which mechanism is operational in any given situation. Previous studies have proposed that the in-out asymmetry (IOA), where a peripheral flanker interferes with the target more than a foveal flanker, is diagnostic of crowding. However, several studies have documented inconsistencies in the occurrence of this asymmetry, particularly at locations beyond the horizontal meridian, casting doubt on its ability to delineate crowding. In this study, to determine if IOA is diagnostic of crowding, we extensively charted its properties. We asked a relatively large set of participants (n = 38) to identify a briefly presented peripheral letter flanked by a single inward or outward letter at one of four locations. We also manipulated target location uncertainty and attentional allocation by blocking, randomizing or pre-cueing the target location. Using multilevel Bayesian regression analysis, we found robust IOA at all locations, although its strength was modulated by target location, location uncertainty, and attentional allocation. Our findings suggest that IOA can be an excellent marker of crowding, to the extent that it is not observed in other flanker-interference mechanisms, such as masking.
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Affiliation(s)
| | - Jirko Rubruck
- School of Psychology, University of Aberdeen, Aberdeen, UK
| | - Nikki Kipling
- Department of Psychology, University of Essex, Essex, UK
| | - Alasdair D F Clarke
- Department of Psychology, University of Essex, Essex, UK
- https://www.essex.ac.uk/people/clark28201/alasdair-clarke
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31
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Purokayastha S, Roberts M, Carrasco M. Voluntary attention improves performance similarly around the visual field. Atten Percept Psychophys 2021; 83:2784-2794. [PMID: 34036535 PMCID: PMC8514247 DOI: 10.3758/s13414-021-02316-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2021] [Indexed: 12/14/2022]
Abstract
Performance as a function of polar angle at isoeccentric locations across the visual field is known as a performance field (PF) and is characterized by two asymmetries: the HVA (horizontal-vertical anisotropy) and VMA (vertical meridian asymmetry). Exogenous (involuntary) spatial attention does not affect the shape of the PF, improving performance similarly across polar angle. Here we investigated whether endogenous (voluntary) spatial attention, a flexible mechanism, can attenuate these perceptual asymmetries. Twenty participants performed an orientation discrimination task while their endogenous attention was either directed to the target location or distributed across all possible locations. The effects of attention were assessed either using the same stimulus contrast across locations or equating difficulty across locations using individually titrated contrast thresholds. In both experiments, endogenous attention similarly improved performance at all locations, maintaining the canonical PF shape. Thus, despite its voluntary nature, like exogenous attention, endogenous attention cannot alleviate perceptual asymmetries at isoeccentric locations.
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Affiliation(s)
| | - Mariel Roberts
- Department of Psychology, New York University, New York, NY, USA
| | - Marisa Carrasco
- Department of Psychology, New York University, New York, NY, USA.
- Center for Neural Science, New York University, 6 Washington Place, Room 970, New York, NY, 10003, USA.
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32
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Shechter A, Yashar A. Mixture model investigation of the inner-outer asymmetry in visual crowding reveals a heavier weight towards the visual periphery. Sci Rep 2021; 11:2116. [PMID: 33483608 PMCID: PMC7822962 DOI: 10.1038/s41598-021-81533-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 01/05/2021] [Indexed: 01/30/2023] Open
Abstract
Crowding, the failure to identify a peripheral item in clutter, is an essential bottleneck in visual information processing. A hallmark characteristic of crowding is the inner-outer asymmetry in which the outer flanker (more eccentric) produces stronger interference than the inner one (closer to the fovea). We tested the contribution of the inner-outer asymmetry to the pattern of crowding errors in a typical radial crowding display in which both flankers are presented simultaneously on the horizontal meridian. In two experiments, observers were asked to estimate the orientation of a Gabor target. Instead of the target, observers reported the outer flanker much more frequently than the inner one. When the target was the outer Gabor, crowding was reduced. Furthermore, when there were four flankers, two on each side of the target, observers misreported the outer flanker adjacent to the target, not the outermost flanker. Model comparisons suggested that orientation crowding reflects sampling over a weighted sum of the represented features, in which the outer flanker is more heavily weighted compared to the inner one. Our findings reveal a counterintuitive phenomenon: in a radial arrangement of orientation crowding, within a region of selection, the outer item dominates appearance more than the inner one.
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Affiliation(s)
- Adi Shechter
- The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, The University of Haifa, Haifa, Israel
- The Department of Learning Disabilities, Faculty of Education, The University of Haifa, Haifa, Israel
| | - Amit Yashar
- The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, The University of Haifa, Haifa, Israel.
- The Department of Special Education, Faculty of Education, The University of Haifa, 199 Abba Khoushy Ave, 3498838, Haifa, Israel.
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33
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Yildirim FZ, Coates DR, Sayim B. Redundancy masking: The loss of repeated items in crowded peripheral vision. J Vis 2021; 20:14. [PMID: 32330230 PMCID: PMC7405779 DOI: 10.1167/jov.20.4.14] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Crowding is the deterioration of target identification in the presence of neighboring objects. Recent studies using appearance-based methods showed that the perceived number of target elements is often diminished in crowding. Here we introduce a related type of diminishment in repeating patterns (sets of parallel lines), which we term “redundancy masking.” In four experiments, observers were presented with arrays of small numbers of lines centered at 10° eccentricity. The task was to indicate the number of lines. In Experiment 1, spatial characteristics of redundancy masking were examined by varying the inter-line spacing. We found that redundancy masking decreased with increasing inter-line spacing and ceased at spacings of approximately 0.25 times the eccentricity. In Experiment 2, we assessed whether the strength of redundancy masking differed between radial and tangential arrangements of elements as it does in crowding. Redundancy masking was strong with radially arranged lines (horizontally arranged vertical lines), and absent with tangentially arranged lines (vertically arranged horizontal lines). In Experiment 3, we investigated whether target size (line width and length) modulated redundancy masking. There was an effect of width: Thinner lines yielded stronger redundancy masking. We did not find any differences between the tested line lengths. In Experiment 4, we varied the regularity of the line arrays by vertically or horizontally jittering the positions of the lines. Redundancy masking was strongest with regular spacings and weakened with decreasing regularity. Our experiments show under which conditions whole items are lost in crowded displays, and how this redundancy masking resembles—and partly diverges from—crowded identification. We suggest that redundancy masking is a contributor to the deterioration of performance in crowded displays with redundant patterns.
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34
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Barbot A, Xue S, Carrasco M. Asymmetries in visual acuity around the visual field. J Vis 2021; 21:2. [PMID: 33393963 PMCID: PMC7794272 DOI: 10.1167/jov.21.1.2] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 11/10/2020] [Indexed: 12/21/2022] Open
Abstract
Human vision is heterogeneous around the visual field. At a fixed eccentricity, performance is better along the horizontal than the vertical meridian and along the lower than the upper vertical meridian. These asymmetric patterns, termed performance fields, have been found in numerous visual tasks, including those mediated by contrast sensitivity and spatial resolution. However, it is unknown whether spatial resolution asymmetries are confined to the cardinal meridians or whether and how far they extend into the upper and lower hemifields. Here, we measured visual acuity at isoeccentric peripheral locations (10 deg eccentricity), every 15° of polar angle. On each trial, observers judged the orientation (± 45°) of one of four equidistant, suprathreshold grating stimuli varying in spatial frequency (SF). On each block, we measured performance as a function of stimulus SF at 4 of 24 isoeccentric locations. We estimated the 75%-correct SF threshold, SF cutoff point (i.e., chance-level), and slope of the psychometric function for each location. We found higher SF estimates (i.e., better acuity) for the horizontal than the vertical meridian and for the lower than the upper vertical meridian. These asymmetries were most pronounced at the cardinal meridians and decreased gradually as the angular distance from the vertical meridian increased. This gradual change in acuity with polar angle reflected a shift of the psychometric function without changes in slope. The same pattern was found under binocular and monocular viewing conditions. These findings advance our understanding of visual processing around the visual field and help constrain models of visual perception.
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Affiliation(s)
- Antoine Barbot
- Department of Psychology, New York University, New York, NY, USA
- Center for Neural Science, New York University, New York, NY, USA
- Spinoza Centre for Neuroimaging, Amsterdam, Netherlands
| | - Shutian Xue
- Department of Psychology, New York University, New York, NY, USA
| | - Marisa Carrasco
- Department of Psychology, New York University, New York, NY, USA
- Center for Neural Science, New York University, New York, NY, USA
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35
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Herrera-Esposito D, Coen-Cagli R, Gomez-Sena L. Flexible contextual modulation of naturalistic texture perception in peripheral vision. J Vis 2021; 21:1. [PMID: 33393962 PMCID: PMC7794279 DOI: 10.1167/jov.21.1.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 12/01/2020] [Indexed: 11/24/2022] Open
Abstract
Peripheral vision comprises most of our visual field, and is essential in guiding visual behavior. Its characteristic capabilities and limitations, which distinguish it from foveal vision, have been explained by the most influential theory of peripheral vision as the product of representing the visual input using summary statistics. Despite its success, this account may provide a limited understanding of peripheral vision, because it neglects processes of perceptual grouping and segmentation. To test this hypothesis, we studied how contextual modulation, namely the modulation of the perception of a stimulus by its surrounds, interacts with segmentation in human peripheral vision. We used naturalistic textures, which are directly related to summary-statistics representations. We show that segmentation cues affect contextual modulation, and that this is not captured by our implementation of the summary-statistics model. We then characterize the effects of different texture statistics on contextual modulation, providing guidance for extending the model, as well as for probing neural mechanisms of peripheral vision.
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Affiliation(s)
- Daniel Herrera-Esposito
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Ruben Coen-Cagli
- Department of Systems and Computational Biology and Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Leonel Gomez-Sena
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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36
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Malania M, Pawellek M, Plank T, Greenlee MW. Training-Induced Changes in Radial-Tangential Anisotropy of Visual Crowding. Transl Vis Sci Technol 2020; 9:25. [PMID: 32879781 PMCID: PMC7442869 DOI: 10.1167/tvst.9.9.25] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 07/08/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose One of the diagnostic features of visual crowding, radial–tangential anisotropy, has been observed both in behavioral experiments as well as in responses of the blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signal. As has been shown previously, crowding is stronger for radially arranged flankers, and this tendency is reflected in BOLD signal suppression. In the current study, we examined the effect of practice on the neural correlates of crowding. We expected that training on a crowding task would cause shrinkage of the crowding zone that would be mirrored in corresponding BOLD signal responses. Methods Pre- and post-training fMRI images were acquired in 17 healthy volunteers using a 3-tesla MRI scanner. Participants were trained over 4 consecutive days on a crowding task. Results Comparison of the pre- and post-training behavioral data indicates a significant shrinkage of the crowding zone as a result of training. Moreover, we observed a pronounced radial–tangential anisotropy in the BOLD signal prior to training; that is, radial flankers induced a larger reduction in the BOLD signal compared to equally spaced tangential flankers. After training, this radial–tangential anisotropy in the BOLD signal was significantly reduced. Specifically, we found significant changes in BOLD responses for the radial flanker configuration. Conclusions Our results demonstrate that training-induced changes in the anisotropic shape of the crowding zone are reflected in the BOLD signal in the early visual cortex. Translational Relevance Perceptual learning tasks may have the potential to improve visual performance by promoting neural plasticity. Our results could motivate the development of suitable rehabilitation protocols for patients with central vision loss.
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Affiliation(s)
- Maka Malania
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Maja Pawellek
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany.,Children's University Hospital, University of Regensburg, Regensburg, Germany
| | - Tina Plank
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Mark W Greenlee
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
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37
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Abstract
We have compared two explanations for poor peripheral binding. Binding is the ability to assign the correct features (e.g., color, direction of motion, orientation) to objects. Wu, Kanai, and Shimojo (Nature, 429(6989), 262, 2004) showed that subjects performed poorly on binding dot color with direction of motion in the periphery. Suzuki, Wolfe, Horowitz, and Noguchi (Vision Research, 82, 58-65, 2013) similarly showed that subjects had trouble binding color with line orientation in the periphery. These authors concluded that performance in the periphery was poor because binding is poor in the periphery. However, both studies used red and green stimuli. We tested an alternative hypothesis, that poor peripheral binding is in part due to poor peripheral red/green color vision. Eccentricity-dependent changes in visual processing cause peripheral red/green vision to be worse than foveal vision. In contrast, blue/yellow vision remains centrifugally more stable. We tested 9 subjects in a replication and extension of Suzuki and colleagues' line orientation judgment, in red and green, and in blue and yellow. There were three central conditions: (1) red (or blue) all horizontal, green (or yellow) all vertical; (2) red (or blue) all vertical, green (or yellow) all horizontal; or (3) random pairing of color and orientation. In both the red/green and the blue/yellow color schemes, peripheral performance was influenced by central line orientation, replicating Suzuki and colleagues. However, the effect with blue/yellow lines was smaller, indicating that poor peripheral "binding," as hypothesized by both Wu and colleagues and Suzuki and colleagues, is due in part to their use of red and green stimuli.
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38
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Strasburger H. Seven Myths on Crowding and Peripheral Vision. Iperception 2020; 11:2041669520913052. [PMID: 32489576 PMCID: PMC7238452 DOI: 10.1177/2041669520913052] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 02/13/2020] [Indexed: 12/03/2022] Open
Abstract
Crowding has become a hot topic in vision research, and some fundamentals are now widely agreed upon. For the classical crowding task, one would likely agree with the following statements. (1) Bouma's law can be stated, succinctly and unequivocally, as saying that critical distance for crowding is about half the target's eccentricity. (2) Crowding is predominantly a peripheral phenomenon. (3) Peripheral vision extends to at most 90° eccentricity. (4) Resolution threshold (the minimal angle of resolution) increases strongly and linearly with eccentricity. Crowding increases at an even steeper rate. (5) Crowding is asymmetric as Bouma has shown. For that inner-outer asymmetry, the peripheral flanker has more effect. (6) Critical crowding distance corresponds to a constant cortical distance in primary visual areas like V1. (7) Except for Bouma's seminal article in 1970, crowding research mostly became prominent starting in the 2000s. I propose the answer is "not really" or "not quite" to these assertions. So should we care? I think we should, before we write the textbook chapters for the next generation.
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Affiliation(s)
- Hans Strasburger
- Georg-August-Universität, Göttingen, Germany
Ludwig-Maximilians-Universität, München, Germany
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39
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Lonnqvist B, Clarke ADF, Chakravarthi R. Crowding in humans is unlike that in convolutional neural networks. Neural Netw 2020; 126:262-274. [PMID: 32272430 DOI: 10.1016/j.neunet.2020.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 03/10/2020] [Accepted: 03/23/2020] [Indexed: 10/24/2022]
Abstract
Object recognition is a primary function of the human visual system. It has recently been claimed that the highly successful ability to recognise objects in a set of emergent computer vision systems-Deep Convolutional Neural Networks (DCNNs)-can form a useful guide to recognition in humans. To test this assertion, we systematically evaluated visual crowding, a dramatic breakdown of recognition in clutter, in DCNNs and compared their performance to extant research in humans. We examined crowding in three architectures of DCNNs with the same methodology as that used among humans. We manipulated multiple stimulus factors including inter-letter spacing, letter colour, size, and flanker location to assess the extent and shape of crowding in DCNNs. We found that crowding followed a predictable pattern across architectures that was different from that in humans. Some characteristic hallmarks of human crowding, such as invariance to size, the effect of target-flanker similarity, and confusions between target and flanker identities, were completely missing, minimised or even reversed. These data show that DCNNs, while proficient in object recognition, likely achieve this competence through a set of mechanisms that are distinct from those in humans. They are not necessarily equivalent models of human or primate object recognition and caution must be exercised when inferring mechanisms derived from their operation.
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Affiliation(s)
- Ben Lonnqvist
- Business School, University of Aberdeen, United Kingdom of Great Britain and Northern Ireland.
| | - Alasdair D F Clarke
- Department of Psychology, University of Essex, United Kingdom of Great Britain and Northern Ireland.
| | - Ramakrishna Chakravarthi
- School of Psychology, University of Aberdeen, United Kingdom of Great Britain and Northern Ireland.
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40
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Bornet A, Kaiser J, Kroner A, Falotico E, Ambrosano A, Cantero K, Herzog MH, Francis G. Running Large-Scale Simulations on the Neurorobotics Platform to Understand Vision - The Case of Visual Crowding. Front Neurorobot 2019; 13:33. [PMID: 31191291 PMCID: PMC6549494 DOI: 10.3389/fnbot.2019.00033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/14/2019] [Indexed: 11/13/2022] Open
Abstract
Traditionally, human vision research has focused on specific paradigms and proposed models to explain very specific properties of visual perception. However, the complexity and scope of modern psychophysical paradigms undermine the success of this approach. For example, perception of an element strongly deteriorates when neighboring elements are presented in addition (visual crowding). As it was shown recently, the magnitude of deterioration depends not only on the directly neighboring elements but on almost all elements and their specific configuration. Hence, to fully explain human visual perception, one needs to take large parts of the visual field into account and combine all the aspects of vision that become relevant at such scale. These efforts require sophisticated and collaborative modeling. The Neurorobotics Platform (NRP) of the Human Brain Project offers a unique opportunity to connect models of all sorts of visual functions, even those developed by different research groups, into a coherently functioning system. Here, we describe how we used the NRP to connect and simulate a segmentation model, a retina model, and a saliency model to explain complex results about visual perception. The combination of models highlights the versatility of the NRP and provides novel explanations for inward-outward anisotropy in visual crowding.
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Affiliation(s)
- Alban Bornet
- Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jacques Kaiser
- FZI Research Center for Information Technology, Karlsruhe, Germany
| | - Alexander Kroner
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Egidio Falotico
- The BioRobotics Institute, Scuola Superiore Sant’Anna, Pontedera, Italy
| | | | | | - Michael H. Herzog
- Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Gregory Francis
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
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41
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Wallis TS, Funke CM, Ecker AS, Gatys LA, Wichmann FA, Bethge M. Image content is more important than Bouma's Law for scene metamers. eLife 2019; 8:42512. [PMID: 31038458 PMCID: PMC6491040 DOI: 10.7554/elife.42512] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 03/09/2019] [Indexed: 11/16/2022] Open
Abstract
We subjectively perceive our visual field with high fidelity, yet peripheral distortions can go unnoticed and peripheral objects can be difficult to identify (crowding). Prior work showed that humans could not discriminate images synthesised to match the responses of a mid-level ventral visual stream model when information was averaged in receptive fields with a scaling of about half their retinal eccentricity. This result implicated ventral visual area V2, approximated ‘Bouma’s Law’ of crowding, and has subsequently been interpreted as a link between crowding zones, receptive field scaling, and our perceptual experience. However, this experiment never assessed natural images. We find that humans can easily discriminate real and model-generated images at V2 scaling, requiring scales at least as small as V1 receptive fields to generate metamers. We speculate that explaining why scenes look as they do may require incorporating segmentation and global organisational constraints in addition to local pooling. As you read this digest, your eyes move to follow the lines of text. But now try to hold your eyes in one position, while reading the text on either side and below: it soon becomes clear that peripheral vision is not as good as we tend to assume. It is not possible to read text far away from the center of your line of vision, but you can see ‘something’ out of the corner of your eye. You can see that there is text there, even if you cannot read it, and you can see where your screen or page ends. So how does the brain generate peripheral vision, and why does it differ from what you see when you look straight ahead? One idea is that the visual system averages information over areas of the peripheral visual field. This gives rise to texture-like patterns, as opposed to images made up of fine details. Imagine looking at an expanse of foliage, gravel or fur, for example. Your eyes cannot make out the individual leaves, pebbles or hairs. Instead, you perceive an overall pattern in the form of a texture. Our peripheral vision may also consist of such textures, created when the brain averages information over areas of space. Wallis, Funke et al. have now tested this idea using an existing computer model that averages visual input in this way. By giving the model a series of photographs to process, Wallis, Funke et al. obtained images that should in theory simulate peripheral vision. If the model mimics the mechanisms that generate peripheral vision, then healthy volunteers should be unable to distinguish the processed images from the original photographs. But in fact, the participants could easily discriminate the two sets of images. This suggests that the visual system does not solely use textures to represent information in the peripheral visual field. Wallis, Funke et al. propose that other factors, such as how the visual system separates and groups objects, may instead determine what we see in our peripheral vision. This knowledge could ultimately benefit patients with eye diseases such as macular degeneration, a condition that causes loss of vision in the center of the visual field and forces patients to rely on their peripheral vision.
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Affiliation(s)
- Thomas Sa Wallis
- Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls Universität Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, Berlin, Germany
| | - Christina M Funke
- Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls Universität Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, Berlin, Germany
| | - Alexander S Ecker
- Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls Universität Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, Berlin, Germany.,Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, United States.,Institute for Theoretical Physics, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Leon A Gatys
- Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Felix A Wichmann
- Neural Information Processing Group, Faculty of Science, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Matthias Bethge
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, United States.,Institute for Theoretical Physics, Eberhard Karls Universität Tübingen, Tübingen, Germany.,Max Planck Institute for Biological Cybernetics, Tübingen, Germany
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Melnik N, Coates DR, Sayim B. Emergent features in the crowding zone: When target-flanker grouping surmounts crowding. J Vis 2019; 18:19. [PMID: 30372753 DOI: 10.1167/18.9.19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Crowding is the impairment of target identification when the target is surrounded by nearby flankers. Two hallmarks of crowding are that it is stronger when the flankers are close to the target and when the target strongly groups with the flankers. Here we show the opposite of both. A chevron target (pointing up or down) was presented at 8° eccentricity in the right visual field. It was surrounded by four flankers. Three of the flankers varied (pointing left or right). The fourth, the critical flanker (CF), was fixed in one orientation (left, right, up, down), yielding different configurations with the target. The CF's distance to the target was varied. Target identification depended strongly on the distance and the orientation of the CF. Remarkably, when the target and the CF grouped into a good configuration and elicited an emergent feature, performance was high if the CF was close to the target. This effect was particularly strong when participants were informed about the different CF-target configurations before the experiment. Reducing crowding and grouping by asynchronous presentation of the CF and the other items abolished the effect. When participants reported the entire configuration of the CF and the target, performance rapidly decreased with increasing spacing when the CF and the target were different but not when they were the same, indicating different spatial extents of the corresponding grouping processes. Our results show that the features emerging from the configurations of the target and a flanker strongly modulate crowding. Strong target-flanker grouping can benefit performance.
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Affiliation(s)
- Natalia Melnik
- Institute of Psychology, University of Bern, Bern, Switzerland
| | - Daniel R Coates
- Institute of Psychology, University of Bern, Bern, Switzerland.,College of Optometry, University of Houston, Houston, TX, USA
| | - Bilge Sayim
- Institute of Psychology, University of Bern, Bern, Switzerland.,SCALab - Sciences Cognitives et Sciences Affectives, CNRS, UMR 9193, University of Lille, Lille, France
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Linkage between retinal ganglion cell density and the nonuniform spatial integration across the visual field. Proc Natl Acad Sci U S A 2019; 116:3827-3836. [PMID: 30737290 PMCID: PMC6397585 DOI: 10.1073/pnas.1817076116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The integration of visual information over space is critical to human pattern vision. For either luminance detection or object recognition, the position of the target in the visual field governs the size of a window within which visual information is integrated. Here we analyze the relationship between the topographic distribution of ganglion cell density and the nonuniform spatial integration across the visual field. We find that the variation in the retinal ganglion cell (RGC) density across the human retina is closely matched to the variation in the extent of spatial integration. Our study suggests that a fixed number of RGCs subserves spatial integration of visual input, independent of the visual-field location. The ability to integrate visual information over space is a fundamental component of human pattern vision. Regardless of whether it is for detecting luminance contrast or for recognizing objects in a cluttered scene, the position of the target in the visual field governs the size of a window within which visual information is integrated. Here we analyze the relationship between the topographic distribution of ganglion cell density and the nonuniform spatial integration across the visual field. The extent of spatial integration for luminance detection (Ricco’s area) and object recognition (crowding zone) are measured at various target locations. The number of retinal ganglion cells (RGCs) underlying Ricco’s area or crowding zone is estimated by computing the product of Ricco’s area (or crowding zone) and RGC density for a given target location. We find a quantitative agreement between the behavioral data and the RGC density: The variation in the sampling density of RGCs across the human retina is closely matched to the variation in the extent of spatial integration required for either luminance detection or object recognition. Our empirical data combined with the simulation results of computational models suggest that a fixed number of RGCs subserves spatial integration of visual input, independent of the visual-field location.
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Chakravarthi R, Herbert A. Two's company, three's a crowd: Individuation is necessary for object recognition. Cognition 2018; 184:69-82. [PMID: 30576886 DOI: 10.1016/j.cognition.2018.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 11/30/2022]
Abstract
Object recognition is essential for navigating the real world. Despite decades of research on this topic, the processing steps necessary for recognition remain unclear. In this study, we examined the necessity and role of individuation, the ability to select a small number of spatially distinct objects irrespective of their identity, in the recognition process. More specifically, we tested if the ability to rapidly individuate and enumerate a small number of objects (subitizing) can be impaired by crowding. Crowding is flanker-induced interference that specifically impedes the recognition process. We found that subitizing is impaired when objects are close to each other (Experiment 1), and if the target objects are surrounded by irrelevant but perceptually similar flankers (Experiments 2-4). This impairment cannot be attributed to confusion between targets and flankers, wherein flankers are inadvertently included in or targets are excluded from enumeration (Experiments 3-4). Importantly, the flanker induced interference was comparable in both subitizing and crowding tasks (Experiment 4), suggesting that individuation and identification share a common processing pathway. We conclude that individuation is an essential stage in the object recognition pipeline and argue for a cohesive proposal that both crowding and subitizing are due to limitations of selective attention.
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Affiliation(s)
| | - Amy Herbert
- School of Psychology, University of Aberdeen, Kings College, Aberdeen AB24 3FX, UK
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Perceptual averaging of facial expressions requires visual awareness and attention. Conscious Cogn 2018; 62:110-126. [PMID: 29573970 DOI: 10.1016/j.concog.2018.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/27/2017] [Accepted: 03/13/2018] [Indexed: 11/23/2022]
Abstract
Humans, as highly social animals, are regularly exposed to the faces of conspecifics-often more than one at a time. This feature of social living is important for understanding face perception, not just because it means that information from faces is available in bulk, but also because it changes the way individuals are perceived. For instance, when two faces are seen nearby one another, they tend to look like each other. This phenomenon of perceptual averaging is robust when both faces are seen and attended. But in everyday life, some faces may not receive the full benefit of attention, or they may not be visible at all. We evaluated whether perceptual averaging of relatively complex and simple information on faces, including facial expression and head orientation, can still occur even in these circumstances. In particular, we used object-substitution masking (OSM) and a dual-task designed to disrupt visual awareness and attention, respectively, during evaluations of briefly presented face pairs. Disruptions of awareness or attention eliminated averaging of facial expression, whereas orientation averaging persisted in spite of these challenges. These results demonstrate boundary conditions for the process of perceptual averaging. More generally, they provide insight into how the visual system processes multitudes of objects, both simple and complex, both with and without attention and awareness.
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Visual Working Memory Is Independent of the Cortical Spacing Between Memoranda. J Neurosci 2018; 38:3116-3123. [PMID: 29459370 PMCID: PMC5864153 DOI: 10.1523/jneurosci.2645-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/05/2017] [Accepted: 12/11/2017] [Indexed: 11/26/2022] Open
Abstract
The sensory recruitment hypothesis states that visual short-term memory is maintained in the same visual cortical areas that initially encode a stimulus' features. Although it is well established that the distance between features in visual cortex determines their visibility, a limitation known as crowding, it is unknown whether short-term memory is similarly constrained by the cortical spacing of memory items. Here, we investigated whether the cortical spacing between sequentially presented memoranda affects the fidelity of memory in humans (of both sexes). In a first experiment, we varied cortical spacing by taking advantage of the log-scaling of visual cortex with eccentricity, presenting memoranda in peripheral vision sequentially along either the radial or tangential visual axis with respect to the fovea. In a second experiment, we presented memoranda sequentially either within or beyond the critical spacing of visual crowding, a distance within which visual features cannot be perceptually distinguished due to their nearby cortical representations. In both experiments and across multiple measures, we found strong evidence that the ability to maintain visual features in memory is unaffected by cortical spacing. These results indicate that the neural architecture underpinning working memory has properties inconsistent with the known behavior of sensory neurons in visual cortex. Instead, the dissociation between perceptual and memory representations supports a role of higher cortical areas such as posterior parietal or prefrontal regions or may involve an as yet unspecified mechanism in visual cortex in which stimulus features are bound to their temporal order. SIGNIFICANCE STATEMENT Although much is known about the resolution with which we can remember visual objects, the cortical representation of items held in short-term memory remains contentious. A popular hypothesis suggests that memory of visual features is maintained via the recruitment of the same neural architecture in sensory cortex that encodes stimuli. We investigated this claim by manipulating the spacing in visual cortex between sequentially presented memoranda such that some items shared cortical representations more than others while preventing perceptual interference between stimuli. We found clear evidence that short-term memory is independent of the intracortical spacing of memoranda, revealing a dissociation between perceptual and memory representations. Our data indicate that working memory relies on different neural mechanisms from sensory perception.
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Liu R, Patel BN, Kwon M. Age-related changes in crowding and reading speed. Sci Rep 2017; 7:8271. [PMID: 28811585 PMCID: PMC5557829 DOI: 10.1038/s41598-017-08652-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/17/2017] [Indexed: 12/18/2022] Open
Abstract
Crowding, the inability to recognize objects in clutter, is known to play a role in developmental changes in reading speed. Here, we investigated whether crowding also plays a role in age-related changes in reading speed. We recruited 18 young (mean age: 22.6 ± 3.5; range: 18~31) and 21 older adults (mean age: 58.2 ± 7.0; range: 50~73) with normal vision. Reading speed was measured with short blocks of text. The degree of crowding was determined by measuring crowding zone (the distance between a target and flankers required to yield a criterion recognition accuracy) and the size of the visual span (an uncrowded window in the visual field within which letters can be recognizable reliably). Measurements were made across the central 16-degree visual field using letter-recognition tasks. Our results showed that, compared to young adults, older adults exhibited significantly slower reading speed (a decrease by 30%) and larger crowding: an enlargement of crowding zone (an increase by 31%) and shrinkage of the visual span (a decrease by 6.25 bits). We also observed significant correlations between reading speed and each of the crowding measures. Our results suggest that crowding increases with age. Age-related changes in crowding may in part explain slower reading in older adults.
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Affiliation(s)
- Rong Liu
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Bhavika N Patel
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - MiYoung Kwon
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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Coates DR. Diagnosing the Periphery: Using the Rey-Osterrieth Complex Figure Drawing Test to Characterize Peripheral Visual Function. Iperception 2017; 8:2041669517705447. [PMID: 28607664 PMCID: PMC5453411 DOI: 10.1177/2041669517705447] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Peripheral vision is strongly limited by crowding, the deleterious influence of neighboring stimuli on target perception. Many quantitative aspects of this phenomenon have been characterized, but the specific nature of the perceptual degradation remains elusive. We utilized a drawing technique to probe the phenomenology of peripheral vision, using the Rey-Osterrieth Complex Figure, a standard neuropsychological clinical instrument. The figure was presented at 12° or 6° in the right visual field, with eye tracking to ensure that the figure was only presented when observers maintained stable fixation. Participants were asked to draw the figure with free viewing, capturing its peripheral appearance. A foveal condition was used to measure copying performance in direct view. To assess the drawings, two raters used standard scoring systems that evaluated feature positions, spatial distortions, and omission errors. Feature scores tended to decrease with increasing eccentricity, both within and between conditions, reflecting reduced resolution and increased crowding in peripheral vision. Based on evaluation of the drawings, we also identified new error classes unique to peripheral presentation, including number errors for adjacent similar features and distinctive spatial distortions. The multifaceted nature of the Rey-Osterrieth Complex Figure-containing configural elements, detached compound features, and texture-like components-coupled with the flexibility of the free-response drawing paradigm and the availability of standardized scoring systems, provides a promising method to probe peripheral perception and crowding.
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Affiliation(s)
- Daniel R. Coates
- Laboratory of Experimental Psychology, KU Leuven, Leuven, Belgium; Institute of Psychology, University of Bern, Bern, Switzerland
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Variations in crowding, saccadic precision, and spatial localization reveal the shared topology of spatial vision. Proc Natl Acad Sci U S A 2017; 114:E3573-E3582. [PMID: 28396415 DOI: 10.1073/pnas.1615504114] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Visual sensitivity varies across the visual field in several characteristic ways. For example, sensitivity declines sharply in peripheral (vs. foveal) vision and is typically worse in the upper (vs. lower) visual field. These variations can affect processes ranging from acuity and crowding (the deleterious effect of clutter on object recognition) to the precision of saccadic eye movements. Here we examine whether these variations can be attributed to a common source within the visual system. We first compared the size of crowding zones with the precision of saccades using an oriented clock target and two adjacent flanker elements. We report that both saccade precision and crowded-target reports vary idiosyncratically across the visual field with a strong correlation across tasks for all participants. Nevertheless, both group-level and trial-by-trial analyses reveal dissociations that exclude a common representation for the two processes. We therefore compared crowding with two measures of spatial localization: Landolt-C gap resolution and three-dot bisection. Here we observe similar idiosyncratic variations with strong interparticipant correlations across tasks despite considerably finer precision. Hierarchical regression analyses further show that variations in spatial precision account for much of the variation in crowding, including the correlation between crowding and saccades. Altogether, we demonstrate that crowding, spatial localization, and saccadic precision show clear dissociations, indicative of independent spatial representations, whilst nonetheless sharing idiosyncratic variations in spatial topology. We propose that these topological idiosyncrasies are established early in the visual system and inherited throughout later stages to affect a range of higher-level representations.
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Agaoglu MN, Chung STL. Interaction between stimulus contrast and pre-saccadic crowding. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160559. [PMID: 28386420 PMCID: PMC5367283 DOI: 10.1098/rsos.160559] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 01/04/2017] [Indexed: 06/07/2023]
Abstract
Objects that are briefly flashed around the time of saccades are mislocalized. Previously, robust interactions between saccadic perceptual distortions and stimulus contrast have been reported. It is also known that crowding depends on the contrast of the target and flankers. Here, we investigated how stimulus contrast and crowding interact with pre-saccadic perception. We asked observers to report the orientation of a tilted Gabor presented in the periphery, with or without four flanking vertically oriented Gabors. Observers performed the task either following a saccade or while maintaining fixation. Contrasts of the target and flankers were independently set to either high or low, with equal probability. In both the fixation and saccade conditions, the flanked conditions resulted in worse discrimination performance-the crowding effect. In the unflanked saccade trials, performance significantly decreased with target-to-saccade onset for low-contrast targets but not for high-contrast targets. In the presence of flankers, impending saccades reduced performance only for low-contrast, but not for high-contrast flankers. Interestingly, average performance in the fixation and saccade conditions was mostly similar in all contrast conditions. Moreover, the magnitude of crowding was influenced by saccades only when the target had high contrast and the flankers had low contrasts. Overall, our results are consistent with modulation of perisaccadic spatial localization by contrast and saccadic suppression, but at odds with a recent report of pre-saccadic release of crowding.
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Affiliation(s)
- Mehmet N. Agaoglu
- School of Optometry, University of California, Berkeley, 360 Minor Hall, Berkeley, CA 94720-2020, USA
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