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Shechter A, Medina S, Share DL, Yashar A. Language-universal and script-specific factors in the recognition of letters in visual crowding: The effects of lexicality, hemifield, and transitional probabilities in a right-to-left script. Cortex 2024; 171:319-329. [PMID: 38070387 DOI: 10.1016/j.cortex.2023.10.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/26/2023] [Accepted: 10/23/2023] [Indexed: 02/12/2024]
Abstract
Peripheral letter recognition is fundamentally limited not by the visibility of letters but by the spacing between them, i.e., 'crowding'. Crowding imposes a significant constraint on reading, however, the interplay between crowding and reading is not fully understood. Using a letter recognition task in varying display conditions, we investigated the effects of lexicality (words versus pseudowords), visual hemifield, and transitional letter probability (bigram/trigram frequency) among skilled readers (N = 14. and N = 13) in Hebrew - a script read from right to left. We observed two language-universal effects: a lexicality effect and a right hemifield (left hemisphere) advantage, as well as a strong language-specific effect - a left bigram advantage stemming from the right-to-left reading direction of Hebrew. The latter finding suggests that transitional probabilities are essential for parafoveal letter recognition. The results reveal that script-specific contextual information such as letter combination probabilities is used to accurately identify crowded letters.
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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; Department of Learning Disabilities, Faculty of Education, University of Haifa, Haifa, Israel
| | - Sivan Medina
- Department of Learning and Instructional Sciences, Faculty of Education, University of Haifa, Haifa, Israel
| | - David L Share
- The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, The University of Haifa, Haifa, Israel; Department of Learning Disabilities, Faculty of Education, 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; Department of Special Education, Faculty of Education, University of Haifa, Haifa, Israel.
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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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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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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: 0] [Impact Index Per Article: 0] [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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Mixture-modeling approach reveals global and local processes in visual crowding. Sci Rep 2022; 12:6726. [PMID: 35468981 PMCID: PMC9038733 DOI: 10.1038/s41598-022-10685-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/11/2022] [Indexed: 11/21/2022] Open
Abstract
Crowding refers to the inability to recognize objects in clutter, setting a fundamental limit on various perceptual tasks such as reading and facial recognition. While prevailing models suggest that crowding is a unitary phenomenon occurring at an early level of processing, recent studies have shown that crowding might also occur at higher levels of representation. Here we investigated whether local and global crowding interference co-occurs within the same display. To do so, we tested the distinctive contribution of local flanker features and global configurations of the flankers on the pattern of crowding errors. Observers (n = 27) estimated the orientation of a target when presented alone or surrounded by flankers. Flankers were grouped into a global configuration, forming an illusory rectangle when aligned or a rectangular configuration when misaligned. We analyzed the error distributions by fitting probabilistic mixture models. Results showed that participants often misreported the orientation of a flanker instead of that of the target. Interestingly, in some trials the orientation of the global configuration was misreported. These results suggest that crowding occurs simultaneously across multiple levels of visual processing and crucially depends on the spatial configuration of the stimulus. Our results pose a challenge to models of crowding with an early single pooling stage and might be better explained by models which incorporate the possibility of multilevel crowding and account for complex target-flanker interactions.
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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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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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Temporal crowding is a unique phenomenon reflecting impaired target encoding over large temporal intervals. Psychon Bull Rev 2021; 28:1885-1893. [PMID: 34080137 DOI: 10.3758/s13423-021-01943-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2021] [Indexed: 11/08/2022]
Abstract
Crowding refers to impaired object identification when presented with other objects, and it is well established that spatial crowding-crowding from adjacent objects-affects many aspects of visual perception and cognition. A similar interference also occurs across time-the identification of a target object is impaired when distracting objects precede and succeed it. When such interference is observed with relatively long interitem intervals it is termed temporal crowding. Thus far, little was known about temporal crowding and its underlying processes. Particularly it was unknown which aspects of visual processing are impaired by temporal crowding, and the answer to this question bears critical theoretical implications. To reveal the nature of this impairment we used a continuous-report task and a mixture-model analysis. In three experiments, observers viewed sequences of three oriented items separated by relatively long intervals (170-475ms). The target was the second item in the sequence, and the task was to reproduce its orientation. The findings suggest that temporal crowding impairs target encoding and increases substitution errors, but there was no evidence of a reduced signal-to-noise ratio. This pattern of results was similar regardless of stimuli duration and target-distractor similarity. However, it differed considerably from the pattern found for ordinary masking and spatial crowding, indicating that temporal crowding is a unique phenomenon. Moreover, the finding that temporal crowding affected the precision of target encoding even when the items were separated by almost half a second suggests that visual processing requires a surprisingly long time to complete.
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