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Urale PWB, Schwarzkopf DS. Effects of cortical distance on the Ebbinghaus and Delboeuf illusions. Perception 2023:3010066231175014. [PMID: 37335155 DOI: 10.1177/03010066231175014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
The Ebbinghaus and Delboeuf illusions affect the perceived size of a target circle depending on the size and proximity of circular inducers or a ring. Converging evidence suggests that these illusions are driven by interactions between contours mediated by their cortical distance in primary visual cortex. We tested the effect of cortical distance on these illusions using two methods: First, we manipulated retinal distance between target and inducers in a two-interval forced choice design, finding that targets appeared larger with a closer surround. Next, we predicted that targets presented peripherally should appear larger due to cortical magnification. Hence, we tested the illusion strength when positioning the stimuli at various eccentricities, with results supporting this hypothesis. We calculated estimated cortical distances between illusion elements in each experiment and used these estimates to compare the relationship between cortical distance and illusion strength across our experiments. In a final experiment, we modified the Delboeuf illusion to test whether the influence of the inducers/annuli in this illusion is influenced by an inhibitory surround. We found evidence that an additional outer ring makes targets appear smaller compared to a single-ring condition, suggesting that near and distal contours have antagonistic effects on perceived target size.
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Affiliation(s)
- Poutasi W B Urale
- School of Optometry & Vision Science, The University of Auckland, New Zealand
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2
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Mruczek REB, Fanelli M, Kelly S, Caplovitz GP. The combination of target motion and dynamic changes in context greatly enhance visual size illusions. Front Hum Neurosci 2022; 16:959367. [PMID: 36188172 PMCID: PMC9519898 DOI: 10.3389/fnhum.2022.959367] [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] [Received: 06/01/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Perceived size is a function of viewing distance, retinal images size, and various contextual cues such as linear perspective and the size and location of neighboring objects. Recently, we demonstrated that illusion magnitudes of classic visual size illusions may be greatly enhanced or reduced by adding dynamic elements. Specifically, a dynamic version of the Ebbinghaus illusion (classically considered a “size contrast” illusion) led to a greatly enhanced illusory effect, whereas a dynamic version of the Corridor illusion (a “size constancy” illusion) led to a greatly diminished illusory effect. Although these differences may arise from the different processes underlying these illusions (size contrast vs. size constancy), the dynamic variants we tested in our previous work also differed in the nature of the dynamic elements; specifically, whereas the Dynamic Ebbinghaus included a moving target and inducers that changed size and position, the Dynamic Corridor only included a moving target on a static background. Here, we explore further dynamic versions of the Ebbinghaus illusion and the Corridor and Ponzo illusions by separately manipulating three types of dynamic elements: target motion, context translation, and dynamic changes in context. Across five experiments examining 21 dynamic illusory configurations, adding target motion or a dynamically changing context separately resulted in little-to-no illusory effect. In contrast, the combination of target motion and a dynamically changing context led to a robust size illusion, consistent with an interactive effect. However, illusory effects that exceeded the matched classic, static illusory configuration were only observed for the dynamic versions of the Ebbinghaus illusion and the Revealed Ponzo illusions, in which the contextual elements changed size. We conclude that the combination of target motion and a dynamically changing context are necessary to produce dynamic size illusions, but that enhancement above and beyond static illusions may be largely specific to size contrast effects. Our results have important implications for the integration of motion signals, a ubiquitous environmental stimulus, in the perception of object size.
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Affiliation(s)
- Ryan E. B. Mruczek
- Department of Psychology, College of the Holy Cross, Worcester, MA, United States
- *Correspondence: Ryan E. B. Mruczek,
| | - Matthew Fanelli
- Department of Psychology, College of the Holy Cross, Worcester, MA, United States
| | - Sean Kelly
- Department of Psychology, College of the Holy Cross, Worcester, MA, United States
| | - Gideon P. Caplovitz
- Department of Psychology, University of Nevada, Reno, Reno, NV, United States
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The Prospects of Utilizing Geometrical Visual Illusions as Tools for Neuroscience. Symmetry (Basel) 2022. [DOI: 10.3390/sym14081687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Geometrical visual illusions have long been used as tools in neuroscience. Most commonly, researchers have taken illusions as a given and attempted to explain phenomenal impressions in terms of known neural mechanisms. In a psychophysical approach to this topic, it is customary to modify stimuli until conditions for which illusions are enhanced, attenuated, or annihilated have been found. Additionally, the focus is not exclusively on response bias but equally on sensitivity, because observers may fall prey to an illusion but at the same time be able to discriminate between stimuli perfectly. For the T-figure, the length of the undivided line is usually overestimated relative to the length of the divided line, and evidence has accrued that suggests that the illusion may be due to the processing of the figure as a coherent unit (a “T-schema”). Dissecting the T or tilting its lines influenced the amount of illusion, suggesting that interactions between orientation-sensitive and end-inhibited neurons are at work. Examples of cognate research with the Ponzo, Ebbinghaus, and Müller-Lyer illusions are also discussed.
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Kirsch W, Kunde W. On the origin of the Ebbinghaus illusion: The role of figural extent and spatial frequency of stimuli. Vision Res 2021; 188:193-201. [PMID: 34364022 DOI: 10.1016/j.visres.2021.07.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/20/2021] [Accepted: 07/27/2021] [Indexed: 11/17/2022]
Abstract
An object is perceived as larger when it is surrounded by smaller context objects than when it is surrounded by larger context objects. The origin of this well-known phenomenon, called as Ebbinghaus or Titchener circles illusion, is still puzzling. Here we introduce a basic explanation of how this illusion could emerge and provide some preliminary empirical support for this idea. In essence, we suggest that changes in the figural extent and in the spatial frequency of the stimulus pattern entail adjustments of the size and resolution of the attentional field, which are accompanied by changes in spatial coding. This approach is consistent with previous observations and can enable a deeper understanding of geometric illusions.
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Affiliation(s)
| | - Wilfried Kunde
- Department of Psychology, University of Würzburg, Germany
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Cretenoud AF, Grzeczkowski L, Kunchulia M, Herzog MH. Individual differences in the perception of visual illusions are stable across eyes, time, and measurement methods. J Vis 2021; 21:26. [PMID: 34029369 PMCID: PMC8164370 DOI: 10.1167/jov.21.5.26] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Vision scientists have tried to classify illusions for more than a century. For example, some studies suggested that there is a unique common factor for all visual illusions. Other studies proposed that there are several subclasses of illusions, such as illusions of linear extent or distortions. We previously observed strong within-illusion correlations but only weak between-illusion correlations, arguing in favor of an even higher multifactorial space with-more or less-each illusion making up its own factor. These mixed results are surprising. Here, we examined to what extent individual differences in the perception of visual illusions are stable across eyes, time, and measurement methods. First, we did not find any significant differences in the magnitudes of the seven illusions tested with monocular or binocular viewing conditions. In addition, illusion magnitudes were not significantly predicted by visual acuity. Second, we observed stable individual differences over time. Last, we compared two illusion measurements, namely an adjustment procedure and a method of constant stimuli, which both led to similar individual differences. Hence, it is unlikely that the individual differences in the perception of visual illusions arise from instability across eyes, time, and measurement methods.
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Affiliation(s)
- Aline F Cretenoud
- Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,
| | - Lukasz Grzeczkowski
- Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Active Perception and Cognition, Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany.,
| | - Marina Kunchulia
- Institute of Cognitive Neurosciences, Free University of Tbilisi, Tbilisi, Georgia.,Laboratory of Vision Physiology, Ivane Beritashvili Center of Experimental Biomedicine, Tbilisi, Georgia.,
| | - Michael H Herzog
- Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,
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Wang A, Chen L, Jiang Y. Anodal Occipital Transcranial Direct Current Stimulation Enhances Perceived Visual Size Illusions. J Cogn Neurosci 2020; 33:528-535. [PMID: 33326330 DOI: 10.1162/jocn_a_01664] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Human early visual cortex has long been suggested to play a crucial role in context-dependent visual size perception through either lateral interaction or feedback projections from higher to lower visual areas. We investigated the causal contribution of early visual cortex to context-dependent visual size perception using the technique of transcranial direct current stimulation and two well-known size illusions (i.e., the Ebbinghaus and Ponzo illusions) and further elucidated the underlying mechanism that mediates the effect of transcranial direct current stimulation over early visual cortex. The results showed that the magnitudes of both size illusions were significantly increased by anodal stimulation relative to sham stimulation but left unaltered by cathodal stimulation. Moreover, the anodal effect persisted even when the central target and surrounding inducers of the Ebbinghaus configuration were presented to different eyes, with the effect lasting no more than 15 min. These findings provide compelling evidence that anodal occipital stimulation enhances the perceived visual size illusions, which is possibly mediated by weakening the suppressive function of the feedback connections from higher to lower visual areas. Moreover, the current study provides further support for the causal role of early visual cortex in the neural processing of context-dependent visual size perception.
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Affiliation(s)
- Anqi Wang
- Research Center of Brain and Cognitive Neuroscience, Liaoning Normal University.,Key Laboratory of Brain and Cognitive Neuroscience, Dalian, China
| | - Lihong Chen
- Research Center of Brain and Cognitive Neuroscience, Liaoning Normal University.,Key Laboratory of Brain and Cognitive Neuroscience, Dalian, China
| | - Yi Jiang
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences.,University of Chinese Academy of Sciences.,Chinese Institute for Brain Research, Beijing, China.,Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
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Wang A, Hu X, Wu B, Chen L, Luo W. Low-spatial-frequency priming potentiates the high-level mechanisms of contextual influence. Vision Res 2020; 177:1-5. [DOI: 10.1016/j.visres.2020.07.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 07/15/2020] [Accepted: 07/15/2020] [Indexed: 11/28/2022]
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Rashal E. Perceptual grouping leads to objecthood effects in the Ebbinghaus illusion. J Vis 2020; 20:11. [PMID: 32766742 PMCID: PMC7438686 DOI: 10.1167/jov.20.8.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 06/18/2020] [Indexed: 11/24/2022] Open
Abstract
The Ebbinghaus illusion is argued to be a product of low-level contour interactions or a higher cognitive comparison process. We examined the effect of grouping on the illusion by manipulating objecthood, i.e., the degree to which an object is a cohesive perceptual entity. We hypothesized that reduced objecthood would decrease the illusion magnitude, because the objects become less efficient in the comparison process. To test this hypothesis, we used a version of the illusion where the target and flanking objects were squares that were composed from their corners or sides. Degree of objecthood was manipulated by changing the gap size or rotation angle of the elements constructing the objects, so that larger gaps and angles produced less cohesive objects than smaller. Participants performed an adjustment procedure on the test target to match a control target in size. In addition, subjective reports of the objects' shape were collected as a measure of perceived shape. Our results show decreased illusion magnitude with increasing gap size and rotation angle. Surprisingly, the perceived shape of the objects did not correlate with illusion magnitude. These results provide novel evidence of the role of mid-level processes in the Ebbinghaus illusion and point to a dissociation between subjective and objective measures of objecthood.
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Affiliation(s)
- Einat Rashal
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
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Takao S, Clifford CWG, Watanabe K. Ebbinghaus illusion depends more on the retinal than perceived size of surrounding stimuli. Vision Res 2018; 154:80-84. [PMID: 30389387 DOI: 10.1016/j.visres.2018.10.010] [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: 10/02/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 11/28/2022]
Abstract
A stimulus surrounded by smaller/larger stimuli appears larger/smaller (Ebbinghaus illusion). We examined whether the Ebbinghaus illusion would depend on the retinal or perceived size of the surrounding stimuli. The flash-lag effect, where a flashed stimulus perceptually lags moving stimuli, was used to dissociate the retinal from perceived size of the surrounding stimuli. Two sets of four surrounding disks changed their size smoothly: one with larger disks shrinking, the other with smaller disks expanding. Two identical central disks were presented briefly at various timings relative to the moment when the surrounding disks were physically identical in their size (coincidence time). A significant flash-lag effect was observed for size change (Experiment 1). Participants reported the two central disks being in equal size when they appeared only slightly before the coincidence time. However, this asynchrony was not significantly different from zero and was significantly smaller than the perceptual delay expected from the flash-lag effect (Experiment 2). These results suggest that the Ebbinghaus illusion depends more on the retinal than perceived size of the surrounding stimuli.
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Affiliation(s)
- Saki Takao
- Faculty of Science and Engineering, Waseda University, Tokyo, Japan; School of Psychology, University of New South Wales, Sydney, Australia.
| | | | - Katsumi Watanabe
- Faculty of Science and Engineering, Waseda University, Tokyo, Japan; Art & Design, University of New South Wales, Sydney, Australia
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