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1.
J Vis ; 24(7): 12, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-39028900

RESUMO

Perceiving verticality is crucial for accurate spatial orientation. Previous research has revealed that tilted scenes can bias verticality perception. Verticality perception bias can be represented as the sum of multiple periodic functions that play a role in the perception of visual orientation, where the specific factors affecting each periodicity remain uncertain. This study investigated the influence of the width and depth of an indoor scene on each periodic component of the bias. The participants were presented with an indoor scene showing a rectangular checkerboard room (Experiment 1), a rectangular aperture on the wall (Experiment 2), or a rectangular dotted room (Experiment 3), with various aspect ratios. The stimuli were presented with roll orientations ranging from 90° clockwise to 90° counterclockwise. The participants were asked to report their subjective visual vertical (SVV) perceptions. The contributions of 45°, 90°, and 180° periodicities to the SVV error were assessed by the weighted vector sum model. In Experiment 1, the periodic components of the SVV error increased with the aspect ratio. In Experiments 2 and 3, only the 90° component increased with the aspect ratio. These findings suggest that extended transverse surfaces may modulate the periodic components of verticality perception.


Assuntos
Sinais (Psicologia) , Percepção de Profundidade , Orientação Espacial , Estimulação Luminosa , Humanos , Adulto Jovem , Masculino , Feminino , Percepção de Profundidade/fisiologia , Orientação Espacial/fisiologia , Estimulação Luminosa/métodos , Adulto , Percepção Espacial/fisiologia , Percepção de Forma/fisiologia
2.
J Vis ; 24(7): 13, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-39046722

RESUMO

Super recognizers (SRs) are people that exhibit a naturally occurring superiority for processing facial identity. Despite the increase of SR research, the mechanisms underlying their exceptional abilities remain unclear. Here, we investigated whether the enhanced facial identity processing of SRs could be attributed to the lack of sequential effects, such as serial dependence. In serial dependence, perception of stimulus features is assimilated toward stimuli presented in previous trials. This constant error in visual perception has been proposed as a mechanism that promotes perceptual stability in everyday life. We hypothesized that an absence of this constant source of error in SRs could account for their superior processing-potentially in a domain-general fashion. We tested SRs (n = 17) identified via a recently proposed diagnostic framework (Ramon, 2021) and age-matched controls (n = 20) with two experiments probing serial dependence in the face and shape domains. In each experiment, observers were presented with randomly morphed face identities or shapes and were asked to adjust a face's identity or a shape to match the stimulus they saw. We found serial dependence in controls and SRs alike, with no difference in its magnitude across groups. Interestingly, we found that serial dependence impacted the performance of SRs more than that of controls. Taken together, our results show that enhanced face identity processing skills in SRs cannot be attributed to the lack of serial dependence. Rather, serial dependence, a beneficial nested error in our visual system, may in fact further stabilize the perception of SRs and thus enhance their visual processing proficiency.


Assuntos
Reconhecimento Facial , Estimulação Luminosa , Humanos , Feminino , Masculino , Adulto , Adulto Jovem , Reconhecimento Facial/fisiologia , Estimulação Luminosa/métodos , Percepção de Forma/fisiologia , Pessoa de Meia-Idade
3.
J Vis ; 24(6): 6, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38843389

RESUMO

Infant primates see poorly, and most perceptual functions mature steadily beyond early infancy. Behavioral studies on human and macaque infants show that global form perception, as measured by the ability to integrate contour information into a coherent percept, improves dramatically throughout the first several years after birth. However, it is unknown when sensitivity to curvature and shape emerges in early life or how it develops. We studied the development of shape sensitivity in 18 macaques, aged 2 months to 10 years. Using radial frequency stimuli, circular targets whose radii are modulated sinusoidally, we tested monkeys' ability to radial frequency stimuli from circles as a function of the depth and frequency of sinusoidal modulation. We implemented a new four-choice oddity task and compared the resulting data with that from a traditional two-alternative forced choice task. We found that radial frequency pattern perception was measurable at the youngest age tested (2 months). Behavioral performance at all radial frequencies improved with age. Performance was better for higher radial frequencies, suggesting the developing visual system prioritizes processing of fine visual details that are ecologically relevant. By using two complementary methods, we were able to capture a comprehensive developmental trajectory for shape perception.


Assuntos
Percepção de Forma , Macaca mulatta , Reconhecimento Visual de Modelos , Estimulação Luminosa , Animais , Percepção de Forma/fisiologia , Estimulação Luminosa/métodos , Reconhecimento Visual de Modelos/fisiologia , Masculino , Feminino
4.
J Vis ; 24(6): 5, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38842835

RESUMO

Ensemble processing allows the visual system to condense visual information into useful summary statistics (e.g., average size), thereby overcoming capacity limitations to visual working memory and attention. To examine the role of attention in ensemble processing, we conducted three experiments using a novel paradigm that merged the action effect (a manipulation of attention) and ensemble processing. Participants were instructed to make a simple action if the feature of a cue word corresponded to a subsequent shape. Immediately after, they were shown an ensemble display of eight ovals of varying sizes and were asked to report either the average size of all ovals or the size of a single oval from the set. In Experiments 1 and 2, participants were cued with a task-relevant feature, and in Experiment 3, participants were cued with a task-irrelevant feature. Overall, the task-relevant cues that elicited an action influenced reports of average size in the ensemble phase more than the cues that were passively viewed, whereas task-irrelevant cues did not bias the reports of average size. The results of this study suggest that attention influences ensemble processing only when it is directed toward a task-relevant feature.


Assuntos
Atenção , Sinais (Psicologia) , Estimulação Luminosa , Humanos , Atenção/fisiologia , Adulto Jovem , Masculino , Feminino , Estimulação Luminosa/métodos , Adulto , Memória de Curto Prazo/fisiologia , Tempo de Reação/fisiologia , Percepção de Tamanho/fisiologia , Percepção de Forma/fisiologia , Desempenho Psicomotor/fisiologia , Reconhecimento Visual de Modelos/fisiologia
5.
Cereb Cortex ; 34(6)2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38832533

RESUMO

The two visual pathways model posits that visual information is processed through two distinct cortical systems: The ventral pathway promotes visual recognition, while the dorsal pathway supports visuomotor control. Recent evidence suggests the dorsal pathway is also involved in shape processing and may contribute to object perception, but it remains unclear whether this sensitivity is independent of attentional mechanisms that were localized to overlapping cortical regions. To address this question, we conducted two fMRI experiments that utilized different parametric scrambling manipulations in which human participants viewed novel objects in different levels of scrambling and were instructed to attend to either the object or to another aspect of the image (e.g. color of the background). Univariate and multivariate analyses revealed that the large-scale organization of shape selectivity along the dorsal and ventral pathways was preserved regardless of the focus of attention. Attention did modulate shape sensitivity, but these effects were similar across the two pathways. These findings support the idea that shape processing is at least partially dissociable from attentional processes and relies on a distributed set of cortical regions across the visual pathways.


Assuntos
Atenção , Imageamento por Ressonância Magnética , Estimulação Luminosa , Vias Visuais , Humanos , Atenção/fisiologia , Masculino , Feminino , Vias Visuais/fisiologia , Vias Visuais/diagnóstico por imagem , Adulto , Adulto Jovem , Imageamento por Ressonância Magnética/métodos , Estimulação Luminosa/métodos , Mapeamento Encefálico/métodos , Reconhecimento Visual de Modelos/fisiologia , Percepção de Forma/fisiologia , Córtex Visual/fisiologia , Córtex Visual/diagnóstico por imagem
6.
J Vis ; 24(6): 9, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38856981

RESUMO

Four experiments were conducted to gain a better understanding of the visual mechanisms related to how integration of partial shape cues provides for recognition of the full shape. In each experiment, letters formed as outline contours were displayed as a sequence of adjacent segments (fragments), each visible during a 17-ms time frame. The first experiment varied the contrast of the fragments. There were substantial individual differences in contrast sensitivity, so stimulus displays in the masking experiments that followed were calibrated to the sensitivity of each participant. Masks were displayed either as patterns that filled the entire screen (full field) or as successive strips that were sliced from the pattern, each strip lying across the location of the letter fragment that had been shown a moment before. Contrast of masks were varied to be lighter or darker than the letter fragments. Full-field masks, whether light or dark, provided relatively little impairment of recognition, as was the case for mask strips that were lighter than the letter fragments. However, dark strip masks proved to be very effective, with the degree of recognition impairment becoming larger as mask contrast was increased. A final experiment found the strip masks to be most effective when they overlapped the location where the letter fragments had been shown a moment before. They became progressively less effective with increased spatial separation from that location. Results are discussed with extensive reference to potential brain mechanisms for integrating shape cues.


Assuntos
Sensibilidades de Contraste , Percepção de Forma , Reconhecimento Visual de Modelos , Mascaramento Perceptivo , Estimulação Luminosa , Humanos , Mascaramento Perceptivo/fisiologia , Sensibilidades de Contraste/fisiologia , Estimulação Luminosa/métodos , Adulto , Reconhecimento Visual de Modelos/fisiologia , Percepção de Forma/fisiologia , Masculino , Feminino , Sinais (Psicologia) , Adulto Jovem
7.
J Neurophysiol ; 132(1): 130-133, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38863428

RESUMO

Recent functional magnetic resonance imaging (fMRI) experiments revealed similar neural representations across different types of two-dimensional (2-D) visual stimuli; however, real three-dimensional (3-D) objects affording action differentially affect neural activation and behavioral results relative to 2-D objects. Recruitment of multiple sensory regions during unisensory (visual, haptic, and auditory) object shape tasks suggests that shape representation may be modality invariant. This mini-review explores the overlapping neural regions involved in object shape representation, across 2-D, 3-D, visual, and haptic experiments.


Assuntos
Imageamento por Ressonância Magnética , Humanos , Percepção Visual/fisiologia , Animais , Percepção do Tato/fisiologia , Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Encéfalo/diagnóstico por imagem , Percepção de Forma/fisiologia
8.
J Vis ; 24(6): 15, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38913017

RESUMO

The watercolor effect (WCE) is a striking visual illusion elicited by a bichromatic double contour, such as a light orange and a dark purple, hugging each other on a white background. Color assimilation, emanating from the lighter contour, spreads onto the enclosed surface area, thereby tinting it with a chromatic veil, not unlike a weak but real color. Map makers in the 17th century utilized the WCE to better demarcate the shape of adjoining states, while 20th-century artist Bridget Riley created illusory watercolor as part of her op-art. Today's visual scientists study the WCE for its filling-in properties and strong figure-ground segregation. This review emphasizes the superior strength of the WCE for grouping and figure-ground organization vis-à-vis the classical Gestalt factors of Max Wertheimer (1923), thereby inspiring a notion of form from induced color. It also demonstrates that a thin chromatic line, flanking the inside of a black Mondrian-type pattern, induces the WCE across a large white surface area. Phenomenological, psychophysical, and neurophysiological approaches are reviewed.


Assuntos
Percepção de Cores , Humanos , Percepção de Cores/fisiologia , História do Século XX , Ilusões Ópticas/fisiologia , Percepção de Forma/fisiologia , História do Século XVII , História do Século XIX , História do Século XVIII
9.
Cortex ; 176: 129-143, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38781910

RESUMO

Does the human brain represent perspectival shapes, i.e., viewpoint-dependent object shapes, especially in relatively higher-level visual areas such as the lateral occipital cortex? What is the temporal profile of the appearance and disappearance of neural representations of perspectival shapes? And how does attention influence these neural representations? To answer these questions, we employed functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and multivariate decoding techniques to investigate spatiotemporal neural representations of perspectival shapes. Participants viewed rotated objects along with the corresponding objective shapes and perspectival shapes (i.e., rotated round, round, and oval) while we measured their brain activities. Our results revealed that shape classifiers trained on the basic shapes (i.e., round and oval) consistently identified neural representations in the lateral occipital cortex corresponding to the perspectival shapes of the viewed objects regardless of attentional manipulations. Additionally, this classification tendency toward the perspectival shapes emerged approximately 200 ms after stimulus presentation. Moreover, attention influenced the spatial dimension as the regions showing the perspectival shape classification tendency propagated from the occipital lobe to the temporal lobe. As for the temporal dimension, attention led to a more robust and enduring classification tendency towards perspectival shapes. In summary, our study outlines a spatiotemporal neural profile for perspectival shapes that suggests a greater degree of perspectival representation than is often acknowledged.


Assuntos
Atenção , Mapeamento Encefálico , Imageamento por Ressonância Magnética , Magnetoencefalografia , Humanos , Magnetoencefalografia/métodos , Imageamento por Ressonância Magnética/métodos , Atenção/fisiologia , Masculino , Feminino , Adulto , Adulto Jovem , Mapeamento Encefálico/métodos , Estimulação Luminosa/métodos , Lobo Occipital/fisiologia , Lobo Occipital/diagnóstico por imagem , Reconhecimento Visual de Modelos/fisiologia , Percepção de Forma/fisiologia , Encéfalo/fisiologia , Encéfalo/diagnóstico por imagem
10.
PLoS One ; 19(5): e0303562, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38809944

RESUMO

Classical experiments using hierarchical stimuli to investigate the ability of capuchin monkeys to integrate visual information based on global or local clues reported findings suggesting a behavioral preference for local information of the image. Many experiments using mosaics have been conducted with capuchin monkeys to identify some of their perceptual phenotypes. As the identification of an image in a mosaic demands the integration of elements that share some visual features, we evaluated the discrimination of shapes presented in solid and mosaic stimuli in capuchin monkeys. Shape discrimination performance was tested in 2 male adult capuchin monkeys in an experimental chamber with a touchscreen video monitor, in three experiments: (i) evaluation of global and local processing using hierarchical stimuli; (ii) evaluation of target detection using simple discrimination procedures; (iii) evaluation of shape discrimination using simple discrimination and delayed matching-to-sample procedures. We observed that both monkeys had preferences for local processing when tested by hierarchical stimuli. Additionally, detection performance for solid and mosaic targets was highly significant, but for shape discrimination tasks we found significant performance when using solid figures, non-significant performance when using circle and square shapes in mosaic stimuli, and significant performance when using Letter X and Number 8 shapes in mosaic stimuli. Our results are suggestive that the monkeys respond to local contrast and partly to global contrast in mosaic stimuli.


Assuntos
Sapajus , Animais , Masculino , Estimulação Luminosa , Discriminação Psicológica/fisiologia , Percepção de Forma/fisiologia , Reconhecimento Visual de Modelos/fisiologia
11.
Can J Exp Psychol ; 78(2): 88-99, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38722576

RESUMO

Localisation of simple stimuli such as angle vertices may contribute to a plethora of illusory effects. We focus on the Müller-Lyer illusion in an attempt to measure and characterise a more elementary effect that may contribute to the magnitude of said illusion. Perceived location error of angle vertices (a single set of Müller-Lyer fins) and arcs in a 2D plane was measured with the aim to provide clarification of ambiguous results from studies of angle localisation and expand the results to other types of stimuli. In three experiments, we utilised the method of constant stimuli in order to determine perceived locations of angle vertices (Experiments 1 and 2) as well as circular and elliptical arcs (Experiment 3). The results show significant distortions of perceived compared to objective vertex locations (all effect sizes d > 1.01, p < .001). Experiment 2 revealed strong effects of angle size and fin length on localisation error. Mislocalization was larger for more acute angles and longer angle fins (both ηp² = .43, p < .001). In Experiment 3, localisation errors were larger for longer arcs (ηp² = .19, p = .001) irrespective of shape (circular or elliptical). We discuss the effect in the context of modern trends in research of the Müller-Lyer illusion as well as the widely popular centroid theory. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Assuntos
Ilusões Ópticas , Percepção Espacial , Humanos , Adulto , Feminino , Masculino , Ilusões Ópticas/fisiologia , Adulto Jovem , Percepção Espacial/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Percepção de Forma/fisiologia
12.
Vision Res ; 221: 108433, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38772272

RESUMO

Rectangularity and perpendicularity of contours are important properties of 3D shape for the visual system and the visual system can use them asa prioriconstraints for perceivingshape veridically. The presentarticle provides a comprehensive review ofpriorstudiesofthe perception of rectangularity and perpendicularity anditdiscussestheir effects on3D shape perception from both theoretical and empiricalapproaches. It has been shown that the visual system is biased to perceive a rectangular 3D shape from a 2D image. We thought that this bias might be attributable to the likelihood of a rectangular interpretation but this hypothesis is not supported by the results of our psychophysical experiment. Note that the perception ofa rectangular shape cannot be explained solely on the basis of geometry. A rectangular shape is perceived from an image that is inconsistent with a rectangular interpretation. To address thisissue, we developed a computational model that can recover a rectangular shape from an image of a parallelopiped. The model allows the recovered shape to be slightly inconsistent so that the recovered shape satisfies the a priori constraints of maximum compactness and minimal surface area. This model captures someof thephenomenaassociated withthe perception of the rectangular shape that were reported inpriorstudies. This finding suggests that rectangularity works for shape perception by incorporatingitwith someadditionalconstraints.


Assuntos
Percepção de Forma , Humanos , Percepção de Forma/fisiologia , Psicofísica , Percepção de Profundidade/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa/métodos
13.
Invest Ophthalmol Vis Sci ; 65(5): 33, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38771569

RESUMO

Purpose: This study explored early (contrast discrimination) and intermediate (global form perception) visual processing in primary subtypes of glaucoma: primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). We aimed to understand early and intermediate visual processing in POAG and PACG, matched for similar visual field defect severity. Methods: Early visual processing was measured using a contrast discrimination task described by Porkorny and Smith (1997), and intermediate processing using a global form perception task using glass pattern coherence thresholds. Thresholds were determined centrally and at a single midperipheral location (12.5°) in a quadrant without visual field defects. Controls were tested in corresponding quadrants to individuals with glaucoma. Results: Sixty participants (20 POAG, 20 PACG, and 20 age-matched controls), aged 50 to 77 years, were included. Visual field defects were matched between POAG and PACG, with mean deviation values of -6.53 ± 4.46 (range: -1.5 to -16.85) dB and -6.2 ± 4.24 (range: -1.37 to -16.42) dB, respectively. Two-Way ANOVA revealed significant differences in thresholds between the glaucoma groups and the control group for both contrast discrimination and global form perception tasks, with higher thresholds in the glaucoma groups. Post hoc analyses showed no significant contrast discrimination difference between POAG and PACG, but POAG had significantly higher thresholds than PACG for form perception. Conclusions: In form perception, POAG showed slightly worse performance than PACG, suggesting that individuals with POAG may experience more severe functional damage than PACG of similar visual field severity.


Assuntos
Sensibilidades de Contraste , Percepção de Forma , Glaucoma de Ângulo Fechado , Glaucoma de Ângulo Aberto , Campos Visuais , Humanos , Glaucoma de Ângulo Aberto/fisiopatologia , Glaucoma de Ângulo Fechado/fisiopatologia , Pessoa de Meia-Idade , Idoso , Masculino , Feminino , Campos Visuais/fisiologia , Sensibilidades de Contraste/fisiologia , Percepção de Forma/fisiologia , Pressão Intraocular/fisiologia , Limiar Sensorial/fisiologia , Testes de Campo Visual
14.
Cortex ; 176: 62-76, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38754211

RESUMO

Human visual experience of objects comprises a combination of visual features, such as color, position, and shape. Spatial attention is thought to play a role in creating a coherent perceptual experience, integrating visual information coming from a given location, but the mechanisms underlying this process are not fully understood. Deficits of spatial attention in which this integration process does not occur normally, such as neglect, can provide insights regarding the mechanisms of spatial attention in visual object recognition. In this study, we describe a series of experiments conducted with an individual with neglect, DH. DH presents characteristic lack of awareness of the left side of individual objects, evidenced by poor object and face recognition, and impaired word reading. However, he exhibits intact recognition of color within the boundaries of the same objects he fails to recognize. Furthermore, he can also report the orientation and location of a colored region on the neglected left side despite lack of awareness of the shape of the region. Overall, DH shows selective lack of awareness of shape despite intact processing of basic visual features in the same spatial location. DH's performance raises intriguing questions and challenges about the role of spatial attention in the formation of coherent object percepts and visual awareness.


Assuntos
Atenção , Conscientização , Transtornos da Percepção , Humanos , Masculino , Transtornos da Percepção/fisiopatologia , Atenção/fisiologia , Conscientização/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Percepção Visual/fisiologia , Percepção Espacial/fisiologia , Estimulação Luminosa/métodos , Reconhecimento Psicológico/fisiologia , Pessoa de Meia-Idade , Percepção de Forma/fisiologia , Idoso
15.
J Vis ; 24(5): 12, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38787569

RESUMO

Materials exhibit an extraordinary range of visual appearances. Characterizing and quantifying appearance is important not only for basic research on perceptual mechanisms but also for computer graphics and a wide range of industrial applications. Although methods exist for capturing and representing the optical properties of materials and how they vary across surfaces (Haindl & Filip, 2013), the representations are typically very high-dimensional, and how these representations relate to subjective perceptual impressions of material appearance remains poorly understood. Here, we used a data-driven approach to characterizing the perceived appearance characteristics of 30 samples of wood veneer using a "visual fingerprint" that describes each sample as a multidimensional feature vector, with each dimension capturing a different aspect of the appearance. Fifty-six crowd-sourced participants viewed triplets of movies depicting different wood samples as the sample rotated. Their task was to report which of the two match samples was subjectively most similar to the test sample. In another online experiment, 45 participants rated 10 wood-related appearance characteristics for each of the samples. The results reveal a consistent embedding of the samples across both experiments and a set of nine perceptual dimensions capturing aspects including the roughness, directionality, and spatial scale of the surface patterns. We also showed that a weighted linear combination of 11 image statistics, inspired by the rating characteristics, predicts perceptual dimensions well.


Assuntos
Madeira , Humanos , Feminino , Adulto , Masculino , Adulto Jovem , Propriedades de Superfície , Estimulação Luminosa/métodos , Percepção de Forma/fisiologia , Reconhecimento Visual de Modelos/fisiologia
16.
J Exp Psychol Hum Percept Perform ; 50(6): 605-625, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38573695

RESUMO

Object-based warping is a visual illusion in which dots appear farther apart from each other when superimposed on an object. Previous research found that the illusion's strength varies with the perceived objecthood of the display. We tested whether objecthood alone determines the strength of the visual illusion or if low-level factors separable from objecthood also play a role. In Experiments 1-2, we varied low-level features to assess their impact on the warping illusion. We found that the warping illusion is equally strong for a variety of shapes but varies with the elements by which shape is defined. Shapes composed of continuous edges produced larger warping effects than shapes defined by disconnected elements. In Experiment 3, we varied a display's objecthood while holding low-level features constant. Displays with matched low-level features produced warping effects of the same size even when the perceived unity of the elements in the display varied. In Experiments 4-6, we tested whether displays with low-level features predicted to be important in spatial warping produced the visual illusion even when the display weakly configured into a single object. Results showed that the presence of low-level features like contour solidity and convexity determined warping effect sizes over and above what could be accounted for by the display's perceived objecthood. Our findings challenge the view that the spatial warping illusion is solely object-based. Other factors like the solidity of contours and contours' position relative to reference dots appear to play separate and important roles in determining warping effect sizes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Assuntos
Percepção de Forma , Ilusões Ópticas , Reconhecimento Visual de Modelos , Humanos , Adulto , Adulto Jovem , Reconhecimento Visual de Modelos/fisiologia , Ilusões Ópticas/fisiologia , Percepção de Forma/fisiologia , Masculino , Feminino , Percepção Espacial/fisiologia
17.
Vision Res ; 219: 108394, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38579407

RESUMO

Contour Integration (CI) is the ability to integrate elemental features into objects and is a basic visual process essential for object perception and recognition, and for functioning in visual environments. It is now well documented that people with schizophrenia (SZ), in addition to having cognitive impairments, also have several visual perceptual deficits, including in CI. Here, we retrospectively characterize the performance of both SZ and neurotypical individuals (NT) on a series of contour shapes, made up of Gabor elements, that varied in terms of closure and curvature. Participants in both groups performed a CI training task that included 7 different families of shapes (Lines, Ellipse, Blobs, Squiggles, Spiral, Circle and Letters) for up to 40 sessions. Two parameters were manipulated in the training task: Orientation Jitter (OJ, i.e., orientation deviations of individual Gabor elements from ideal for each shape) and Inducer Number (IN, i.e., number of Gabor elements defining the shape). Results show that both OJ and IN thresholds significantly differed between the groups, with higher (OJ) and lower (IN) thresholds observed in the controls. Furthermore, we found significant effects as a function of the contour shapes, with differences between groups emerging with contours that were considered more complex, e.g., due to having a higher degree of curvature (Blobs, Spiral, Letters). These data can inform future work that aims to characterize visual integration impairments in schizophrenia.


Assuntos
Percepção de Forma , Esquizofrenia , Humanos , Percepção de Forma/fisiologia , Esquizofrenia/fisiopatologia , Adulto , Feminino , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Limiar Sensorial/fisiologia , Estimulação Luminosa/métodos , Estudos de Casos e Controles , Reconhecimento Visual de Modelos/fisiologia , Adulto Jovem
18.
Vision Res ; 220: 108400, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38603923

RESUMO

It is well known that objects become grouped in perceptual organization when they share some visual feature, like a common direction of motion. Less well known is that grouping can change how people perceive a set of objects. For example, when a pair of shapes consistently share a common region of space, their aspect ratios tend to be perceived as more similar (are attracted toward each other). Conversely, when shapes are assigned to different regions in space their aspect ratios repel from each other. Here we examine whether the visual system produce both attractive and repulsive distortions when the state of grouping between a pair of shapes changes on a moment-to-moment basis. Observers viewed a pair of ellipses that differed in terms of how flat or tall they were and reported the aspect ratio of one ellipse from the pair. Each ellipse was defined by a cloud of coherently-moving dots, and the dots within the two ellipses had either the same or different directions of motion, varying from trial-to-trial. We found that the cued ellipse's aspect ratio was reported to be repelled from the aspect ratio of the uncued ellipse when the shapes had different directions of motion compared to when they had the same direction of motion. These results suggest that the visual system can adaptively alter visual experience based on grouping, in particular, repelling the appearance of objects when they do not appear to go together, and it can do so quickly and flexibly.


Assuntos
Julgamento , Percepção de Movimento , Estimulação Luminosa , Humanos , Percepção de Movimento/fisiologia , Estimulação Luminosa/métodos , Julgamento/fisiologia , Percepção de Forma/fisiologia , Adulto , Sinais (Psicologia) , Masculino , Feminino , Psicofísica , Adulto Jovem , Análise de Variância , Reconhecimento Visual de Modelos/fisiologia
19.
Jpn J Ophthalmol ; 68(3): 183-191, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38598144

RESUMO

PURPOSE: To assess the impact of glaucoma on perceiving three-dimensional (3D) shapes based on monocular depth cues. STUDY DESIGN: Clinical observational study. METHODS: Twenty glaucoma patients, subjected to binocular visual-field sensitivity (binocular-VFS) tests using a Humphrey Visual Field Analyzer, and 20 age-matched healthy volunteers, underwent two tasks: identifying the nearest vertex of a 3D shape using monocular shading (3D-SfS), texture (3D-SfT), or motion (3D-SfM) cues, and distinguishing elementary one-dimensional (1D) features of these cues. The association of the visual-field index (VFI) of binocular-VFS with 3D shape perception in glaucoma patients was also examined. RESULTS: Glaucoma patients demonstrated reduced accuracy in distinguishing 1D luminance brightness and a larger "error-in-depth" between the perceived and actual depths for 3D-SfM and 3D-SfS compared to healthy volunteers. Six glaucoma patients with a 100% VFI for binocular-VFS exhibited a similar error-in-depth to the other fourteen glaucoma patients; they had a larger error-in-depth for 3D-SfM compared to healthy volunteers. No correlation between the error-in-depth values and the VFI values of binocular-VFS was observed. CONCLUSIONS: The 3D shape perception in glaucoma patients varies based on the depth cue's characteristics. Impaired 1D discrimination and larger thresholds for 3D-SfM in glaucoma patients with a 100% VFI for binocular-VFS indicate more pronounced perceptual deficits of lower-level elementary features for 3D-SfS and higher-level visual processing of 3D shapes for 3D-SfM. The effects of the location and degree of binocular visual-field defects on 3D shape perception remain to be elucidated. Our research provides insights into the 3D shape extraction mechanism in glaucoma.


Assuntos
Sinais (Psicologia) , Percepção de Profundidade , Glaucoma , Visão Binocular , Visão Monocular , Campos Visuais , Humanos , Masculino , Feminino , Percepção de Profundidade/fisiologia , Visão Binocular/fisiologia , Campos Visuais/fisiologia , Pessoa de Meia-Idade , Idoso , Glaucoma/fisiopatologia , Glaucoma/diagnóstico , Visão Monocular/fisiologia , Testes de Campo Visual , Pressão Intraocular/fisiologia , Percepção de Forma/fisiologia , Adulto
20.
Invest Ophthalmol Vis Sci ; 65(4): 13, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38573617

RESUMO

Purpose: The purpose of this study was to assess motion-defined form perception, including the association with clinical and sensory factors that may drive performance, in each eye of children with deprivation amblyopia due to unilateral cataract. Methods: Coherence thresholds for orientation discrimination of motion-defined form were measured using a staircase procedure in 30 children with deprivation amblyopia and 59 age-matched controls. Visual acuity, stereoacuity, fusion, and interocular suppression were also measured. Fixation stability and fellow-eye global motion thresholds were measured in a subset of children. Results: Motion-defined form coherence thresholds were elevated in 90% of children with deprivation amblyopia when viewing with the amblyopic eye and in 40% when viewing with the fellow eye. The deficit was similar in children with a cataract that had been visually significant at birth (congenital) and in children for whom the cataract appeared later in infancy or childhood (developmental). Poorer motion-defined form perception in amblyopic eyes was associated with poorer visual acuity, poorer binocular function, greater interocular suppression, and the presence of nystagmus. Fellow-eye deficits were not associated with any of these factors, but a temporo-nasal asymmetry for global motion perception in favor of nasalward motion suggested a general disruption in motion perception. Conclusions: Deficits in motion-defined form perception are common in children with deprivation amblyopia and may reflect a problem in motion processing that relies on binocular mechanisms.


Assuntos
Ambliopia , Catarata , Percepção de Forma , Percepção de Movimento , Recém-Nascido , Criança , Humanos , Olho
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