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Attention, Perception & Psychophysics Feb 2024Time and space are intimately related to each other. Previous evidence has shown that stimulus size can affect perceived duration even when size differences are...
Time and space are intimately related to each other. Previous evidence has shown that stimulus size can affect perceived duration even when size differences are illusory. In the present study, we investigated the effect of visual-spatial illusions on duration judgments in a temporal reproduction paradigm. Specifically, we induced the Ebbinghaus illusion (Exp. 1) and the horizontal-vertical illusion (Exp. 2) during the encoding phase of the target interval or the reproduction phase. The results showed (a) that illusory size affects temporal processing similarly to the way physical size does, (b) that the effect is independent of whether the illusion appeared during encoding or reproduction, and (c) that the interference between size and temporal processing is bidirectional. These results suggest a rather late locus of size-time interference in the processing stream.
Topics: Humans; Illusions; Size Perception; Judgment; Time Perception; Optical Illusions; Visual Perception
PubMed: 37386344
DOI: 10.3758/s13414-023-02737-x -
Perception Aug 2023The purpose of this study was to establish whether wing length and the ability to form spatial mental images and vivid images affected optical illusions obtained in the...
The purpose of this study was to establish whether wing length and the ability to form spatial mental images and vivid images affected optical illusions obtained in the Müller-Lyer figures, both real and imagined. The study involved a group of 137 fine arts college students who were shown two forms of the Müller-Lyer figures with different wing length (15 and 45 mm). In the imagined situation, a plain horizontal line was presented, and participants were expected to imagine the arrowheads aligned in the same way as in the real situation. Discrepancies in the perception of the horizontal lines in the Müller-Lyer illusion ("Point of Subjective Equality") were measured both in the real and imagined situation. Participants were then asked to complete the Vividness of Visual Imagery Questionnaire and the Measure of the Ability to Form Spatial Mental Imagery. It emerged that, in the condition of 45 mm wing length, participants were significantly more susceptible to the illusion than those in the condition of 15 mm wing length. Additionally, in the real situation, participants scoring high in spatial image were significantly more resistant to the illusion than those scoring low.
Topics: Humans; Illusions; Optical Illusions
PubMed: 37384424
DOI: 10.1177/03010066231178232 -
Attention, Perception & Psychophysics Oct 2023In the present study, the features of summation of effects caused by contextual distracting dots in the length-matching task (a variant of the filled-space illusion)...
In the present study, the features of summation of effects caused by contextual distracting dots in the length-matching task (a variant of the filled-space illusion) were investigated. In the first two series of psychophysical experiments, the illusion magnitude was measured as a function of the displacement of distractors (either single or double sets of dots) orthogonally to the main axis of the stimulus. It was demonstrated that with increasing displacement, the illusion smoothly decreases for a single set of distractors, while for two sets, the illusion first increases to a certain maximum value, and then gradually decreases. In the third and fourth series of experiments, magnitude of the illusion was measured as a function of the luminance of one set of distracting dots, while the luminance of the other set was fixed. It has been shown that increasing the luminance until the same value is reached for both sets leads to a monotonous growth in the illusion magnitude; after that, the illusion asymptotically decreases to an almost constant level. The theoretical interpretation of the established functional dependencies was performed using a quantitative model based on the assumption that the illusion may arise due to the weighted summation of the distractor-induced normalized neural activity, which leads to the perceptual mislocalization of terminators of stimulus spatial intervals.
Topics: Humans; Optical Illusions; Photic Stimulation; Vision, Ocular
PubMed: 37369970
DOI: 10.3758/s13414-023-02744-y -
BMC Ophthalmology Jun 2023Cataracts affect the optics of the eye in terms of absorption, blur, and scattering. When cataracts are unilateral, they cause differences between the eyes that can...
BACKGROUND
Cataracts affect the optics of the eye in terms of absorption, blur, and scattering. When cataracts are unilateral, they cause differences between the eyes that can produce visual discomfort and harm binocular vision. These interocular differences can also induce differences in the processing speed of the eyes that may cause a spontaneous Pulfrich effect, a visual illusion provoking important depth misperceptions. Interocular differences in light level, like those present in unilateral cataracts, can cause the Classic Pulfrich effect, and interocular differences in blur, like those present in monovision, a common correction for presbyopia, can cause the Reverse Pulfrich effect. The visual system may be able to adapt, or not, to the new optical condition, depending on the degree of the cataract and the magnitude of the monovision correction.
CASE PRESENTATION
Here, we report a unique case of a 45-year-old patient that underwent unilateral cataract surgery resulting in a monovision correction of 2.5 diopters (D): left eye emmetropic after the surgery compensated with a monofocal intraocular lens and right eye myopic with a spherical equivalent of -2.50 D. This patient suffered severe symptoms in binocular vision, which can be explained by a spontaneous Pulfrich effect (a delay measured of 4.82 ms, that could be eliminated with a 0.19 optical density filter). After removing the monovision with clear lens extraction in the second eye, symptoms disappeared. We demonstrate that, at least in this patient, both Classic and Reverse Pulfrich effects coexist after unilateral cataract surgery and that can be readapted by reverting the interocular differences. Besides, we report that the adaptation/readaptation process to the Reverse Pulfrich effect happens in a timeframe of weeks, as opposed to the Classic Pulfrich effect, known to have timeframes of days. Additionally, we used the illusion measured in the laboratory to quantify the relevance of the spontaneous Pulfrich effect in different visual scenarios and tasks, using geometrical models and optic flow algorithms.
CONCLUSIONS
Measuring the different versions of the Pulfrich effect might help to understand the visual discomfort reported by many patients after cataract surgery or with monovision and could guide compensation or intervention strategies.
Topics: Humans; Middle Aged; Vision, Monocular; Cataract Extraction; Lenses, Intraocular; Lens Implantation, Intraocular; Cataract; Presbyopia
PubMed: 37353733
DOI: 10.1186/s12886-023-03041-w -
Perception Jul 2023The 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...
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.
Topics: Humans; Illusions; Optical Illusions; Size Perception; Gravitation; Retina
PubMed: 37335155
DOI: 10.1177/03010066231175014 -
I-Perception 2023The glare illusion is an illusory perception of brightness enhancement and self-luminosity from a glare pattern, which consists of a central white area and surrounding...
The glare illusion is an illusory perception of brightness enhancement and self-luminosity from a glare pattern, which consists of a central white area and surrounding areas with radial darkening luminance gradients. Here, we report a phenomenon we call "the switching glare illusion." In this phenomenon, observers experience perceptual alternation in which the glare effect repeatedly appears and disappears or attenuates when the multiple glare patterns are arranged in a grid pattern. This perceptual alternation is caused by a figure-ground reversal in the grid pattern. Since such a phenomenon has not been reported for a single glare pattern, this is caused by arranging multiple glare patterns in a grid. This new finding is worthy for further studies for understanding the mechanisms underlying the glare effect and brightness perception.
PubMed: 37325197
DOI: 10.1177/20416695231179627 -
SAGE Open Medical Case Reports 2023In this case report, we describe a rare imaging finding of foveal duplication identified on spectral domain optical coherence tomography (OCT) through undilated pupils...
In this case report, we describe a rare imaging finding of foveal duplication identified on spectral domain optical coherence tomography (OCT) through undilated pupils in a 49-year-old asymptomatic anxious lady with type 2 diabetes mellitus who visited the retina clinic for diabetic retinopathy screening. A simple patient counseling for cooperation during a repeat OCT scan with dilated pupils revealed that the twin fovea-like duplication was an illusion. This case illustrates the necessity of pupillary dilation and reimaging in the presence of unusual artifacts, such as foveal duplication, to prevent clinicians from ordering unnecessary additional tests.
PubMed: 37325166
DOI: 10.1177/2050313X231180034 -
Perception Aug 2023Ponzo is a familiar name in psychology because of the illusion that takes his name. He had a long and productive career in Italy, and some of his work was translated for...
Ponzo is a familiar name in psychology because of the illusion that takes his name. He had a long and productive career in Italy, and some of his work was translated for international journals already in his lifetime. However, few of these papers are available in English. We provide a commentary that considers how his name came to be associated with an illusion he did not discover. We explain the content of several papers, some of which are often cited in a wrong context in the literature (i.e., papers on touch mentioned in relation to the Ponzo illusion). More importantly, we discuss his contribution to the study of perceived numerosity, and provide a full translation of his important 1928 paper, including a redrawing of its 28 illustrations.
Topics: Male; Humans; Illusions; Optical Illusions; Touch Perception; Italy; Size Perception
PubMed: 37248612
DOI: 10.1177/03010066231176744 -
Scientific Reports Apr 2023Visual illusions are a gateway to understand how we construct our experience of reality. Unfortunately, important questions remain open, such as the hypothesis of a...
Visual illusions are a gateway to understand how we construct our experience of reality. Unfortunately, important questions remain open, such as the hypothesis of a common factor underlying the sensitivity to different types of illusions, as well as of personality correlates of illusion sensitivity. In this study, we used a novel parametric framework for visual illusions to generate 10 different classic illusions (Delboeuf, Ebbinghaus, Rod and Frame, Vertical-Horizontal, Zöllner, White, Müller-Lyer, Ponzo, Poggendorff, Contrast) varying in strength, embedded in a perceptual discrimination task. We tested the objective effect of the illusions on errors and response times, and extracted participant-level performance scores (n=250) for each illusion. Our results provide evidence in favour of a general factor underlying the sensitivity to different illusions (labelled Factor i). Moreover, we report a positive link between illusion sensitivity and personality traits such as Agreeableness, Honesty-Humility, and negative relationships with Psychoticism, Antagonism, Disinhibition, and Negative Affect.
Topics: Humans; Illusions; Optical Illusions; Size Perception; Personality Disorders; Personality
PubMed: 37087480
DOI: 10.1038/s41598-023-33148-5 -
Bio Systems May 2023In a previous paper, the authors proposed a mathematical definition of a public language and a new model of consciousness based on that public language. Consciousness...
In a previous paper, the authors proposed a mathematical definition of a public language and a new model of consciousness based on that public language. Consciousness spans a wide range of disciplines, including medicine, philosophy, mathematics, physics, and psychology, and it is desirable that the model of consciousness should also be able to answer questions of consciousness in each discipline. This paper applies the HLbC model proposed by the authors to the question of psychological consciousness and examines whether it can explain the phenomenon. Regarding the problem of so-called optical illusions, such as Rubin's vase, it can be explained by the fact that consciousness is caused by a stochastic fluctuation of consciousness with respect to figures that can be interpreted in multiple ways. Empathy and mutual understanding are also proposed to be mathematically represented and understood in terms of the Kullback-Leibler divergence, which is the basis of the HLbC model. Furthermore, the HLbC model was applied to prospect theory, the basis of behavioural economics, and confirmed that its properties can be successfully explained. From the above, we confirmed that the proposed HLbC model can explain the phenomenon of psychological consciousness.
Topics: Humans; Consciousness; Language; Philosophy
PubMed: 37061160
DOI: 10.1016/j.biosystems.2023.104890