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Consciousness and Cognition Aug 2019Recent studies suggest that the accuracy of perceptual judgments can be influenced by the perceived illusory size of a stimulus, with judgments being more accurate for...
Recent studies suggest that the accuracy of perceptual judgments can be influenced by the perceived illusory size of a stimulus, with judgments being more accurate for increased illusory size. This phenomenon seems consistent with recent neuroscientific findings that representations in early visual areas reflect the perceived (illusory) size of stimuli rather than the physical size. We further explored this idea with the moon illusion, in which the moon appears larger when it is close to the horizon and smaller when it is higher in the sky. Participants (n=230) adjusted the orientation of an image of the moon on a smartphone to match the perceived orientation of the moon in the sky. Contrary to previous studies that investigated accuracy and size illusions, we found slightly lower perceptual judgment accuracy when the moon appeared large (close to the horizon) compared to when it appeared small (high in the sky).
Topics: Adult; Female; Humans; Illusions; Judgment; Male; Moon; Optical Illusions; Size Perception; Visual Perception; Young Adult
PubMed: 31158723
DOI: 10.1016/j.concog.2019.05.002 -
Experimental Brain Research Apr 2019Milner and Goodale (the visual brain in action, Oxford University Press Inc., Oxford, 1995) proposed a functional dissociation between vision-for-action and...
Milner and Goodale (the visual brain in action, Oxford University Press Inc., Oxford, 1995) proposed a functional dissociation between vision-for-action and vision-for-perception (i.e., the "two-visual system hypothesis", TVSH). Supporting the TVSH, it has been claimed that visual illusions affect perception but not actions. However, at least for the Ebbinghaus illusion, numerous studies have revealed consistent illusion effects on grasping. Thus, whether illusions affect actions remains controversial. To further investigate the dissociation predicted by the TVSH, we used a visual version of the Uznadze illusion (the same stimulus will feel smaller after feeling a larger stimulus and larger after feeling a smaller stimulus). Based on kinematic recordings of finger aperture in a motor (precision grip) and a perceptual task (manual estimation), we report two main findings. First, both action and perception are strongly affected by the Uznadze illusion. Second, the illusion decreases similarly in both tasks when inducing-induced pairs had different shape and color, in comparison to the equivalent condition where these features are the same. These results are inconsistent with a perception-action dissociation as predicted by the TVSH and suggest that, at least in the present conditions, vision-for-perception and vision-for-action are similarly affected by contextual cues.
Topics: Adult; Female; Humans; Illusions; Male; Motor Activity; Optical Illusions; Size Perception; Touch Perception; Visual Perception; Young Adult
PubMed: 30683958
DOI: 10.1007/s00221-019-05480-8 -
Nature May 1993
Topics: Optical Illusions
PubMed: 8483496
DOI: 10.1038/363119b0 -
Journal of Experimental Psychology.... Jan 2018We present the first empirical evidence that experience alters lightness perception. The role of experience in lightness perception was investigated through a...
We present the first empirical evidence that experience alters lightness perception. The role of experience in lightness perception was investigated through a cross-cultural comparison of 2 visual contrast phenomena: simultaneous lightness contrast and White's illusion. The Himba, a traditional seminomadic group known to have a local bias in perception, showed enhanced simultaneous lightness contrast but reduced White's illusion compared with groups that have a more global perceptual style: Urban-dwelling Himba and Westerners. Thus, experience of the urban environment alters lightness perception and we argue it does this by fostering the tendency to integrate information from across the visual scene. (PsycINFO Database Record
Topics: Adolescent; Adult; Contrast Sensitivity; Cross-Cultural Comparison; Female; Humans; London; Male; Middle Aged; Namibia; Optical Illusions; Urban Population; Urbanization; Young Adult
PubMed: 29309192
DOI: 10.1037/xhp0000498 -
Vision Research May 2006The Pinna illusion (Pinna & Brelstaff, 2000) consists of two concentric rings of micropatterns that appear to counter-rotate when the observer moves towards the...
The Pinna illusion (Pinna & Brelstaff, 2000) consists of two concentric rings of micropatterns that appear to counter-rotate when the observer moves towards the stimulus. There have been several reports that the illusion is stronger when the retinal expansion is produced by observer self-motion than when produced on a computer screen without observer self-motion. In fact, we found that the illusion is as strong (or stronger) when the retinal expansion is produced on a computer screen without observer self-motion. In a second series of experiments the strength of the Pinna illusion was inferred from the amount of physical counter-rotation required to null it. The strength of the illusion is relatively unaffected by changes to the global structure of the display but minor changes to the micropatterns comprised in the display can effectively eliminate the illusion. We provide a simple model of optical flow that is in very good agreement with many of the results reported.
Topics: Female; Fixation, Ocular; Humans; Judgment; Male; Models, Biological; Motion; Motion Perception; Movement; Optical Illusions; Orientation; Photic Stimulation; Psychophysics; Retina; Rotation
PubMed: 16260024
DOI: 10.1016/j.visres.2005.09.011 -
Vision Research Dec 2010Milner and Goodale's (1995) proposal of a functional division of labor between vision-for-perception and vision-for-action is supported by neuropsychological,... (Meta-Analysis)
Meta-Analysis Review
Milner and Goodale's (1995) proposal of a functional division of labor between vision-for-perception and vision-for-action is supported by neuropsychological, brain-imaging, and psychophysical evidence. However, there remains considerable debate as to whether, as their proposal would predict, the effect of contextual illusions on vision-for-action can be dissociated from that on vision-for-perception. Meta-analytical efforts examining the effect of the Müller-Lyer (ML) illusion on pointing (Bruno, Bernardis, & Gentilucci, 2008) or grasping (Bruno & Franz, 2009) have been conducted to resolve the controversy. To complement this work, here we re-analyzed 17 papers detailing 21 independent studies investigating primary saccades to target locations that were perceptually biased by the ML illusion. Using a corrected percent illusion effect measure to compare across different studies and across experimental conditions within studies, we find that saccadic eye movements are always strongly biased by the illusion although the size of this effect can be reduced by factors such as display duration and between-trials variability in display length and orientation, possibly due to a process of saccadic adaptation. In contrast to some reports, we find no general support for differences between voluntary and reflexive saccades or between saccades performed in conjunction with a pointing movement and saccades performed without pointing. We conclude that studies on the effect of the Müller-Lyer illusion do not provide evidence for a functional dissociation between primary saccades and perception.
Topics: Humans; Optical Illusions; Saccades; Time Factors; Visual Perception
PubMed: 20858510
DOI: 10.1016/j.visres.2010.09.016 -
Journal of Comparative Psychology... Feb 2016A long-standing debate surrounds the issue of whether human and nonhuman species share similar perceptual mechanisms. One experimental strategy to compare visual...
A long-standing debate surrounds the issue of whether human and nonhuman species share similar perceptual mechanisms. One experimental strategy to compare visual perception of vertebrates consists in assessing how animals react in the presence of visual illusions. To date, this methodological approach has been widely used with mammals and birds, while few studies have been reported in distantly related species, such as fish. In the present study we investigated whether fish perceive the brightness illusion, a well-known illusion occurring when 2 objects, identical in physical features, appear to be different in brightness. Twelve guppies (Poecilia reticulata) were initially trained to discriminate which rectangle was darker or lighter between 2 otherwise identical rectangles. Three different conditions were set up: neutral condition between rectangle and background (same background used for both darker and lighter rectangle); congruent condition (darker rectangle in a darker background and lighter rectangle in a lighter background); and incongruent condition (darker rectangle in a lighter background and lighter rectangle in a darker background). After reaching the learning criterion, guppies were presented with the illusory pattern: 2 identical rectangles inserted in 2 different backgrounds. Guppies previously trained to select the darker rectangle showed a significant choice of the rectangle that appears to be darker by human observers (and vice versa). The human-like performance exhibited in the presence of the illusory pattern suggests the existence of similar perceptual mechanisms between humans and fish to elaborate the brightness of objects.
Topics: Animals; Optical Illusions; Photic Stimulation; Poecilia; Visual Perception
PubMed: 26881944
DOI: 10.1037/com0000020 -
Acta Neurobiologiae Experimentalis 2017In the filled-space (or Oppel-Kundt) illusion, the filled part of the stimulus for most observers appears longer in comparison with the empty one. In the first two...
In the filled-space (or Oppel-Kundt) illusion, the filled part of the stimulus for most observers appears longer in comparison with the empty one. In the first two experimental series of the present study, we investigated the illusory effect as a function of continuous filling (by a shaft-line segment) of the reference spatial interval of the three-dot stimulus. It was demonstrated that for the fixed length of the reference interval, the magnitude of the illusion increases non-linearly with the shaft length. For the fixed length of the shaft, the illusion magnitude gradually decreases with the lengthening of the reference interval. In the third series, psychophysical examination of the conventional Oppel-Kundt stimulus with different number of equally spaced elements (dots) subdividing its filled part was performed. Based on the analysis of the functional dependencies established, we have proposed a simple computational model that was successfully applied to fit the experimental data obtained in the present study.
Topics: Adult; Computer Simulation; Female; Form Perception; Humans; Male; Optical Illusions; Photic Stimulation; Psychophysics; Space Perception; Young Adult
PubMed: 28691720
DOI: 10.21307/ane-2017-048 -
Animal Cognition Mar 2015The tendency of fish to perceive the Ebbinghaus illusion was investigated. Redtail splitfins (Xenotoca eiseni, family Goodeidae) were trained to discriminate between two...
The tendency of fish to perceive the Ebbinghaus illusion was investigated. Redtail splitfins (Xenotoca eiseni, family Goodeidae) were trained to discriminate between two disks of different sizes. Then, fish were presented with two disks of the same size surrounded by disks of large or small size (inducers) arranged to produce the impression (to a human observer) of two disks of different sizes (in the Ebbinghaus illusion, a central disk surrounded by small inducers appears bigger than an identical one surrounded by large inducers). Fish chose the stimulus that, on the basis of a perception of the Ebbinghaus illusion, appeared deceptively larger or smaller, consistent with the condition of training. These results demonstrate that redtail splitfins tend to perceive this particular illusion. The results are discussed with reference to other related illusions that have been recently observed to be experienced by fish (such as the Navon effect), and with regard to their possible evolutionary implications.
Topics: Animals; Cyprinodontiformes; Discrimination Learning; Male; Optical Illusions; Size Perception; Visual Perception
PubMed: 25413845
DOI: 10.1007/s10071-014-0821-5 -
Perception 2011We report a new angle illusion observed when viewing a real scene involving a straight road. The scene portrays two white lines which outline a traffic lane on a road...
We report a new angle illusion observed when viewing a real scene involving a straight road. The scene portrays two white lines which outline a traffic lane on a road and converge to a vanishing point. In experiment 1, observers estimated the angle created by these converging lines in this scene or in its image projected onto a screen. Results showed strong underestimation of the angle, ie over 50% for observations of both the real scene and its projected image. Experiment 2 assessed how depth cues in projected images influence the angle illusion. Results showed that this angle illusion disappeared when scene information surrounding convergent lines was removed. In addition, the illusion was attenuated with projection of an inverted scene image. These findings are interpreted in terms of a misadoption of depth information in the processing of angle perception in a flat image; in turn, this induces a massive angle illusion.
Topics: Adult; Attention; Depth Perception; Female; Humans; Male; Optical Illusions; Orientation; Photic Stimulation; Visual Perception
PubMed: 22416592
DOI: 10.1068/p7068