-
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 -
Vision Research 2004Objective of this research is to study the presence of 3D flash lag illusion created by a moving object that has a motion-in-depth and a flash object. An object...
Objective of this research is to study the presence of 3D flash lag illusion created by a moving object that has a motion-in-depth and a flash object. An object consisting of two thin sticks was simulated to approach the subject who observed it with a stereoscope. In the process of approaching, another stick was briefly presented in the middle of the moving sticks. Five human subjects took part in our experiments and all perceived 3D flash lag illusion. The perceived depth created by 3D flash lag illusion was measured by two different psychophysical experiments, by use of a vernier caliper and by a method of nulling with another depth cue. We studied relation between the perceived depth and the presentation distance. The experimental results indicate that the perceived gap by 3D flash lag illusion is independent from the presentation distance.
Topics: Adult; Depth Perception; Humans; Motion Perception; Optical Illusions; Psychophysics; Vision Disparity; Vision, Binocular
PubMed: 15149831
DOI: 10.1016/j.visres.2004.03.026 -
Psychological Science May 2024Motion silencing is a striking and unexplained visual illusion wherein changes that are otherwise salient become difficult to perceive when the changing elements also...
Motion silencing is a striking and unexplained visual illusion wherein changes that are otherwise salient become difficult to perceive when the changing elements also move. We develop a new method for quantifying illusion strength (Experiments 1a and 1b), and we demonstrate a privileged role for rotational motion on illusion strength compared with highly controlled stimuli that lack rotation (Experiments 2a to 3b). These contrasts make it difficult to explain the illusion in terms of lower-level detection limits. Instead, we explain the illusion as a failure to attribute changes to locations. Rotation exacerbates the illusion because its perception relies upon structured object representations. This aggravates the difficulty of attributing changes by demanding that locations are referenced relative to both an object-internal frame and an external frame. Two final experiments (4a and 4b) add support to this account by employing a synchronously rotating external frame of reference that diminishes otherwise strong motion silencing. All participants were Johns Hopkins University undergraduates.
Topics: Humans; Motion Perception; Adult; Female; Male; Young Adult; Optical Illusions; Rotation
PubMed: 38564652
DOI: 10.1177/09567976241235104 -
Acta Neurobiologiae Experimentalis 2010A subdivided path in the visual field usually appears longer than an empty path of the same length. This phenomenon, known as the filled/empty or Oppel-Kundt illusion,...
A subdivided path in the visual field usually appears longer than an empty path of the same length. This phenomenon, known as the filled/empty or Oppel-Kundt illusion, depends on multiple properties of the visual stimulus, but the functional dependences have not been yet precisely characterized. We studied the illusory effect as a function of its two main determinants, the height of vertical strokes subdividing a spatial interval of a fixed length (visual angle 2.8 degree) and the number of the filling strokes, using the standard-variable distance matching paradigm. Non-monotonic dependence of the effect (over-reproduction of the spatial extension) on the varied parameters was observed in two experimental series. In the first series, the maximum effect was obtained for the fillers height roughly equal to the delimiters height (visual angle 0.25 degree); in the second series, the maximum effect was obtained for 11-13 equispaced fillers, and more accurately estimated to 15-16 as a result of a functional fit. Both data series were successfully modeled by curves generated by a single two-parametric system of form functions. Problems of determination of the maximum effect are discussed, and arguments for a genuinely multivariate approach are presented.
Topics: Adult; Female; Humans; Male; Neuropsychological Tests; Optical Illusions; Photic Stimulation; Visual Fields; Visual Perception; Young Adult
PubMed: 21196950
DOI: 10.55782/ane-2010-1814 -
Cognition Apr 2011Pigeons are susceptible to several size and length illusions, but in some cases the bias has been shown to be opposite to that seen in humans. To further investigate how...
Pigeons are susceptible to several size and length illusions, but in some cases the bias has been shown to be opposite to that seen in humans. To further investigate how their perceptual system works, we asked how pigeons perceive orientation illusions. We used the Zöllner illusion, in which parallel lines look non-parallel due to series of short crosshatches superimposed on the lines. First, we trained six birds to peck at the narrower (or wider) of the two gaps at the end of a pair of non-parallel target lines. After adapting the subjects to target lines with randomly oriented crosshatches (which result in no illusion at least to humans), we tested the pigeons' responses on randomly inserted probe trials, in which crosshatches that should induce the standard Zöllner-like illusion for humans replaced the random-oriented ones. The results suggested that pigeons do perceive an illusion from Zöllner figures, but in the direction opposite to that of humans. We propose that pigeons, contrary to humans, may assimilate the two lines of different orientations (each main line and crosshatch), which results in underestimation of acute angles, and this in turn may lead to a reversed Zöllner illusion. Such assimilation dominance appears consistent with previous reports obtained for line length and size illusions in this species.
Topics: Animals; Columbidae; Male; Optical Illusions; Orientation; Pattern Recognition, Visual; Photic Stimulation; Visual Perception
PubMed: 21109240
DOI: 10.1016/j.cognition.2010.10.020 -
Acta Psychologica Apr 2018The Ebbinghaus illusion, in which a central target surrounded by larger context figures looks smaller than when surrounded by smaller context figures, is usually...
The Ebbinghaus illusion, in which a central target surrounded by larger context figures looks smaller than when surrounded by smaller context figures, is usually classified as a size contrast illusion. Thus "size contrast" is the dominant account of this effect. However, according to an alternative "contour interaction" account this phenomenon has little to do with size contrast but is rather caused by distance-dependent attractive and repulsive interactions between neural representation of contours. Here evidence is presented against the size contrast account and consistent with the contour interaction account. Experiment 1 was a control study confirming that the illusion can be obtained using displays consisting only of squares, which are more convenient to manipulate than the standardly used circles. In Experiment 2, the standard configuration involving small context figures surrounding the target was compared to a novel configuration, which involved many "spread" small context figures. The illusory effect of the standard context was stronger than the illusory effect of the spread context, in accord with the prediction of the contour interaction account, and contrary to the prediction of the size contrast account. In Experiment 3 two novel configurations were used, based on standard and spread contexts. The results were in accord with the prediction of the contour interaction account, whereas the size contrast account had no prediction because the stimuli did not involve conventional size contrast. Additional aspects of the stimuli and an account of the illusion based on a perspective interpretation are also discussed.
Topics: Adolescent; Female; Form Perception; Humans; Male; Optical Illusions; Photic Stimulation; Pleasure; Random Allocation; Size Perception
PubMed: 29499478
DOI: 10.1016/j.actpsy.2018.02.011 -
Perception 2011A sudden luminance increment on a moving stimulus was perceived significantly along the trajectory, in the direction of motion, from its displayed position. A nonlinear...
A sudden luminance increment on a moving stimulus was perceived significantly along the trajectory, in the direction of motion, from its displayed position. A nonlinear relationship with stimulus speed, for a Fröhlich-like illusion, but not for the luminance-increment illusion, challenges certain models of spatial mislocalisation and argues for different processes underlying the two illusions.
Topics: Analysis of Variance; Contrast Sensitivity; Humans; Motion Perception; Optical Illusions; Photic Stimulation; Sensory Thresholds
PubMed: 21513190
DOI: 10.1068/p6767 -
Journal of Neurophysiology Nov 1950
Topics: Optical Illusions; Retina; Vision, Ocular
PubMed: 14784865
DOI: 10.1152/jn.1950.13.6.413 -
Perceptual and Motor Skills Jun 2011Prior research has shown that methods of meditation, breath control, and different kinds of yoga breathing affect attention and visual perception, including decreasing... (Randomized Controlled Trial)
Randomized Controlled Trial
Prior research has shown that methods of meditation, breath control, and different kinds of yoga breathing affect attention and visual perception, including decreasing the size of certain optical illusions. Evaluating relationships sheds light on the perceptual and cognitive changes induced by yoga and related methods, and the locus of the effects. In the present study, the degree of optical illusion was assessed using Müller-Lyer stimuli before and immediately after two different kinds of practice, a high frequency yoga breathing called kapalabhati, and breath awareness. A nonyoga, control session tested for practice effects. Thirty participants (with group M age = 26.9 yr., SD = 5.7) practiced the two techniques for 18 min. on two separate days. The control group had 15 nonyoga practitioners assessed before and after 18 min. in which they did not perform any specific activity but were seated and relaxed. After both kapalabhati and breath awareness there was a significant decrease in the degree of optical illusion. The possibility that this was due to a practice or repetition effect was ruled out when 15 nonyoga practitioners showed no change in the degree of illusion when retested after 18 min. The changes were interpreted as due to changes in perception related to the way the stimuli were judged.
Topics: Adult; Attention; Awareness; Discrimination, Psychological; Humans; Male; Optical Illusions; Pattern Recognition, Visual; Respiration; Yoga; Young Adult
PubMed: 21853784
DOI: 10.2466/02.20.22.PMS.112.3.981-990 -
Journal of Vision May 2017"The dress" has provoked intensive commentary among psychophysicists, especially in relation to color vision. Researchers have shown that manipulating illuminance cues...
"The dress" has provoked intensive commentary among psychophysicists, especially in relation to color vision. Researchers have shown that manipulating illuminance cues can influence the perceived colors of the dress. Here we investigate whether illusory shifts in brightness can shift color perception of the dress. Drifting achromatic gratings with fast off and fast on shading profiles are known to give an illusion of brightening or darkening, respectively. We superimposed rotating sawtooth gratings on a series of dress images that morphed from extreme white/gold through to blue/black. In a sample of 18 adults (11 with white/gold dress percept and seven with blue/black percept), a two-alternative, forced-choice constant stimulus task measured the morphed image point at which each observer was equally likely to categorize the dress as white/gold or blue/black (the point of subjective equality or PSE). Despite manifest individual differences in the PSE, the two sawtooth temporal profiles consistently changed the perceived colors of the dress. Perceptual dimming shifted color categorization toward blue/black whereas perceptual brightening shifted color categorization toward white/gold. We conclude that color categorization is influenced substantially by illusory shifts in brightness.
Topics: Adolescent; Adult; Color Perception; Color Vision; Cues; Female; Humans; Individuality; Lighting; Male; Middle Aged; Optical Illusions; Young Adult
PubMed: 28505664
DOI: 10.1167/17.5.6