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Journal of Vision Aug 2017It is a common perceptual experience that smaller objects appear to move faster than larger ones when their physical speeds are the same in either the laboratory or...
It is a common perceptual experience that smaller objects appear to move faster than larger ones when their physical speeds are the same in either the laboratory or daily life. In this study, we show that the speed-size illusion is correlated with retinal image speed distribution bias. The illusion was quantified with a two-alternative, forced choice speed comparison paradigm, and retinal image speed distributions for different image sizes were obtained by simulation. Simulation results show that smaller retinal images tend to have slower projected speed, and the retinal image speed distribution bias correlates with the strength of the speed-size illusion. Furthermore, exposure to a training movie containing unnatural motion statistics tended to modulate the illusion in a way that was consistent with the speed distribution bias. We discuss how the data could be explained by empirical ranking theory, Bayesian theory, and motion adaptation.
Topics: Adult; Bayes Theorem; Female; Humans; Male; Motion; Motion Perception; Optical Illusions; Retina; Young Adult
PubMed: 28763527
DOI: 10.1167/17.9.1 -
Perception 2010
Topics: Depth Perception; Humans; Optical Illusions; Perceptual Distortion; Visual Perception
PubMed: 20465166
DOI: 10.1068/p3903ed -
Vision Research Sep 2002The change in apparent orientation of lines and gratings induced by surrounding or preceding patterns of a different orientation (the tilt illusion and tilt...
The change in apparent orientation of lines and gratings induced by surrounding or preceding patterns of a different orientation (the tilt illusion and tilt after-effect) has been abundantly documented, but there is no unanimity about the effect of such inducing patterns on orientation discrimination thresholds. In particular, because inducing contours that are almost orthogonal cause the direction of the tilt illusion to reverse, evidence for an improvement of orientation discrimination with orthogonal adaptation has been welcomed on theoretical ground as supporting concepts of inversion of polarity of neural connection between cortical cells with oriented receptive fields for large orientation differences. In careful psychophysical experiments on human observers with several kinds of test and orthogonal adaptation patterns the average ratio of adapted/unadapted discrimination thresholds in paired sets of data was 1.027+/-0.13, which does not differ significantly from unity and hence constitutes evidence that orthogonal adaptation does not improve orientation discrimination.
Topics: Adaptation, Physiological; Discrimination, Psychological; Humans; Optical Illusions; Orientation; Pattern Recognition, Visual; Psychophysics; Sensory Thresholds
PubMed: 12350422
DOI: 10.1016/s0042-6989(02)00192-x -
Perception 1998
Topics: Gravitation; Humans; Optical Illusions; Visual Perception
PubMed: 10070552
DOI: 10.1068/p270503 -
Proceedings. Biological Sciences Oct 2010Primates possess the remarkable ability to differentiate faces of group members and to extract relevant information about the individual directly from the face.... (Comparative Study)
Comparative Study
Primates possess the remarkable ability to differentiate faces of group members and to extract relevant information about the individual directly from the face. Recognition of conspecific faces is achieved by means of holistic processing, i.e. the processing of the face as an unparsed, perceptual whole, rather than as the collection of independent features (part-based processing). The most striking example of holistic processing is the Thatcher illusion. Local changes in facial features are hardly noticeable when the whole face is inverted (rotated 180 degrees ), but strikingly grotesque when the face is upright. This effect can be explained by a lack of processing capabilities for locally rotated facial features when the face is turned upside down. Recently, a Thatcher illusion was described in the macaque monkey analogous to that known from human investigations. Using a habituation paradigm combined with eye tracking, we address the critical follow-up questions raised in the aforementioned study to show the Thatcher illusion as a function of the observer's species (humans and macaques), the stimulus' species (humans and macaques) and the level of perceptual expertise (novice, expert).
Topics: Adolescent; Adult; Animals; Eye Movements; Face; Female; Humans; Macaca mulatta; Male; Optical Illusions; Pattern Recognition, Visual; Time Factors
PubMed: 20484235
DOI: 10.1098/rspb.2010.0438 -
Attention, Perception & Psychophysics Aug 2023Using a dual-task paradigm, the present investigation examined whether processes related to line orientation play a critical role in the production of the Poggendorff...
Using a dual-task paradigm, the present investigation examined whether processes related to line orientation play a critical role in the production of the Poggendorff illusion. In Experiment 1, we assessed the magnitude of the Poggendorff illusion under three different task conditions. In the single-task condition, participants were asked to report how they perceive the alignment of transversal lines in the Poggendorff figure. In two different dual-task conditions, the participants were asked to read aloud the time displayed on a digital or analogue clock while also performing the Poggendorff perception task. The method of constant stimuli was used to calculate the point of subjective equality (PSE) and bistability width values, which represent illusion strength and perceptual uncertainty, respectively. PSEs indicated that the magnitude of the illusion did not vary between single, dual-analogue, and dual-digital task conditions, which suggests that the additional demands placed by the dual tasks had no effect on the illusion strength. Perceptual uncertainty and clock-reading errors were greater in the dual-analogue task condition. Experiment 2 revealed that the analogue clockface was more difficult to read than the digital clockface. Based on these results, we conclude that having participants perform a secondary task does not influence the magnitude of the Poggendorff illusion.
Topics: Humans; Illusions; Optical Illusions
PubMed: 36949260
DOI: 10.3758/s13414-023-02660-1 -
Journal of Vision Mar 2017In everyday behavior, two of the most common visually guided actions-eye and hand movements-can be performed independently, but are often synergistically coupled. In...
In everyday behavior, two of the most common visually guided actions-eye and hand movements-can be performed independently, but are often synergistically coupled. In this study, we examine whether the same visual representation is used for different stages of saccades and pointing, namely movement preparation and execution, and whether this usage is consistent between independent and naturalistic coordinated eye and hand movements. To address these questions, we used the Ponzo illusion to dissociate the perceived and physical sizes of visual targets and measured the effects on movement preparation and execution for independent and coordinated saccades and pointing. During independent movements, we demonstrated that both physically and perceptually larger targets produced faster preparation for both effectors. Furthermore, participants who showed a greater influence of the illusion on saccade preparation also showed a greater influence on pointing preparation, suggesting that a shared mechanism involved in preparation across effectors is influenced by illusions. However, only physical but not perceptual target sizes influenced saccade and pointing execution. When pointing was coordinated with saccades, we observed different dynamics: pointing no longer showed modulation from illusory size, while saccades showed illusion modulation for both preparation and execution. Interestingly, in independent and coordinated movements, the illusion modulated saccade preparation more than pointing preparation, with this effect more pronounced during coordination. These results suggest a shared mechanism, dominated by the eyes, may underlie visually guided action preparation across effectors. Furthermore, the influence of illusions on action may operate within such a mechanism, leading to dynamic interactions between action modalities based on task demands.
Topics: Adult; Eye; Female; Hand; Humans; Male; Ocular Physiological Phenomena; Optical Illusions; Psychomotor Performance; Saccades; Visual Perception; Young Adult
PubMed: 28362898
DOI: 10.1167/17.3.23 -
Vision Research Apr 1997Disk-shaped luminance increments were added to the intersections of a Hermann grid consisting of medium grey bars on a black background. Illusory spots, darker than the...
Disk-shaped luminance increments were added to the intersections of a Hermann grid consisting of medium grey bars on a black background. Illusory spots, darker than the background, were perceived as flashing within the white disks with each flick of the eye. This striking phenomenon may be referred to as the scintillating grid illusion. We determined the conditions necessary for cancelling the Hermann grid illusion, as well as the luminance requirements and the size ratio between disks and bars that elicits the scintillation effect. The fact that scanning eye movements are necessary to produce the scintillation effect sets it apart from the Hermann grid illusion.
Topics: Eye Movements; Female; Humans; Lighting; Male; Neural Inhibition; Optical Illusions; Pattern Recognition, Visual; Photometry
PubMed: 9196721
DOI: 10.1016/s0042-6989(96)00255-6 -
Current Biology : CB Jan 2009Subjective visual experience leaves two distinct, overlapping 'footprints' within visual cortex: a small 'footprint' evident in multi-unit activity, and a much larger... (Review)
Review
Subjective visual experience leaves two distinct, overlapping 'footprints' within visual cortex: a small 'footprint' evident in multi-unit activity, and a much larger 'footprint' that dominates activity indexed by haemodynamic responses.
Topics: Animals; Awareness; Haplorhini; Humans; Neural Pathways; Optical Illusions; Visual Cortex; Visual Perception
PubMed: 19138589
DOI: 10.1016/j.cub.2008.11.009 -
Journal of Vision Jun 2020Vision scientists have attempted to classify visual illusions according to certain aspects, such as brightness or spatial features. For example, Piaget proposed that...
Vision scientists have attempted to classify visual illusions according to certain aspects, such as brightness or spatial features. For example, Piaget proposed that visual illusion magnitudes either decrease or increase with age. Subsequently, it was suggested that illusions are segregated according to their context: real-world contexts enhance and abstract contexts inhibit illusion magnitudes with age. We tested the effects of context on the Müller-Lyer and Ponzo illusions with a standard condition (no additional context), a line-drawing perspective condition, and a real-world perspective condition. A mixed-effects model analysis, based on data from 76 observers with ages ranging from 6 to 66 years, did not reveal any significant interaction between context and age. Although we found strong intra-illusion correlations for both illusions, we found only weak inter-illusion correlations, suggesting that the structure underlying these two spatial illusions includes several specific factors.
Topics: Adolescent; Adult; Aged; Child; Ependymoglial Cells; Female; Humans; Illusions; Individuality; Male; Middle Aged; Optical Illusions; Young Adult
PubMed: 32511665
DOI: 10.1167/jov.20.6.4