scholarly journals Flashed Müller-Lyer and Poggendorff Virtual Illusions

i-Perception ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 204166952110156
Author(s):  
Stuart Anstis ◽  
Patrick Cavanagh
Keyword(s):  
Poggendorff Illusion ◽  
Moving Frame ◽  
Illusory Effect ◽  
Line Segments ◽  
Lyer Illusion ◽  
Before And After ◽  
Position Shift ◽  
Initial Arrangement

A moving frame can dramatically displace the perceived location of stimuli flashed before and after the motion. Here, we use a moving frame to rearrange flashed elements into the form of classic illusions. Without the moving frame, the initial arrangement of the flashed elements has no illusory effect. The question is whether the frame-induced displacement of position precedes or follows the processes underlying the illusions. This illusory offset of flashed chevrons does generate a Müller-Lyer illusion and the illusory offset of two line segments does create a Poggendorff illusion. We conclude that the site where the frame-induced position shift emerges must precede the site at which the Müller-Lyer and Poggendorf illusions arise.

Perception of Eye Scans with the Müller-Lyer Stimuli: Evidence for Filter Theory

1982 ◽  
Vol 54 (3) ◽  
pp. 683-692 ◽  
Author(s):  
J. Timothy Petersik
Keyword(s):  
Horizontal Line ◽  
Modulation Transfer ◽  
Physical Stimulus ◽  
Line Segments ◽  
Filter Theory ◽  
Lyer Illusion ◽  
Wide Range ◽  
Scan Path ◽  
Low Pass ◽  
Perceptual Distortions

Ginsburg's filter theory successfully accounts for the perceptual distortions perceived in a wide range of illusions and bistable phenomena. Essentially, the theory proposes that illusory distortions are the natural consequence of low-pass spatial filtering (based upon the human modulation transfer function) of the physical stimulus. With regard to the Müller-Lyer illusion, predictions based upon filter theory and human scan-path data are in accord. However, data linking filter theory's predictions regarding perceptual experiences associated with the illusion to the eye-scan results have been missing. In the present experiment subjects provided subjective estimations of their own eye scans while viewing each of the following stimuli: the fins-out member of the Müller-Lyer illusion, the fins-in member of the Müller-Lyer illusion, and a finless horizontal line (variations of each stimulus consisted of one, two, and three line segments). The analysis of these data supported three predictions that were derived from filter theory. Potential problems facing filter theory are also addressed.

The Poggendorff Illusion and Apparent Interparallel Extents

Perception ◽  
1992 ◽  
Vol 21 (5) ◽  
pp. 599-610 ◽  
Author(s):  
Ross H Day ◽  
Erica J Stecher ◽  
Andrea L Parker
Keyword(s):  
Poggendorff Illusion ◽  
Parallel Line ◽  
Significant Error ◽  
The Other ◽  
Misalignment Effect ◽  
The Third ◽  
Horizontal Extent ◽  
Lyer Illusion

An explanation of the Poggendorff misalignment effect in terms of apparent contraction of interparallel extent resulting from the Müller-Lyer illusion was tested in three experiments. Three of the eight stimulus figures had oblique transversals outside the parallels in the usual way, three had them inside, and two were controls consisting of the transversals only. Müller-Lyer forms were differently delineated between the parallels for the inside-transversal and outside-transversal figures, and were not delineated in the control figures. In the first experiment apparent misalignment occurred in four of the six parallel-line figures and in neither of the controls. In the second experiment oblique extent between the parallels was underestimated in six of the eight figures and right-angle extent was overestimated in all of them. The results of the third experiment showed that right-angle (horizontal) extent between the parallels without transversals is estimated without significant error. The data from the three experiments do not support the interparallel-extent explanation of apparent misalignment. Instead, the results are interpreted in terms of independent perceptual compromises, one involving alignment of the transversals and the other the distance between them.

Geometric-Optical Illusions Under Isoluminance?

2017 ◽  
Author(s):  
Kai Hamburger ◽  
Thorsten Hansen ◽  
Karl R. Gegenfurtner
Keyword(s):  
Poggendorff Illusion ◽  
Ponzo Illusion ◽  
Ebbinghaus Illusion ◽  
Optical Illusions ◽  
Magnocellular System ◽  
Lyer Illusion ◽  
System P ◽  
Visual Areas ◽  
Parvocellular System ◽  
Delboeuf Illusion

This chapter briefly introduces nine classical geometric-optical illusions. These include the Delboeuf illusion, the Ebbinghaus illusion, the Judd illusion, the Müller-Lyer illusion, the Ponzo illusion, the vertical illusion, the Hering illusion, the Poggendorff illusion, and the Zoellner illusion. It then demonstrates that they persist under different luminance conditions and under isoluminance. The empirical findings show that our conscious percept is similarly affected by luminance conditions and isoluminance, suggesting that joint contour processing (chromatic and luminance) may extend well beyond early visual areas. The chapter further discusses these concepts in terms of the magnocellular system, the parvocellular system, and the koniocellular system.

The Mueller-Lyer Illusion Produced by Features in Maps

1996 ◽  
Vol 40 (23) ◽  
pp. 1242-1246
Author(s):  
William Schmidt ◽  
Douglas J. Gillan
Keyword(s):  
Present Experiment ◽  
Road Segment ◽  
Place Names ◽  
Line Segments ◽  
The Road ◽  
Lyer Illusion ◽  
Road Segments

Maps consist of lines converging onto line segments. These converging lines resemble elements of the Mueller-Lyer illusion (MLEs) which cause map readers to overestimate the length of a road segment (if the lines go outward from the end of the segment) or underestimate the length (if the lines go inward from the end of the segment) (Gillan, Schmidt, & Hanowski, 1996). The present experiment investigates whether a similar effect occurs when place names converge on a road segment. Subjects estimated road segments framed by outward-going MLEs made up of place names to be significantly longer than road segments framed by inward-going MLEs. The type of characters in the place names (English characters vs. symbols) and requiring subjects to locate the road segment by the names in the MLE had no effect on the degree of misestimation induced. The implications of these findings for a variety of displays are discussed.

Poggendorff Illusion as a Function of Orientation of Transversal and Parallel Lines

1976 ◽  
Vol 43 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Barry S. Anton
Keyword(s):  
Visual Acuity ◽  
Line Segment ◽  
Poggendorff Illusion ◽  
Human Subjects ◽  
Parallel Line ◽  
Normal Vision ◽  
Transversal Line ◽  
Line Segments ◽  
Adult Human ◽  
Parallel Lines

Adult human subjects (8 male, 8 female undergraduates) with normal vision were required to judge various orientations of the Poggendorff illusion. The transversal and parallel line-segments of the illusion were manipulated to produce the orientations to be judged. Minimum illusion occurred when the transversal line-segment was oriented 90° with respect to true vertical or true horizontal. Magnitude of illusion increased as the transversal line-segment deviated from these positions. The findings suggested that there is a stability of horizontal and vertical orientations. In addition, the hypothesis that visual acuity plays a role in the perception of the Poggendorff illusion was proposed.

scholarly journals Nonlinear dynamics of turbulent waves in fluids and plasmas

2005 ◽  
Vol 12 (1) ◽  
pp. 13-24 ◽  
Author(s):  
K. He ◽  
A. C.-L. Chian
Keyword(s):  
Saddle Point ◽  
Phase Synchronization ◽  
Moving Frame ◽  
Wave System ◽  
Steady Wave ◽  
Phase Dynamics ◽  
Onset Of Turbulence ◽  
Before And After ◽  
Spatial Regularity ◽  
Phase Slips

Abstract. In a model drift wave system that is interesting both in fluids and plasmas, we find that an embedded moving saddle point plays an important role at the onset of turbulence. Here the saddle point is actually a saddle steady wave, in its moving frame the wave system can be transformed into a set of coupled oscillators whose motion is affected by the saddle steady wave as if it is a potential. It is found that a collision with the saddle point triggers a crisis, following the collision another dynamic event occurs which involves a transition in the phase state of the master oscillator. Only after the latter event the spatial regularity is destroyed. The phase dynamics before and after the transition is further investigated. It is found that in a spatially coherent state before the transition the oscillators reach a functional phase synchronization collectively with or without phase slips, after the transition in the turbulent state an on-off imperfect synchronization is established among the oscillators with long wavelengths. When the synchronization is on, their amplitudes grow up simultaneously, giving rise to a burst in the total wave energy. A power law behavior is observed in the correlation function between phases of the oscillators. Potential application of our results in prediction of energy bursts in turbulence is discussed.

The Effect of Line-Figure Information on the Magnitude of the Dot Forms of the Poggendorff and Müller-Lyer Illusions

Perception ◽  
1986 ◽  
Vol 15 (4) ◽  
pp. 483-490 ◽  
Author(s):  
John Predebon
Keyword(s):  
Poggendorff Illusion ◽  
Cognitive Factors ◽  
Lyer Illusion ◽  
Cognitive Components ◽  
Informed Group

The magnitudes of the dot and line forms of the Poggendorff illusion and the Brentano version of the Müller-Lyer illusion were assessed in two groups of subjects: the informed group was given information about the implied figure configuration in the dot pattern, the uninformed group was not. The informed group produced a significantly greater dot illusion than the uninformed group, and there was no difference between the two groups in the magnitudes of the line illusions. The experiments are discussed in the context of Coren and Porac's proposal that illusion-inducing mechanisms can be divided into structural and cognitive components. The results suggest that about 64% of the magnitude of the Poggendorff illusion and about 54% of the Müller-Lyer illusion can be attributed to the involvement of cognitive factors.

scholarly journals Paradoxical stabilization of relative position in moving frames

2021 ◽  
Vol 118 (25) ◽  
pp. e2102167118
Author(s):  
Mert Özkan ◽  
Stuart Anstis ◽  
Bernard M. ’t Hart ◽  
Mark Wexler ◽  
Patrick Cavanagh
Keyword(s):  
Frame Of Reference ◽  
Moving Frame ◽  
Moving Frames ◽  
Visual Stability ◽  
Left Edge ◽  
Before And After ◽  
Left And Right ◽  
The Right ◽  
Object Relative ◽  
As If

To capture where things are and what they are doing, the visual system may extract the position and motion of each object relative to its surrounding frame of reference [K. Duncker, Routledge and Kegan Paul, London 161–172 (1929) and G. Johansson, Acta Psychol (Amst.) 7, 25–79 (1950)]. Here we report a particularly powerful example where a paradoxical stabilization is produced by a moving frame. We first take a frame that moves left and right and we flash its right edge before, and its left edge after, the frame’s motion. For all frame displacements tested, the two edges are perceived as stabilized, with the left edge on the left and right edge on the right, separated by the frame’s width as if the frame were not moving. This stabilization is paradoxical because the motion of the frame itself remains visible, albeit much reduced. A second experiment demonstrated that unlike other motion-induced position shifts (e.g., flash lag, flash grab, flash drag, or Fröhlich), the illusory shift here is independent of speed and is set instead by the distance of the frame’s travel. In this experiment, two probes are flashed inside the frame at the same physical location before and after the frame moves. Despite being physically superimposed, the probes are perceived widely separated, again as if they were seen in the frame’s coordinates and the frame were stationary. This paradoxical stabilization suggests a link to visual stability across eye movements where the displacement of the entire visual scene may act as a frame to stabilize the perception of relative locations.

Collinearity Judgment as a Function of Induction Angle

1994 ◽  
Vol 78 (2) ◽  
pp. 655-674 ◽  
Author(s):  
Ernest Greene
Keyword(s):  
Line Segment ◽  
Poggendorff Illusion ◽  
Orientation Selectivity ◽  
Induction Effect ◽  
Neural Models ◽  
Line Segments ◽  
Tilt Illusion ◽  
Test Segment ◽  
Segment Orientation ◽  
Basic Induction

The misalignment which is seen in the Poggendorff illusion can be studied with better control by using a configuration which has only two line segments. Two experiments were conducted in which subjects judged collinearity of a test segment, this judgment being subjected to a biasing influence from a second (induction) segment. Exp. 1 held the test segment at one of three orientations relative to the observer (30°, 45°, and 60°) and systematically varied the orientation of the induction segment in 15° increments through the range of possible positions. The orientation of the page relative to the observer was varied as well. Exp. 2 varied the test segment through a greater range of angles and sampled more levels of induction segment orientation. Analysis indicated that projection errors follow orderly rules similar in kind to but different in magnitude from those observed for the Tilt Illusion, most notably, (a) misprojection is greatest when the orientation of the interfering line is similar to that of the line segment being projected and (b) the strength of this influence decreases as the relative angle becomes orthogonal. Also, the orientation of the segment being projected relative to the observer serves to modulate the strength of the basic induction effect. These perceptual interactions are discussed in relation to neural models for orientation selectivity.

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