Circular Vection as a Function of the Relative Sizes, Distances, and Positions of Two Competing Visual Displays

Perception ◽  
1989 ◽  
Vol 18 (5) ◽  
pp. 657-665 ◽  
Author(s):  
Ian P Howard ◽  
Thomas Heckmann
Keyword(s):  
The Other ◽  
Relative Distance ◽  
Illusory Motion ◽  
Visual Displays ◽  
Circular Vection ◽  
Central Display ◽  
Motion Contrast ◽  
Moving Stimulus

In studies where it is reported that illusory self-rotation (circular vection) is induced more by peripheral displays than by central displays, eccentricity may have been confounded with perceived relative distance and area. Experiments are reported in which the direction and magnitude of vection induced by a central display in the presence of a surround display were measured. The displays varied in relative distance and area and were presented in isolation, with one moving and one stationary display, or with both moving in opposite directions. A more distant display had more influence over vection than a near display. A central display induced vection if seen in isolation or through a ‘window’ in a stationary surrounding display. Motion of a more distant central display weakened vection induced by a nearer surrounding display moving the other way. When the two displays had the same area their effects almost cancelled. A moving central display nearer than a textured stationary surround produced vection in the same direction as the moving stimulus. This phenomenon is termed ‘contrast-motion vection’ because it is probably due to illusory motion of the surround induced by motion of the centre. Unequivocal statements about the dominance of an eccentric display over a central display cannot be made without considering the relative distances and sizes of the displays and the motion contrast between them.

High Phi and Ghost Phi

2017 ◽  
Author(s):  
Mark Wexler
Keyword(s):  
Slow Rotation ◽  
Illusory Motion ◽  
Motion Adaptation ◽  
Random Texture ◽  
Motion Energy ◽  
Moving Stimulus ◽  
Transient Events ◽  
Fast Motion ◽  
Direction Opposite

When a moving stimulus is followed by certain transient events, an illusion of very fast motion is perceived, in which a random texture undergoes a slow rotation, but every second most observers perceive a very fast jump in the direction opposite to the preceding or “inducing” rotation. These jumps are illusory: during the perceived jump, every frame is a new, random texture, uncorrelated with the previous textures; the last of these random textures is set to turning once again, and the sequence repeats. Thus there is there is no specific correspondence between the textures before, during, and after the jumps and no motion energy corresponding to the jumps. These illusory jumps are called “high phi.” If the transient is immediately “undone,” a different kind of illusory motion is perceived, called “ghost phi.” This example shows a study of the effects of motion adaptation.

The Effects of Visual Depth and Eccentricity on Manual Bias, Induced Motion, and Vection

Perception ◽  
1993 ◽  
Vol 22 (8) ◽  
pp. 929-945 ◽  
Author(s):  
Fred H Previc ◽  
Michael Donnelly
Keyword(s):  
The Other ◽  
Manual Control ◽  
Roll Motion ◽  
Entire Body ◽  
Manual Tracking ◽  
Visual Depth ◽  
Visual Inputs ◽  
Central Display ◽  
Induced Motion ◽  
The Relationship

The relationship between the effects of visual-surround roll motion on compensatory manual tracking of a central display and the perceptual phenomena of induced motion and vection were investigated. To determine if manual-control biases generated in the direction of surround rotation compensate primarily for the perceived counterrotation of the central display (‘induced motion’) or the perceived counterrotation of the entire body (‘vection’), the depth and eccentricity of the visual surround were varied. In the first experiment, twelve subjects attempted to keep an unstable central display level while viewing rotating visual surrounds in three depth planes: near (∼20 cm in front of the central display), coplanar, and far (∼21 cm behind the central display). In the second experiment, twelve additional subjects viewed a rotating surround that was presented either in the full visual field (0–110 deg) or in central and peripheral regions of similar width. Manual-control biases and induced motion were shown to be closely related to one another and strongly influenced both by central and by peripheral surround motion at or beyond the plane of fixation. Vection, on the other hand, was shown to be much more dependent on peripheral visual inputs.

A Method of Stereoptically Simulating Manifolds of Three-Dimensional Objects Using Only a Single Display Pattern: A Shape-Depth-Texture Invariance

1989 ◽  
Vol 68 (3_suppl) ◽  
pp. 1163-1175 ◽  
Author(s):  
Thomas L. Harrington ◽  
Denise Quon
Keyword(s):  
Three Dimensional ◽  
The Other ◽  
Real Object ◽  
Visual Displays ◽  
Three Dimensional Objects ◽  
Advantages And Disadvantages ◽  
Display Surface ◽  
The Family

A means of conceptualizing and generating visual displays that are “self-stereoptic manifolds” is described. First, single patterns that can replace pairs of stereograms to produce illusions of depth are defined and an example is shown. Patterns such as these produce illusory three-dimensional objects hanging in space before or behind the display surface. It is further demonstrated geometrically that such a display actually has three-dimensional information embedded in it peculiar to each of a family, or manifold, of objects that can be experienced one at a time. Each object of the family appears when the viewer looks in space where it “exists.” The others remain invisible unless their locations are fixated. If any member of a specific manifold of three-dimensional illusory objects is physically duplicated as a real object and textured in the same way that the illusory object appeared to be, then this new real object will, in turn, generate an illusion of each of the other objects of the manifold when the observer fixates in space where each “exists.” Also, if then the viewer looks where the original display previously was, the newly constructed object will disappear and the display will reappear. The geometry and the advantages and disadvantages in relation to a stereoptic pair are discussed.

Depth Cues and Apparent Oscillatory Motion

1969 ◽  
Vol 29 (2) ◽  
pp. 508-510 ◽  
Author(s):  
R. Canestrari ◽  
M. Farne
Keyword(s):  
Frontal Plane ◽  
Vertical Motion ◽  
Oscillatory Motion ◽  
The Other ◽  
Illusory Motion ◽  
The Real ◽  
Depth Cues ◽  
Pictorial Depth ◽  
Texture Density ◽  
Aerial Perspective

The phenomenon of illusory motion described by Ames as the “rotating trapezoidal window,” the writers interpret as being given by the (monocular “pictorial”) depth cues inherent in the stimulus. In this paper three cues are separately examined: (i) aerial perspective, (ii) interposition, and (iii) gradient of texture density. The stimulus that is seen nearer is also seen moving in a nearer position than the other, and the real rotary motion is thus interpreted as an oscillatory motion or as a vertical motion in the frontal plane.

Illusory motion in visual displays

1984 ◽  
Vol 24 (9) ◽  
pp. 1083-1090 ◽  
Author(s):  
A.M.M. Lelkens ◽  
J.J. Koenderink
Keyword(s):  
Illusory Motion ◽  
Visual Displays

Processing Speed in the Motion-Induction Effect

Perception ◽  
1995 ◽  
Vol 24 (5) ◽  
pp. 477-490 ◽  
Author(s):  
Michael von Grünau ◽  
Zeina Saikali ◽  
Jocelyn Faubert
Keyword(s):  
Processing Speed ◽  
The Other ◽  
Local Processing ◽  
Induction Effect ◽  
Illusory Motion ◽  
Top Down ◽  
Differential Processing ◽  
Gradient Direction ◽  
Other Hand ◽  
The One

The motion-induction effect, where an illusory motion is perceived within a bar when it is shown next to a spot presented slightly earlier, was studied with respect to the idea that it is based on differential processing speeds between the two ends of the bar. First, by using just a bar with a luminance gradient, the existence of a motion illusion (gradient motion) within such a bar was demonstrated, presumably due to the different processing speeds of differential luminances. When such a bar was used in the motion-induction effect, it was shown to modulate, for short delays, the strength of the effect up or down, according to the direction of the gradient with respect to the position of the spot. When the same bar was used in the double-motion-induction effect (split priming), in which motion is usually away from the later spot, it totally determined the perceived direction of illusory motion, independently of gradient direction with respect to the later spot or the time between the two spots. These results demonstrate, on the one hand, that differential local processing speed is a likely mechanism to underlie the motion-induction effect. On the other hand, they also suggest the involvement of other more global (and perhaps top—down) processes.

Age Effects on the Perception of Motion Illusions

Perception ◽  
10.1068/p5886 ◽  
2009 ◽  
Vol 38 (4) ◽  
pp. 508-521 ◽  
Author(s):  
Jutta Billino ◽  
Kai Hamburger ◽  
Karl R Gegenfurtner
Keyword(s):  
Age Effects ◽  
The Other ◽  
Illusory Effect ◽  
Illusory Motion ◽  
Age Related ◽  
Lower Likelihood ◽  
Underlying Mechanisms ◽  
Age Range ◽  
Processing Mechanisms ◽  
Effect Of Age

Anomalous motion illusions represent a popular class of illusions and several studies have made an effort to explain their perception. However, understanding is still inconsistent. Age-related differences in susceptibility to illusory motion may contribute to further clarification of the underlying processing mechanisms. We investigated the effect of age on the perception of four different anomalous motion illusions. The Enigma illusion, the Rotating-Snakes illusion, the Pinna illusion, and the Rotating-Tilted-Lines illusion were tested on a total of one hundred and thirty-nine participants covering an age range from 3 to 82 years. In comparison with young adults, children showed a lower likelihood of perceiving motion in all illusions with the exception of the Rotating-Tilted-Lines illusion. For adult subjects, we found significant age effects in the Rotating-Snakes illusion and the Rotating-Tilted-Lines illusion: occurrence of the illusory effect decreased with age. The other two illusions turned out to be unaffected by aging. Finally, inter-correlations between different motion illusions revealed that only the Pinna illusion and the Rotating-Tilted-Lines illusion correlated significantly with each other. The results confirm that anomalous motion illusions should not be considered as a homogeneous group. Possible links between perceptual data and neurophysiological changes related to age are discussed. Perceptual differences due to age provide the opportunity to improve our understanding of illusory motion and point to specific underlying mechanisms.

The Arbitrariness Argument

2018 ◽  
Author(s):  
Meghan Sullivan
Keyword(s):  
Rational Choice ◽  
The Other ◽  
Relative Distance ◽  
Buridan’S Ass ◽  
Making Choices ◽  
Rational Preferences ◽  
Rule Out

This chapter presents a non‐arbitrariness argument against near bias: (1) At any given time, a prudentially rational agent’s preferences are insensitive to arbitrary differences. (2) Relative distance from the present is an arbitrary difference between events. (3) If you are near‐biased, your preferences are sensitive to when an event is scheduled relative to the present. (C) So at any given time, near‐biased preferences are not rational. This chapter focuses on objections to (1) (the Non‐Arbitrariness principle), offering cases to support the Non‐Arbitrariness principle. It considers and rejects Preference Uniqueness (i.e., any total set of reasons uniquely determines a set of rational preferences) as a way of defending (1) in favor of moderate preference permissivism. It argues that the Non‐Arbitrariness principle does not rule out rational choice in Buridan’s ass cases. While it is irrational to prefer one option to the other, it is not irrational to act by making choices.

Auditory Saltation in the Vertical Midsagittal Plane

Perception ◽  
10.1068/p5140 ◽  
2005 ◽  
Vol 34 (3) ◽  
pp. 371-377 ◽  
Author(s):  
Susan E Boehnke ◽  
Dennis P Phillips
Keyword(s):  
Trial Type ◽  
Source Location ◽  
The Other ◽  
Illusory Motion ◽  
Midsagittal Plane ◽  
Real Motion ◽  
Anchor Points ◽  
Motion Percept ◽  
Spatial Locations ◽  
First Time

Auditory saltation is an illusion in which a train of clicks, the first half of which is presented at one location and the other half of which is presented from a second location, is perceived as originating not only from the anchor points, but also from locations between them. That is, intermediate members of the series of clicks have their spatial locations systematically misperceived. In the present study, auditory saltation was examined for the first time in the vertical midsagittal plane. Subjects rated the perceived continuity of motion for 8-click trains systematically varied in inter-click interval (ICI), direction of motion (up, down), and trial type (‘saltation’ versus ‘real’ motion). In all listeners, saltation stimuli supported robust saltation, but only for trials with ICIs less than about 120 ms. Real motion was rated as continuous for all ICIs. These data indicate that the auditory-saltation illusion can exploit monaural stimulus cues for source location in the generation of the illusory motion percept.

Isolated nearest neighbors

1982 ◽  
Vol 19 (02) ◽  
pp. 444-449 ◽  
Author(s):  
David K. Pickard
Keyword(s):  
Point Processes ◽  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Poisson Processes ◽  
The Other ◽  
Relative Distance ◽  
Nearest Point ◽  
Degree Of Isolation

For point processes, a pair of points is isolated if each is the nearest neighbor of the other, and its degree of isolation is the relative distance to the next-nearest point. The frequency with which such pairs occur and the distribution of their degree of isolation are obtained for Poisson processes in ℝ v . Similar results are obtained for some related models, incidentally solving a problem proposed by D. P. Shine.

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