Motion Aftereffects of Wagon Wheels: Motion Aftereffects Follow Apparent Rather Than Real Movement

1994 ◽  
Vol 79 (1) ◽  
pp. 131-140
Author(s):  
Roderick P. Power
Keyword(s):  
Apparent Movement ◽  
Motion Aftereffect ◽  
Flickering Light ◽  
Wagon Wheel ◽  
True Motion ◽  
Apparent Direction ◽  
Illusory Movement ◽  
Motion Aftereffects ◽  
Direction Opposite ◽  
True Direction

Power and Moulden have proposed a model which accounts for the movement of gratings in apertures including the barber pole illusion. It predicts the direction of motion aftereffects which follow from perceived veridical motion and the direction of these aftereffects which follow from the illusory movement experienced during the barber pole illusion. At a perceptual level, the model predicts motion aftereffects will follow direction of apparent movement rather than veridical direction. Four experiments tested this prediction. In Exp. 1 a spiral was viewed under flickering light so it appeared to be moving in the direction opposite to true motion, and the aftereffect was opposite to the apparent direction. In Exp. 2 the spiral was viewed through a narrow aperture so that it was effectively a grating appearing to move in the opposite direction to veridical motion. Again, the motion aftereffect was opposite to the apparent rather than true direction of rotation. In Exp. 3 a sectored disc was used, and similar results were obtained. In Exp. 4 the sectored disc was videotaped so that it appeared to be rotating in the direction opposite to true motion. The after motion to this “wagon wheel” effect was opposite to its apparent direction of rotation on the screen. In all experiments the predictions were confirmed, thereby confirming the general principle that motion aftereffecrs follow apparent rather than real direction of movemenr.

Apparent Velocity of Motion Aftereffects in Central and Peripheral Vision

Perception ◽  
1986 ◽  
Vol 15 (5) ◽  
pp. 603-612 ◽  
Author(s):  
Michael J Wright
Keyword(s):  
Visual Field ◽  
Time Course ◽  
Peripheral Vision ◽  
Temporal Frequency ◽  
Motion Aftereffect ◽  
Apparent Velocity ◽  
Real Motion ◽  
Temporal Decay ◽  
Spatial Grain ◽  
Motion Aftereffects

Adapting to a drifting grating (temporal frequency 4 Hz, contrast 0.4) in the periphery gave rise to a motion aftereffect (MAE) when the grating was stopped. A standard unadapted foveal grating was matched to the apparent velocity of the MAE, and the matching velocity was approximately constant regardless of the visual field position and spatial frequency of the adapting grating. On the other hand, when the MAE was measured by nulling with real motion of the test grating, nulling velocity was found to increase with eccentricity. The nulling velocity was constant when scaled to compensate for changes in the spatial ‘grain’ of the visual field. Thus apparent velocity of MAE is constant across the visual field, but requires a greater velocity of real motion to cancel it in the periphery. This confirms that the mechanism underlying MAE is spatially-scaled with eccentricity, but temporally homogeneous. A further indication of temporal homogeneity is that when MAE is tracked, by matching or by nulling, the time course of temporal decay of the aftereffect is similar for central and for peripheral stimuli.

scholarly journals The Perceived Direction of Textured Gratings and Their Motion Aftereffects

Perception ◽  
1995 ◽  
Vol 24 (12) ◽  
pp. 1383-1396 ◽  
Author(s):  
David Alais ◽  
Maarten J van der Smagt ◽  
Frans A J Verstraten ◽  
Wim A van de Grind
Keyword(s):  
Motion Aftereffect ◽  
Sine Wave ◽  
Circular Aperture ◽  
High Luminance ◽  
One Dimensional ◽  
Square Wave ◽  
Aperture Problem ◽  
Motion Energy ◽  
Motion Aftereffects ◽  
Do So

The stimuli in these experiments are square-wave luminance gratings with an array of small random dots covering the high-luminance regions. Owing to the texture, the direction of these gratings, when seen through a circular aperture, is disambiguated because the visual system is provided with an unambiguous motion energy. Thus, the direction of textured gratings can be varied independently of grating orientation. When subjects are required to judge the direction of textured gratings moving obliquely relative to their orientation, they can do so accurately (experiment 1). This is of interest because most studies of one-dimensional motion perception have involved (textureless) luminance-defined sine-wave or square-wave gratings, and the perceived direction of these gratings is constrained by the aperture problem to be orthogonal to their orientation. Thus, direction and orientation have often been confounded. Interestingly, when subjects are required to judge the direction of an obliquely moving textured grating during a period of adaptation and then the direction of the motion aftereffect (MAE) immediately following adaptation (experiments 2 and 3), these directions are not directly opposite each other. MAE directions were always more orthogonal to the orientation of the adapting grating than the corresponding direction judgments during adaptation (by as much as 25°). These results are not readily explained by conventional MAE models and possible accounts are considered.

Local and Global Properties of Motion Aftereffects

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 170-170
Author(s):  
N J Wade ◽  
V Pardieu ◽  
M T Swanston
Keyword(s):  
Vision Research ◽  
Motion Aftereffect ◽  
Test Display ◽  
Adaptation Process ◽  
Local Motion ◽  
Motion Adaptation ◽  
Global Properties ◽  
Differential Adaptation ◽  
Induced Motion ◽  
Motion Aftereffects

The local motion adaptation at the basis of the motion aftereffect (MAE) can be expressed in a variety of ways, depending upon the structure of the test display (N J Wade, L Spillmann, M T Swanston Vision Research in press). This has been demonstrated with MAEs from induced motion: if adaptation is to two moving (Surround) gratings, an MAE is seen in the central grating if two gratings surround it, but in the flanking gratings when they are themselves surrounded in the test stimulus. We report two experiments in which the characteristics of the test display and of the local adaptation process have been examined. In experiment 1, five vertical gratings were presented during adaptation; the outermost and central gratings remained stationary and those flanking the centre moved laterally. The test display always consisted of three stationary gratings: either the central three or the lower three equivalent to the locations of the adaptation display. MAEs were only recorded in the Centre and not in the Surround, irrespective of whether the Centre or Surround had been exposed to motion during adaptation. MAEs in the Centre were in opposite directions, reflecting the influence of Surround adaptation. The influence of adapting motion in different directions was examined in experiment 2. The upper grating always received the same direction of motion during adaptation, and the lower grating was absent, stationary, or moving in the same or in the opposite direction. The results indicate that an MAE is visible in the upper grating only after differential adaptation between the upper and lower gratings.

Motion Aftereffect: A Global Mechanism for the Perception of Rotation

Perception ◽  
1980 ◽  
Vol 9 (2) ◽  
pp. 175-182 ◽  
Author(s):  
Patrick Cavanagh ◽  
Olga Eizner Favreau
Keyword(s):  
Motion Aftereffect ◽  
Mirror Image ◽  
Test Figure ◽  
Spiral Motion ◽  
Logarithmic Spirals ◽  
Motion Aftereffects ◽  
Storage Properties

Observers adapted to motion by looking at rotating logarithmic spirals. They were tested with a stationary mirror image of the adapting spiral in which all contours were at 90° to those of the first spiral. Motion aftereffects were reported in the contrarotational direction—that is, observers who had seen clockwise rotating motion reported seeing counterclockwise aftereffects. These aftereffects lasted one-third as long as the aftereffects obtained when the adapting spiral was used as the test figure. These two aftereffects were shown to have different storage properties, thereby indexing the operation of at least two different mechanisms. We interpret the motion aftereffect that is obtained with the mirror-image stimulus as indicative of the existence of global rotation detectors.

Psychophysical Evidence for an Extrastriate Contribution to a Pattern-Selective Motion Aftereffect

Perception ◽  
1988 ◽  
Vol 17 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Peter Wenderoth ◽  
Rohan Bray ◽  
Syren Johnstone
Keyword(s):  
Striate Cortex ◽  
Motion Aftereffect ◽  
Temporal Area ◽  
Middle Temporal ◽  
Pattern Motion ◽  
Component Motion ◽  
The Individual ◽  
The Right ◽  
Motion Aftereffects ◽  
Vertical Test

A stationary vertical test grating appears to drift to the left after adaptation to an inducing grating drifting to the right, this being known as the motion aftereffect (MAE). Pattern-specific motion aftereffects (PSMAEs) induced by superimposed pairs of gratings in which the component gratings drift up and down but the observer sees a single coherent plaid drifting to the right have been investigated. Two experiments are reported in which it is demonstrated that the PSMAE is tuned more to the motion of the pattern than to the orientation and direction of motion of the component gratings. However, when subjects adapt to the component gratings in alternation, aftereffect magnitude is dependent upon the individual grating orientations and motion directions. These results can be interpreted in terms of extrastriate contributions to the PSMAE, possibly arising from the middle temporal area, where some cells, unlike those in striate cortex (V1), are tuned to pattern motion rather than to component motion.

scholarly journals Type of Featural Attention Differentially Modulates hMT+ Responses to Illusory Motion Aftereffects

2009 ◽  
Vol 102 (5) ◽  
pp. 3016-3025 ◽  
Author(s):  
Miguel Castelo-Branco ◽  
Lajos R. Kozak ◽  
Elia Formisano ◽  
João Teixeira ◽  
João Xavier ◽  
...  
Keyword(s):  
Selective Attention ◽  
Motion Aftereffect ◽  
Human Motion ◽  
Real Surface ◽  
Illusory Motion ◽  
Real Motion ◽  
Motion Signal ◽  
Color Features ◽  
Motion Aftereffects ◽  
Global Activity

Activity in the human motion complex (hMT+/V5) is related to the perception of motion, be it either real surface motion or an illusion of motion such as apparent motion (AM) or motion aftereffect (MAE). It is a long-lasting debate whether illusory motion-related activations in hMT+ represent the motion itself or attention to it. We have asked whether hMT+ responses to MAEs are present when shifts in arousal are suppressed and attention is focused on concurrent motion versus nonmotion features. Significant enhancement of hMT+ activity was observed during MAEs when attention was focused either on concurrent spatial angle or color features. This observation was confirmed by direct comparison of adapting (MAE inducing) versus nonadapting conditions. In contrast, this effect was diminished when subjects had to report on concomitant speed changes of superimposed AM. The same finding was observed for concomitant orthogonal real motion (RM), suggesting that selective attention to concurrent illusory or real motion was interfering with the saliency of MAE signals in hMT+. We conclude that MAE-related changes in the global activity of hMT+ are present provided selective attention is not focused on an interfering feature such as concurrent motion. Accordingly, there is a genuine MAE-related motion signal in hMT+ that is neither explained by shifts in arousal nor by selective attention.

The Duration of the Motion Aftereffect following Adaptation to First-Order and Second-Order Motion

Perception ◽  
1994 ◽  
Vol 23 (10) ◽  
pp. 1211-1219 ◽  
Author(s):  
Timothy Ledgeway ◽  
Andrew T Smith
Keyword(s):  
Motion Aftereffect ◽  
Second Order ◽  
Adaptation Stimulus ◽  
Motion Patterns ◽  
First Order ◽  
Parallel Motion ◽  
Significant Difference ◽  
Cross Adaptation ◽  
Identification Threshold ◽  
Direction Opposite

The magnitude of the motion aftereffect (MAE) obtained following adaptation to first-order or to second-order motion was measured by estimating its duration. The second-order adaptation stimulus was composed of contrast-modulated noise produced by multiplying two-dimensional (2-D) noise by a drifting 1 cycle deg−1 sine grating. The first-order adaptation stimulus was composed of luminance-modulated noise produced by summing, rather than multiplying, the noise and the sine grating. The test stimuli were directionally ambiguous motion patterns composed of either two oppositely drifting sine gratings added to noise or the contrast-modulated equivalent. The adaptation and test stimuli were equated for visibility by presenting them at the same multiple of direction-identification threshold. All possible combinations of first-order and second-order adaptation and test stimuli were examined in order to compare the magnitudes of the MAEs obtained following same adaptation and cross adaptation. After adaptation the test stimuli always appeared to drift coherently in the direction opposite to that of adaptation and the magnitudes of this MAE were very similar for all conditions examined. Statistical analyses of the results showed that there was no significant difference between the durations of the MAEs obtained in the same-adaptation and cross-adaptation conditions. The cross-adaptation effects suggest that either first-order or second-order motion are detected by a common low-level mechanism, or that separate parallel motion-detecting mechanisms exist, for the two types of motion, that interact at some later stage of processing.

A Selective History of the Study of Visual Motion Aftereffects

Perception ◽  
1994 ◽  
Vol 23 (10) ◽  
pp. 1111-1134 ◽  
Author(s):  
Nicholas J Wade
Keyword(s):  
Visual Processing ◽  
Visual Motion ◽  
Motion Aftereffect ◽  
Theoretical Research ◽  
Motion Processing ◽  
Visual Science ◽  
Stationary Objects ◽  
Major Review ◽  
Cortical Visual Processing ◽  
Motion Aftereffects

The visual motion aftereffect (MAE) was initially described after observation of movements in the natural environment, like those seen in rivers and waterfalls: stationary objects appeared to move briefly in the opposite direction. In the second half of the nineteenth century the MAE was displaced into the laboratory for experimental enquiry with the aid of Plateau's spiral. Such was the interest in the phenomenon that a major review of empirical and theoretical research was written in 1911. In the latter half of the present century novel stimuli (like drifting gratings, isoluminance patterns, spatial and luminance ramps, random-dot kinematograms, and first-order and second-order motions), introduced to study space and motion perception generally, have been applied to examine MAEs. Developing theories of cortical visual processing have drawn upon MAEs to provide a link between psychophysics and physiology; this has been most pronounced in the context of monocular and binocular channels in the visual system, the combination of colour and contour information, and in the cortical sites most associated with motion processing. The relatively unchanging characteristic of the study of MAEs has been the mode of measurement: duration continues to be used as an index of its strength, although measures of threshold elevation and nulling with computer-generated motions are becoming more prevalent. The MAE is a part of the armoury of motion phenomena employed to uncover the mysteries of vision. Over the last 150 years it has proved itself immensely adaptable to the shifts of fashion in visual science, and it is likely to continue in this vein.

Subjective Velocity Estimates of Apparent Movement following Visual Stimulation

1971 ◽  
Vol 33 (3_suppl) ◽  
pp. 1029-1030
Author(s):  
John K. Collins
Keyword(s):  
Visual Motion ◽  
Intertrial Interval ◽  
Visual Stimulation ◽  
Apparent Movement ◽  
Motion Aftereffect ◽  
Apparent Velocity ◽  
Stationary Target ◽  
Apparent Rotation ◽  
The Mean

Tracking the apparent movement of a stationary target following prior stimulation by rotation was used to estimate the subjective velocity of the visual motion aftereffect. 10 Ss were given 4 trials each with the apparent velocity averaged over a 10-sec. period following 60 sec. stimulation. The intertrial interval was 5 min. The mean apparent rotation was 1.5° per sec. with SD of 1.6°.

A New Phenomenon of Apparent Movement and its After-Effect

1950 ◽  
Vol 2 (3) ◽  
pp. 119-123 ◽  
Author(s):  
J. A. Deutsch
Keyword(s):  
Apparent Movement ◽  
Spiral Pattern ◽  
Flickering Light ◽  
After Effects ◽  
Apparent Rotation ◽  
Wide Range ◽  
After Effect

It is found that a stationary spiral pattern gives an appearance of movement in a flickering light, and, furthermore, that this apparent rotation gives rise to the same kind of after-effect as a spiral actually rotating. The illusion is obtainable over a wide range of conditions. Detailed results are given in the case of six subjects, but a large number of subjects experienced the illusion. The experimenter has as yet found no one who was not subject to the illusion itself. The after-effects are not universally experienced.

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