scholarly journals Spectral-motion aftereffects and the tritone paradox among Canadian subjects

1998 ◽  
Vol 60 (2) ◽  
pp. 209-220 ◽  
Author(s):  
Lloyd A. Dawe ◽  
John R. Platt ◽  
Eydra Welsh
Keyword(s):  
Tritone Paradox ◽  
Motion Aftereffects

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.

Motion aftereffects following inspection of contrarotating stimuli

1973 ◽  
Vol 13 (12) ◽  
pp. 2587-2589 ◽  
Author(s):  
John A. Woolsey ◽  
Colin V. Newman
Keyword(s):  
Motion Aftereffects

scholarly journals The parallel between reverse-phi and motion aftereffects

2007 ◽  
Vol 7 (11) ◽  
pp. 8 ◽  
Author(s):  
Roger J. E. Bours ◽  
Marijn C. W. Kroes ◽  
Martin J. M. Lankheet
Keyword(s):  
Motion Aftereffects

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.

Some new pitch paradoxes and their implications

1992 ◽  
Vol 336 (1278) ◽  
pp. 391-397 ◽  
Keyword(s):  
Speech Production ◽  
Spectral Envelope ◽  
Pitch Class ◽  
Speech Characteristics ◽  
Class C ◽  
Tritone Paradox ◽  
Sound Patterns ◽  
The Way

This paper explores two new paradoxical sound patterns. The tones used to produce these patterns consist of six octave-related harmonics, whose amplitudes are scaled by a bell-shaped spectral envelope; these tones are clearly defined in terms of pitch class (C, C#, D, and so on) but are poorly defined in term s of height. One pattern consists of two tones that are separated by a half-octave. It is heard as ascending when played in one key, yet as descending when played in a different key. Further, when the pattern is played in any one key it is heard as ascending by some listeners but as descending by others (the tritone paradox). Another pattern that consists of simultaneous pairs of tones displays related properties (the semitone paradox). It is shown that the way the tritone paradox is perceived correlates with the speech characteristics of the listener, including his or her linguistic dialect. The findings suggest that the same, culturally acquired representation of pitch classes influences both speech production and also perception of this musical pattern.

scholarly journals Velocity Dependence of the Interocular Transfer of Dynamic Motion Aftereffects

Perception ◽  
10.1068/p3442 ◽  
2003 ◽  
Vol 32 (7) ◽  
pp. 855-866 ◽  
Author(s):  
Ran Tao ◽  
Martin J M Lankheet ◽  
Wim A van de Grind ◽  
Richard J A van Wezel
Keyword(s):  
Signal To Noise Ratio ◽  
Dominant Role ◽  
Dynamic Test ◽  
Interocular Transfer ◽  
Adaptation Stimulus ◽  
Motion Adaptation ◽  
Pixel Array ◽  
Noise Test ◽  
Motion Aftereffects ◽  
Measured Strength

It is well established that motion aftereffects (MAEs) can show interocular transfer (IOT); that is, motion adaptation in one eye can give a MAE in the other eye. Different quantification methods and different test stimuli have been shown to give different IOT magnitudes, varying from no to almost full IOT. In this study, we examine to what extent IOT of the dynamic MAE (dMAE), that is the MAE seen with a dynamic noise test pattern, varies with velocity of the adaptation stimulus. We measured strength of dMAE by a nulling method. The aftereffect induced by adaptation to a moving random-pixel array was compensated (nulled), during a brief dynamic test period, by the same kind of motion stimulus of variable luminance signal-to-noise ratio (LSNR). The LSNR nulling value was determined in a Quest-staircase procedure. We found that velocity has a strong effect on the magnitude of IOT for the dMAE. For increasing speeds from 1.5 deg s−1 to 24 deg s−1 average IOT values increased about linearly from 18% to 63% or from 32% to 83%, depending on IOT definition. The finding that dMAEs transfer to an increasing extent as speed increases, suggests that binocular cells play a more dominant role at higher speeds.

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