scholarly journals The “Spinner” Illusion: More Dots, More Speed?

i-Perception ◽  
2017 ◽  
Vol 8 (3) ◽  
pp. 204166951770797
Author(s):  
Hiroshi Ashida ◽  
Alan Ho ◽  
Akiyoshi Kitaoka ◽  
Stuart Anstis
Keyword(s):  
Test Stimulus ◽  
Temporal Frequency ◽  
Angular Speed ◽  
Circular Path ◽  
Reference Stimulus ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Speed Perception ◽  
Perceived Speed

The perceived speed of a ring of equally spaced dots moving around a circular path appears faster as the number of dots increases (Ho & Anstis, 2013, Best Illusion of the Year contest). We measured this “spinner” effect with radial sinusoidal gratings, using a 2AFC procedure where participants selected the faster one between two briefly presented gratings of different spatial frequencies (SFs) rotating at various angular speeds. Compared with the reference stimulus with 4 c/rev (0.64 c/rad), participants consistently overestimated the angular speed for test stimuli of higher radial SFs but underestimated that for a test stimulus of lower radial SFs. The spinner effect increased in magnitude but saturated rapidly as the test radial SF increased. Similar effects were observed with translating linear sinusoidal gratings of different SFs. Our results support the idea that human speed perception is biased by temporal frequency, which physically goes up as SF increases when the speed is held constant. Hence, the more dots or lines, the greater the perceived speed when they are moving coherently in a defined area.

scholarly journals The effect of blue light filtering lenses on speed perception

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adiba Ali ◽  
Maitreyee Roy ◽  
Hind Saeed Alzahrani ◽  
Sieu K. Khuu
Keyword(s):  
Test Stimulus ◽  
Blue Light ◽  
Motion Perception ◽  
Unintended Consequences ◽  
Reference Stimulus ◽  
Choice Procedure ◽  
Speed Perception ◽  
Forced Choice Procedure ◽  
Perceived Speed ◽  
Method Of Constant Stimuli

AbstractBlue-light filtering lenses (BFLs) are marketed to protect the eyes from blue light that may be hazardous to the visual system. Because BFLs attenuate light, they reduce object contrast, which may impact visual behaviours such as the perception of object speed which reduces with contrast. In the present study, we investigated whether speed perception is affected by BFLs. Using a two-interval forced-choice procedure in conjunction with Method of Constant Stimuli, participants (n = 20) judged whether the perceived speed of a moving test stimulus (1.5–4.5°/s) viewed through a BFL was faster than a reference stimulus (2.75°/s) viewed through a clear lens. This procedure was repeated for 3 different BFL brands and chromatic and achromatic stimuli. Psychometric function fits provided an estimate of the speed at which both test and reference stimuli were matched. We find that the perceived speed of both chromatic and achromatic test stimuli was reduced by 6 to 20% when viewed through BFLs, and lenses that attenuated the most blue-light produced the largest reductions in perceived speed. Our findings indicate that BFLs whilst may reduce exposure to hazardous blue light, have unintended consequences to important visual behaviours such as motion perception.

Perceived Speed of Moving Cyclopean Corrugations Increases with Increasing Disparity Amplitude

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 195-195
Author(s):  
A M Johns ◽  
B J Rogers ◽  
R A Eagle
Keyword(s):  
Spatial Frequency ◽  
Feature Tracking ◽  
Temporal Frequency ◽  
Reference Stimulus ◽  
Experimental Control ◽  
The Poor ◽  
Random Dot Stereograms ◽  
Matching Performance ◽  
Perceived Speed ◽  
Central Fixation

In order to investigate how cyclopean motion is coded by the visual system, the points of subjective equality (PSEs) were measured for (i) speed, (ii) spatial frequency (SF), and (iii) temporal frequency (TF) as a function of peak-to-trough disparity amplitude for cyclopean corrugations. Two panels (3.0 deg × 7.0 deg) of dynamic random-dot stereograms were located 0.5 deg on either side of a central fixation spot. Each panel contained a horizontally oriented sinusoidal cyclopean corrugation whose SF, TF, and disparity amplitude were under experimental control. On each trial, the cyclopean corrugations were displaced vertically in opposite directions. Subjects judged which panel contained the higher SF, TF, or speed depending on condition. The reference stimulus was a sinusoidal corrugation with SF=0.4 cycles deg−1, TF=0.8 Hz, speed of 2.0 deg s−1, and peak-to-trough disparity amplitude of 8 min arc around fixation. We found that, as the peak-to-trough disparity amplitude of the test stimulus increased from 2 min arc to 32 min arc, the PSE for speed decreased from 2.21 deg s−1 to 1.67 deg s−1, compared to a reference speed of 2.00 deg s−1. However, across the same levels of disparity amplitude, the PSE for SF remained constant and the PSE for TF varied but with no consistent pattern. Thus, perceived speed increases with increased disparity amplitude. As all levels of disparity amplitude were above threshold, cyclopean speed cannot be detected by a purely ‘feature-tracking’ mechanism. These metamers and the poor TF matching performance suggest that cyclopean speed is coded by a sparse number of temporal mechanisms.

Differential Motion Thresholds to Sinusoidal Gratings at Two Eccentricities

1991 ◽  
Vol 73 (3) ◽  
pp. 765-766
Author(s):  
Mark C. Chorlton ◽  
David C. Finlay ◽  
Marx L. Manning ◽  
W. Ross Fulham ◽  
John Boulton
Keyword(s):  
Frequency Tuning ◽  
Temporal Frequency ◽  
Differential Motion ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Minimum Velocity

Differential motion thresholds were measured at eccentricities of 9° and 16.6° using computer-generated sinusoidal gratings. Three spatial frequencies (0.51, 0.25, and 0.13 cycles/deg) were examined at reference velocities of 2, 4, 8, 16, 52, and 48 deg/sec. Minimum differential velocity thresholds were between 20 and 30% of the reference velocities for the three spatial frequencies at both eccentricities Increasing eccentricity produced an increase in the velocity at which minimum velocity discrimination occurred. Temporal frequency tuning was between 4 and 8 Hz, regardless of eccentricity.

Uniform-Field Flicker Masking in Control and Specifically-Disabled Readers

Perception ◽  
1988 ◽  
Vol 17 (2) ◽  
pp. 203-214 ◽  
Author(s):  
Frances Martin ◽  
William J Lovegrove
Keyword(s):  
Test Stimulus ◽  
Contrast Sensitivity ◽  
Temporal Frequency ◽  
Control Group ◽  
Uniform Field ◽  
Complex Situation ◽  
Spatial Frequencies ◽  
Stationary Test ◽  
Disabled Readers ◽  
Transient System

Possible transient-system deficiencies in subjects with specific reading disabilities (SRDs) were investigated in groups of 13-year-old SRDs and control normal readers. In experiment 1, in which a 6 Hz uniform-field flicker (UFF) mask and a stationary test stimulus were used, it was found that the overall effect of UFF masking was to reduce differences in contrast sensitivity between SRDs and normal readers. In experiments 2a and 2b, with UFF masks of 6 and 20 Hz and a 6 Hz moving (experiment 2a) or flickering (experiment 2b) test stimulus, contrast sensitivity in both groups was decreased in the presence of the 6 Hz UFF mask. Only the control group, however, showed a further decrease in sensitivity with the 20 Hz UFF mask. This indicates that the groups differ in terms of a mechanism sensitive to high temporal frequencies. A 20 Hz counterphase flickering test stimulus was used in experiment 3 in the presence of 6 Hz UFF, and it was found that SRDs are less sensitive than controls to 20 Hz flicker across all spatial frequencies used. The 6 Hz mask, however, did not differentially affect the two groups. These findings provide further evidence for a transient-system deficit in the visual systems of SRDs, but also suggest a more complex situation by showing that the two groups differ in a high-temporal-frequency mechanism.

Spatial and temporal analysis by neurons in the representation of the central visual field in the cat's lateral suprasylvian visual cortex

1990 ◽  
Vol 5 (5) ◽  
pp. 463-468 ◽  
Author(s):  
Martin S. Gizzi ◽  
Ephraim Katz ◽  
J. Anthony Movshon
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Temporal Frequency ◽  
Visual Fields ◽  
Receptive Fields ◽  
Visual Signals ◽  
Field Size ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Areas 17 And 18

AbstractWe studied quantitatively the receptive-field properties of 74 units recorded from the representation of the central visual fields in the cat's lateral suprasylvian (LS) visual cortex. In agreement with previous workers, we found that LS receptive fields tended to be large and to lack discernible spatial structure. They resembled the complex receptive fields of areas 17 and 18 in their general organization. We examined the responses of these neurons to moving optimally oriented sinusoidal gratings that varied in spatial and temporal frequency of drift. Most LS neurons were selective for the spatial frequency of sinusoidal gratings; 7% responded to all spatial frequencies below a cutoff value. In agreement with previous reports, the optimal spatial frequencies for LS neurons covered a wider range than is seen in either area 17 or 18 alone (0.05–1 cycle/deg), but are certainly included in the range covered by both these afferent areas. Individual neurons in LS responded to a range of spatial frequencies broader than is typical for neurons in areas 17 and 18. The effect of varying the drift rate of otherwise optimal gratings was similar in LS to that reported for areas 17 and 18. Most neurons were optimally responsive to drift rates between 0.5 and 4 Hz, and resolved frequencies as high as 10–30 Hz. A few neurons had optima higher than 6 Hz and resolved frequencies in excess of 30 Hz. We conclude that the receptive fields of LS neurons reflect rather closely the properties of their afferents from areas 17 and 18. Apart from the increased incidence of directional selectivity in LS and the increase in receptive-field size seen there, we find no evidence for a significant reorganization of visual signals.

Difference of Spatial Frequency Selectivity between Static and Flicker Motion Aftereffects

Perception ◽  
1994 ◽  
Vol 23 (11) ◽  
pp. 1313-1320 ◽  
Author(s):  
Hiroshi Ashida ◽  
Naoyuki Osaka
Keyword(s):  
Spatial Frequency ◽  
Test Stimulus ◽  
Motion Aftereffect ◽  
Frequency Selectivity ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Early Processing ◽  
Motion Aftereffects

The strength of motion aftereffect (MAE) was measured with the use of sinusoidal gratings of several spatial frequencies, to examine the spatial frequency selectivity of two types of MAE. With ordinary static grating as a test stimulus, to measure ‘static MAE’, the maximum aftereffect for each adapting spatial frequency was obtained at the testing stimuli of the same spatial frequency, showing spatial frequency selectivity. However, in the case when the sinusoidally flickering grating was used as a test stimulus, to measure ‘flicker MAE’, no spatial frequency selectivity was observed. The two types of MAE were considered to be based on different mechanisms. Static MAE is thought to depend on the spatiotemporal channel mechanism in the early processing stages, whereas flicker MAE might reflect higher-level processes which might occur at the extrastriate regions.

Visual Contrast Sensitivity Functions Obtained with Colored and Achromatic Gratings

1979 ◽  
Vol 21 (2) ◽  
pp. 225-228 ◽  
Author(s):  
Michael A. Nelson ◽  
Ronald L. Halberg
Keyword(s):  
Contrast Sensitivity ◽  
Spatial Information ◽  
Sensitivity Functions ◽  
Visual Contrast ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Visual Contrast Sensitivity ◽  
Contrast Thresholds

Threshold contrasts for red, green, and achromatic sinusoidal gratings were measured. Spatial frequencies ranged from 0.25 to 15 cycles/deg. No significant differences in contrast thresholds were found among the three grating types. From this finding it was concluded that, under conditions of normal viewing, no significant differences should be expected in the acquisition of spatial information from monochromatic or achromatic displays of equal resolution.

Acuity-sensitivity trade-offs of X and Y cells in the cat lateral geniculate complex: role of the medial interlaminar nucleus in scotopic vision

1992 ◽  
Vol 68 (4) ◽  
pp. 1235-1247 ◽  
Author(s):  
D. Lee ◽  
C. Lee ◽  
J. G. Malpeli
Keyword(s):  
Contrast Sensitivity ◽  
Adaptation Level ◽  
Special Role ◽  
A Cells ◽  
Lateral Geniculate ◽  
Spatial Frequencies ◽  
Wide Range ◽  
Sinusoidal Gratings ◽  
X Cells ◽  
Y Cells

1. The cat medial interlaminar nucleus (MIN) receives inputs almost exclusively from tapetal retina, suggesting that the MIN has a special role in dim-light vision. In this study we compared the sensitivities of cells in the MIN with those in layers A and magnocellular C of the lateral geniculate nucleus (LGNd), using drifting sinusoidal gratings to determine contrast thresholds as a function of spatial frequency and retinal adaptation level over the entire scotopic range. 2. About one-half of the cells recorded in the MIN and layer A had brisk responses that could be nulled by properly positioned, counterphased sinusoidal gratings, and were classified as X cells. The rest of the cells in the MIN and layer A, as well as all cells recorded in layer C, were Y cells. 3. MIN cells had higher contrast sensitivity than layer A cells for low spatial frequencies (0.15 cycles/deg and below) over a wide range of adaptation levels, both overall and for separate comparisons within X or Y cells. Layer C Y cells were intermediate in sensitivity between MIN and layer A Y cells. For low spatial frequencies, Y cells as a group were more sensitive than X cells, whereas the reverse was true for high spatial frequencies. 4. These data enable one to determine the lowest adaptation level at which stimuli of a given contrast can be detected for a given structure. At the lowest spatial frequencies, the MIN can function at adaptation levels approximately 1 log unit below layer A, averaged over all stimulus contrasts. In contrast, the tapetum lowers luminance threshold by at most 0.16 log unit. 5. For scotopic conditions and eccentricities within 15 degrees of the area centralis, contrast sensitivity decreases with eccentricity for low spatial frequencies and remains flat or slightly increases for high spatial frequencies. This relationship, which is opposite to that found for photopic vision, is strongest for MIN Y cells. 6. These data support the hypothesis that the retinal conflict between sensitivity and acuity is ameliorated in the CNS through separate thalamic relays with different degrees of afferent convergence. MIN cells have higher luminance sensitivity than layer A cells, but at the expense of acuity. Layer C appears to occupy an intermediate position in this trade-off.

Temporal and Spatial Frequency Tuning of the Flicker Motion Aftereffect

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 12-12
Author(s):  
P J Bex ◽  
F A J Verstraten ◽  
I Mareschal
Keyword(s):  
Spatial Frequency ◽  
Frequency Tuning ◽  
Temporal Frequency ◽  
Motion Aftereffect ◽  
Sine Wave ◽  
Test Grating ◽  
Spatial Frequency Tuning ◽  
Spatial Frequencies ◽  
Low Pass ◽  
Sine Wave Gratings

The motion aftereffect (MAE) was used to study the temporal-frequency and spatial-frequency selectivity of the visual system at suprathreshold contrasts. Observers adapted to drifting sine-wave gratings of a range of spatial and temporal frequencies. The magnitude of the MAE induced by the adaptation was measured with counterphasing test gratings of a variety of spatial and temporal frequencies. Independently of the spatial or temporal frequency of the adapting grating, the largest MAE was found with slowly counterphasing test gratings (∼0.125 – 0.25 Hz). For slowly counterphasing test gratings (<∼2 Hz), the largest MAEs were found when the test grating was of similar spatial frequency to that of the adapting grating, even at very low spatial frequencies (0.125 cycle deg−1). However, such narrow spatial frequency tuning was lost when the temporal frequency of the test grating was increased. The data suggest that MAEs are dominated by a single, low-pass temporal-frequency mechanism and by a series of band-pass spatial-frequency mechanisms at low temporal frequencies. At higher test temporal frequencies, the loss of spatial-frequency tuning implicates separate mechanisms with broader spatial frequency tuning.

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