Respective Contribution of Orientation Contrast and Illusion of Self-Tilt to the Rod-And-Frame Effect

Perception ◽  
1995 ◽  
Vol 24 (6) ◽  
pp. 623-630 ◽  
Author(s):  
Corinne Cian ◽  
Dominique Esquivié ◽  
Pierre Alain Barraud ◽  
Christian Raphel
Keyword(s):  
Contrast Effect ◽  
Visual Angle ◽  
Angular Size ◽  
The Other ◽  
Frame Effect ◽  
Tilt Illusion ◽  
Orientation Contrast ◽  
Respective Contribution ◽  
Adjustment Test ◽  
Rod And Frame

The visual angle subtended by the frame seems to be an important determinant of the contribution of orientation contrast and illusion of self-tilt (ie vection) to the rod-and-frame effect. Indeed, the visuovestibular factor (which produces vection) seems to be predominant in large displays and the contrast effect in small displays. To determine how these two phenomena are combined to account for the rod-and-frame effect, independent estimates of the magnitude of each component in relation to the angular size subtended by the display were examined. Thirty-five observers were exposed to three sets of experimental situations: body-adjustment test (illusion of self-tilt only), the tilt illusion (contrast only) and the rod-and-frame test, each display subtending 7, 12, 28, and 45 deg of visual angle. Results showed that errors recorded in the three situations increased linearly with the angular size. Whatever the size of the frame, both mechanisms, contrast effect (tilt illusion) and illusory effect on self-orientation (body-adjustment test), are always present. However, rod-and-frame errors became greater at a faster rate than the other two effects as the size of the stimuli became larger. Neither one nor the other independent phenomen, nor the combined effect could fully account for the rod-and-frame effect whatever the angular size of the apparatus.

Obliquity Integration: Variations on a Theme of Delbœuf

Perception ◽  
1993 ◽  
Vol 22 (6) ◽  
pp. 705-712
Author(s):  
Giovanni B Vicario ◽  
Giulio Vidotto ◽  
Elena Zambianchi
Keyword(s):  
Frame Of Reference ◽  
The Other ◽  
Geometrical Illusion ◽  
Tilt Illusion ◽  
Variations On A Theme ◽  
Rod And Frame

An optical—geometrical illusion, described by Delbœuf and not familiar to specialists, is investigated. The results of two experiments show that the divergence between a bar filled with parallel slanting lines and a line drawn above it is clearly related to this angle of the lines which fill the bar. The illusion is already present when this angle is 10°, reaches its maximum at 20°, decreases at 30°, and almost disappears at 40°. These results are similar to those found for the tilt illusion, are slightly different from those found for the rod-and-frame illusion, and differ greatly from those found for the Zöllner illusion. The other variables considered—the distance between the slanting lines filling up the bar, the distance between the upper line and the bar, and the width of the bar—do not influence the illusion as much. Since either the line appears as diverging from the bar, or the bar seems inclined in relation to the line, the illusion should be considered a complex one. The small oblique lines inside the bar induce obliquity in the opposite sense in the display, but which of the elements is seen as diverging from the other depends on which of the two is established as the frame of reference.

The Distinction between the Rod-and-Frame Illusion and the Rod-and-Frame Test

Perception ◽  
1974 ◽  
Vol 3 (2) ◽  
pp. 205-212 ◽  
Author(s):  
P M Wenderoth
Keyword(s):  
Angular Function ◽  
Frame Effect ◽  
Tilt Illusion ◽  
Single Frame ◽  
Frame Tilt ◽  
Attraction Effects ◽  
Gravitational Vertical ◽  
Rod And Frame Test ◽  
Rod And Frame

Errors in vertical settings of a test rod occur when the rod is enclosed in a laterally-tilted square-outline frame. The majority of previous experiments which have investigated this rod-and-frame effect have used a single frame tilt, usually 28°, and have tabulated errors as average unsigned deviations from gravitational vertical. Evidence is presented that, when the illusion is measured by taking algebraic differences between constant (signed) errors made with and without the frame being present, illusions occur in the direction of frame tilt for frame tilts up to about 25° from vertical (repulsion effects) but that directionally opposite illusions (attraction effects) occur for frame tilts between 25° and 45°. At the frame tilts used most frequently in previous studies (25° to 30°) little or no illusion occurs. A distinction is drawn between the rod-and-frame illusion (RFI), which has an angular function similar to the simple tilt illusion and aftereffect, and the rod-and-frame test (RFT), which uses unsigned deviations from vertical as its measure of error and which probably bears little or no relationship to the RFI.

Mediolateral somitic origin of ribs and dermis determined by quail-chick chimeras

Development ◽  
2000 ◽  
Vol 127 (21) ◽  
pp. 4611-4617 ◽  
Author(s):  
I. Olivera-Martinez ◽  
M. Coltey ◽  
D. Dhouailly ◽  
O. Pourquie
Keyword(s):  
Skeletal Muscles ◽  
Body Wall ◽  
Primitive Streak ◽  
Axial Skeleton ◽  
Lateral Compartment ◽  
The Body ◽  
The Other ◽  
Lateral Part ◽  
Respective Contribution ◽  
Epaxial Muscles

Somites are transient mesodermal structures giving rise to all skeletal muscles of the body, the axial skeleton and the dermis of the back. Somites arise from successive segmentation of the presomitic mesoderm (PSM). They appear first as epithelial spheres that rapidly differentiate into a ventral mesenchyme, the sclerotome, and a dorsal epithelial dermomyotome. The sclerotome gives rise to vertebrae and ribs while the dermomyotome is the source of all skeletal muscles and the dorsal dermis. Quail-chick fate mapping and diI-labeling experiments have demonstrated that the epithelial somite can be further subdivided into a medial and a lateral moiety. These two subdomains are derived from different regions of the primitive streak and give rise to different sets of muscles. The lateral somitic cells migrate to form the musculature of the limbs and body wall, known as the hypaxial muscles, while the medial somite gives rise to the vertebrae and the associated epaxial muscles. The respective contribution of the medial and lateral somitic compartments to the other somitic derivatives, namely the dermis and the ribs has not been addressed and therefore remains unknown. We have created quail-chick chimeras of either the medial or lateral part of the PSM to examine the origin of the dorsal dermis and the ribs. We demonstrate that the whole dorsal dermis and the proximal ribs exclusively originates from the medial somitic compartment, whereas the distal ribs derive from the lateral compartment.

Neuronal responses to static texture patterns in area V1 of the alert macaque monkey

1992 ◽  
Vol 67 (4) ◽  
pp. 961-980 ◽  
Author(s):  
J. J. Knierim ◽  
D. C. van Essen
Keyword(s):  
Contrast Effect ◽  
Macaque Monkey ◽  
Average Difference ◽  
Contrast Effects ◽  
Neuronal Responses ◽  
Suppression Effect ◽  
Orientation Contrast ◽  
Classical Receptive Field ◽  
Oriented Line

1. We recorded responses from neurons in area V1 of the alert macaque monkey to textured patterns modeled after stimuli used in psychophysical experiments of pop-out. Neuronal responses to a single oriented line segment placed within a cell's classical receptive field (CRF) were compared with responses in which the center element was surrounded by rings of elements placed entirely outside the CRF. The orientations of the surround elements either matched the center element, were orthogonal to it, or were random. 2. The addition of the textured surround tended to suppress the response to the center element by an average of 34%. Overall, almost 80% of the 122 cells analyzed in detail were significantly suppressed by at least one of the texture surrounds. 3. Cells tended to respond more strongly to a stimulus in which there was a contrast in orientation between the center and surround than to a stimulus lacking such contrast. The average difference was 9% of the response to the optimally oriented center element alone. For the 32% of the cells showing a statistically significant orientation contrast effect, the average difference was 28%. 4. Both the general suppression and orientation contrast effects originated from surround regions at the ends of the center bar as well as regions along the sides of the center bar. 5. The amount of suppression induced by the texture surround decreased as the density of the texture elements decreased. 6. Both the general suppression and the orientation contrast effects appeared early in the population response to the stimuli. The general suppression effect took approximately 7 ms to develop, whereas the orientation contrast effect took 18-20 ms to develop. 7. These results are consistent with a possible functional role of V1 cells in the mediation of perceptual pop-out and in the segregation of texture borders. Possible anatomic substrates of the effects are discussed.

scholarly journals Determinants of the rod-and-frame effect: Role of organization and subjective contour

1980 ◽  
Vol 27 (2) ◽  
pp. 136-140 ◽  
Author(s):  
Michael J. Streibel ◽  
Richard D. Barnes ◽  
George D. Julness ◽  
Sheldon M. Ebenholtz
Keyword(s):  
Subjective Contour ◽  
Frame Effect ◽  
Rod And Frame

Response Variables in the Estimation of Relative Frequency

1965 ◽  
Vol 21 (3) ◽  
pp. 867-873 ◽  
Author(s):  
Gordon F. Pitz
Keyword(s):  
Contrast Effect ◽  
Relative Frequency ◽  
The Other ◽  
Total Frequency ◽  
Response Modes ◽  
Relationship Of ◽  
Log Ratio ◽  
The Relationship ◽  
Response Variables

6 groups of 20 Ss each observed a sequential series of digits, 4s and 8s, and judged what proportion (P) of the total was made up by one of the digits. Three kinds of response were used, estimates of percentage, the ratio of one frequency to the other, and the two frequencies themselves. P was varied from .1 to .9, either by holding total frequency constant, or by holding one frequency constant and varying the second. All responses were converted to log ratios, and the relationship of log estimated ratio to log ratio was found to be generally linear. There were significant differences in scales of proportion for the three response modes, and for the two methods of P variation. Percentages, ratios and frequencies gave different slopes, which were possibly a function of an assimilation-contrast effect. Differences due to methods of P variation were thought to result primarily from differences in total frequency at certain levels of P.

scholarly journals Orientation contrast effects in the rod-and-frame test

1979 ◽  
Vol 25 (5) ◽  
pp. 419-424 ◽  
Author(s):  
Donald R. Goodenough ◽  
Philip K. Oltman ◽  
Eric Sigman ◽  
James Rosso ◽  
Herbert Mertz
Keyword(s):  
Contrast Effects ◽  
Orientation Contrast ◽  
Rod And Frame Test ◽  
Rod And Frame

Comparison of Five Methods of Presenting the Rod-and-Frame Test

1969 ◽  
Vol 29 (1) ◽  
pp. 147-151 ◽  
Author(s):  
Gene Lester
Keyword(s):  
Frame Effect ◽  
Undergraduate Women ◽  
Rod And Frame Test ◽  
Rod And Frame

Fifty undergraduate women were tested with 5 versions of the Rod-and-frame Test. One method yielded a significantly smaller variance than any other. The same method also gave a smaller frame effect than has previously been noted for female Ss.

scholarly journals The gap between rod and frame influences the rod-and-frame effect with small and large inducing displays

1993 ◽  
Vol 54 (1) ◽  
pp. 14-19 ◽  
Author(s):  
Pierluigi Zoccolotti ◽  
Gabriella Antonucci ◽  
Donatella Spinelli
Keyword(s):  
Frame Effect ◽  
Rod And Frame

A Comparison of Visual Tilt Illusions Measured by the Techniques of Vertical Setting, Parallel Matching, and Dot Alignment

Perception ◽  
1979 ◽  
Vol 8 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Peter Wenderoth ◽  
Alan Parkinson ◽  
Dennis White
Keyword(s):  
Test Line ◽  
Visual Display ◽  
The Other ◽  
Matching Task ◽  
Independent Evidence ◽  
Tilt Illusion ◽  
Parallel Matching ◽  
Attraction Effects ◽  
Task Conditions ◽  
Alignment Errors

The tilt illusion (TI) was investigated by using both short (19 min) and long (2 deg 6 min) test lines, at three angles of test line-inducing line separation (15°, 45°, and 75°). Three groups of ten observers each provided data under one of three task conditions: vertical judgment, parallel matching, and dot alignment on a common visual display. The main result was that both the vertical judgment and the parallel matching task provided similar, classic TI angular functions with the means ordered 15° > 45° > 75° and with small attraction effects at 75° in three of the four relevant functions. The third task, dot alignment, yielded results different from the average of the other two: no attraction effects occurred and, with the short test line, the obtained mean illusion at 45° exceeded those at the other intersect angles. These results are consistent with alignment data reported by others. One explanation is that the inducing line produces an apparent bowing of the test line which would be reflected in dot alignments but not in vertical setting or in parallel matching. However, direct evidence does not support this hypothesis. An alternate hypothesis, for which independent evidence exists, is that alignment errors reflect perceptual mistracking but that the origin of these errors is not at the tip of the test line but within it. Although this does not explain dot alignment errors, it highlights their complexity and the need to interpret them with caution.

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