Infant color vision: Influence of surround chromaticity on spontaneous looking preferences

2004 ◽  
Vol 21 (3) ◽  
pp. 389-395 ◽  
Author(s):  
MARIA PEREVERZEVA ◽  
DAVIDA Y. TELLER
Keyword(s):  
Test Stimulus ◽  
Color Vision ◽  
Experimental Conditions ◽  
Infant Looking

When infants are tested with stimuli of various chromaticities embedded in a dark or achromatic (white) surround, they show maximal preference for stimuli of maximal colorimetric purity, and minimal preference for achromatic stimuli. We investigated how this pattern of preferences changes with changes of surround chromaticity. Sixteen-week-old infants were tested in two experimental conditions. The surrounds in the first condition were red and white; and in the second condition green and white. The three test stimuli varied in colorimetric purity from white to red in the first condition, and from white to green in the second condition. A test stimulus that appeared achromatic to adults when viewed in the chromatic surround was included. Infant spontaneous looking preferences changed with changes of surround chromaticity. The changes were consistent with the conclusion that infant looking behavior is governed by a preference for the stimuli that differ maximally in purity from the surround. The implications of this pattern of results are discussed.

Opponent Hues in Visual Masking

1978 ◽  
Vol 46 (3) ◽  
pp. 979-983
Author(s):  
Michael Gamble
Keyword(s):  
Test Stimulus ◽  
Color Vision ◽  
Visual Masking ◽  
Masking Effect ◽  
Subjective Confidence ◽  
Temporal And Spatial ◽  
Masking Stimulus ◽  
Temporal Interactions ◽  
Temporal Sequences ◽  
Forward Sequence

Temporal interactions among opponent and non-opponent hues were investigated in a visual masking paradigm in which both backward and forward temporal sequences were employed. Subjective confidence ratings rather than identification thresholds alone served as response indicators for masking sequences. Results indicate that in the backward sequence (test stimulus followed by masking stimulus) a greater masking effect occurred when the stimuli were of non-opponent hue pairs (red-yellow, red-blue, green-yellow, green-blue) than when compared with opponent hue pairs (red-green, yellow-blue). For the forward sequence (test stimulus preceded by masking stimulus) the masking effect was reduced when compared with the backward sequence. These findings appear to reflect the presumed temporal and spatial antagonistic qualities of opponent hue processes as postulated in the Hering model of color vision.

scholarly journals Synesthesia does not help to recover perceptual dominance following flash suppression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Diana Jimena Arias ◽  
Dave Saint-Amour
Keyword(s):  
Test Stimulus ◽  
Target Detection ◽  
Visual Awareness ◽  
The Other ◽  
Visual Noise ◽  
Experimental Conditions ◽  
Suppression Condition ◽  
Colour Sensation ◽  
Perceptual Dominance ◽  
Better Than

AbstractGrapheme-colour synesthesia occurs when letters or numbers elicit an abnormal colour sensation (e.g., printed black letters are perceived as coloured). This phenomenon is typically reported following explicit presentation of graphemes. Very few studies have investigated colour sensations in synesthesia in the absence of visual awareness. We took advantage of the dichoptic flash suppression paradigm to temporarily render a stimulus presented to one eye invisible. Synesthetic alphanumeric and non-synesthetic stimuli were presented to 21 participants (11 synesthetes) in achromatic and chromatic experimental conditions. The test stimulus was first displayed to one eye and then masked by a sudden presentation of visual noise in the other eye (flash suppression). The time for an image to be re-perceived following the onset of the suppressive noise was calculated. Trials where there was no flash suppression performed but instead mimicked the perceptual suppression of the flash were also tested. Results showed that target detection by synesthetes was significantly better than by controls in the absence of flash suppression. No difference was found between the groups in the flash suppression condition. Our findings suggest that synesthesia is associated with enhanced perception for overt recognition, but does not provide an advantage in recovering from a perceptual suppression. Further studies are needed to investigate synesthesia in relation to visual awareness.

After-effects and the integration of patterns of neural activity within a channel

1980 ◽  
Vol 290 (1038) ◽  
pp. 39-55 ◽  
Keyword(s):  
Test Stimulus ◽  
Neural Activity ◽  
The Other ◽  
Additive Effects ◽  
Experimental Conditions ◽  
After Effects ◽  
Subsequent Test ◽  
Model Based

Prolonged inspection of an adapting stimulus changes the appearance of a subsequent test stimulus. There are five distinct viewing conditions under which such ‘after-effects’ may be generated. These are MON-MON (inspect with one eye, test same eye), BIN-BIN (inspect with both eyes, test both eyes), BIN-MON (inspect with both eyes, test only one eye), MON-BIN (inspect with one eye, test with both) and TRANSFER (inspect with one eye, test with the other eye). A model based upon the assumption of the linearly additive effects of adaptation generated in ‘dominance classes’ of cortical units that are driven either by one eye, or the other eye, or by either eye or both eyes together, is described. This model generates predictions concerning the expected relative magnitudes of after-effects generated under the five viewing modes described above, and experiments are described that confirm these predictions. The model can be extended to generate predictions about other experimental conditions. A more complex version of the model is consistent with electrophysiologically derived estimates of the proportion of cortical units in each dominance class.

Infant color vision and color preferences: A tribute to Davida Teller

2013 ◽  
Vol 30 (5-6) ◽  
pp. 243-250 ◽  
Author(s):  
ANGELA M. BROWN ◽  
DELWIN T. LINDSEY
Keyword(s):  
Color Vision ◽  
Color Space ◽  
Color Perception ◽  
Forced Choice ◽  
Data Sets ◽  
Data Set ◽  
Color Preferences ◽  
Vision Science ◽  
Wide Range ◽  
Infant Looking

AbstractAlmost 40 years ago, Davida Teller developed the forced-choice preferential looking method for studying infant visual capabilities and used it to study infant color vision. About 10 years ago, she used infant looking preferences to study infant color perception. Here, we examine four data sets in which the infant looking preference was measured using a wide range of saturated colors. Three of those data sets, from papers by Marc Bornstein and by Davida Teller and Anna Franklin and their respective collaborators, were fit successfully using MacLeod and Boynton’s model of the equiluminant plane in color space, in spite of the varied luminances used in those studies. A fourth data set, from a paper by Zemach, Chang, and Teller, was less well fit by that model. Apparently, infants are able to ignore luminance, and pay attention just to the color of stimuli. These results are discussed in the context of Davida Teller’s work on the philosophy of vision science.

scholarly journals Synesthesia does not help to recover perceptual dominance following flash suppression

2019 ◽  
Author(s):  
Diana Jimena Arias ◽  
Dave Saint-Amour
Keyword(s):  
Test Stimulus ◽  
Matched Control ◽  
Visual Awareness ◽  
The Other ◽  
Experimental Conditions ◽  
Color Sensation ◽  
Significant Difference ◽  
Abstract Stimuli ◽  
Better Than ◽  
Perceptual Phenomenon

AbstractGrapheme-color synesthesia is a perceptual phenomenon that occurs when letters or numbers elicit an abnormal color sensation (e.g., printed black letters are perceived as colored graphemes). Grapheme-color synesthesia is typically reported following explicit presentation of graphemes. Very few studies have investigated color sensations in synesthesia in the absence of visual awareness. To address this issue, we took advantage of the dichoptic flash suppression paradigm to temporarily render a stimulus presented to one eye invisible. Synesthesic alphanumeric and non-synesthetic abstract stimuli were presented to 11 synesthete and 11 matched control participants in achromatic and chromatic experimental conditions. The test stimulus was first displayed to one eye and then masked following the sudden presentation of visual noise in the other eye. The time for an image to be perceived following the onset of the suppressive noise was calculated in each condition. Trials free of flash suppression but mimicking the perceptual suppression of the flash were also tested. Results showed that target detection by synesthetes was significantly better than by controls in the absence of flash suppression. However, no statistically significant difference was found between the groups when the test stimulus was interocularly suppressed, either for synesthetic or non-synesthetic stimuli. This study suggests that synesthesia can be associated with enhanced perception for overt recognition, but does not occur in the absence of visual awareness.

Electrolytic Isolation of Twin-Type Shock Deformation Structures

1967 ◽  
Vol 25 ◽  
pp. 318-319
Author(s):  
F. I. Grace ◽  
L. E. Murr
Keyword(s):  
Grain Boundaries ◽  
Thin Foil ◽  
Electrolyte Composition ◽  
Experimental Conditions ◽  
Average Current Density ◽  
Electron Transmission ◽  
Deformation Structures ◽  
The Matrix ◽  
Average Current ◽  
Specimen Edge

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.

Site of Lysosome Production During Hepatic Injury

1969 ◽  
Vol 27 ◽  
pp. 348-349
Author(s):  
Nalin J. Unakar
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Mouse Liver ◽  
Hepatic Injury ◽  
Close Approximation ◽  
Experimental Conditions ◽  
Toxic Injury

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 548-549 ◽  
Author(s):  
N. J. Zaluzec
Keyword(s):  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
Incident Beam ◽  
Thin Foil ◽  
Experimental Conditions ◽  
X Ray ◽  
Microchemical Analysis ◽  
Analytical Electron ◽  
Image Position ◽  
Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

SEM analysis of the change in the reaction rates with deposit structures in the copper-iron cementation system

1978 ◽  
Vol 36 (1) ◽  
pp. 456-457
Author(s):  
V. Annamalai ◽  
L.E. Murr
Keyword(s):  
Structural Characteristics ◽  
Secondary Electron Emission ◽  
Copper Deposit ◽  
Reaction Rates ◽  
Sem Analysis ◽  
Experimental Conditions ◽  
Major Drawback ◽  
Emission Mode ◽  
Scrap Iron ◽  
Image Position

Economical recovery of copper metal from leach liquors has been carried out by the simple process of cementing copper onto a suitable substrate metal, such as scrap-iron, since the 16th century. The process has, however, a major drawback of consuming more iron than stoichiometrically needed by the reaction.Therefore, many research groups started looking into the process more closely. Though it is accepted that the structural characteristics of the resultant copper deposit cause changes in reaction rates for various experimental conditions, not many systems have been systematically investigated. This paper examines the deposit structures and the kinetic data, and explains the correlations between them.A simple cementation cell along with rotating discs of pure iron (99.9%) were employed in this study to obtain the kinetic results The resultant copper deposits were studied in a Hitachi Perkin-Elmer HHS-2R scanning electron microscope operated at 25kV in the secondary electron emission mode.

Relative Intensities in ED Patterns From Thin Gold Films

1972 ◽  
Vol 30 ◽  
pp. 636-637
Author(s):  
R. H. Morriss ◽  
J. D. C. Peng ◽  
C. D. Melvin
Keyword(s):  
Theoretical Calculations ◽  
Diffraction Theory ◽  
Gold Films ◽  
Reasonable Accuracy ◽  
Experimental Conditions ◽  
Crystal Perfection ◽  
Heavy Atoms ◽  
Fine Focus ◽  
Convergent Beam ◽  
Beam Diffraction

Although dynamical diffraction theory was modified for electrons by Bethe in 1928, relatively few calculations have been carried out because of computational difficulties. Even fewer attempts have been made to correlate experimental data with theoretical calculations. The experimental conditions are indeed stringent - not only is a knowledge of crystal perfection, morphology, and orientation necessary, but other factors such as specimen contamination are important and must be carefully controlled. The experimental method of fine-focus convergent-beam electron diffraction has been successfully applied by Goodman and Lehmpfuhl to single crystals of MgO containing light atoms and more recently by Lynch to single crystalline (111) gold films which contain heavy atoms. In both experiments intensity distributions were calculated using the multislice method of n-beam diffraction theory. In order to obtain reasonable accuracy Lynch found it necessary to include 139 beams in the calculations for gold with all but 43 corresponding to beams out of the [111] zone.

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