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PubMed2004

Color term knowledge does not affect categorical perception of color in toddlers.

Categorical perception of color is shown when colors from the same category are discriminated less easily than equivalently spaced colors that cross a category boundary. The current experiments tested various models of categorical perception. Experiment 1 tested for categorical responding in 2- to 4-year-olds, the age range for the onset establishment of color term knowledge. Experiment 2 tested for categorical responding in Himba toddlers, whose language segments the color space differently from the way in which the English language does so. Experiment 3 manipulated the conditions of the task to explore whether the categorical responding in Experiments 1 and 2 was equivalent to categorical perception. Categorical perception was shown irrespective of naming and was not stronger in those children with more developed color term knowledge. Cross-cultural differences in the extent of categorical perception were not found. These findings support universalistic models of color categorization and suggest that color term knowledge does not modify categorical perception, at least during the early stages of childhood.

Child Language↗
PubMed2007

Color naming reflects optimal partitions of color space.

The nature of color categories in the world's languages is contested. One major view holds that color categories are organized around universal focal colors, whereas an opposing view holds instead that categories are defined at their boundaries by linguistic convention. Both of these standardly opposed views are challenged by existing data. Here, we argue for a third view based on a proposal by Jameson and D'Andrade [Jameson KA, D'Andrade RG (1997) in Color Categories in Thought and Language, eds Hardin CL, Maffi L (Cambridge Univ Press, Cambridge, U.K.), pp 295-319]: that color naming across languages reflects optimal or near-optimal divisions of an irregularly shaped perceptual color space. We formalize this idea, test it against color-naming data from a broad range of languages and show that it accounts for universal tendencies in color naming while also accommodating some observed cross-language variation.

Color↗
PubMed2001

Coloring single stroop elements: reducing automaticity or slowing color processing?

Automaticity theory and the effect of coloring a single element were tested with all or only 1 element colored in Stroop tasks. The 312 participants in 5 experiments indicated stimulus presentation color by key press. Experiments 1 and 2 replicated those of D. Besner, J. A. Stoltz, and C. Boutilier (1997) with some changes, and revealed similar results: less Stroop interference with only 1 letter colored. Besner et al. (1997) interpreted the results as indicating that coloring a single letter eliminates automatic reading processes. The cause of that reduction in Stroop interference was investigated in Experiments 3, 4, and 5 using color words, bars, and rectangles. The effect of coloring 1 element was to increase color-naming time by the same amount for congruent and neutral, nonverbal stimuli, but not for incongruent stimuli. The results are interpreted in terms of automaticity theory, and a continuous flow approach to the Stroop effect is presented.

Attention↗
PubMed2003

Coloring only a single letter does not eliminate color-word interference in a vocal-response Stroop task: automaticity revealed.

The presence of an interference effect in naming the print color of color words (J. R. Stroop, 1935) suggests that responses associated with the irrelevant-word dimension of the display are activated involuntarily. In the present study, the author examined the conditions under which coloring a single letter in a word reduced interference in vocal responding (D. Kahneman & A. Henik, 1981) or eliminated it in manual responding (D. Besner, J. A. Stolz, & C. Boutilier, 1997). In Experiment 1, color-word interference was significant under vocal responding for the Besner et al. displays. In Experiment 2, the author replicated the Kahneman and Henik effect with the Besner et al. stimuli. The results of Experiment 3 showed that semantic effects are not eliminated by coloring only a single letter. Coloring a single letter does not prevent the activation of the irrelevant-word dimension of the colored color word.

Adolescent↗
PubMed2000

The relationship of raw broiler breast meat color and pH to cooked meat color and pH.

Three replicate trials were conducted to determine the influence of raw breast meat color and pH on subsequent cooked meat color and pH. In each trial, approximately 50 breast fillets were obtained from a commercial processing plant based on being either normal, lighter than normal, or darker than normal. Color (L* = lightness, a* = redness, and b* = yellowness) of each fillet was determined in triplicate on the underside surface of the fillet (to avoid scalding effects), and the pH was determined on a tissue sample removed from the posterior portion of each fillet. Fillets were then cooked in steam at 98 C for 20 min and cooled to room temperature, and a second sample was removed from the posterior section for cooked meat pH. Cooked meat color was measured on an exposed surface, to avoid cooking-related discoloration. The data were subjected to linear regression analysis to determine the relationship between raw and cooked values. Results indicated a significant linear relationship between raw and cooked values for each color parameter as well as pH. Model R2 values were 0.43, 0.40, 0.64, and 0.78 for L*, a*, b*, and pH, respectively. There were also significant linear relationships between raw meat L* and raw muscle pH (R2 = 0.59) as well as cooked meat L* and raw meat pH (R2 = 0.36). These results indicate that raw breast meat color and pH affect cooked breast meat color and pH but that cooking reduces the degree of color variation. Moreover, cooked meat lightness is more closely associated with raw breast meat pH than with cooked meat pH.

Analysis of Variance↗
PubMed2006

Color object detection using spatial-color joint probability functions.

Object detection in unconstrained images is an important image understanding problem with many potential applications. There has been little success in creating a single algorithm that can detect arbitrary objects in unconstrained images; instead, algorithms typically must be customized for each specific object. Consequently, it typically requires a large number of exemplars (for rigid objects) or a large amount of human intuition (for nonrigid objects) to develop a robust algorithm. We present a robust algorithm designed to detect a class of compound color objects given a single model image. A compound color object is defined as having a set of multiple, particular colors arranged spatially in a particular way, including flags, logos, cartoon characters, people in uniforms, etc. Our approach is based on a particular type of spatial-color joint probability function called the color edge co-occurrence histogram. In addition, our algorithm employs perceptual color naming to handle color variation, and prescreening to limit the search scope (i.e., size and location) for the object. Experimental results demonstrated that the proposed algorithm is insensitive to object rotation, scaling, partial occlusion, and folding, outperforming a closely related algorithm based on color co-occurrence histograms by a decisive margin.

Algorithms↗
PubMed1987

Color discrimination by the cotton-top tamarin (Saguinus oedipus oedipus) and its relation to fruit coloration.

Old World monkeys and apes have been reported to differ from New World monkeys in their abilities to discriminate colors across the visible spectrum. Old World monkeys and apes (Macaca, Pan, Pongo) discriminate colors quite accurately, while some New World monkeys studied (Saimiri, Cebus) have shown lower sensitivity to and poorer discrimination of long wavelength light. This study examined the color discrimination ability of another New World primate, the cotton-top tamarin, Saguinus oedipus oedipus (family Callitrichidae). The tamarins were trained to discriminate a set of Munsell color chips, both within the same hue category and from the 2 hue categories on either side of the training hue. Results indicated that the cotton-top tamarin can make accurate discriminations across the visible spectrum. Human subjects were tested under similar conditions in order to compare their color discrimination abilities to those of the tamarins. The tamarins and human subjects had the most difficulty discriminating the same hues. The discrimination abilities of the monkeys were assessed in relation to the coloration of fruits eaten in a natural environment. A list of the species of fruits commonly eaten by various species of New World monkeys was compiled and the coloration of fruits at maturity was noted. It was found that most New World primate species eat fruits whose mature coloration ranges across most of the spectrum.

Adolescent↗
PubMed1996

Conventional color Doppler velocity sonography versus color Doppler energy sonography for the diagnosis of acute experimental torsion of the spermatic cord.

OBJECTIVE: We compared color Doppler velocity sonography and color Doppler energy sonography for the diagnosis of spermatic cord torsion in a canine model and determined the degree of torsion necessary to acutely halt testicular blood flow. MATERIALS AND METHODS: Spermatic cord torsion was created in five dogs by exposing and rotating the ipsilateral testis 0 degree, 180 degrees, 270 degrees, 360 degrees, 450 degrees, and 540 degrees. Detorsion followed. The testicles were scanned at each torsion stop using both color Doppler velocity sonography and color Doppler energy sonography. Doppler parameters were optimized (by phantom and test scans) and maintained at a tolerable noise level throughout the experiment. Readers who were unaware of the degree of torsion compared flow in the rotated and contralateral control testes. RESULTS: Flow became undetectable by color Doppler velocity sonography and color Doppler energy sonography at 450 degrees in four of five cases and at 540 degrees in one of five cases. We found no significant difference between the velocity and the energy techniques for detecting this absence of flow (p > .05, Wilcoxon test). We found a significant difference in degree of flow for both techniques when comparing controls and all degrees of torsion combined (p < .006, Mann-Whitney test), but significance was achieved at lesser degrees of torsion with the velocity technique than with the energy technique (180 degrees and 360 degrees, respectively, Wilcoxon test). CONCLUSION: Color Doppler energy sonography was not significantly more sensitive than color Doppler velocity sonography for the diagnosis of spermatic cord torsion in this model. Complete occlusion of arterial inflow occurred at 450-540 degrees of torsion.

Animals↗
PubMed1989

Effects of luminance contrast on color spreading and illusory contour in the neon color spreading effect.

The present study examined whether color spreading and illusory contours in the neon color spreading effect of Ehrenstein figures are governed by different mechanisms. In the experiment, Ehrenstein figures with colored crosses inserted in the central gaps were used. There were three luminance conditions: the luminance of the Ehrenstein figures was lower than, the same as, or higher than the luminance of the background. In each condition, 16 trials (2 sets of instructions X 8 repetitions) were conducted in a random order. Subjects were required to adjust the luminance of the colored crosses according to one of the two sets of instruction given before each trial. One was to adjust the upper and lower thresholds in the luminance of the colored crosses such that their color was seen to spread out of the crosses. The other was to adjust the thresholds such that circular illusory contours were visible. It was found that illusory contours disappeared and the color spreading remained when the crosses and the Ehrenstein figures were in or nearly in isoluminance or when the Ehrenstein figures and the background were in isoluminance. These results suggest that color spreading and illusory contours are governed by different mechanisms.

Adult↗
PubMed2002

Initial color change and color retention with a hydrogen peroxide bleaching strip.

PURPOSE: A randomized, double blind clinical trial was conducted to evaluate initial color improvement and post-treatment color retention following vital bleaching with a strip-based tooth whitening system. MATERIALS AND METHODS: After balancing for baseline color, 57 healthy adults were randomized to either whitening strips with a 5.3% hydrogen peroxide bleaching gel (Crest Whitestrips) or placebo strips without hydrogen peroxide. Maxillary and mandibular anterior teeth were treated twice daily for 30 minutes each over a 2-week period, and efficacy was measured objectively by comparing digital images of teeth collected at baseline, end-of-treatment (Week 2) and 6 months after treatment (Month 6). RESULTS: The whitening strip group experienced a highly significant (P< 0.0001) reduction in yellow of -2.0 deltab* units versus baseline and -1.95 deltab* units versus placebo, with similar results noted for the other color parameters in the study. Most of the initial color change remained at 6 months post-treatment, with the whitening strip group continuing to demonstrate highly significant (P< 0.0001) improvements in tooth color relative to baseline and placebo. Age was found to significantly contribute to initial color improvement, with younger subjects experiencing a greater initial reduction in yellowness compared to older participants, but not to post-treatment color retention. The whitening strips were well tolerated, with minor tooth sensitivity and oral irritation representing the most common findings during treatment. There were no persistent or new treatment-related adverse events during the 6-month monitoring period.

Adolescent↗
PubMed2005

[Comparison of semitransparent colored labels with opaque colored labels for prevention of adverse drug administration].

BACKGROUND: We made a semitransparent color label to supplement a demerit of an opaque color label for prevention of adverse drug administration, and evaluated whether a semitransparent color label is superior to an opaque color label. METHODS: We prepared a total of 16 syringes (8 colors; two syriges of each color) in the opaque (NC) group and in the semitransparent (CL) group. Each ten subjects were asked to pick up the same drug label alternately in each group, and we measured the time and the number of syringes until the examinee can pick up the five correct syringes. We also examined the adhesiveness of the label to the syringe for six hours in each group. RESULTS: The time and syringe number until the examinee could pick up five correct syringes were 24.6+/-4.6 seconds and 16.2+/-2.7 in NC group (P= 0.0004) and 10.9+/-3.7 seconds and 6.5+/-1.7 in CL group, respectively (n-10, each, P <0.0001). In CL group the label adhered to the syringes tightly for six hours, whereas all the labels in NC group were detached (P<0.0001). CONCLUSIONS: The semitransparent color label is superior to the opaque color label in discrimination and adhesion.

Anesthetics↗
PubMed1983

Limited improvement of color deficient vision with colored filters.

For over a hundred years, colored filters have helped people with less than normal color vision, to discriminate colors. Filtered light does not restore missing or abnormal pigments within the defective eye. Contrast and discrimination provided by a suitable colored filter can help discrimination of a given set of colors, but may prevent seeing other sets of colors. The use and limitations of color filters are described as aids for color deficient vision.

Color Vision Defects↗
PubMed1990

Problems and pitfalls in the performance and interpretation of color Doppler flow imaging: observations based on the influences of technical and physiological factors on the color Doppler examination of mitral regurgitation.

Color Doppler flow imaging has become an integral part of the echocardiographic examination. By providing real-time, two-dimensional spatial maps of normal and abnormal cardiac blood flows, this technique provides important information that may be used to guide patient management. The acquisition and display of color Doppler flow information may be influenced by technical factors, by the physiological condition of the patient, by abnormalities of cardiac morphology, and, on occasion, by artifact. In this article, the results of a study performed to evaluate the influence of technical factors on the color Doppler assessment of mitral regurgitation are reported. Mitral regurgitation jet area size changed significantly with variation in the control settings for color gain, color process, color map, color image resolution, and sector width. A review of those factors that influence the performance and interpretation of the color Doppler flow examination is provided and their significance discussed.

Echocardiography, Doppler↗
PubMed2005

Statistical and molecular analyses of evolutionary significance of red-green color vision and color blindness in vertebrates.

Red-green color vision is strongly suspected to enhance the survival of its possessors. Despite being red-green color blind, however, many species have successfully competed in nature, which brings into question the evolutionary advantage of achieving red-green color vision. Here, we propose a new method of identifying positive selection at individual amino acid sites with the premise that if positive Darwinian selection has driven the evolution of the protein under consideration, then it should be found mostly at the branches in the phylogenetic tree where its function had changed. The statistical and molecular methods have been applied to 29 visual pigments with the wavelengths of maximal absorption at approximately 510-540 nm (green- or middle wavelength-sensitive [MWS] pigments) and at approximately 560 nm (red- or long wavelength-sensitive [LWS] pigments), which are sampled from a diverse range of vertebrate species. The results show that the MWS pigments are positively selected through amino acid replacements S180A, Y277F, and T285A and that the LWS pigments have been subjected to strong evolutionary conservation. The fact that these positively selected M/LWS pigments are found not only in animals with red-green color vision but also in those with red-green color blindness strongly suggests that both red-green color vision and color blindness have undergone adaptive evolution independently in different species.

Animals↗
PubMed1986

The ability of protan color defectives to perform color-dependent air traffic control tasks.

Air traffic controllers perform a variety of tasks which require them to identify, discriminate and name colors. Qualification standards for this occupation require applicants to have normal color vision. Although the validity of this standard has been questioned, Adams and Tague recently presented evidence in this Journal (1985;62:744-50) that protanopes cannot perform color-dependent air traffic control tasks reliably. In our study, the results of 7 severe and 2 moderate protans are compared to those of 78 normals on a set of tasks which simulated critical tasks performed daily by air traffic controllers. The four tasks included discriminating red from black pencil marks on flight progress strips, color-naming of 1(0) and 0.1(0) discs, and identification of colored line segments embedded in a multi-colored background. The severe protans we tested performed none of the tasks as well as normals. While the performance of the moderate protans was better, statistical conclusions could not be drawn. Our set of tasks bears many similarities to the set used by Adams and Tague and it appears we were trying to answer the same questions. The results of the two studies are similar and the conclusions are the same: severe protans cannot perform color-dependent air traffic control tasks reliably.

Accidents, Aviation↗
PubMed1987

Major genes of eye color and hair color linked to LU and SE.

Eye color and hair color were studied in a large Danish family material, tested earlier for a comprehensive set of genetic marker systems. We found strong evidence for linkage of "green eye color" or GEY to the Lutheran-Secretor systems (combined lod score 9.19). This would appear to identify a major gene with influence towards "green eye color". We also found evidence for linkage of GEY to "brown hair color" or BRHC (lod score 5.06), which would appear to identify a second major gene influence in the same region of chromosome 19. Concerning the obvious association in the general population between eye color and hair color which could imitate linkage if it were reflected within sibships, we did not recognize any such intrafamilial association; in the pooled informative sibships GEY and BRHC were independently distributed (as were LU-SE and GEY).

ABO Blood-Group System↗
PubMed1985

Color blindness and Rorschach color responsivity.

Color vision deficits occur in 10% of the American white male population. Thus, color blindness may invalidate diagnostic hypotheses generated from Rorschach data. The Rorschach protocols of 43 white, college male color-blind subjects were compared to the protocols of normally sighted controls. The color-blind group manifested fewer pure "C" responses. No significant between group differences emerged for any of the other primary Rorschach color variables. Pure "C" responses rarely figure prominently in Rorschach evaluations, and the apparent lowered frequency of these responses by the color-blind is insufficient to warrant modification of current Rorschach practice. The data suggest that color blindness is unlikely to confound Rorschach assessment.

Adult↗
PubMed1982

Opponent-colors approach to color rendering.

Starting with an opponent-colors formulation of color vision, two parameters, t and d, may be defined that express an illuminant's ability to realize red-green and blue-yellow contrasts of objects. For instance, calculation of t and d for daylight shows that on a gray day, color contrasts are actually reduced. By these measures, many common vapor-discharge illuminants systematically distort object colors. Because red-green contrasts contribute to border distinctness, and both types of color contrast contribute to brightness, such systematic distortions probably affect the overall clarity and brightness of what is perceived visually, Experimental data are consistent with this idea. In relation to color-constancy (retinex) experiments, it is approximately true that the visual system discounts the color of an illuminant but not its t and d.

Color↗