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PubMed2006

Influence of the amount of UV component in daylight simulator on the color of dental composite resins.

STATEMENT OF PROBLEM: Color of fluorescent substances is influenced by the amount of ultraviolet (UV) component in the illumination. Color of fluorescent dental composite resins may change by the amount of UV component in the ambient light, but there have been few studies on this subject. PURPOSE: The purpose of this study was to determine the differences in color and color parameters such as lightness, chroma, and hue of composite resins created by varying the amount of UV component of a pulsed-xenon source that is conditioned to approximate the Commission Internationale de l'Eclairage (CIE) standard illuminant D65. MATERIAL AND METHODS: A spectrophotometer, in which the UV component of a daylight simulator could be adjusted, was developed. Eight light-polymerized dental composite resins, A3 shade, were studied. Five disk-shaped specimens, 10 x 3 mm, were prepared for each material. Color of specimens was measured on a reflection spectrophotometer over a white background relative to 3 illuminations, which had the same spectral power distribution of the CIE standard illuminant D65 in visible range, but different UV component. D65 indicated the illumination in which the UV component of the pulsed-xenon source was adjusted to the CIE standard illuminant D65 using a UV adjustment tile. UV-EXC indicated the illumination in which the UV component of the source was excluded with a UV filter. UV-INC indicated the illumination in which the UV component was included. Differences in color parameters by the illumination were analyzed with repeated-measures 1-way analysis of variance (ANOVA) by the brand of composite resins. Differences in color (DeltaE*(ab)) and color parameters such as lightness (DeltaL*), chroma (DeltaC*(ab)), and hue angle (Deltah) were analyzed with 3-way ANOVA, with the independent variables of brand of composite resin, combination of illuminations, and type of color parameters (alpha = .05). RESULTS: Color differences (DeltaE*(ab)) by the amount of UV component in the illuminations ranged between 0.3 and 1.4 for D65 and UV-EXC, between 0.3 and 0.5 for D65 and UV-INC, and between 0.2 and 1.6 for UV-EXC and UV-INC. Based on the repeated-measures ANOVA, lightness was not influenced by the amount of the UV component in the illumination, however, chroma and hue angle were influenced by the amount of UV component. Based on the 3-way ANOVA, differences in color and color parameters (DeltaE*(ab), DeltaL*, DeltaC*(ab), and Deltah) by the amount of the UV component were influenced by all of the 3 factors, and there were significant interactions between all the combinations of factors (P < .05). CONCLUSION: Though there were significant differences in color and color parameters by the amount of the UV component in the D65-simulated xenon source, color difference caused by the UV component was lower than 1.6, which is in the visually acceptable range.

Analysis of Variance↗

PubMedDate not supplied

Color scaling of discs and natural objects at different luminance levels.

Assigning a basic color name to an object and rating the amount of a particular hue is a fundamental visual capability. Traditional color scaling studies have used increment flashes or isoluminant stimuli of a homogeneous color. Natural objects, however, do not contain a single color but are characterized by a distribution of different chromatic hues. Here we study color scaling using photographs of natural fruit objects. Stimuli were either homogeneous spots, digital photographs of fruit objects (e.g., banana), or outline shapes of the fruit objects. Stimuli were displayed on a CRT monitor on a homogeneous white background; its luminance was varied above and below the medium gray. The chromaticity of the stimuli was varied in 36 equally spaced chromatic directions in the isoluminant plane of the Derrington-Krauskopf-Lennie (DKL) color space. For each stimuli, subjects rated the amount of red, green, blue, and yellow in the stimulus on a scale from 0-8. In agreement with earlier studies we found that the positions of the peak ratings for each color do not coincide with the cardinal axis of DKL color space and are largely invariant under changes of the background luminance. For the average rating we found a dependence on background luminance for all colors: yellow ratings increase with darker backgrounds, whereas ratings for the other colors, in particular green, decrease. For the fruit objects, we found a selective increase in the average color rating for the natural fruit color. For example, the average rating for yellow was 1.7 times higher for the banana images compared to disc stimuli. No such selective increase was found for outline shapes. We conclude that the distribution of hues in natural objects with a characteristic object color can have a profound effect on color scaling and color appearance.

Adaptation, Ocular↗

PubMed1990

Segregation of basic colors in an information display.

Previous studies of the role of color in visual search have shown efficient coding for as many as six colors in a high-density display. In an effort to increase this limit, we established an optimal basic color code from extensive surface-color-naming data. This code yielded excellent segregation in a visual search task: The time required to find a critical target of a cued color increased only marginally as up to nine groups of different colors were added to the display. It made no difference whether the cue was provided by name or by example. Significant color differences in this task triggered a second experiment, which examined the detectability of the critical target feature in the periphery. A close correlation was found to exist in the order of color performance between the two experiments. Color segregation was tested again in a third experiment, in which subjects were required to count the number of targets of the cued color. The colors again segregated well. A final experiment tested the proposition that it was the basic nature of the colors that was responsible for the good segregation. When seven basic colors were pitted against seven equally discriminable nonbasic ones in a modified version of the visual search task, no significant difference was found between the two groups. It is concluded that basic colors segregate well not because they are universally named but because they are well separated in color space.

Adult↗

PubMedDate not supplied

Resolution of binocular rivalry: Perceptual misbinding of color.

Is neural binding of color and form required for perception of a unified colored object? Individual cells selectively tuned to both color and orientation are proposed to moot the binding problem. This study reveals perceptual misbinding of color, thereby revealing separate neural representations of color and form followed by a subsequent binding process. Low luminance-contrast, rivalrous chromatic gratings were presented dichoptically. Each grating had alternating chromatic and gray stripes (e.g., red/gray in the left eye, green/gray in the right eye). Observers viewed the two rivalrous, 2 cpd gratings for 1 min. The duration of exclusive visibility was measured for four percepts: left-eye stimulus, right-eye stimulus, fusion of the two colors, or a two-color grating (e.g. a red/green grating). The percept of a two-color grating (misbinding) was observed with Michelson luminance contrast in the grating up to 20%. In general, for a given level of luminance contrast either misbinding (low luminance contrast) or color mixture (high luminance contrast) was observed, but not both of them. The perceived two-color gratings show that two rivalrous chromaticities are both represented neurally when color and form are combined to give a unified percept. "Resolution" of competing chromatic signals from the two eyes is not restricted to color dominance and color mixture. The transition from misbinding to color mixture by increasing luminance contrast shows that luminance edges have an important role in correct localization of color.

Color Perception↗

PubMed1996

Primate striate and prestriate cortical neurons during discrimination. II. separable temporal codes for color and pattern.

1. In the previous paper we reported our analysis of the responses of neurons in cortical areas V1, V2, and V4 to a set of stimuli that consisted of all 36 combinations of six colors and six patterns. Neurons in all three cortical areas simultaneously encoded information about both the color and pattern of the stimulus in the number and temporal distribution of spikes in their responses. To account for this ability, we propose that a neuron's response consists of separable temporal codes representing the color and pattern of the stimulus that are multiplexed together. 2. We used nonlinear regression to fit the model parameters to the data. We used the responses to 30 of the 36 stimuli as a training set to estimate the parameters of the model and the responses to the remaining 6 stimuli as a test set. After training, the model fitted the responses to stimuli in the training sets very well and predicted the responses to stimuli in the test sets. Thus neuronal responses to colored patterns contain separate temporal codes representing color and pattern. 3. After establishing the model parameters, we obtained the waveforms that represented each neuron's temporal codes for the six colors and six patterns of our stimulus set. We then proceeded with a series of analyses to determine whether these waveforms were viable candidates for neuronal codes. Cluster analysis revealed that there were only a few different classes of waveforms representing each color and pattern, and there were many neurons in each class. Further, neurons that used similar waveforms to represent one color or pattern also tended to use similar waveforms to represent other colors or patterns. The waveforms representing five of the six colors and three of the six patterns were similar in the two monkeys used in this study. 4. We compared the shapes of the code waveforms across cortical areas and found no differences among areas in the shapes of the waveforms representing four of the six colors. In contrast, we found that there were differences among areas in the shapes of the waveforms representing all six patterns. These results suggest that messages about color are encoded at an early level and are then propagated upward, but that messages about pattern are altered in each successive cortical area. 5. Our results offer a neurophysiological explanation for the psychophysical evidence that color and form are processed by different channels. We propose that the psychophysical channels for color and pattern arise from the separability of the temporal codes for color and pattern in the responses of single neurons. This hypothesis implies that psychophysical channels correspond to classes of temporal codes rather than to classes of neurons.

Animals↗

PubMed2006

Category-specific cortical mapping: color-naming areas.

OBJECT: It has been hypothesized that a certain degree of specialization exists within language areas, depending on some specific lexical repertories or categories. To spare hypothetical category-specific cortical areas and to gain a better understanding of their organization, the authors studied patients who had undergone electrical stimulation mapping for brain tumors and they compared an object-naming task with a category-specific task (color naming). METHODS: Thirty-six patients with no significant preoperative language deficit were prospectively studied during a 2-year period. Along with a reading task, both object- and color-naming tasks were used in brain mapping. During color naming, patients were asked to identify 11 visually presented basic colors. The modality specificity of the color-naming sites found was subsequently tested by asking patients to retrieve the color attributes of objects. High individual variability was observed in language organization among patients and in the tasks performed. Significant interferences in color naming were found in traditional language regions-that is, Broca (p < 0.003) and Wernicke centers (p = 0.05)--although some color-naming areas were occasionally situated outside of these regions. Color-naming interferences were exclusively localized in small cortical areas (< 1 cm2). Anatomical segregation of the different naming categories was apparent in 10 patients; in all, 13 color-specific naming areas (that is, sites evoking no object-naming interference) were detected in the dominant-hemisphere F3 and the supramarginal, angular, and posterior parts of the temporal gyri. Nevertheless, no specific brain region was found to be consistently involved in color naming (p > 0.05). At five sites, although visually presented color-naming tasks were impaired by stimulation, auditory color naming (for example, "What color is grass?") was performed with no difficulty, showing that modality-specific areas can be found during naming. CONCLUSIONS: Within language areas, a relative specialization of cortical language areas for color naming can be found during electrical stimulation mapping.

Adult↗

PubMed1999

Color diagnosticity in object recognition.

Does color influence object recognition? In the present study, the degree to which an object was associated with a specific color was referred to as color diagnosticity. Using a feature listing and typicality measure, objects were identified as either high in color diagnosticity or low in color diagnosticity. According to the color diagnosticity hypothesis, color should more strongly influence the recognition of high color diagnostic (HCD) objects (e.g., a banana) than the recognition of low color diagnostic (LCD) objects (e.g., a lamp). This prediction was supported by results from classification, naming, and verification experiments, in which subjects were faster to identify color versions of HCD objects than they were to identify achromatic versions and incongruent color versions. In contrast, subjects were no faster to identify color versions of LCD objects than they were to identify achromatic and incongruent color versions. Moreover, when shape information was degraded but color information preserved, subjects were less impaired in their recognition of degraded HCD objects than of degraded LCD objects, relative to their nondegraded versions. Collectively, these results suggest that color plays a role in the recognition of HCD objects.

Adult↗

PubMed1997

Evaluation of Kojima-Matsubara color vision test plates: validity in young children.

PURPOSE: We examined a pseudoisochromatic color plate test by Kojima and Matsubara for young children which uses drawings of familiar objects rather than letters or numbers. First, we evaluated the test's efficacy as a color deficiency screener and its validity in classifying the types of color deficiencies by comparing its results with those from the Moreland anomaloscope. Second, we eliminated the chromatic factor and evaluated the functional ability of young children to perform the task by determining how many correct responses were obtained using modified black/white replicas of the test plates. METHODS: Part 1: Twenty color-normal and 13 color-deficient adults were diagnosed and classified with the Ishihara test, Panel D-15 test, and anomaloscope. Subjects were then tested with the Kojima-Matsubara test and result were compared with those from the anomaloscope. Part 2: Fifty children aged 3 to 7 years were tested with modified black/white test plate replicas. The number of correct responses for each plate was determined for five different age groups. RESULTS: Part 1: Among the 20 color-normal subjects, 18 read all 10 plates correctly and 2 subjects missed 1 of the 10. Only 1 of the 13 color-deficient subjects exhibited the expected responses for plates 2 to 6 (used for color deficiency screening). The color-deficient subjects' responses for plates 7 to 10, which are used to classify red-green defects, were varied and only the protanomalous subjects (n = 2) followed the expected response pattern. Part 2: Of the 10 black/white modified plates, only 2 were correctly identified by all 50 children. The other plates had a recognition rate that ranged from 32 to 98%. CONCLUSIONS: Because the response patterns given by most of the color-deficient adult subjects were different from those in the test manual, ambiguous results would occur if the Kojima-Matsubara test were used for color vision screening or the diagnosis of color deficiency. In addition, the difficulty that many of the young children exhibited in identifying the objects in the black/white replica plates suggests that there would be a large number of false positive errors (classifying a color normal as color deficient) when using this test in young children.

Adult↗

PubMed2006

The difference between the constitutive and facultative skin color does not reflect skin phototype in Asian skin.

BACKGROUND/PURPOSE: The assessment of the sensitivity of human skin to ultraviolet (UV) radiation is important in the area of phototherapy, photodermatoses, photo-aging, photo-carcinogenesis, and photo-protection. Some reports have shown that quantitatively measured skin color is a good indicator for predicting UV sensitivity to human skin in Caucasians. In this study, our aim was to define the correlation between skin color and the skin phototype assessed by the Fitzpatrick method in Asian brown skin. METHODS: A total of 180 medical students with similar life styles were included in this study. Their skin phototype was classified according to the system introduced by Fitzpatrick. Then, using a Minolta Spectrophotometer CM-2002, their skin color was determined on the buttocks and forehead. The buttock color was taken as the constitutive skin color, and the forehead color as the facultative skin color. Using these measured values, we compared the skin color with the skin phototype to find their correlation. Also, we investigated whether the difference between the constitutive and facultative skin colors of each individual had a relationship with his or her skin phototype. RESULTS: The constitutive skin color became darker with increasing skin phototype, and this change was statistically significant. As for the facultative skin color, it also became darker with increasing skin phototype, but was less well correlated with the skin phototype than the constitutive skin color. However, the difference between the constitutive and facultative skin colors did not show consistent results in predicting the skin phototype. CONCLUSION: In this study, we found that the constitutive skin color can be a good indicator of the skin phototype. However, the difference between the constitutive and facultative skin colors of each individual does not give any meaningful information for the assessment of his or her skin phototype in Asian skin.

Adult↗

PubMed1993

Color Doppler imaging findings in patients with Budd-Chiari syndrome: correlation with venographic findings.

OBJECTIVE: This study was undertaken to evaluate color Doppler imaging findings in patients with Budd-Chiari syndrome and to compare these findings with results of venography. SUBJECTS AND METHODS: In a prospective study, 21 patients with proved Budd-Chiari syndrome had color Doppler imaging. Sonographic evaluations ware performed to detect appropriately directed flow in the hepatic veins, portal vein, and inferior vena cava. Intrahepatic collaterals were characterized when present. Results of color Doppler imaging were compared with those of angiography in 20 patients. Color Doppler images of the hepatic veins were also obtained in a reference group (20 control subjects, 20 patients with hepatomegaly, and 20 patients with cirrhosis). RESULTS: Color Doppler imaging showed abnormalities of anatomy or flow in one or more of the main hepatic veins in all 21 patients with Budd-Chiari syndrome. Commonly observed abnormalities were visualization of a hepatic vein on real-time sonograms that had no flow or retrograde flow on color Doppler sonograms (11 cases) and no visualization of part or all of a hepatic vein on either real-time or color Doppler sonograms (10 cases). When compared with venographic findings (16 patients), findings on color Doppler sonograms could be used to distinguish patent from occluded hepatic veins in all cases. In our reference group, real-time and color Doppler sonograms showed normal hepatic veins in all control subjects. Real-time sonograms clearly showed hepatic veins in 12 of 20 patients with hepatomegaly; color Doppler sonograms showed flow in the hepatic veins in all 20 of these patients. Among 20 patients with cirrhosis, real-time sonograms showed hepatic veins in only seven; color Doppler imaging confirmed patent veins in 17. Intrahepatic collaterals typical of Budd-Chiari syndrome were observed in 10 of 21 patients with the syndrome. The portal vein was assessed by using color Doppler imaging in all 21 patients with Budd-Chiari syndrome; portograms were available for comparison in 10 patients. Findings were consistent in eight; in two cases, the direction of flow was reversed on color Doppler sonograms compared with portograms. For the inferior vena cava, venographic and sonographic findings correlated in 16 of 20 cases. Color Doppler sonograms did not show a caval web in one patient. CONCLUSION: Abnormalities of the hepatic veins, portal veins, and inferior vena cava detected on color Doppler sonograms in patients with Budd-Chiari syndrome correlate well with findings on venograms.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1999

Cortical regions associated with perceiving, naming, and knowing about colors.

Positron emission tomography (PET) was used to investigate whether retrieving information about a specific object attribute requires reactivation of brain areas that mediate perception of that attribute. During separate PET scans, subjects passively viewed colored and equiluminant gray-scale Mondrians, named colored and achromatic objects, named the color of colored objects, and generated color names associated with achromatic objects. Color perception was associated with activations in the lingual and fusiform gyri of the occipital lobes, consistent with previous neuroimaging and human lesion studies. Retrieving information about object color (generating color names for achromatic objects relative to naming achromatic objects) activated the left inferior temporal, left frontal, and left posterior parietal cortices, replicating previous findings from this laboratory. When subjects generated color names for achromatic objects relative to the low-level baseline of viewing gray-scale Mondrians, additional activations in the left fusiform/lateral occipital region were detected. However, these activations were lateral to the occipital regions associated with color perception and identical to occipital regions activated when subjects simply named achromatic objects relative to the same low-level baseline. This suggests that the occipital activations associated with retrieving color information were due to the perception of object form rather than to the top-down influence of brain areas that mediate color perception. Taken together, these results indicate that retrieving previously acquired information about an object's typical color does not require reactivation of brain regions that subserve color perception.

Adult↗

PubMed2001

Impact of color blindness on recognition of blood in body fluids.

BACKGROUND: Color blindness is a common hereditary X-linked disorder. OBJECTIVE: To investigate whether color blindness affects the ability to detect the presence of blood in body fluids. METHODS: Ten color-blind subjects and 20 sex- and age-matched control subjects were shown 94 photographs of stool, urine, or sputum. Frank blood was present in 57 (61%) of the photographs. Surveys were done to determine if board-certified internists had ever considered whether color blindness would affect detection of blood and whether an inquiry on color blindness was included in their standard medical interview. RESULTS: Color-blind subjects were significantly less able to identify correctly whether pictures of body fluids showed blood compared with non-color-blind controls (P =.001); the lowest rate of correct identifications occurred with pictures of stool (median of 26 [70%] of 37 for color-blind subjects vs 36.5 [99%] of 37 for controls; P<.001). The more severely color-blind subjects were significantly less accurate than those with less severe color deficiency (P =.009). Only 2 (10%) of the 21 physicians had ever considered the possibility that color blindness might affect the ability of patients to detect blood, and none routinely asked their patients about color blindness. CONCLUSIONS: Color blindness impairs recognition of blood in body fluids. Color-blind individuals and their health care providers need to be made aware of this limitation.

Adult↗

PubMed1995

Visual evoked cortical potentials and psychophysical determination of color contrast thresholds along different chromatic axes.

Color vision can be assessed by examining the color contrast threshold along various color axes. We investigated the possibility of determining these thresholds objectively by means of visual evoked cortical potentials. A color-calibrated flicker-free (112-Hz) monitor and a 14-bit-per-gun board allowed visualization of colors with specified xyY CIE 1931 coordinates. Horizontal grating, 1 c/deg were sinusoidally alternated at 8 Hz for both visual evoked cortical potential recordings and psychophysical determinations. Two healthy emmetropic 35 year-old subjects performed color brightness matching along each color axis, before any recording and reduction in color contrast. For each color axis, extrapolation to zero voltage of the visual evoked cortical potential amplitude versus log color contrast response allowed determination of the color contrast threshold. The visual evoked cortical potential-derived threshold changed considerably with the color axis, with evident intersubject differences. These differences were similar to those observed in the psychophysically determined thresholds. Visual evoked cortical potential responses to suitable chromatic stimuli allow determination of color contrast thresholds that correspond well to those determined psychophysically. Hence, with the visual evoked cortical potential, accurate objective assessment of color vision is feasible and may be useful in both research and clinical settings.

Adult↗

PubMed1996

Neuronal mechanisms of color categorization in areas V1, V2 and V4 of macaque monkey visual cortex.

A landmark study conducted by Berlin and Kay (Basic Color Terms, University of California Press, Berkeley, 1969, pp. 1-12) demonstrates that well-developed languages contain exactly 11 basic color terms. The basic colors (8 chromatic and 3 achromatic) are situated in specific locations of color space, suggesting a fixed relationship between specific hue and luminance. To determine the physiologic origins of the basic colors, we have studied the responses of cells in visual cortical areas V1, V2 and V4 of the behaving macaque monkey, using chromatic and achromatic stimuli of varying luminance. A total of 569 cells (291 from V1, 205 from V2, 73 from V4) were obtained, and classified as 'B' (bright; 43-50% of the total cells in each area), 'D' (dark; 6-12% of the total), and 'B/D' (bright/dark; 27-28% of the total) color or non-color cells according to each cell's color/luminance preference in relation to the neutral gray background. About two thirds of 'B' cells in each area were color specific, whereas the proportion of color cells in 'B/D' and 'D' categories was lower. In all three areas (v1, V2, V4), color cells with preferences for midspectral colors (such as yellow, lime and green) also preferred high luminance levels, while color cells with preferences for endspectral colors (such as red and blue) responded preferentially to luminance levels closer to background. The date provide evidence for categorical color perception within the visual system, as well as providing a physiological basis for the increased saliency of endspectral contours observed at equiluminance in psychophysical studies.

Action Potentials↗

PubMed2005

The nature of infant color categorization: evidence from eye movements on a target detection task.

Infants respond categorically to color. However, the nature of infants' categorical responding to color is unclear. The current study investigated two issues. First, is infants' categorical responding more absolute than adults' categorical responding? That is, can infants discriminate two stimuli from the same color category? Second, is color categorization in infants truly perceptual? Color categorization was tested by recording adults' and infants' eye movements on a target detection task. In Experiment 1, adults were faster at fixating a colored target when it was presented on a colored background from a different color category (between-category) than when it was presented on a colored background from the same color category (within-category), even when within- and between-category chromatic differences were equated in CIE (Committee International d'Eclairage) color space. This category effect was found for two chromatic separation sizes. In Experiment 2, 4-month-olds also responded categorically on the task. Infants were able to fixate the target when the background color was from the same category. However, as with adults, infants were faster at fixating the target when the target background chromatic difference was between-category than when it was within-category. This implies that infant color categorization, like adult color categorization, is truly perceptual.

Adult↗

PubMed2003

Is color an intrinsic property of object representation?

The role of color in object representation was examined by using a variation of the Stroop paradigm in which observers named the displayed colors of objects or words. In experiment 1, colors of color-diagnostic objects were manipulated to be either typical or atypical of the object (eg a yellow banana versus a purple banana). A Stroop-like effect was obtained, with faster color-naming times for the typical as compared to the atypical condition. In experiment 2, naming colors on words specifying these same color-diagnostic objects reversed this pattern, with the typical condition producing longer response times than the atypical condition. In experiment 3, a blocked condition design that used the same words and colors as experiment 2 produced the standard Stroop-like facilitation for the typical condition. These results indicate that color is an intrinsic property of an object's representation at multiple levels. In experiment 4, we examined the specific level(s) at which color-shape associations arise by following the tasks used in experiments 1 and 2 with a lexical-decision task in which some items were conceptually related to items shown during color naming (eg banana/monkey). Priming for these associates was observed following color naming of words, but not pictures, providing further evidence that the color-shape associations responsible for the differing effects obtained in experiments 1 and 2 are due to the automatic activation of color-shape associations at different levels of representation.

Adult↗

PubMed2000

Contribution of S opponent cells to color appearance.

We measured the regions in isoluminant color space over which observers perceive red, yellow, green, and blue and examined the extent to which the colors vary in perceived amount within these regions. We compared color scaling of various isoluminant stimuli by using large spots, which activate all cone types, to that with tiny spots in the central foveola, where S cones, and thus S opponent (S(o)) cell activity, are largely or entirely absent. The addition of S(o) input to that from the L and M opponent cells changes the chromatic appearance of all colors, affecting each primary color in different chromatic regions in the directions and by the amount predicted by our color model. Shifts from white to the various chromatic stimuli we used produced sinusoidal variations in cone activation as a function of color angle for each cone type and in the responses of lateral geniculate cells. However, psychophysical color-scaling functions for 2 degrees spots were nonsinusoidal, being much more peaked. The color-scaling functions are well fit by sine waves raised to exponents between 1 and 3. The same is true for the color responses of a large subpopulation of striate cortex cells. The narrow color tuning, the discrepancies between the spectral loci of the peaks of the color-scaling curves and those of lateral geniculate cells, and the changes in color appearance produced by eliminating S(o) input provide evidence for a cortical processing stage at which the color axes are rotated by a combination of the outputs of S(o) cells with those of L and M opponent cells in the manner that we postulated earlier. There seems to be an expansive response nonlinearity at this stage.

Color Perception↗

PubMed1994

Children's emotional associations with colors.

In this study children's emotional associations with colors were investigated. Sixty children (30 girls, 30 boys), equally divided into groups of 5-year-olds and 6 1/2-year-olds, were asked their favorite color and were then shown nine different colors, one at a time and in a random order. For each color, children were asked, "How does (the color) make you feel?" All children were able to verbally express an emotional response to each color, and 69% of children's emotional responses were positive (e.g., happiness, excitement). Responses also demonstrated distinct color-emotion associations. Children had positive reactions to bright colors (e.g., pink, blue, red) and negative emotions for dark colors (e.g., brown, black, gray). Children's emotional reactions to bright colors became increasingly positive with age, and girls in particular showed a preference for brighter colors and a dislike for darker colors. Boys were more likely than girls were to have positive emotional associations with dark colors. Potential sources for children's color-emotion concepts, such as gender-related and idiosyncratic experiences, are discussed.

Age Factors↗