Population heterogeneity and color stimulus heterogeneity in agent-based color categorization

Investigating the interactions between universal and culturally specific influences on color categorization across individuals and cultures has proven to be a challenge for human color categorization and naming research. The present article simulates the evolution of color lexicons to evaluate the role of two realistic constraints found in the human phenomenon: (i) heterogeneous observer populations and (ii) heterogeneous color stimuli. Such constraints, idealized and implemented as agent categorization and communication games, produce interesting and unexpected consequences for stable categorization solutions evolved and shared by agent populations. We find that the presence of a small fraction of color deficient agents in a population, or the presence of a “region of increased salience” in the color stimulus space, break rotational symmetry in population categorization solutions, and confine color category boundaries to a subset of available locations. Further, these heterogeneities, each in a different, predictable, way, might lead to a change of category number and size. In addition, the concurrent presence of both types of heterogeneity gives rise to novel constrained solutions which optimize the success rate of categorization and communication games. Implications of these agent-based results for psychological theories of color categorization and the evolution of color naming systems in human societies are discussed.     

色彩间接效应：现象学和时间现论

色彩间接效应即色彩通过社觉产生的生理和心理效应。本文从中西结合医学的角度研究了ＤＣＩＥ,提出了色－植物神经模型,并建立了相应的时间理论。     

Model-based prediction of human hair color using DNA variants

Predicting complex human phenotypes from genotypes is the central concept of widely advocated personalized medicine, but so far has rarely led to high accuracies limiting practical applications. One notable exception, although less relevant for medical but important for forensic purposes, is human eye color, for which it has been recently demonstrated that highly accurate prediction is feasible from a small number of DNA variants. Here, we demonstrate that human hair color is predictable from DNA variants with similarly high accuracies. We analyzed in Polish Europeans with single-observer hair color grading 45 single nucleotide polymorphisms (SNPs) from 12 genes previously associated with human hair color variation. We found that a model based on a subset of 13 single or compound genetic markers from 11 genes predicted red hair color with over 0.9, black hair color with almost 0.9, as well as blond, and brown hair color with over 0.8 prevalence-adjusted accuracy expressed by the area under the receiver characteristic operating curves (AUC). The identified genetic predictors also differentiate reasonably well between similar hair colors, such as between red and blond-red, as well as between blond and dark-blond, highlighting the value of the identified DNA variants for accurate hair color prediction.     

Neural network approach for image chromatic adaptation for skin color detection

The goal of image chromatic adaptation is to remove the effect of illumination and to obtain color data that reflects precisely the physical contents of the scene. We present in this paper an approach to image chromatic adaptation using Neural Networks (NN) with application for detecting--adapting human skin color. The NN is trained on randomly chosen color images containing human subject under various illuminating conditions, thereby enabling the model to dynamically adapt to the changing illumination conditions. The proposed network predicts directly the illuminant estimate in the image so as to adapt to human skin color. The comparison of our method with Gray World, White Patch and NN on White Patch methods for skin color stabilization is presented. The skin regions in the NN stabilized images are successfully detected using a computationally inexpensive thresholding operation. We also present results on detecting skin regions on a data set of test images. The results are promising and suggest a new approach for adapting human skin color using neural networks.     

Comparative colorimetry in cytophotometric measurements of azure B-eosin Y-stained and Giemsa-stained blood cell smears

The advantages of the Commission Internationale de l'Eclairage (CIE) color measurements and the use of the standardizable purified azure B-eosin Y stain, as compared to the commonly used commercial Giemsa stain, were studied. Color measurement and analysis according to the CIE standards allows the comparison of color measurements from different slides stained by either the same or different procedures. Moreover, measurements from different cytophotometric systems can be compared. The results can also be directly correlated with human visual subjective color estimates and thus used to quantify the human observations. The color information in the air-dried cell specimens, which differs from the color characteristics of the components of the staining solution, was measured and analyzed.     

Comprehensive candidate gene study highlights UGT1A and BNC2 as new genes determining continuous skin color variation in Europeans

Natural variation in human skin pigmentation is primarily due to genetic causes rooted in recent evolutionary history. Genetic variants associated with human skin pigmentation confer risk of skin cancer and may provide useful information in forensic investigations. Almost all previous gene-mapping studies of human skin pigmentation were based on categorical skin color information known to oversimplify the continuous nature of human skin coloration. We digitally quantified skin color into hue and saturation dimensions for 5,860 Dutch Europeans based on high-resolution skin photographs. We then tested an extensive list of 14,185 single nucleotide polymorphisms in 281 candidate genes potentially involved in human skin pigmentation for association with quantitative skin color phenotypes. Confirmatory association was revealed for several known skin color genes including HERC2, MC1R, IRF4, TYR, OCA2, and ASIP. We identified two new skin color genes: genetic variants in UGT1A were significantly associated with hue and variants in BNC2 were significantly associated with saturation. Overall, digital quantification of human skin color allowed detecting new skin color genes. The variants identified in this study may also contribute to the risk of skin cancer. Our findings are also important for predicting skin color in forensic investigations.     

多尺度植物色彩表征及其与人体响应的关系

色彩是人们对植物外观的第一印象,与植物视觉特征和人体响应关系密切,因此,对森林美景度提升和公众适宜性契合具有重要作用。结合色彩学形成的历史关键节点和1个世纪以来植物色彩的研究动态,将植物色彩研究的发展历程划分为萌芽、形成、发展和繁荣等4个阶段,并简介了各阶段的主要特点。同时,从植物器官、植物个体、植物群体(涵盖种群和群落)、整体景观等4个视觉尺度以及审美、生理与心理等3个影响层面,阐述与评价了植物色彩传达机制与人体响应关系的相关研究。在此基础上,围绕植物色彩特征提取中存在的色彩要素定量、特征因子选取、色彩量化方法等方面的不足之处,对未来研究方向进行展望,提出植物色彩尺度与公众响应关系剖析、较大尺度色彩评价因子的深入挖掘、色彩量化方法的多学科融入、公众对植物色彩响应关系综合比对、森林景观美景度提升实践等5个方向的发展趋势,以期为全面地了解植物色彩的传达机制与影响、科学地开展不同精度和尺度下的植物色彩研究提供参考。     

The effect of unconscious color hue saturation on emotional state of human

The aim of the study was to investigate influence of color hue saturation on emotional state of human. We use frontal EEG asymmetry to determine subject's emotional state. Our emotional stimuli summon opposite dynamics of frontal EEG asymmetry. Negative stimuli elicits decreasing of the value of frontal EEG asymmetry and positive stimuli increases the value of frontal EEG asymmetry in fronto-polar and frontal leads. Such dynamics of frontal EEG asymmetry point the emotional experience in accordance the stimulus modality. Blue and red color modification of stimuli leads changes in dynamics of frontal EEG asymmetry during presentation of emotional stimuli and after. In fact, that no one subject gave a report about color difference between stimuli during an experiment, we conclude that influence of color modification was unconscious. Our result shows the possibility of unconscious perception color modification to emotional state of human.     

Differentiation of granulocytes in Pappenheim stained blood cell smears using standardized cytophotometric analysis

The well-known problems of the low reproducibility of peripheral blood smear analysis have for some time stimulated endeavours to automate blood cell classification. In the cytophotometric standardized color measurement and analysis, the computed color characteristics for the first time refer to an internationally accepted color system, allowing not only an international comparison of the computer color measurements but an unproblematic mutual interchange of color information between man and machine based on both the human visual color impressions and the conventional morphological color attributes of the white blood cells. The discriminatory power of the method is demonstrated by differentiating the cytoplasm granulations in basophil, eosinophil and neutrophil granulocytes.     

Quantitative genetics of human skin color

Skin color has long been of interest to human geneticists and often used as an example of a human quantitative trait under relatively wellunderstood genetic control. Although the basic biology of melanin production and the method of measurement are areas in which skin color studies are fairly well advanced, compared to other quantitative traits, the evolutionary significance and mode of inheritance are still being debated. In view of the many steps involved in the production and dispersion of melanin and the large number of loci involved in coat color of laboratory animals, it is suggested that genetic control of human skin color must be fairly complex. Studies that have found evidence for relatively few loci effecting the differences between racial groups may either be using inappropriate methods, or they may be concentrating attention on only that portion of genetic variability that distinguishes between major world groups, particularly blacks and whites. Genetic analysis of intermediate groups and pedigree analysis of rare pigmentation conditions may yield more information on skin color genetics.     

Spectral Test Instrument for Color Vision Measurement

Common displays such as CRT or LCD screens have hmlted capabilities in displaying most color spectra correctly. The main disadvantage of these devices is that they work with three primaries and the colors displayed are the mixture of these three colours. Consequently these devices can be confusing in testing human color identification, because the spectral distribution of the colors displayed is the combined spectrum of the three primaries. We have developed a new instrument for spectrally correct color vision measurement. This instrument uses light emitting diodes (LEDs) and is capable of producing all spectra of perceivable colors, thus with appropriate test methods this instrument can be a reliable and useful tool in testing human color vision and in verifying color vision correction.     

Simultaneous detection of DsRed2-tagged and EGFP-tagged human beta-interferons in the same single cells

The red fluorescent protein DsRed2 is a useful fusion tag for various proteins, together with the enhanced green fluorescent protein (EGFP). These chromoproteins have spectral properties that allow simultaneous distinctive detection of tagged proteins in the same single cells by dual color imaging. We used them for tagging a secretory protein, human interferon-beta (IFN-beta). Expression plasmids for human IFN-beta tagged with DsRed2 or with EGFP at the carboxyl terminal were constructed and their coexpression was examined in Mardin-Darby canine kidney epithelial cells. Although maturation of DsRed2 for coloration was slow and the color intensity was weak compared with EGFP, low temperature treatment (20 degrees C) allowed DsRed2-tagged human IFN-beta to be detected in the cells using color imaging. Consequently, the two chimeric proteins were shown to be colocalized in the same single cells by dual color confocal microscopy. This approach will be useful for investigating subcellular localization of not only cell resident proteins but also secretory proteins.     

Different ranking of avian colors predicted by modeling of retinal function in humans and birds

Abstract: Only during the past decade have vision-system-neutral methods become common practice in studies of animal color signals. Consequently, much of the current knowledge on sexual selection is based directly or indirectly on human vision, which may or may not emphasize spectral information in a signal differently from the intended receiver. In an attempt to quantify this discrepancy, we used retinal models to test whether human and bird vision rank plumage colors similarly. Of 67 species, human and bird models disagreed in 26 as to which pair of patches in the plumage provides the strongest color contrast or which male in a random pair is the more colorful. These results were only partly attributable to human UV blindness. Despite confirming a strong correlation between avian and human color discrimination, we conclude that a significant proportion of the information in avian visual signals may be lost in translation.     

In the eye of the beholder: Is color classification consistent among human observers?

Colorful displays have evolved in multiple plant and animal species as signals to mutualists, antagonists, competitors, mates, and other potential receivers. Studies of color have long relied on subjective classifications of color by human observers. However, humans have a limited ability to perceive color compared to other animals, and human biological, cultural, and environmental variables can influence color perception. Here, we test the consistency of human color classification using fruit color as a model system. We used reflectance data of 67 tropical fruits and surveyed 786 participants to assess the degree to which (a) participants of different cultural and linguistic backgrounds agree on color classification of fruits; and (b) human classification to a discrete set of commonly used colors (e.g., red, blue, green) corresponds to natural clusters based on light reflectance measures processed through visual systems of other animals. We find that individual humans tend to agree on the colors they attribute to fruits across language groups. However, these colors do not correspond to clearly discernible clusters in di‐ or tetrachromatic visual systems. These results indicate that subjective color categorizations tend to be consistent among observers and can be used for large synthetic studies, but also that they do not fully reflect natural categories that are relevant to animal observers.     

Role of light in human skin color viariation.

The major source of color in human skin derives from the presence within the epidermis of specialized melanin-bearing organelles, the melanosomes. Tanning of human skin on exposure to ultraviolet light results from increased amounts of melanin within the epidermis. Melanosomes synthesized by melanocytes are acquired by keratinocytes and transported within them to the epidermal surface. In some cases, the melanosomes are catobolized en route. New information indicates that the multicellular epidermal melanin unit (melanocyte and associated pool of keratinocytes) rather than the melanocyte alone is the focal point for the control of melanin metabolism within mammalian epidermis. Gross human skin color derives from the visual impact of the summed melanin pigmentation of the many epidermal melanin units. In theory, constitutive skin color in man designates the genetically-determined levels of melanin pigmentation developed in the absence of exposure to solar radiation or other environmental influences; facultative skin color or "tan" characterizes the increases in melanin pigmentation above the constitutive level induced by ultraviolet light. The details of genetic regulation of pigment metabolism within the epidermal melanin units are being clarified. In some mammals at least, the function of epidermal melanin units is significantly influenced by hormones which may be regulated by radiations received through the eyes. Based on an evolutionary history of the human family which exceeds ten million years, it is proposed that melanin pigmentation may have played a number of roles in human adaptions to changing biologic and physical environments.     

In Situ Detection of a PCR-Synthesized Human Pancentromeric DNA Hybridization Probe by Color Pigment Immunostaining: Application for Dicentric Assay Automation

We report a low cost and efficient method for synthesizing a human pancentromeric DNA probe by the polymerase chain reaction (PRC) and an optimized protocol for in situ detection using color pigment immunostaining. The DNA template used in the PCR was a 2.4 kb insert containing human alphoid repeated sequences of pancentromeric DNA subcloned into pUC9 (Miller et al. 1988) and the primers hybridized to internal sequences of the 172 bp consensus tandem repeat associated with human centromeres. PCR was performed in the presence of biotin-11-dUTP, and the product was used for in situ hybridization to detect the pancentromeric region of human chromosomes in metaphase spreads. Detection of pancentromeric probe was achieved by immunoenzymatic color pigment painting to yield a permanent image detected at high resolution by bright field microscopy. The ability to synthesize the centromeric probe rapidly and to detect it with color pigment immunostaining will lead to enhanced identification and eventually to automation of various chromosome aberration assays.     

Signatures of selection and gene conversion associated with human color vision variation

Trichromatic color vision in humans results from the combination of red, green, and blue photopigment opsins. Although color vision genes have been the targets of active molecular and psychophysical research on color vision abnormalities, little is known about patterns of normal genetic variation in these genes among global human populations. The current study presents nucleotide sequence analyses and tests of neutrality for a 5.5-kb region of the X-linked long-wave "red" opsin gene (OPN1LW) in 236 individuals from ethnically diverse human populations. Our analysis of the recombination landscape across OPN1LW reveals an unusual haplotype structure associated with amino acid replacement variation in exon 3 that is consistent with gene conversion. Compared with the absence of OPN1LW amino acid replacement fixation since divergence from chimpanzee, the human population exhibits a significant excess of high-frequency OPN1LW replacements. Our results suggest that subtle changes in L-cone opsin wavelength absorption may have been adaptive during human evolution.     

The method for studying of the "magnetic vacuum" effect on color memory in humans

The method for studying the effects of weak magnetic fields and "magnetic vacuum" on the psychophysiological state of a human organism is proposed. This method includes the system of the exposure of a human organism to uniform constant and alternating magnetic fields and the system of computerized psychological tests. The influence of the weakening of constant magnetic field on the psychophysiological state of human organisms was studied. The short-term color memory and reaction rates of 30 subjects have been examined in the local geomagnetic field and in a magnetic field which was reduced in 10 and more times. Statistically significant differences in the color memory test was found in the magnetic field 4 +/- 1 microT in comparison with the results in the geomagnetic field. In the magnetic field 0 +/- 1 microT, slight impairment of color memory was found. Preliminary results in the test of reaction rates showed the tendency to slowing down the reaction rates in the weakened magnetic fields.     

Avian vision and the evolution of egg color mimicry in the common cuckoo

Coevolutionary arms races are a potent force in evolution, and brood parasite-host dynamics provide classical examples. Different host-races of the common cuckoo, Cuculus canorus, lay eggs in the nests of other species, leaving all parental care to hosts. Cuckoo eggs often (but not always) appear to match remarkably the color and pattern of host eggs, thus reducing detection by hosts. However, most studies of egg mimicry focus on human assessments or reflectance spectra, which fail to account for avian vision. Here, we use discrimination and tetrachromatic color space modeling of bird vision to quantify egg background and spot color mimicry in the common cuckoo and 11 of its principal hosts, and we relate this to egg rejection by different hosts. Egg background color and luminance are strongly mimicked by most cuckoo host-races, and mimicry is better when hosts show strong rejection. We introduce a novel measure of color mimicry-"color overlap"-and show that cuckoo and host background colors increasingly overlap in avian color space as hosts exhibit stronger rejection. Finally, cuckoos with better background color mimicry also have better pattern mimicry. Our findings reveal new information about egg mimicry that would be impossible to derive by the human eye.     

Hemispheric difference in human skin color

Previous studies of human skin color have shown a strong relationship between skin color and distance from the equator, which has been interpreted as a link between skin color, latitude, and the intensity of ultraviolet radiation. The underlying assumptions are that UV radiation is greatest at the equator and that it diminishes with increasing latitude to the same extent in both the Northern and Southern Hemispheres. The standard analysis of human skin color is based on these assumptions, such that skin color is assumed to be darkest at the equator, and the decrease of skin color with latitude is assumed to be the same in both hemispheres. A nonlinear piecewise regression model was developed to test these assumptions and applied to mean skin reflectance data from 102 male samples and 65 female samples from across the Old World. For both males and females, skin reflectance (%) is lowest at the equator (darkest skin). Among males, skin reflectance increases roughly 8.2% for every 10 degrees of latitude in the Northern Hemisphere but only 3.3% for every 10 degrees of latitude in the Southern Hemisphere. Among females, the corresponding numbers are 8.1% in the Northern Hemisphere and 4.7% in the Southern Hemisphere. These results indicate that human skin color is darker in the Southern Hemisphere than in the Northern Hemisphere at equivalent latitude. Recent research shows that UV radiation is higher in the Southern Hemisphere than in the Northern Hemisphere at similar latitude. This difference, relating to astronomical and climatic conditions, may have existed in the past at different times and perhaps influenced the evolution of human skin color. Am J Phys Anthropol 104:449–457, 1997. © 1997 Wiley-Liss, Inc.