Assessment of #TheDress With Traditional Color Vision Tests: Perception Differences Are Associated With Blueness

Based on known color vision theories, there is no complete explanation for the perceptual dichotomy of #TheDress in which most people see either white-and-gold (WG) or blue-and-black (BK). We determined whether some standard color vision tests (i.e., color naming, color matching, anomaloscope settings, unique white settings, and color preferences), as well as chronotypes, could provide information on the color perceptions of #TheDress. Fifty-two young observers were tested. Fifteen of the observers (29%) reported the colors as BK, 21 (40%) as WG, and 16 (31%) reported a different combination of colors. Observers who perceived WG required significantly more blue in their unique white settings than those who perceived BK. The BK, blue-and-gold, and WG observer groups had significantly different color preferences for the light cyan chip. Moreland equation anomaloscope matching showed a significant difference between WG and BK observers. In addition, #TheDress color perception categories, color preference outcomes, and unique white settings had a common association. For both the bright and dark regions of #TheDress, the color matching chromaticities formed a continuum, approximately following the daylight chromaticity locus. Color matching to the bright region of #TheDress showed two nearly distinct clusters (WG vs. BK) along the daylight chromaticity locus and there was a clear cutoff for reporting WG versus BK. All results showing a significant difference involved blue percepts, possibly due to interpretations of the illuminant interactions with the dress material. This suggests that variations in attributing blueness to the #TheDress image may be significant variables determining color perception of #TheDress.Fil: Feitosa-Santana, Claudia. Universidade Federal do ABC; BrasilFil: Lutze, Margaret. Depaul University; Estados UnidosFil: Barrionuevo, Pablo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; ArgentinaFil: Cao, Dingcai. University of Illinois; Estados Unido

The color of night: Surface color perception under dim illuminations

Several studies document rudimentary color vision under dim illumination. Here, hue perceptions of paper color samples were determined for a wide range of light levels, including very low light levels where rods alone mediate vision. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10-0.0003 Lux. Triads of samples were chosen representing each of eight basic color categories; red, pink, orange, yellow, green, blue, purple, and gray. Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above 0.32 Lux, observers sorted the samples into the originally chosen color groups with few exceptions. For 0.1-0.01 Lux, the red and orange samples were usually correctly identified as either red or orange. The remaining samples tended to be grouped into two categories, associated with the scotopic sample reflectance. The lowest reflectance samples were below threshold and were named black. The higher reflectance group was named predominately as green or blue-green three observers; the fourth observer used blue or achromatic. At the three dimmest levels 0.0032 Lux there continued to be conspicuous color percepts. Color categories were reliably assigned based on relative sample scotopic lightness. Of the samples above threshold, those with lower reflectance were classified as red or orange all observers and the higher reflectance samples as green or blue-green three observers or achromatic or blue the fourth observer. Rods and L-cones presumably mediated color percepts at the intermediate light levels used in the study. At the three lowest light levels there were distinct color appearances mediated exclusively by rods. We speculate that at these light levels the visual system estimates probable colors based on prior natural experienc

The color of night : surface color categorization by color defective observers under dim illuminations

People with normal trichromatic color vision experience variegated hue percepts under dim illuminations where only rod photoreceptors mediate vision. Here, hue perceptions were determined for persons with congenital color vision deficiencies over a wide range of light levels, including very low light levels where rods alone mediate vision. Deuteranomalous trichromats, deuteranopes and protanopes served as observers. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10 to 0.0003 Lux (1.0 to −3.5 log Lux). Triads of samples were chosen representing each of eight basic color categories; “red,” “pink,” “orange,” “yellow,” “green,” “blue,” “purple,” and “gray.” Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above −0.5 log Lux, the dichromatic and anomalous trichromatic observers sorted the samples into the original representative color groups, with some exceptions. At light levels where rods alone mediate vision, the color names assigned by the deuteranomalous trichromats were similar to the color names used by color normals; higher scotopic reflectance samples were classified as blue-green-grey and lower reflectance samples as red-orange. Color names reported by the dichromats at the dimmest light levels had extensive overlap in their sample scotopic lightness distributions. Dichromats did not assign scotopic color names based on the sample scotopic lightness, as did deuteranomalous trichromats and colour-normals. We reasoned that the reduction in color gamut that a dichromat experiences at photopic light levels leads to a limited association of rod color perception with objects differing in scotopic reflectance.\ud \u

The Relationship between Vegetable Intake and Weight Outcomes: A Systematic Review of Cohort Studies

The relationship between vegetable consumption and measures of adiposity was assessed in cohort studies. Seven databases were searched from inception until October 2018. The quality of individual studies was assessed using the Joanna Briggs Institute Critical Appraisal of Cohort Studies tool. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was applied to determine the quality of the body of evidence. Ten studies were included. Six measured change in vegetable intake over time. Two showed that increasing vegetable consumption resulted in weight loss of 0.09–0.1 kg over four years (p < 0.001). Increased vegetable intake was also associated with a reduced risk of weight gain and overweight or obesity (Odds ratios (ORs) ranged from 0.18 to 0.88) in other studies. Four studies measured vegetable intake at the baseline only. One showed that intakes >4 servings/day reduced the risk of weight gain (OR 0.27 (95% confidence interval (CI) 0.08–0.99) and another found an inverse association with waist circumference in women (−0.36 cm per vegetable serving/day). This review provides moderate quality evidence for an inverse association between vegetable intake and weight-related outcomes in adults. When these findings are coupled with no apparent harm from vegetable consumption, the evidence-base can be used with acceptable confidence to guide practice and policy