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It is well established that skin lightness-darkness is associated with social outcomes, but little is known regarding the social salience of skin undertones (redness and yellowness). Our study addresses two related research questions on this topic: first, we ask whether red and yellow undertones are consistently perceived by observers; second, we ask whether red and yellow undertones are associated with expectations of discrimination across a range of social settings. We address these questions using novel survey data in which skin lightness-darkness and undertones are captured using CIELAB measurements and a two-dimensional categorical skin color scale. Although we find skin lightness-darkness to be the strongest and most consistent predictor of discrimination expectations, respondents also perceived skin undertones consistently, and skin yellowness was associated with a higher predicted likelihood of discrimination net of lightness-darkness in certain social settings. Our findings suggest that colorism can extend beyond a light-dark binary and emphasize the value of capturing undertones, particularly yellowness, in social surveys assessing skin color.
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Characterization of human lightness discrimination thresholds for independent spectral variations
The lightness of an object is an intrinsic property that depends on its surface reflectance spectrum. The visual system estimates an object's lightness from the light reflected off its surface. However, the reflected light also depends on object extrinsic properties of the scene, such as the light source. For stable perception, the visual system needs to discount the variations due to the object extrinsic properties. We characterize this perceptual stability for variation in two spectral properties of the scene: the reflectance spectra of background objects and the intensity of light sources. We measure human observers’ thresholds of discriminating computer-generated images of 3D scenes based on the lightness of a spherical target object in the scene. We measured change in discrimination thresholds as we varied the reflectance spectra of the objects and the intensity of the light sources in the scene, both individually and simultaneously. For small amounts of extrinsic variations, the discrimination thresholds remained nearly constant indicating that the thresholds were dominated by observers’ intrinsic representation of lightness. As extrinsic variation increased, it started affecting observers’ lightness judgment and the thresholds increased. We estimated that the effects of extrinsic variations were comparable to observers’ intrinsic variation in the representation of object lightness. Moreover, for simultaneous variation of these spectral properties, the increase in threshold squared compared to the no-variation condition was a linear sum of the corresponding increase in threshold squared for the individual properties, indicating that the variations from these independent sources combine linearly.
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- Award ID(s):
- 2054900
- PAR ID:
- 10544416
- Publisher / Repository:
- SAGE Publications
- Date Published:
- Journal Name:
- i-Perception
- Volume:
- 15
- Issue:
- 5
- ISSN:
- 2041-6695
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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