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5.8: The Physiology of Color Vision- Constructing Visual Reality

  • Page ID
    324853
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    To understand how skin color is perceived, we must examine the human visual system. Color vision begins when light enters the eye and is focused onto the retina, which contains photoreceptor cells: rods for low-light vision and cones for color. Humans are typically trichromatic, possessing three types of cone cells sensitive to short (S), medium (M), and long (L) wavelengths of light, light that loosely corresponds to blue, green, and red.

    The process of color perception is not a simple translation of wavelength to color. In this trichromatic process, color is derived from comparing the relative stimulation levels of the S, M, and L cones. These cone photoreceptors react differently to different types of wavelengths: S cones will react to the darkest colors (blue-based), M cones will react to somewhat darker colors (green-based), and L cones will react to the lightest colors (red-based). Color then, is the perception of light when light from any given object enters the view of our eyes. Upon entrance, the light triggers a reaction from our cones that is then transmitted via the optic nerve to the visual cortex in the brain, forming the sensation of color. This neurological process is highly interpretive and subject to context, lighting, and cognitive biases. The brain does not simply record wavelength data; it constructs a stable perceptual reality from it. This constructed nature of visual perception is the biological precursor to the social construction of racial categories based on skin tone.


    This page titled 5.8: The Physiology of Color Vision- Constructing Visual Reality is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Salvador Jiménez Murguía.