What is Color Vision?
We live in a world surrounded by colors. They way in which we are able to observe these colors is called color vision. Vision is our ability to make INFERENCES. Color vision is the ability of an organism to distinguish objects based on the frequencies of light that they emit (their color).
Color is the frequency of light waves that our eyes can detect. Color is a measure of how quickly the light waves move (in other words a measure of their frequency). As humans, we are able to observe the light waves in the visible light spectrum. The visible light spectrum ranges from red at the lowest frequency end to violet at the highest frequency end. Objects look like they are certain colors because they emit a certain frequency of light more than the other frequencies of light. However, all colors are absorbed in each object. For example, a pencil will look yellow because even though it absorbs all light frequencies, it only emits or reflects the yellow light frequency, which we can observe through our eyes. (Shapely, 1993) The human eye is equipped with photoreceptor cells (light-sensitive cells) in the retina called cones. Cones allow organisms to perceive color. There are three types of cone cells in the human eye. They are named according to the wavelength of light that they can detect; S cones detect small wavelengths of light (i.e. blues), M cones detect medium wavelengths of light (i.e. greens), L cones detect large wavelengths of light (i.e. reds). Since humans have three different types of cones, we are referred to as organisms with trichromatic vision (“tri”= three, “chromatic”=color). Individuals that are color blind possess less than three different types of cones, or they may possess all three types of cones with one or more cones being defective in their sensitivity to light. (Shapely, 1993) Types of Color Blindness:
(Simunovic, 2010) There are also confirmed cases of individuals that are tetrachromatic. Tetrachromats possess four types of cones. These individuals have “super human” vision, and are able to perceive far more colors than the average trichromatic individual. (Greenwood, 2012) The cause of color blindness is thought to be mostly genetic. Inherited color blindness most likely stems from mutations on the X chromosome. Some forms of color blindness are progressive, the individual's impairments may get worse over their lifetime. However, most forms of color blindness are stationary, impairment does not progress any further. (Simunovic, 2010) What is it like to be colorblind? Here is a short clip from the documentary "No Such Thing As Color" by Laura Evans, obtained from KidsHealth.org, that can give us some insight on what it feels like to be colorblind. |
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Anthony Martinez Stephen Buckley Megan Giamei Amy Pagoulidis Nadia Rodriguez |