Tetrachromatism

June 8, 2006 in links, science

From Wikipedia:

The term tetrachromat describes a human or an animal whose vision is based on four colors (from Greek: tettares = "four", chroma = "color"). Humans are ordinarily trichromats, meaning three-color vison is normal for our species. For other species of animals, however, tetrachromacy is normal; e.g. some species of spiders, most marsupials, birds, and reptiles, and many species of fish.

It could be possible for a human to have four distinct types of color receptors, rather than the usual three. In theory, such a person would have an extra and slightly different copy of either the medium- or long-wave cones. If these four types are sufficiently distinct in spectral sensitivity and neural ability develops to distinctly process the input from all four types of cones, a person may be a tetrachromat. However, the cone cells of animal tetrachromats have a different, more evenly-spaced, spectral sensitivity distribution than is believed possible for human tetrachromats.

Evidence suggests that such humans do exist, and that for genetic reasons, all are female. Their brains do appear to adapt to use the additional color information.

I want to be a tetrachromat!  I'm bored with just three primary colors…