Tetrachromacy

Tetrachromacy is an ability which helps many beings, who are known as tetrachromats, to see a better variety of colors. That ability is found in animals, in insects and in fish, including some people who usually are women. Researchers believe that those four kinds of cone cells might vary from beings to beings, for example, they help some women to see the blue, the green, the red, and the true yellow color, while some of other beings (non-humans) might see four other different kinds of colors. In humans, tetrachromacy is not a kind of visual problem, since it does not affect the way they live. Online tests does not help people to know whether they are tetrachromats because many screens are based on RGB (red, blue, green) systems. That ability is still being studied, a lot of changes might occur.