Tetrachromacy

A woman with tetrachromacy

Newcastle University neuroscientist Dr. Gabriele Jordan, recently announced that she has identified a woman who is a "tetrachromat," that is, a woman with the ability to see much greater color depth than the ordinary person.

According to Daily Mail, an ordinary person can perceive a million different hues of colors. The power to distinguish the hues comes from cells in our eyes called cones. In the average person, there are three types of cones each of which is triggered by different wavelengths of light.

Discover Magazine explains that most people have three types of cones, and are said to be "trichromats." Color blind individuals have only two types of cones and they are said to be "dichromats." Almost all animals, including dogs and New World Monkeys are dichromats.

However, scientists have long believed that there are people with four cones who can see a wider range of colors than most of us can detect. These persons are called "tetrachromats," and can see a hundred million colors. From the perspective of such people, the hues familiar to trichromats fracture further into more subtle shades of differences that have not been given names since most of us are trichromats who cannot see these shades and name them.

Jordan and her colleagues have for 20 years searched for people endowed with super color vision, or tetrachromatic vision. According to Discover Magazine, Jordan found a tetrachromat two year ago. Although the person is the first tetrachromat known to science, the researchers believe there are others.

Discover Magazine reports that Jordan and her team found many people with four types of cones but only one person passed the tests for tetrachromatic vision. The woman, identified as subject cDa29, is a doctor living in northern England. Jordan and her colleagues believe there may be other persons with tetrachromatic vision.

Jordan told Discover Magazine that she was very excited by her discovery. It took 20 years to search for her to identify the first true tetrachromat. But a question immediately arose: Why is it that there are people with four cones who apparently do not exhibit tetrachromatic vision?

See more in: http://digitaljournal.com/article/326976