Your eyes have components called rods and cones that help you see light and color. you're inRetina, the thin layer of tissue at the back of your eyeball near your optic nerve.
The rods and cones are crucial for vision. The rods are sensitive to light and are important for being able to see in the dark. The cones are responsible for your ability to see color.
Most humans, as well as other primates like gorillas, orangutans, and chimpanzees (and even some marsupials) only see color through three different types of cones. This color display system is known astrichrome("three colors").
However, there is evidence that there are people who have four different color perception channels. This is called tetrachromacy.
Tetrachromacy is thought to be rare among humans. Research has shown that it is more common in women than in men. AStudy 2010suggested that nearly 12 percent of women might have this fourth channel of color perception.
Males are not as likely to be tetrachromatic. Actually, it is more likelycolorblind, or unable to see as many colors as women. This is due to hereditary abnormalities in their cones.
Let's learn more about how tetrachromacy compares to typical trichromatic vision, what causes tetrachromacy, and how to find out if you have it.
The typical person has three types of cones on the retina that allow them to see different colors on the spectrum:
- Shortwave cone (S):sensitive to short-wavelength colors such as violet and blue
- Central axis cone (M):sensitive to medium wavelength colors such as yellow and green
- Long wave cone (L):sensitive to long-wave colors like red and orange
This is known as the trichrome theory. The photopigments in these three types of cones give you the ability to see the full color spectrum.
Photopigments are made up of a protein called opsin and a light-sensitive molecule. This molecule is known as 11-cis retinal. Different types of photopigments respond to specific color wavelengths that they are sensitive to, making it possible for you to perceive those colors.
Tetrachromats have a fourth type of cone with a photopigment that allows the perception of more colors that are not in the typically visible spectrum. Specter is better known as ROY G. BIV (Reducate,oOffer,Ygelb,GRAMSreen,BLue,yoindigo andvioleta).
The existence of this additional photopigment may allow a tetrachromat to see more detail or variety in the visible spectrum. This is called the tetrachromism theory.
While trichromats can see approximatelya million colors, tetrachromats can potentially see a staggering 100 million colorsjay neitz, PhD, a professor of ophthalmology at the University of Washington who has extensively researched color vision.
(Video) Tetrachromats Don't Have Superpowers
This is how your color perception normally works:
- The retina receives light from its pupil. This is the opening in the iris, the colored part of your eye.
- Light and color travel through theSpringfrom your eye and become part of a focused image projected on the retina.
- The cones convert light and color information into three separate signals: red, green, and blue.
- These three types of signals are sent to the brain and processed into a mental awareness of what you are seeing.
The typical human has three different types of cones that separate visual color information into red, green, and blue signals. These signals can be combined in the brain to form an overall visual message.
Tetrachromats have an additional type of cone that allows them to see a fourth dimension of color. It is the result of a genetic mutation.
And there's actually a good genetic reason tetrachromats are more likely to be female. The possibility of a tetrachromic mutation is only transmitted through the X chromosome.
Females get two X chromosomes, one from their mother (XX) and one from their father (XY). They are more likely to inherit the necessary genetic mutation from both X chromosomes.
Males only get one X chromosome. Their mutations usually result in abnormal trichromy, or color blindness. This means that your M or L cones are not seeing the correct colors.
You are the mother or daughter of someone with abnormal trichromiamost likelybe a tetrachrome. One of your X chromosomes can carry normal M and L genes. The other probably carries normal L genes, as well as mutated L genes that were passed down through a parent or child with abnormal trichromia.
One of your two X chromosomes is expressed in some cone cells while the other X chromosome is expressed in others. Due to the variety of different X genes transmitted by both the mother and the father, a retinal mosaic of four different cone types is produced.
Some species, including humans, do not need tetrachromacy for any evolutionary purpose. You have almost completely lost the ability. In other species, tetrachromacy has to do with survival.
Several species of birds like
This, in turn, has led to insects evolving to see these colors. This way they know exactly which plants to choose for pollination.
It can be hard to know if you are tetrachromatic if you have never been tested. You may take your ability to see additional colors for granted simply because you have no other visual system to compare yours to.
The first way to find out your status is to undergo a genetic test. A complete profile of your personal genome can find the mutations in your genes that may have led to your fourth cones. Genetic testing of your parents can also find the mutated genes that have been passed on to you.
But how do you know if you can actually tell the extra colors of that extra cone?
That's where research comes into play. There are several ways to tell if you are tetrachromatic.
The color matching test is the most conclusive test for tetrachromacy. As part of a research study, it goes like this:
- The researchers presented study participants with a set of two color mixes that look the same for trichromats but differ for tetrachromats.
- Participants rate from 1 to 10 how similar these mixes are.
- Participants are given the same sets of color mixes at different times, without being told that they are the same combinations, to see if their responses change or remain the same.
True tetrachromats evaluate these colors the same way each time, meaning they can actually distinguish between the colors represented in the two pairs.
Trichromats can grade the same color mixtures differently at different times, which means they just pick random numbers.
Warning about online tests
Please note that any online test that claims to be able to identify tetrachromacy should be approached with the utmost skepticism. CorrespondentResearchers at Newcastle University, the limitations of color representation on computer screens make online proofing impossible.
Tetrachromats are rare, but sometimes they make big waves in the media.
a participant of2010 Journal of Vision study, known only as cDa29, had perfect tetrachromatic vision. He made no mistakes in his color matching tests and his responses were incredibly fast.
She is the first person scientifically proven to have tetrachromia. Her story was subsequently picked up by numerous scientific media, such asDiscoverMagazine.
2014 artist and tetrachromatAntike Concettashared his art and experiences with theBBC. For example, in his own words, tetrachromacy allows him to see "muffled grays... [like] oranges, yellows, greens, blues, and pinks."
While your own chances of being a tetrachromat may be slim, these stories show just how fascinating this oddity is to those of us with normal tricone vision.
Is tetrachromacy a real thing? ›
Tetrachromacy is thought to be rare among human beings. Research has shown that it's more common in women than in men. A 2010 study suggested that nearly 12 percent of women may have this fourth color perception channel. Men aren't as likely to be tetrachromats.What percent of the world is tetrachromat? ›
Based on world population estimate of 7.30 billion, that would mean only 1.36% of the world's population has true four-color vision and can be called tetrachromats, nowhere near the 25% that Derval claims.How do you tell if you are tetrachromatic? ›
If you see between 20 and 32 colors, you have three types of color receptors. About 50 percent of the population are trichromats. If you see between 33 and 39 colors, you are a tetrachromat and have four types of cones.What is the mutation that causes tetrachromacy? ›
Antico has an exotic condition known as tetrachromacy, which is caused by a mutation on the x chromosome. That mutation tacks on an extra type of cone to the usual three varieties humans are born with in their retinas, leading those with the condition to be able to experience a flood of rainbow hues.Why are most tetrachromats usually female? ›
Since women have two X chromosomes, they could potentially carry two different versions of the gene, each encoding for a cone that is sensitive to slightly different parts of the spectrum. In addition to the other two, unaffected cones, they would therefore have four in total – making them a “tetrachromat”.What do tetrachromacy people see? ›
Tetrachromats can see colors that most people cannot — up to 100 million, estimates suggest, which is 100 times that of the average human. Most people have three cells, or receptors, in their retinas, but tetrachomats have a fourth receptor, which may be what allows for their heightened color perception.