Lucky Tetrachromats See World With Up to 100 Million Colors


A tetrachromat is a person with four functioning types of cone cells, enabling her to see up to 100 times more colors than a trichromat. Hans Solcer/Getty
A tetrachromat is a person with four functioning types of cone cells, enabling her to see up to 100 times more colors than a trichromat. Hans Solcer/Getty

We all see the world in a unique way, just like our mothers always told us. But have you ever lain in bed, struggling for sleep, and gone down the rabbit hole of wondering if your perceptions were actually entirely distinctive and rare? How would you ever know if what you smell, taste, feel, hear or see is entirely exceptional?

Scientists have been frustrated by that question for years when it comes to a very particular case of perception. They've long known that most humans are trichromats, meaning we have three types of cone cells in our eyes that perceive color, and that most color-blind folks are dichromats, and have at least one type of nonfunctioning cone.

But in 1948, a scientist named HL de Vries tested the daughters of color-blind men and discovered that while they weren't color-blind, they did need small adjustments to make a correct hue match in tests. He wondered if perhaps they actually had four cones in their eyes (including the mutant cone passed from their fathers) and were seeing more colors as opposed to fewer, thus needing to more carefully calibrate to a specific hue.

After a study where mothers of color-blind sons were tested and no "extra" color perception was found, the researchers tried a new test in 2007. Three colors were shown, including one that looked the same to those with three cones but would be another shade to a person with "better" color perception. They tested 25 women, and one woman answered every single one correctly. A woman with four functioning cones — a tetrachromat — seemed to be found. (With scientists finding more examples as time went on.)

Now remember that it doesn't seem to be the case that every single one of the 12 percent of women with four cones has super-vision, and it's quite difficult to determine if one has the ability to see different hues.

Even if you did, keep in mind your perception of the world would be the same colors you always saw — even if there were millions more than most people see.