The Paradox of Tetrachromacy



How much different would life be were we to add millions of more colors to our visual palette? A tetrochromat may be able to answer that question. A tetrochromat is an individual with an additional photoreceptor in their retina, allowing that person to perceive a more gradated spectrum of colors compared with the conventional trichromat. Thanks to the female’s dual X chromosome carried on each cell, this phenomenon is believed to occur only in women and not in men.

Four-coned women are not typically aware of their superior color acuity. This makes sense given that everything we see is created, produced and marketed by three-coned individuals. Indeed, human handiwork operates predominantly in a trichromatic space. Not only is it difficult to self-identify as tetrachromatic, it is just as challenging to craft experiments to ferret out these supervisual prodigies. The very nature of the phenomenon that makes it tricky to test for, a bit like someone trapped in a two-dimensional world checking for extra dimensions.

One explanation of the anomaly is that the neural connections required to bear witness to a more subtle kaleidoscope of shades may lie dormant, waiting to be activated. Perhaps it is only after focused training that women can make use of their additional sensory feedback. This hypothesis would be consistent with several studies showing that individuals who work in highly color-sensitive environments, such as textile and manufacturing, have greater color discrimination. Activation by immersion may be the best way to identify tetrachromacy.

A new piece in Discover Magazine chronicles one British scientist’s attempt to track down some of these women and untap their full visual potential.

From the article:

“[These women] might experience a range of colors invisible to the rest. It’s possible these so-called tetrachromats see a hundred million colors, with each familiar hue fracturing into a hundred more subtle shades for which there are no names, no paint swatches. And because perceiving color is a personal experience, they would have no way of knowing they see far beyond what we consider the limits of human vision.”

“We now know tetrachromacy exists,” Jordan says. “But we don’t know what allows someone to become functionally tetrachromatic, when most four-coned women aren’t.” Jay Neitz, a vision researcher at the University of Washington, thinks that potential tetrachromats may need practice to awaken their abilities. “Most of the things that we see as colored are manufactured by people who are trying to make colors that work for trichromats,” he says. “It could be that our whole world is tuned to the world of the trichromat.” He also suspects the natural world may not have enough variation in color for the brain to learn to use a fourth cone. Tetrachromats might never need to draw on their full capacity. They may be trapped in a world tailored to creatures with lesser powers. Perhaps if these women regularly visited a lab where they had to learn—really learn—to tell extremely subtle shades apart, they would awaken in themselves the latent abilities of their fourth cone. Then they could begin to see things they had never tried to see before, a kaleidoscope of colors beyond our imagining.”


External linkThe Humans With Super Human Vision

Further reading:

Some women may perceive millions more colors than the rest of us. Are you one of them?

Feature image via