What is the color of Henri IV’s white horse? If the answer to this question is unanimous, seeing the dress of the animal with your own eyes would however divide the assembly. It turns out that the hues vary considerably from one individual to another, and this for many reasons. From the anatomy of our eyes, to the way our brain processes information, to the language we speak, our date of birth or even our geographical environment, our perception of the world can change.
As Scientific American reports, each cultural group has its own distinctions between colors and learns to classify them differently. In some languages like Old Welsh, no differentiation is made between blue and green, both belong to a category of crane. In contrast, in Russian siniy denotes dark blue while goluboy is reserved for a lighter blue. Jenny Bosten, a neuroscientist at the University of Sussex in England, wonders: “Do we really see colors differently or is it just a linguistic question?”
We do seem to have a distinct perception of hues, even between similars. Let the person who didn’t butt heads with those around him in 2015 over the explosive subject of the famous blue and black (or white and gold!) dress cast the first stone. “Individuals who see it as blue and black actually perceive it as illuminated by a yellowish light, while the white and gold team perceives a bluish light. It is the brain that makes a judgment on the type of lighting of the dress”reveals the neuroscientist.
This perception depends among other things on the colors that we are used to encountering. “In York, a rather gray and dark city in winter, and green in summer, a study was carried out and it was found that the wavelength that residents perceive as pure yellow changes with the season. The date of birth also has an impact on our vision according to the color of the light to which we were exposed during our visual development.exposes Jenny Bosten.
The anatomy of the eye
This difference can also be related to the physiological aspect. With age, especially after 40, the lens turns yellow and the amount of blue light that reaches the retina is reduced. In addition, a correlation would also have been established with the color of the iris: people with blue eyes seem to perform better in the tests of discernment of shades. Finally, “Diet can play a role. The more lutein and zeaxanthin, found in leafy greens, you consume, the more macular pigment –which absorbs short blue wavelengths– will be thick, explains Jenny Boston.
Most people have three types of cones – light photoreceptors – in the retina. Nevertheless, genetic variation can alter color vision if one of the cones is different, as in red-green color blindness. This is an anomaly in the L (sensitive to red light) and M (sensitive to green light) photoreceptors.
In case of dichromatism, only two of the three cones will be present or functional, and the affected person will then have one-dimensional color vision, depriving him of an entire axis of color perception. On the contrary, more than 50% of women have four types of photoreceptors, but “Very few are aware of it. Two of the cones are very slightly different, which is not enough for them to have tetrachromatic vision.says the scientist.
So what does our neighbor actually perceive? Do we have the same definition of blue or red as he does? We will probably never know.