Debate about colors: does matter or brain determine?

If we were asked to imagine a banana, most of us would most likely imagine a yellow fruit with a distinctive elongated shape. The idea of a transparent, orange or purple banana is ridiculous. Color contributes significantly to how we perceive and imagine things, enriching our visual experiences and conveying meaning to the world around us, but what exactly is color?

Think about the "yellow" color in the bananas you depicted. Is this yellow color intrinsic to the banana itself, and is found within the peel as an essential and inherent feature of the fruit? Or is it a cognitive construct consisting of the complex processes of our brain... Is it the illusion of color? These questions are at the heart of the debate about what color really is, whether it's a physical or chemical aspect of things, or whether it's something the brain creates.

What is color and how do we see it?

Color is defined as an intrinsic physical property of matter. When light falls on the surface of an object, the object absorbs certain wavelengths and reflects other wavelengths. The wavelengths emitted then reach our eyes, enabling us to perceive color.

Humans can only record wavelengths between 400-700 nm, which we call the optical spectrum. This is a small part of the broad electromagnetic spectrum, which includes radio waves, microwaves, infrared, visible light, ultraviolet rays, X-rays, and gamma rays. The wavelength of 700 nm looks red, while one wavelength of 400 nm appears purple, but the wavelength, for example, 100 nm is invisible to us.

Physiologically, the retina, located at the back of the eye, receives light. They contain photoreceptor cells known as sticks, which respond to low or dim light, and cones, which react to brighter conditions. These cells interact with different wavelengths of light and send signals to the brain via the optic nerve. The signal is transmitted first to the thalamus region and then to the visual cortex, where color information is combined with other visual data, such as shape and movement, culminating in an overall image.

At first glance, this scientific explanation validates the assertion that color is a feature of matter, not the product of the brain's imagination.

But wait!

If color is an inherent property of matter, shouldn't body color be the same for everyone? However, didn't we all find ourselves in disagreements about the color of the object? As the famous saying goes: "My red is not your red." For a clear example, let me (re)introduce you to the infamous dress.

Same object, different color

In 2015, a social media post showing a dress worn to a wedding sparked fierce debate about its color. Two camps appeared. While some strongly saw the dress as blue and black, the actual color of the dress, others insisted it was gold and white.

This was a strange question for scientists as well, who wondered why the brains of different people deceive them into seeing the colors of the dress differently.

Scientists specializing in vision have suggested that the variation in color perception stems from differences in the interpretation of the lighting conditions surrounding the garment. Color perception is prone to changes in environmental lighting.

Normally, the brain corrects these changes, ensuring a constant perception of colors, a phenomenon known as color fastness.

However, the brain's ability to correct can falter. This is what creates optical illusions. Take the Rubik's cube in the image shown below; although both squares have identical shades of gray, watching them under different lighting conditions creates the illusion of dramatically different colors.

While the scenarios of the dress and the Rubik's cube share elements of optical illusion, there is a crucial difference between the two. Unlike the dress box, where individuals see colors differently, the optical illusion in the cube box is universal, it deceives us all in the same way.

The role of the brain and lighting

David Williams, Allen Professor of Medical Optometry and Director of the Center for Optical Science, speaking to Vox, offered some ideas to explain what might happen in the dress scenario. He noted that since the image of the dress lacked sufficient information about lighting conditions, some viewers may see it as brightly lit, while others may see it as less bright.

Recognizing brighter lighting may lead the brain to assume that the dress is made of dark fabrics, such as blue and black. Conversely, the perception of low light may indicate that more light is reflected, causing the dress to appear gold and white.

When asked about the difference in assumptions about light lighting between different people, Williams speculated that it may be due to differences in the way different people's brains work.

How animals see color

Different species have different numbers and distributions of photoreceptors, which are affected by their environments. For example, fish that live in shallow, sunny water have more cones than those that live in deep water.

These differences in the number, distribution, and sensitivity of photoreceptors can lead to diverse color perception. For example, dogs, which contain only two types of cone cells, have bicolor vision, unlike tricolor humans. This makes them less sensitive to red and green hues. Thus, the red body may appear brown or gray to the dog, rather than stand out clearly as it is for us. The wavelength of the "red" color still exists, but if the dog makes a Pantone color wheel, there will be no red color.

Some animals are able to detect wavelengths outside our visible spectrum. Bees can see ultraviolet light, along with blue and green. For bees, the flower is more than just a beautiful pink or vibrant yellow color.

Final Word

Colors play an important role in various aspects of everyday life, including art, culture and politics. We respond to color deeply and emotionally. Artists, marketing heads and designers know this very well. Color exploration is therefore an exploration that contributes significantly to our understanding of emotions, as well as cultural and societal symbols.