How Our Brains Create the Colors We See and Why Reality Isn’t Quite What It Looks Like
When you look at a red apple, a green leaf, or a golden sunset, it feels obvious: these objects are red, green, or gold. But here’s the mind-bending truth — the colors you see don’t actually exist in the world. Color is not a property of objects; it’s a creation of your brain.
How Color Works
Objects themselves do not “have” color. What we perceive as color is the result of light interacting with matter and how our eyes and brain interpret that light. Sunlight and most artificial lights are made up of a spectrum of wavelengths. When light hits an object, some wavelengths are absorbed, and others are reflected. The wavelengths that bounce back to your eyes are what your brain interprets as color.
For example, a banana looks yellow because its surface reflects light in the wavelength range roughly 570–590 nanometers, which our brains perceive as yellow. Change the light source, and the banana might appear completely different. Under a red lamp, that same banana may appear orange or brown.
The Role of Human Eyes: Trichromacy
Humans are trichromats, meaning we have three types of photoreceptor cells (cones) in our retinas, sensitive to short (blue), medium (green), and long (red) wavelengths. The brain combines input from these three cones to generate the perception of millions of colors. This is why humans see a relatively rich but limited range of colors.
How Other Animals See Color: Tetrachromacy and Beyond
Some animals see the world very differently. Many birds, fish, and reptiles are tetrachromats, with four types of cones. This allows them to perceive ultraviolet light in addition to the human-visible spectrum. A flower that appears dull to us might glow with intricate patterns in ultraviolet, visible only to birds or insects. Some butterflies and mantis shrimp have even more complex visual systems, detecting wavelengths humans can’t even imagine.
This means that the human experience of color is only one interpretation of reality, and the world might appear entirely different to other creatures. In a sense, each species experiences its own “version” of reality.
The Science of Paint and Pigments
When we make colored paints, dyes, or inks, we are essentially controlling which wavelengths of light are reflected. Pigments absorb certain wavelengths and reflect others, and our brains interpret the reflected light as specific colors. Mix blue and yellow paint, and the resulting mixture reflects wavelengths that appear green to our eyes. Even in art and design, color is fundamentally a brain-based experience, not an intrinsic property of materials.
Why This Matters
Understanding that color is a mental construct changes how we view reality. It reminds us that our perceptions are models, not mirrors of the world. Everything we see — from a rainbow to a smartphone screen — is filtered through biology and cognition. Even more, it opens fascinating philosophical questions: if color only exists in perception, then in a universe without observers, would there truly be color at all?
References
- Palmer, S. E. (1999). Vision Science: Photons to Phenomenology. MIT Press.
- Wandell, B. A. (1995). Foundations of Vision. Sinauer Associates.
- Fairchild, M. D. (2013). Color Appearance Models. John Wiley & Sons.
- Conway, B. R., & Tsao, D. Y. (2009). “Color Vision: Understanding the Perception of Color.” Annual Review of Neuroscience, 32, 313–336.
- Cronin, T. W., & Bok, M. J. (2016). Animal Color Vision: Behavioral and Physiological Considerations. Springer.
- Osorio, D., & Vorobyev, M. (2008). “A Review of the Evolution of Color Vision in Vertebrates.” Vision Research, 48(20), 2042–2051.