Here is a question that has puzzled philosophers for centuries: is the red you see the same red I see? You and I can both point at a strawberry and agree it is “red.” But the inner experience — the actual sensation of redness in your consciousness — might be entirely different from mine. There is no way to compare our subjective experiences directly. In philosophy, this raw, subjective quality of experience is called qualia.
Colour is not a property of the physical world in the way that wavelength is. Wavelength is objective — it can be measured with instruments. But “red” is a label your brain assigns to a particular pattern of cone stimulation. The colour itself exists only inside your head. This means that colour, at its deepest level, is a subjective psychological phenomenon, not a physical one.
The philosopher Frank Jackson proposed a famous thought experiment in 1982 known as Mary’s Room. Imagine a brilliant scientist named Mary who has spent her entire life in a black-and-white room. She has never seen colour. But she has studied everything there is to know about the physics of light, the neuroscience of colour vision, the wavelengths, the brain processes — every objective fact. Now imagine the door opens and Mary steps outside and sees a red rose for the first time. Does she learn something new?
If yes, then there is something about the experience of seeing red that cannot be captured by physical facts alone. This suggests that qualia — subjective experience — is something over and above the physics. The experiment has been debated for decades and remains one of the most compelling arguments in the philosophy of consciousness.
For a deeper dive into these ideas, these videos explore the topic wonderfully:
One of the most fascinating findings in colour research is that the language you speak can influence how you perceive colour — not just how you describe it.
The ancient Greeks famously had no dedicated word for “blue.” Homer described the sea as “wine-dark” (οἶνοψ, oinops) and the sky as bronze or iron. The word kyanos existed but covered a vague range from dark blue to black. This pattern is not unique to Greek — many ancient languages, including Chinese, Hebrew, and Japanese, developed words for blue relatively late. Some scholars believe that without a distinct word for blue, people were less attentive to it as a separate category, though they could certainly still see the wavelength.
Russian offers a striking modern example. Russian has two mandatory, distinct words for blue: голубой (goluboy) for light blue and синий (siniy) for dark blue. These are not adjective + noun constructions like “light blue” in English — they are basic colour terms, as distinct as “green” and “blue” are to an English speaker. A study by Lera Boroditsky and colleagues (2007) demonstrated that Russian speakers are measurably faster at distinguishing light blue from dark blue compared to English speakers. The linguistic boundary created a perceptual advantage — having two names literally made their brains process the distinction more quickly.
This effect is not limited to Russian. Similar patterns have been found across very different languages and cultures:
Speakers distinguish colours more accurately when they fall across a linguistic category boundary in their language than when both colours fall within the same category — even when the physical difference is identical.
The Himba language has a richer set of green categories than English. Himba speakers show enhanced discrimination between greens that cross their category boundaries, but reduced sensitivity to the blue–green contrast that English speakers find obvious.
Like Russian, Greek has distinct basic terms for light blue (ghalazio) and dark blue (ble). Greek speakers show faster discrimination across that boundary compared to English speakers, who lump both under "blue."
Interestingly, studies on verbal interference — where participants repeat words aloud during colour tasks — show that this linguistic advantage disappears when the language system is occupied. This suggests that language influences colour perception at a higher cognitive level rather than altering early visual processing itself. You still see the same photons — but the categories your language gives you shape how quickly and easily your brain sorts them.
There is a widespread belief that women are better at distinguishing colours than men. Research does show a statistically significant, though modest, advantage: in laboratory colour-matching and colour-naming tasks, women tend to perform slightly better on average.
Several factors contribute to this. On the biological side, the genes for two of the three cone types (M and L) are on the X chromosome, and having two X chromosomes gives women more genetic variability in cone sensitivity — including the possibility of tetrachromacy. On the cultural side, women in many societies are exposed to more colour vocabulary and colour-related decision-making from an early age — clothing, cosmetics, interior design — which provides more practice discriminating subtle differences.
The most likely explanation is that both biology and training contribute. Colour discrimination, like most perceptual skills, improves with practice. Professional painters, textile workers, and designers of any gender develop exceptionally fine colour discrimination — not because of genetics, but because they spend thousands of hours attending to subtle colour differences. The gender gap in the general population likely reflects a combination of slight biological differences amplified by unequal cultural exposure to colour-rich tasks.