Learning is all about asking questions, and no one asks questions better than children. Boise State is home to more than 1,400 faculty members and researchers who are eager to answer these amazing questions.
Today, Nilufar Ali, an assistant research professor and the director of the Brain Aging and Space Neurobiology Lab, answers a child’s question about color perception: “Since we know some people are colorblind, how do we know that everyone else sees color the same way?”
At Boise State, her research focuses on aging-related conditions experienced in Parkinson’s disease, spaceflight and breast cancer, with an emphasis on mitochondrial dysfunction, proteostasis loss and cellular stress responses.
Question: ‘Since we know some people are colorblind, how do we know that everyone else sees color the same way?’
Ali says that the short answer is: we do not know — and we might never know!
Color perception is a deeply complex process, involving not just our eyes, but our brain, genetics and even how we’ve learned to associate certain colors with certain objects.
Let’s simplify this.
Imagine a baby learning about the world. Someone points to an apple and says “red.” The baby eventually learns to associate that object with the word “red.” But here’s the twist — we have no way of knowing if the baby’s experience of “red” is the same as someone else’s. Their subjective experience — what red feels like — could be different.
What the baby sees and feels as “red” could be more like “orange” or even something entirely different to another child. But because both children learn to call it “red,” we assume they’re seeing the same thing — when in fact, we don’t know.
Why might color perception differ?
Color vision is a chain of complex biological and neurological events:
Light reflects off an object — say, a red apple — and enters your eye.
Inside the eye, this light hits the retina, where two main types of cells receive the signal:
- Rod cells — which detect light intensity and shades of gray, mostly useful in low-light situations.
- Cone cells — which detect color. There are three types
- S-cones (short wavelength): respond to blue light.
- M-cones (medium wavelength): respond to green light and
- L-cones (long wavelength): respond to red light.
Here’s the first “magic” moment: These photoreceptor cells contain proteins called opsins, and the structure of these opsins is determined by your genes. That means your sensitivity to colors — even slight hue differences — can vary depending on your genetics. In some people, this leads to color blindness, but even among people with “normal” vision, small genetic differences could subtly alter how color is experienced.
Then comes the second “magic” moment: The signals from these cells are turned into electrical impulses and sent through the optic nerve to the visual cortex in your brain. This is where the brain interprets the raw data and constructs your experience of the world — including color.
Each hemisphere of your brain processes signals from the opposite eye, and your brain combines this input to create a full-color, 3D image of your environment. But since every brain is wired slightly differently, and shaped by different experiences, it’s very likely that subtle variations exist in how we process and perceive color — even among people with similar vision.
So what’s the conclusion?
Unless we can directly access someone else’s mind, we will never truly know whether their perception of “red” is the same as ours. We know that most people share similar biological systems, and we behave as if we see colors the same way — but we cannot verify whether the subjective experience is identical.
Fun fact: Humans are still discovering new colors — in a recent scientific breakthrough at UC Berkeley, researchers used targeted retinal stimulation to reveal a new color called “olo,” never before seen or perceived by the human eye.
Ask your burning question!
It’s your turn! Use the linked form to submit a question and get an answer from one or more of Boise State’s experts.
Want to learn more? Ali recommends the following resources:
- Our Sense of Sight: Part 1
- Physiology, Color Perception
- Molecular genetics of color vision and color vision defects
- Neural mechanisms for color perception in the primary visual cortex
- The Science of How We See Color—And Why We Need Spectrophotometers
- Do we all see colour the same?
- Objectivity and Subjectivity Revisited: Color as a Psychobiological Property
- Visual cortex activity predicts subjective experience after reading books with colored letters
- Scientists claim to have discovered ‘new colour’ no one has seen before
- Novel color via stimulation of individual photoreceptors at population scale