How the Human Eyes and Brain Work Together to See a Colorful World

Senior couple sitting on wooden pier looking at colorful sunset near the sea with a flying flamingo reflected on the calm water

The world is filled with an undeniable beauty. Almost everyone has had moments in life where they’re stopped short by the sheer breathtaking wonder around them. For some this might involve a majestic golden sunset. Others might have fond memories of the whites and blues of a distant snow capped mountain. And of course the beautiful contrast of the stars and planets against the blanket of night is always amazing.

All of these events may seem quite distinct from each other. But they have two important things in common. The beauty comes about through color. However, there’s one other component to keep in mind. Every moment of breathtaking beauty also comes about through the interaction of the world, our eyes and our brain. We often forget that the concept of beauty and color is built upon a foundation of human biology and psychology. But how exactly does the human eye and brain process and appreciate color?

Looking for the Source of Color

A red rose in a dark room where the lights have been dimmed

Think back to the most beautiful landscapes you’ve ever seen. Consider how all of the colors worked together to make a truly breathtaking scene. Now consider where that beauty actually comes from. We naturally start to consider the individual flowers, trees and open skies as a source of beauty. But in fact it’s better to begin with our own eyes.

Objects don’t really possess color in the way we usually assume. Consider a single, beautiful rose. The vibrant red of a rose’s petals has been celebrated in countless songs and poems. What’s more, the green stem of a rose has a vibrant beauty all its own. But now consider what happens when someone begins to dim the lights. As the light in a room diminishes the color of the rose will change. This highlights the fact that our perception of color is actually a view into the ways in which objects reflect and absorb light. Change the lighting in an area and we’ll perceive the color of objects in that setting differently as well.

How the Cornea, Pupil and Lens Work Together to See Color

Illustration of how human eyes see with definition of the eyes anatomy

Now imagine the rose in a fully lit room once again. Some of the light in the room will be absorbed by the rose petals. But some of that light will also be reflected. When we look at the rose we’re essentially seeing that reflected light. This process begins within our eye’s cornea.

The cornea can almost be thought of as a satellite dish of sorts. It takes in the reflected light and sends it to our eye’s pupil. The pupil is the dark mass in the center of our eye. The expansion or dilation of our pupil controls the amount of light we take in. This light will then hit the lens of our eye.

The lens in our eye is quite similar to that in a pair of glasses. Both types of lens focus light. The lens in our eye focuses light in order to send it to the retina. Our retinas are about as thin as a razor blade. However, this deceptively small structure has some advanced functionality.

An Interplay Between Retina and Brain

Illustration of the visualization process of human color vision from seeing with the eyes to processing in the brain

The retina can be thought of as an extension of our brain. In fact, the retina is actually formed from brain tissue. This is part of the reason why we’re able to take in visual information so quickly. Our eyes have a short, and direct, link to the brain. This is an important point because we need to process a lot of information to understand all the information we receive from the world.

Our retinas consist of a full 116 million specialized cells which work with light and color. This consists of 6 million cone cells used for processing visual information in brighter environments. We also have 110 million rod cells which work in lower light environments. Each of the cone cells contain visual pigments which react to specific photonic wavelengths. Humans have three types of photo pigment. This makes our eyes able to differentiate between red, green and blue.

When we look at the rose from before, the reflected light from the petals activates the red photo pigment in our cone cells. Likewise, the rose’s stem activates the green photo pigment in the eye’s cone cells. But now imagine that the rose is in a yellow vase. We’d see the color yellow due to dual activation of red and green photo pigments at the same time.

But what happens if we dim the room’s lighting? Eventually we’ll reach a point where the eye’s rod cells need to handle things. Our rod cells are capable of more precise detail. This is in part why a black and white image tends to look sharper to us. However, rod cells lack the photo pigments found in cones. This is why everything starts to look like a black and white picture as less and less light is present within an environment. However, at the same time we do tend to see some color even when the lights have dimmed past the point where our cone cells are very active. The explanation as to why that’s possible comes from the role of the brain and consciousness in our visual processing.

From the Human Eye to the Brain

Human eye with an image of a brain in the middle of the pupil and iris

There was a time when people thought of consciousness as a singular entity. Today we know that our core identity is made up of countless different neurological processes. And in fact, we often aren’t even aware of much of what our brain is doing. This is especially true when it comes to vision.

We often assume that all the data taken in by the eyes will go directly into our conscious mind. It certainly feels that way. But in reality the data from our eyes needs to be heavily processed before we can really make use of it. And this helps to explain why we sometimes see hints of color when we shouldn’t be physically able to do so. For example, in our earlier example of a rose we’re often still able to see hints of red even in near darkness. Why are we sometimes able to see hints of color in otherwise dimly lit scenes?

The answer is that we never directly observe color in the first place. Our eyes do take in reflected light. But we aren’t conscious of the raw data. What we’re actually seeing is a heavily processed interpretation of data taken in by our eyes. Remember that we imagined the rose placed within a yellow vase?

When we look at the vase we see the color yellow. But our eyes are actually registering stimulation in our cone’s green and red photo pigments. It’s our brain which creates the color yellow by integrating the dual stimulation of different photo pigments. Basically, we don’t directly see anything. Everything we have ever seen or will ever see is the result of unconsciously processed data in our brain.

It’s All in the Mind’s Eye

Illustration of visual perception in the human mind from the eyes and brain

We can better understand the mind’s role in vision by considering a few examples. One of the easiest to consider is how we see a single image when looking out onto a scene. We can once again return to the example of a red rose in a yellow vase. When we look at it we see that singular image. Of course we also take in the entirety of the environment around the flower. But take a moment to consider the fact that we only see the single rose and the single vase. But we have two eyes taking in that data at the same time.

Each of our eyes is taking in slightly different information about the scene in front of us. But we’re not conscious of the fact that we’re continually taking in two separate visual data feeds from the world. When our brain takes in information from our eyes it also integrates information from the two sources of visual data. This is why we don’t see two separate versions of a scene in front of us despite the fact that we have two eyes. The information from each eye is unconsciously processed and essentially stitched together. And when our eyes miss something our mind can even create illusions to essentially fill in the blanks.

A Path Through the Blind Spots

Structure of the human eye and organization of the optic part of the retina

The fact that we’re continually adding information to the data taken in by our eyes might seem like a strange idea at first. But consider the fact that each of our eyes has a blind spot. The point where nerve fibers pass from the retina to the back of our eyeball doesn’t contain any photoreceptors.

This means that both of our eyes pass a signal to the brain which essentially has a hole in it. But we aren’t conscious of any gaping holes in our vision. This is because our mind essentially extrapolates the most likely data to fill in those blank spaces. For example, our left eye might miss a pattern on the vase due to its blind spot. But our right eye might have seen the pattern. If that’s the case then our subconscious can easily extrapolate what the left eye missed from data taken in by the right eye.

Color Consistency and the Unconscious Mind

Woman in red colored long dress standing on mountains enjoying view of rising sun and white fog below

A recent debate over dress color also offers a good example of how our mind fills in details missed by our eye. The dress illusion stems from a situation where the same image will appear differently to various people. A picture of the same dress will appear to have different colors to different people.

The explanation for this phenomenon is also why we’re able to see some colors in a dimly lit room. In the dress example our minds are attempting to compensate for lighting. We’re not consciously aware of the fact that our mind is doing so. But when we see the lighting in the picture our unconscious mind will often start to essentially color correct for it. The same thing happens when we look at objects in a darkened environment.

We know that a rose has red petals. Therefore when there’s not enough light to register colors our unconscious mind will often fill in that detail. We do see hints of red on the flower. However, this is only due to the fact that our unconscious mind is essentially colorizing the black and white image seen by our eyes. If we closed our eyes and someone replaced the red rose for one which had been dyed a different color, we’d still see it as red. This is because in the low light environment the red color had been entirely supplied by our own unconscious processes. We only see red in that situation because we expect to see red.

A Process of Co-Creation

Human hand holding glass ball in front of sunset symbolizing vision in the conscious and unconscious mind

As we examine human vision we begin to see just how complex it really is. The fact that vision seems so straightforward from our own subjective experience highlights just how complex that process really is. It takes a lot of mental processing to take so much complex data and turn it into something we don’t need to consciously consider. We seldom need to really think about seeing the world. Instead, it all seems to happen quite naturally.

In reality our vision is in many ways a continual co-creation with the world. When we look at the beauty around us it’s not just an inherent property of any given thing. We continually add to that beauty by essentially painting the world within our own minds. We create detail our eyes have missed. We mentally compensate for oddities of lighting without even being aware of it.

In reality we should take a lot more credit for beautiful sunsets or the gorgeous colors of a rose. Much of the beauty we perceive comes from the world outside of us. But much of that beauty is also due to our subconscious artistry which is continually painting the world in a myriad of different colors. When we see beauty in the world, we’re also creating it at the same time.