You Can 'See' With Parts of Your Body Other Than Your Eyes

Believe it or not, but your skin has the ability to see light. Flóra Soós/Flickr

A large percentage of our perceptions have been shown to be unconscious, hidden cognitive processes that we don't necessarily need to be aware of but which are essential to how our bodies navigate through the world. Our bodies feel things that we aren't aware of, choose for us which sounds we hear out of the cacophony in the world around us, and even see things beyond where our attention is focused.

This is odd because we like to think of our perceptions as direct links between our consciousness and the outside world, but consciousness isn't actually needed for perception at all. In fact, scientists have recently discovered that much of what our bodies "see" doesn't even require the use of our eyes, reports Inverse.

We now have extensive evidence that our bodies are covered in photoreceptors — specialized light-detecting molecules — that are outside of the eyes. They're on our skin mostly, but also within our central nervous system and even lining some of our internal organs. In other words, cells throughout our bodies essentially have eyes of their own, and they're not telling our conscious minds about what they're seeing, not directly anyway.

What are these cells seeing?

Scientists are only beginning to figure it out. First, understand that all photoreceptors identified so far in animals detect light using a single family of proteins, called the opsins, which utilize a light sensitive molecule derived from vitamin A that changes its structure when exposed to light. Scientists can look for these opsins throughout the body and follow the neural pathways that they stimulate.

Some of the first photoreceptors identified by scientists that do not contribute to conscious vision in animals were found in mice. A 2003 study demonstrated that certain photoreceptor cells in a mouse retina help to monitor light levels so that circadian rhythms can be regulated accordingly, all without contributing to any sort of conscious visual awareness. These were still located in the eye, of course, but the find prompted scientists to wonder if non-visual photoreceptors could be found outside the eye too.

Sure enough, they've been found all over the place. For instance, there are light-sensitive cells on our skin that scientists now suspect play a role in regulating things like our daily cycles of alertness or body temperature. What these cells are seeing are not the complex images of the world that we consciously experience, but rather just simple changes from light to dark that often also come with changes in outside air temperature or the time of day.

These subtle cues might not be part of our visual experience, but they can affect our moods. Just think of all those times your mood suddenly shifted in a way that didn't seem rational to your conscious self. It may have been your non-visual photoreceptors at work, picking up on environmental changes that you were unaware of.

The findings certainly make us rethink the idea of a "third eye," that mystical concept that proposes the existence of an invisible eye that is capable of providing us with perception beyond ordinary sight. Perhaps we do have third eyes, and fourth eyes and fifth eyes and "eyes" all over our bodies that are affecting our intuition in all sorts of unexplored, poorly understood ways.

These extra eyes aren't mystical — they're of the body — but being just outside of our conscious experience, their wisdom still seems mysterious to us.