The Illusion of Reality

"What if I told you that the world around you, with its rich colors, textures, sounds, and scents is an illusion, a show put on for you by your brain?"

The world around us looks very real. The colors and shapes we see, the sounds we hear, the fragrances we smell. It all feels genuine, indisputable, yet like so many of our experiences, our perception of the environment surrounding us is not as we believe it to be.

In some of my previous posts (Entanglement, The Order of Time, A Tale of Two Selves), I have discussed books that have fundamentally challenged and altered my worldview. The Brain: The Story of You by David Eagleman, on which this post is based, is another one of them.

Is Reality "Real"?

The way we experience reality, it feels as if we have a direct access to the exterior world. Take the screen in front of me. I can simply direct my eyes to see the colors and read the words in it, reach out my hand to feel its smooth surface, effortlessly hear the clicking of the keyboard as I type. However, all these perceptions are misleading. The touch, for example, is not truly happening in my fingers, even though I could swear it really feels that way, but in my brain, and so are the vision and the hearing and all of my sensory experiences.

"Seeing isn't happening in your eyes; hearing isn't taking place in your ears; smell isn't happening in your nose. All of your sensory experiences are taking place in storms of activity within the computational material of your brain."

It's kind of ironic that the brain, the key player behind our perception of reality, has actually never been out into the world itself. Instead, it receives information from every sensory organ in the form of electrochemical signals and converts these signals into vision, hearing, smell, touch and taste - in other words, into what we experience as the "real" world.

Moreover, colors, smells, sounds and the like don't actually exist as such. What we perceive as colors, for example, are beams of light with different frequencies and wavelengths that our eyes transmit to our brains as electrochemical signals. What's more, we can't even see most of the light: it has been estimated that the spectrum of light visible to humans makes up about 0.0035% of the full spectrum that exists.

What Colors Really Are (Photo by NASA Science)

"Everything you experience - every sight, sound, smell - rather than being a direct experience, is an electrochemical rendition in a dark theater."

How We Perceive Colors (Photo by Tulip Festival Amstetdam)

At this point in the book I was already mind blown, and I distinctly remember folding my hands in front of my face and wondering how could these seemingly real sensations - the warmth of my skin, the solidity of my rings, the lavender smell of my hand lotion, the dark color of my nail polish - not be actually real. Eventually I wrapped my head around the fact that, yes, all those sensations were not truly as I perceived them, and yes, they were all electrochemical signals that my brain was converting into vision, touch and smell for my benefit. But even after all this time, and after all the scientific proof I have encountered, I sometimes still hold my hands in front of my face and still wonder how on earth can all it all be just electrochemical signals.

And it gets better - or worse (and even more confusing), depending on your perspective.

What Really is Vision?

It turns out vision doesn't function the way we imagine either. Eagleman exemplifies this with the story of Mike May. A chemical explosion left Mike blind when he was 3 years old. At 46, after having built a successful career as a businessman and Paralympic skier, he received a pioneering treatment that was supposed to return his vision. However, even though the treatment was a success in surgical terms and left Mike's eyes functioning properly, he had trouble actually seeing.

After years of going through life without vision, Mike's brain could simply not make sense of all the information it was receiving. Mike was unable to recognize faces, perceive depths or identify objects, and even found skiing more difficult than when he was blind. His eyes could see just fine, but his brain could not.

An MIT experiment with kittens demonstrated that movement is necessary for the visual system to reach normal development. Vision, it turns out, is a whole body experience, and seeing requires more than just eyes. As babies, we do a lot of cross-referencing across senses, which we now know is essential to train our sensory systems. In order to fully make sense of the 3D reality we live in, our brains need to first figure out how our actions get reflected into the world: what happens when I move my hand a little to this side? What if instead I move my leg? Or what if I push this object? Or if I squeeze it?

Photo by Educatall

We don't realize it because we "learned" to see as babies and have done it for our entire lives, but vision is not as effortless as it seems (in fact, it is said to be the most complex of our senses, with over 50% of the brain cortex being devoted to processing visual information). Moreover, vision doesn't happen just with the eyes as we normally think.

Vision and Movement

Interestingly enough, I had an experience some time ago that made me aware that the relationship between vision and movement goes both ways. To follow the story, you need to know two things about me: I have broken the same ankle twice and I am a big yoga enthusiast.

Because of the fractures (and also because I have loose ligaments), I was advised by a physical therapist to implement a routine at home to strengthen my ankles. One of the exercises was the "single leg balance," which, as its name suggests, consists of standing on one leg while lifting the other. The guide started with the easiest version - standing next to a wall for added support, and then added a few difficulty levels until reaching the last one - doing the exercise without support and with the eyes closed. I clearly remember thinking "well, what difference do the eyes make?"

Photo by VeryWellFit

I try to do yoga every day and consistently do balancing exercises more challenging than the "single leg balance", so I was feeling in my comfort zone. However, the moment I closed my eyes, all the balance somehow disappeared. I still remember how baffled I was after trying over and over a pose I had found so easy just moments ago and repeatedly falling over to the side. Movement and vision, it seems, go hand in hand, despite us not being generally aware of it.

The Illusion of Reality

The Brain: The Story of You is full of facts that blew my mind and challenged a perception of reality I had held for over 20 years, so if you are as intrigued and fascinated by this topic as I am, I wholeheartedly recommend you to read it. For now, I will leave you with one last fact: our perception of reality is lagged, so we technically live in the past (by about 80 milliseconds, but still in the past).

How can this happen? Well, as you know, we have multiple senses, and therefore multiple streams of sensory data. However, the brain processes each stream at a different speed. Vision, for instance, is processed at a slower rate than hearing (which tells you something about how complex it is, considering light is actually faster than sound). However, if you clap right in front of your face, you see the hands touching and hear them clapping at the same time, right? As you might imagine by now, not really. The brain hides the difference in arrival times with yet another trick: it waits until it has gathered input from every sensory stream, and only then does it register all the information together in your conscious awareness. As Eagleton puts it:

"The strange consequence of all this is that you live in the past. By the time you think the moment occurs, it's already long gone."