Andrew Parker’s Light Switch Theory proposed vision and the eyes were the driving force of the great diversification of species during the Cambrian explosion. According to Lynne Isabell, the complex human vision is one of the reasons for the large human brain and superior intelligence. She postulated the intricate human visual system and the ability to see a vast array of colors evolved because of the predatory pressure of snakes, and just like Parker, she suggested vision evolved due to predator-prey relationship. Both these theories set out vision as one of the key elements in the human evolution.
But vision does not always paint the right picture of reality, as the McGurk effect shows. And who said vision has to come from the eyes?
The blind Eric Weihenmayer climbed Mount Everest in 2001 with the help of his “tongue vision” and the technology BrainPort:
As neuroscientist David Eagleman explains in his book “Incognito,”
Although the tongue is normally a taste organ, its moisture and chemical environment make it an excellent brain-machine interface when a tingling electrode grid is laid on its surface. The grid translates a video input into patterns of electrical pulses, allowing the tongue to discern qualities usually ascribed to vision, such as distance, shape, direction of movement, and size. The apparatus reminds us that we see not with our eyes, but rather with the brain.
Eagleman reminds that the human ability to perceive through senses is not innate, but rather learned.
If seeing with your tongue sounds strange, think of the experience of a blind person learning to read Braille. At first it’s just bumps; eventually those bumps come to have meaning. And if you’re having a hard time imagining the transition from cognitive puzzle to direct perception, just consider the way you are reading the letters on this page. Your eyes flick effortlessly over the ornate shapes without awareness that you are translating them: the meaning of the words simply comes to you. You perceive the language, not the low-level details of the graphemes. […]
To the reader of cuneiform, New Tai Lue, or Baluchi, the rest of the English script on this page looks as foreign and uninterpretable as their script looks to you. But these letters are effortless for you, because you’ve already turned the chore of cognitive translation into direct perception.
And so it goes with electrical signals coming into the brain: at first they are meaningless; with time they accrue meaning. In the same way that you immediately “see” the meaning in these words, your brain “sees” a timed barrage of electrical and chemical signals as, say, a horse galloping between snow-blanketed pine trees. […]
To Eric Weihenmayer’s brain, his tongue is sending messages in New Tai Lue—but with enough practice, his brain learns to understand the language. At that point, his understanding of the visual world is as directly apparent as the words of his native tongue.
Watch Farther Than the Eye Can See Documentary
Weihenmayer’s story is yet another example of the hidden qualities of human senses. He is the first blind person to climb Mount Everest, and he has climbed all Seven Summits—the highest mountains of each of the seven continents. Watch the BBC documentary about Eric Weihenmayer, Farther Than the Eye Can See.