Blindsight: the mysterious condition that allows blind people to see

Want to see something crazy? Check out this video of a blind man attempting an obstacle course.

Now, before you go to the comments to tell me what a terrible person I am, know that the blind man signed up for this. He opted into the test to demonstrate…wait a minute. Unbelievable. He aced it. Even though this man is cortically blind—literally cannot see a thing—he navigates the perilous hallway with perfection. What is going on?

Let’s investigate: in the 1960s scientists noticed strange behavior from a monkey named Helen. Though Helen was cortically blind (her visual cortex had been completely removed), she exhibited signs of sight. For example, she would blink in response to stimuli that could threaten her eyes or identify the location, size, color, and patterns of objects. Everything pointed to the bizarre conclusion that Helen was somehow capable of sight.

In the following years, researchers began to observe similar phenomena in humans. Like Helen, these blind patients could react to visual stimuli. Some could catch balls when prompted or describe changes in their visual field. While they could not see these queues, they would describe “sensing” a motion or just moving their hands to wherever felt right.

This brings us back to our man in the video. Known as TN, he is the most famous example of what has come to be known as blindsight. Though TN has no conscious visual experience, perceptive tests reveal stunning visual accuracy. He can ace intricate tests and traverse obstacle courses like the one in the video with ease . When asked how he traversed the hallway, he insists he simply walked the way he wanted to. The paradox is inescapable: TN can see—he just isn’t aware of it.

This leads us to a rather uncomfortable conclusion. Not only do we not have to be aware of our vision to see, consciousness to seems to a large degree to have nothing to do with sight. Instead of observing and consciously processing information, our brains work autonomously, taking input and analyzing it on their own. To a certain extent, our consciousness deludes us with the illusion of visual control.

Weekly Show Brain Blindsight Consciousness Brain Blindsight Questions Philosphy

Does the brain really need our consciousness to function?

These questions of consciousness are hardly new. Philosophers and scientist have for centuries pondered what it means to be conscious or whether we are conscious at all. While there are some fascinating theories and experiments, the most striking takeaway is that we really don’t know. The brain seems to be able to do almost everything on its own, and we are aware of only a fraction of its activity. (There will be more about this in a future post).

Note that not all blind people display blindsight—only a small fraction of people who cannot see have this condition. This means no tossing books to blind people. What you can do is read more articles and watch more videos about the phenomena. I’ve included some awesome links below. I hope you find this as amazing as I do. Is it mind-blowing? Surprising? Share your thoughts in the comments. As always, please like, share, or reblog this post if you enjoy it. That small click really helps me out! Be sure to check me out on Twitter and Facebook as well. Thanks for reading! Don’t forget to subscribe for new content every Wednesday! IT’S FREE!

Other related articles:

Top 10 Myths About the Brain (Smithsonian)

What Is Consciousness? (Vsauce)

Mystery of “Blindsight” Allows People to “See,” Study Shows (National Geographic)

Your Brain is a liar and Can’t be Trusted

Come Clean, Now: Are You a Zombie?


Comment question of the week

Does this blow your mind? Or is it actually not that surprising?


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