Blind Man Navigates Obstacle Maze Unaided 191
iammani writes "The NYTimes runs a story about a blind man (blind because of a damaged visual cortex) successfully navigating an obstacle maze, unaided. Scientists have shown for the first time that it is possible for people who are blinded because of damage to the visual (striate) cortex can navigate by 'blindsight,' through which they can detect things in their vicinity without being aware of seeing them."
Its not that hard (Score:5, Interesting)
Re:Its not that hard (Score:5, Interesting)
There is a video of a blind person on youtube who seems to be able to navigate just like a regular person through the use of echoes. He carries and uses a clicker to make sounds.
There is a group which teaches the blind to locate objects through echoes.
Blind awareness? (Score:0, Interesting)
If this is true, then we should try to tap into this ability more often. You know, train ourselves to be able to use it on command or 24/7. I can think of a few instances where this could come in handy.
Turn in your nerd badge (Score:5, Interesting)
For those whose curiosity hasn't entirely been replaced by fashionable knee-jerk skepticism, your optic nerve does not only terminate in what we think of as primary visual cortex, it sends projections to other areas as well, though these areas do not contribute to what most of us think of as "sight"
My daughter confirmed this story for me a year ago (Score:5, Interesting)
My daughter had a stroke before she was born, and as a result, she suffers from Cortical Visual Impairment (CVI), like the subject of this story. At nine months of age, she couldn't tell light from dark, which really screwed up our sleep cycles. Her eyes were fine, but her brain could not process the signals that they were sending to her.
Eventually, she did regain some amount of vision, but her hearing is still her primary way of "seeing" things. Whenever we go into places that are pitch dark, my wife and I are walking into things left and right. My daughter, on the other hand, cruises right around like a bat. She hears walls and other obstructions, and corrects her course to avoid them. Her object avoidance skills greatly diminish when she can use her eyes to see, as her brain has to work much harder to decode what she sees with her eyes.
-- Len
See It Now (Score:5, Interesting)
If you ever want to see this in action, there's a very simple experiment you can do. Put a quarter inside a ring of five loons (Canadian $1 coins). Put another quarter inside a ring of five dimes. The quarter surrounded by dimes will look larger than the other one.
Reach out and pick one up. Put it back. Pick the other one up. Put it back. You'll notice that even though your eye is telling you the two quarters of different sizes, your fingers will automatically spread out just the right amount to pick up either coin.
The illusion works for your regular visual system. The unconscious one gets the answer right.
This works because... (Score:3, Interesting)
Re:Its not that hard (Score:3, Interesting)
Brain Plasticity - his subconscious is figuring out how to make use of some form of input, to give him a sense that something is there.
I bet if he did it over and over, he'd get better at it. It'd strengthen the connections.
Re:Its not that hard (Score:5, Interesting)
That's very cool. It's also proof of how amazing the brain is - the part that makes a 3D model of your surroundings will adapt to any sort of useful input. With just sonic shadows you're working with very limited data, but even so: the navy has spent a ton trying to develop good passive sonar, and it sounds like you're better at it than the technology. Now if someone could just invent a sonic lens, it would close the gap. The only reason light gives better 3D positional information is the lens (though it would also be helpful to hear sub-millimeter wavelengths, as 20 kHz doesn't give much precision).
Re:Blindsight, Deafhearing and Alien Limbs (Score:5, Interesting)
There's also other differences as well. Some women, for instance, have see a fourth set of colors, which gives them a much greater low-light ability (a couple for every thousand women, IIRC) as well as do great things in the visual arts. Other people have vision that extends a bit beyond the normal ranges as well. A good example if this is the typical "normal" body temperature. It was obtained by sampling a large number of people and averaging the result. Vision, hearing, and other senses are similar. So it's not surprising that the occasional blind person can actually tap into these if theirs happen to naturally be more developed than normal.
By tapping into the secondary pathways like this, I can "see" about twice as well as most people in the dark(though it's not really "seeing" like reading a paper or like a cat does). And, as DynaSoar mentioned, I can literally run through areas at night and not hit things as long as there is even a tiny amount of light.(doesn't work in caves/absolute pith black - tried that - heh)
Note - the skill can be learned, though some see better at night than others. I suspect their vision is shifted a bit more towards the infrared or their iris' are a bit larger. It took me about 2-3 years to develop it when I was growing up. My friends and I always spent a lot of time playing outside at night and some of us got pretty good at avoiding things in the dark. The hard part was learning to just trust your instincts. It's a odd feeling, though, as you only notice things a split second before you normally would hit them if you're moving faster than walking speed.
I found that a trick to doing this - and you can try this as well - is to learn to defocus your eyes during the day. Animals do this to track movement. It's a common trick hunters also use to track and find game. If you can then also do this at night, it basically shuts off a lot of your brain's trying to strain itself in low light. Since the average person's brain normally focuses intently upon just a small area in front of them, expanding that to your entire field of vision makes a huge difference.(though as noted, you can't focus on specific objects at the same time) Often, even if you can't actually see details, your eyes will notice things like faint reflections, movements, and so on.
My ex? She's nearly completely blind about 5 minutes after dusk. Opposite end of the scale as it were.
Re:Its not that hard (Score:5, Interesting)
Do you mean this kid?
http://uk.youtube.com/watch?v=qLziFMF4DHA [youtube.com]
(That's part 1 of the documentary. Links to the other parts are in the info box.)
Incredible stuff, he rides a bike and everything!
What isn't explained though is how he's playing video games?
Bilaterality of blindsight is special (Score:2, Interesting)
It is not mentioned very clearly in the NYT article, but it is mentioned in the original Current Biology paper: this patient has BILATERAL lesions in both the left and right visual cortices. IMO, this is what makes this case especially interesting.
Of course, blindsight has been demonstrated many times before, but always in patients with unilateral lesions. This has some methodological advantages (the patients can act as their own control), but the unilaterality has also been criticised. Maybe these patients make microsaccades, maybe some light is reflected by the nose into the other eye halves, etc. In short, maybe some information reached the intact hemisphere.
This is not possible in the present patient, and that is especially interesting. AFAIK, this is the first and only patient with a bilateral blindsight.
-- Geert
Re:Its not that hard (Score:3, Interesting)
Sighted people can learn this, too. I worked in an office where I had my back to a doorway, and through that door was a room full of servers. No one was ever able to sneak up on me because I could hear their sound shadow as they walked by the servers. It took me a while to figure out how I was aware of them, because it wasn't really a conscious thing at first.