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Blind Man Navigates Obstacle Maze Unaided
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."
After some practice I could do it myself. So can you. Start with a hallway with hard walls and walk down it blindfolded using your ears. It may help if you make a high-pitched sound. (at least high-pitched sounds are easier for me) I can only avoid large objects that don't aborb sound myself, but I bet I could get better.
If video games influenced behavior the Pac Man generation would be eating pills and running away from their problems.
For those whose curiosity hasn't entirely been replaced by fashionable knee-jerk skepticism, your optic nerve does not only terminate in what we think of as primary visual cortex, it sends projections to other areas as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 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
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.
I've calculated my velocity with such exquisite precision that I have no idea where I am.
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.