Perceptions: part II.


While I was relaxing, idly thinking of everything and nothing, a stupid movie I once saw popped into my head. It was one of those comic book superhero movies, and the main character was blind. There was a scene wherein the hero was chatting up the love interest. He asked her to wait, as he could tell it was about to rain. As he explained it, the sound of the rain would help aluminate the way she looked to his senses. The rain showed up, and the camera switch to what was presumably his point of view. The girl stood there, her face and body bathed in a flickering glow. She looked more than a little attractive and though this isn’t my favorite flick by a long ways, I always liked that scene.

Back when I first started experimenting with echo location, I read an article that mentioned that using a tongue click is difficult to impossible if there is too much background noise, like when it’s raining. That worried me a bit, as I live in an area where rain isn’t exactly rare, and anytime I go walking through the city, the traffic noise tends to be much louder than rain. So, thinks me to myself, the movie got a detail wrong. Whatever, it’s Hollywood, and besides, he was mister superhero, so maybe what he was saying was true for him, ignoring the fact that he’s entirely fictional.

My brother had been staying with me over the summer. While he was here, he played co-host on my podcast. In one episode or another, he’d brought up shadow vision. There’s some confusion here, as the particular effect he was talking about had several different names, depending on who was talking about it. It’s an ability that people have to use ambient sound to help sense objects around them without using vision. Ambient sound is just the sound that is in your surrounding environment. The world is almost never completely silent, and sometimes, near heavy traffic or in the pounding rain, the ambient sound level can be quite high.

It’s too bad, thinks myself to myself, that I’m not better with that shadow vision or facial vision or whatever they’re calling it now. It would be great to use the vOICe, and use tongue clicks, and whenever it gets too loud for tongue clicks or the vOICe, use ambient sound instead. Still, that article said that loud background sound makes echo location difficult or impossible… wait… How often have you read some article or paper by some researcher or another studying the blind that got it wrong? Just because the article about echo location was written by a blind person, doesn’t mean they’re right. Maybe I’ve been ignoring useful clues about my world because I was convinced there were no useful clues to be found.

What you know, what you think, what you believe changes what you can sense. That’s been well established for me for years from firsthand experience. Maybe I’ve got this wrong.

I started experimenting. The rain provided plenty of background noise, and my porch is enclosed. I’d step back by the door, or move against one wall, or move to the front of the porch, listening to the way the sound changed. I became aware, not of just the sound, but a part of the sound I hadn’t noticed before I started listening more carefully. It’s like being a little kid crawling through a storm drain, or listening to the world through the hose of a shop vacuum cleaner, a sort of shifting hollow almost echo. It changed and shifted as I shifted about. It wasn’t’ long before I was able to sense where the walls were, where I was standing, a little bit more information about the world around me. I actually became rather excited about it.

Over the next few days, I’d now and again listen for the hollow almost echo. I found that it’s there, even when there’s very little noise around me. It’s much easier with traffic noise, or the wind, or the rain, but it’s always present. Curious about the effect, I looked it up. I found this article about how there’s a low frequency buildup of sound that happens along walls and in corners. This is in contrast to tongue clicking, which uses higher frequencies. These standing waves of sound can help you sense where things are, even when you’re not consciously aware of it.

The article mentioned that most blind people experience the effect as a tactile sensation. I’ve noticed that with echo location. Sometimes, when walking around, I’d click my tongue and suddenly notice something that I hadn’t before, like one of the cars parked in my driveway. When that happens, it feels like there’s a thunk. The sensation is like tapping your fingers sharply against a surface, only there are no fingers, and the tactile sensation takes place away from where you’re standing. Experimenting with the use of ambient sound, I’ve mostly felt things looming around me. They often seem almost to shimmer or vibrate, sort of like the lighting in the scene from that stupid movie.

What that article didn’t mention was the Doppler effect. When things are making sound or sound is reflecting off of them, if those things are moving relative to you, the frequency is changed, sounding higher pitched as things approach, and lower as things reseed. This includes when you’re the thing that is moving around stationary objects. The shifting sound was much easier to notice and understand. I found that it helps to move around. That day on the porch, when I first noticed, what I really wanted to do was rock back and forth, causing the frequencies to shift around. I didn’t quite have the guts. I’m all too aware of what it looks like when blind people rock, and all too painfully aware of what people think when they see it. It’s a ticklish issue. I’ve even read articles, written by totally blind folk, imploring other blind people not to rock back and forth in public. And yet… I’ve experimented with it when alone, and it does in fact make it much easier to sense what’s around me, especially if it is rather quiet and I don’t have a convenient hissing background roar to work with.

On the one hand, here’s something I could do that would provide more information. On the other hand, if I do that, I’ll be judged, and judged harshly by those around me. Fortunately, the other way to use Doppler frequency shifts is just to move more quickly. It’s true of every form of sensory substitution I’ve ever experimented with—it works better if you move faster. You don’t need to run, but a decent pace helps. My instinct is to slow down, to move more carefully, but that’s the wrong approach. What’s more, moving that slowly and awkwardly also looks bad. For years after losing the last of my sight, I was creeping along like an arthritic old man. That pace and the amount of tension I was holding in my body tended to cause various aches and pains, as muscles and joints took stresses they apparently weren’t designed for, at least not for days at a time.

Thus far, at least when somewhere somewhat familiar, that’s what working with the vOICe and the other tricks have given me that I most appreciate—the ability and confidence to move in a more relaxed, natural way. I swear I can even breathe better.

In retrospect, I don’t think the article I read really said or meant to suggest that when there is a lot of background noise, using sound becomes impossible. It was talking about actively making sounds, rather than using the sound that is already there. They are slightly different effects. I just managed to confabulate the point, so I ended up tuning out information I could use.

I wonder how much I do that. I wonder how often I tune out what I need, not just with my senses, but in general. More or less by definition, I can’t know what I don’t know. I’ll have to discover it the hard way. The only thing I can do about it is continue to question and experiment and explore. Which is more or less my favorite thing to do anyway.

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