Monday, October 14, 2013

Five methods of environment detection for the blind

I usually write in pre-modern worlds, so I’m going to assume there are no such things as Seeing Eye dogs here—though a science fiction short story once featured a blind alien which used a human as such a service animal. If anyone remembers what the story was called and/or who the author was, please comment and let me know.

Anyway, that made me think of ways blind people in a medieval fantasy might become aware of their surroundings.

1. Sound

Bats and whales use echolocation, but they have suitable modifications and an environment. Water conducts sound better than air does, and bats have large ears, neither of which are likely to apply to humans. Plus, it might be difficult to have a character constantly making high-pitched noises.

Though if a blind person had sensitive enough hearing, he might be able to detect even the quietest sounds—or filter said sounds from the soup of a crowded, noisy room. The problem, though, comes when dealing with the completely inanimate. Navigating a maze or even an unfamiliar house would prove more difficult, but that’s where a different sense comes in.

2. Touch

Some predators make good use of this—and use structures such as whiskers or cobwebs to maximize the amount of their environment they can detect. Humans are at a distinct disadvantage in this respect. By the time you’re close enough to an intruder to touch him, you’re probably too close and have lost the element of surprise.

Though if a human did have skin (or skin-connected structures) which extended far enough, and which could be manipulated into exploring an environment at a distance, that could work.

3. Electrical fields

I like this one because it could work in almost any world—futuristic, steampunk or medieval. There’s real-life precedent for this as well; sharks sense electrical impulses via specialized organs called the ampullae of Lorenzini.

It would also be interesting to know how such a method of detection would work. Do the stronger electrical impulses produced by living creatures feel like the shock you get when you walk across a shag carpet and open a door? Or is it more like a monochromatic pointillist world where significant surges show up like Rorschach blots?

4. Heat

Snakes can sense the warmth given off by their prey, but it would be even more interesting to intensify this ability. The molecules of substances vibrate unless the temperature is absolute zero, in which case your character is unlikely to be doing much either, and enough vibration produces heat.

If the character is a sensitive enough thermometer, he could tell the difference between metal and wood from across a room. Or he could tell which of three identical closed doors had been used shortly before, because one handle would be just a few degrees warmer than the others.

5. Seeing through the eyes of another

The other set of eyes could belong to an animal or person devoted to that purpose—though I wouldn’t want to have the compound eyes of a fly or the multiple eyes of a spider unless my brain was able to handle that kind of input.

Alternately, the blind person might be able to look through the eyes of anyone in the immediate vicinity. That might be interesting, to see yourself from the perspective of a lover or an assassin.

Any other ways of sensing the environment?


Sandra Ulbrich Almazan said...

What about smell?

Marian Perera said...

Knew I'd left something out! It would have to be a bloodhound-level sense of smell, but that would work too.

Randall said...

Does this thread help?

DRC said...

Always such interesting posts. Food for thought. Thanks :)

Loren said...

Blind people have used both guide dogs and canes for centuries. They are low-tech and thus suitable for societies with premodern technology. Wikipedia: "guide dog" and "white cane".

Canes are a sort of artificial whisker. Like whiskers, they extend their users' sense of touch.

An electrostatic sense would likely be experienced as some touch-like sensation, I think. It would also be short-range.

Some organisms can sense magnetic fields, something that's useful for navigation. Some bacteria, and pigeons, have that ability.

Our sense of smell is rather wimpy by most mammalian standards; we have lots of olfactory-receptor pseudogenes in our genome. But an improved sense of smell could work for navigation, at least in areas that one is familiar with.

Loren said...

As to telepathically tapping into guide animals' senses, that has interesting possibilities.

Insect compound eyes don't have much revolution. Each sub-eye or ommatidium has only one set of outputs, meaning that it makes only one pixel of the perceived image. Combining the outputs of the ommatidia will make a regular sort of image, even if a rather low-resolution one.

There's also the question of color vision. It's mainly known in arthropods and vertebrates, though some octopuses also seem to have it.

Insect color vision is roughly yellow, blue, and near-ultraviolet. Many flowers have markings for the convenience of their pollinators, but some flowers do not seem to. Those markingless flowers often have markings in the ultraviolet, meaning that bees can see them even if we can't.

Bees can also see light polarization, something useful for celestial navigation and for recognizing bodies of water.

Closer to home, among vertebrates, many birds see four colors, roughly red, green, blue, and UV. Many mammals, however, have red-green color-blindness, seeing only yellow and blue. To a dog, red through green all looks yellow.

Marian Perera said...

Thanks, Randall, that was the story I had in mind!

DRC - Aw, thank you. :) There are so many fun ideas and concepts I'll never have the time to write fiction about, so I do blog posts about them instead.

Marian Perera said...

Loren - that sounds as though an electrostatic sense could be pretty long-range then. I mean, if you were in a medium that conducted electricity (say, a mist, with all those water droplets), you could sense electrical impulses from quite a distance, couldn't you?

And I had no idea bacteria could detect magnetic fields. I've been away from that particular branch of science way too long, evidently.

Thanks for commenting! I always learn something new from you.