We know that bats use echoes to determine the orientation of objects, which is called echolocation. Humans borrowed this ability from bats and invented radar.
But did you know that some blind people can also echolocation like bats-they perceive the surrounding environment through the sound of their mouths, they are even very good at this, such as the blind Daniel Kish of California, USA. For him, it is a piece of cake to judge whether the object in front of him is a tree, a pillar, or a person through his own slamming sound. He can do much more complicated things than this. For example, by slamming the bar, he can draw a sketch of the interior decoration of a room, and even ride a mountain bike along an unfamiliar route.
Now, through cooperation with Kish, scientists have finally begun to understand the acoustic principles behind this “special function”.
Studies have found that these smashing sounds are highly focused sound waves that radiate in a 60° cone shape; in contrast, the general speaking sound spreads at an angle between 120° and 180°. Scientists say that these blind people have actually solved the problem of sound focusing without knowing it, that is, like bats, they aim sound waves at the space they are interested in, and then receive echoes.
As for how echoes form an overview of objects in the brain of a blind person, little is currently known. Kish believes that the sensations he experiences are somewhat similar to images. This means that this process involves areas of the brain related to vision.
Researchers have been able to artificially synthesize this smashing sound. They use computer-controlled speakers to hit an object thousands of times (you can’t ask a person to hit something endlessly) to figure out how it determines the shape of the object. This provides convenience for in-depth research. For example, researchers can compare which slap sound works best in different situations.
Scientists say that this research may also help us develop better sonar systems that can be applied to autonomous vehicles in the future.
