Human Echolocation: The Ability to "See" with Sound
Introduction
Echolocation, the ability to perceive the environment by emitting sounds and interpreting the returning echoes, is most commonly associated with bats and dolphins. However, humans also possess the capacity to learn and utilize this remarkable skill. For years, a small number of people who are blind have used echolocation, by making a clicking sound with their mouths and listening for the reflection of the sound to judge their surroundings. This article explores the fascinating world of human echolocation, examining how it works, who can learn it, and the benefits it offers, especially to individuals with visual impairments.
The Mechanics of Human Echolocation
Human echolocation mirrors the technique used by bats and dolphins. It relies on an initial audible emission, and subsequent reflection of sound from the environment. Practitioners emit bursts of sounds and listen to the echoes that bounce back to perceive their environment. When people echolocate, they make audible emissions like mouth clicks, finger snaps, whistling, cane taps, or footsteps. These are all in the audible spectrum, as opposed to the ultrasound emissions that bats or dolphins use. The emissions that proficient echolocators prefer to use are mouth clicks. Researchers have measured thousands of these clicks and found that they are very brief (~5 ms), and that the beam of sound spreads out in a way that is referred to as a “beam of an acoustic flashlight”. People also adjust clicks dynamically. For example, people will make more clicks or louder clicks when the echo is comparably weaker or to compensate for interfering noises.
Who Can Learn Echolocation?
Echolocation is a learnable skill that can be acquired by people who are blind as well as by people who are sighted. It was once thought that only blind people could excel at echolocation, but research has shown that anyone can learn the skill. Studies show that echolocation in humans can be so precise that they can distinguish textures such as metal through sound. Similarly, experts at echolocating can precisely identify minimal gaps between objects placed more than a meter away.
Researchers led by psychologist Lore Thaler at Durham University spent ten weeks teaching over two dozen people, some who were blind and some who were not, to observe and navigate their environments by echolocation. Participants were between 21 and 79 years old, and included 12 people who are blind and 14 people who are not blind. Over their ten weeks of echolocation training, they faced tasks like using clicking to figure out whether the pair of disks in front of them had a larger disk at the top or bottom or to identify how a rectangle plank was oriented. The results showed that all of the participants could learn how to echolocate, regardless of their age or whether they were blind.
The Brain Basis of Echolocation
Studies have shown that people who are blind and skilled in echolocation use not only the hearing part of their brain to process echoes, but that they also use those parts of the brain that process vision in sighted people. In people who are normally sighted, early visual cortical areas, such as primary visual cortex, are activated by visual stimulation in a specific pattern that is referred to as retinotopy. Researchers have found that in blind echolocators, the primary visual cortex is activated by acoustic stimulation in a specific pattern that resembles retinotopy. These results suggest that “retinotopic” activity can also be driven by sound, and that this is facilitated by experience with echolocation.
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Benefits of Learning Echolocation
Learning how to echolocate can significantly benefit the everyday lives of blind people. Here are some of the benefits of learning how to echolocate:
- Better mobility: Studies show that echolocation significantly improves special awareness, increasing mobility and your understanding of the environment. For example, learning how to echolocate allows you to detect corners, doorways, and other obstacles that you may not have been aware of.
- Better safety: Similarly, echolocation may help people with blindness and vision loss improve their safety. Reports indicate that people who know how to echolocate can, for instance, more accurately avoid collisions with objects and be more precise when walking near traffic.
- Increased confidence: According to a recent survey, blind people who have learned echolocation are more confident when navigating and interacting with the environment. This is particularly relevant for everyday tasks such as going shopping or taking out the trash.
- Improved well-being: After learning how to echolocate, some people report feeling like they have gained a new sense. Naturally, this has a tremendous impact on well-being, as they report feeling capable of overcoming most challenges after learning how to echolocate.
- Higher salaries: One of the most surprising benefits of echolocation is that it can lead to higher wages. This is probably tied to the increased capabilities of people who echolocate, who may be better suited for jobs that require a lot of interaction with the environment.
How to Learn Echolocation
If you want to learn how to echolocate, you should consider hiring an expert teacher. Echolocation isn’t a very easy skill to pick up, so having the guidance of a trained professional can go a long way in avoiding frustration and stress. But it’s also possible to learn how to echolocate on your own - here’s how to do it:
- Understand the basics of echolocation: Learning how to echolocate will be a lot easier if you understand how it works and the physics behind it. Luckily, a vast amount of information online is available for everyone for free.
- Ensure you have the right equipment and environments: While not much is needed to learn how to echolocate, the process will be much easier if you have a few elements in mind. Most importantly, you’ll need a quiet room; a movable sound source (such as a vacuum cleaner); and objects that vary in size, texture, and shape.
- Train the basic hearing skills: Before learning echolocation, it’s essential to train your basic hearing skills. For example, while on the street, try to locate the direction of the traffic only through its sound. Another similar exercise is to place a sound source in the center of a room, walk around it, and try to determine its direction.
- Pick an echolocation sound: Another crucial step you need to take before starting the echolocation exercises is to pick the sound you’ll use for echolocating. Cane taps, mouth clicks, and finger snaps are all excellent choices - ideally, it should be a sound you can easily make in any situation.
- Perform some basic echolocation training: Initially, you should try to perform some basic echolocation exercises. For example, stand a few meters away from a wall and start walking toward it. Try to stop before touching the wall only by using the sounds you’re making.
- Increase the difficulty of the exercises and practice: After grasping the basics of echolocation, try to increase the difficulty of the exercises. For example, add more obstacles or practice exercises in rooms with different acoustic properties.
Notable Human Echolocators
Several individuals have gained recognition for their exceptional echolocation abilities:
- Daniel Kish: Lost his eyes at a young age due to retinal cancer and taught himself echolocation. He now leads blind teenagers hiking and mountain-biking through the wilderness, and teaches them how to navigate new locations safely, with a technique that he calls "FlashSonar".
- Ben Underwood: Taught himself echolocation at the age of five, becoming able to detect the location of objects by making frequent clicking noises with his tongue.
- Juan Ruiz: Blind from birth, is capable of riding a bicycle, avoiding parked cars and other obstacles, and identifying nearby objects.
- Lawrence Scadden: Lost his sight as a child due to illness, but learned to use echolocation well enough to ride a bicycle in traffic.
- Lucas Murray: Was born blind, and is one of the first British people to have learned human echolocation, having learned it from Daniel Kish.
- Thomas Tajo: Became blind around the age of 7 or 8 due to optic nerve atrophy and taught himself to echolocate. Today he works with Visioneers or World Access to impart independent navigational skills to blind individuals across the world.
Echolocation in Popular Culture
Echolocation has also found its way into popular culture, inspiring characters and plotlines in various forms of media:
- Daredevil (Matt Murdock): A Marvel Comics superhero who is blind but possesses enhanced senses, including the ability to use echolocation to navigate his environment.
- Gregor and the Code of Claw: In the 2007 children's fantasy novel, protagonist Gregor learns echolocation.
- Imagine: In the 2012 film, the main character teaches echolocation to students at a clinic for the visually impaired.
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tags: #can #humans #learn #echolocation #how #to
