Health Talk: Human Echolocation
In the wild, when animals have poor vision, they must use their other senses to make their way around. For decades, studies have suggested that humans too may be able to navigate without using their eyes, but until now this possibility was not confirmed.
A 2009 study from the University of Alcalá de Henares (UAH) in Spain has proven that humans are capable of echolocation, which is used by animals like dolphins and bats. While this ability is not one most humans would claim to use, it is a skill that can be developed. It will be especially useful, scientists believe, for the blind and for rescue workers.
Echolocation relies upon sound in order to navigate and explore. Animals use echolocation to determine the proximity of an object or objects by making clicking sounds and listening for the echo of that sound. By observing the amount of time that elapses between the click and its echo, animals can determine how close or how far away the object is. This works in a way similar to vision. Both seeing and hearing rely upon the reflection of waves (light waves for seeing and sound waves for hearing), and by learning to interpret reflected sound waves, humans can explore the world through sound rather than through sight.
According to this study, humans are capable of learning to listen and interpret sounds to navigate the world without using sight. Unlike in the animal world, however, this ability is not something that comes naturally.
In order to use echolocation, humans would need to participate in a training process to learn how to properly interpret the information they receive. First, a person must learn how to make the proper sounds. According to a June 2009 ScienceDaily.com article, Juan Antonio Martínez, the lead author of the study, believes that “palate clicks” are the best sound to use for echolocation. Palate clicks are made by placing the tongue on the palate, directly behind the teeth, and moving it rapidly backwards.
Once the sound is mastered, learning to use echolocation requires a great deal of practice. Echolocation trainees should practice using clicks to determine whether there are objects in front of them, beginning with small objects and moving on to larger ones. With enough practice, echolocation can be used to determine not only how far an object is, but potentially what kind or size of object is present.
While the possibility of humans using echolocation was only recently confirmed, people have been training themselves to use sounds to judge distances and help with navigation for quite some time. One of the most famous self-taught echolocation users was Ben Underwood. He had his eyes removed because of retinal cancer at the age of two and began to use echolocation to get around at the age of five.
Underwood died of cancer in 2009 at age 16, but in the years before his death, he managed to become proficient in the use of echolocation. YouTube videos and a documentary show Underwood riding a bicycle, playing basketball, and even playing video games, all without the use of sight. Underwood’s ability to use only echolocation to determine what was around him was unique, as he used no other aids to help him around. Instead, he chose to fine-tune his ability to judge his surroundings via sound.
Another well known human echolocation user is Daniel Kish, who also lost his vision due to retinal cancer as a child. Kish taught himself how to use echolocation, determining what kinds of objects were around him, as well as how far away they were. Now, Kish works to help other blind people learn to use echolocation to increase their mobility.
While human echolocation has reportedly been used since the 18th century to help blind humans get around, it was not confirmed or understood until recently that all humans are capable of echolocation with the proper training and practice. Scientists believe that while this skill is very useful for the blind, it is also potentially beneficial for rescue workers, like firefighters, who need to navigate in situations where it is impossible to see clearly, such as smoky rooms.