Human Echolocation: Using Your Ears To "See" In The Dark
Bats don’t see very well. But they eat a bunch of mosquitoes by employing a form of sonar – echolocation – to snatch skeeters right out of the sky – in total darkness.
Other animals use echolocation to navigate. In addition to bats, dolphins send out sonic signals and use the echoes produced by these signals to help them through the day without getting eating by a whale, making it a good day, indeed.
What you may not know is humans use it, too, though not as much as we could. But when trained to use echolocation to locate objects that can’t be picked up visually, humans with vision problems improve their ability to navigate their environment without assistance.
A team of researchers at the University of Alcala de Henares (UAH), a well-respected school in Spain, conducted research on human subjects who employed echolocation to help them, not only avoid objects, but to help identify them.
According to the study’s author, people with vision impairment can learn to distinguish a tree from pavement using nothing more than echolocation. Echolocation helps us identify the location of a sound, almost instantaneously. Because the sound reaches the right and left ear a split second apart, the human brain is programmed to identify the source of a sound long before we see the thing creating the sound.
In addition to protecting us from potential danger, echolocation places us in the environment, as part of a cheering crowd or as a quiet, solo hiker out for an afternoon stroll.
“In certain circumstances, we humans could rival bats in our echolocation or bisonar capacity,” explained Juan Antonio Martenez, the study’s lead author. Martenez points out human echolocation skills are underutilized and he proposes humans employ a special clicking sound to create echoes to help us better utilize the skill.
The study’s authors conclude, “The ideal sound is the ‘palate click’, a click made by placing the tip of the tongue on the palate, just behind the teeth, and moving it backwards, although it is often done downwards, which is wrong,” Martenez explains.
According to the study, no special skills are required and it doesn’t take years to tune your echolocation skills. Simply by heightening awareness of the role hearing plays in “seeing” the world is a big step toward more effective use of this device.
In as little as two weeks, test subjects with varying degrees of site loss were able to identify pavement from trees and, more importantly, where objects were in relation to themselves.
And while not a solution to vision impairment, the study authors put forth a compelling argument that echolocation is (1) under-utilized as a tool by humans and (2) can be learned in a relatively short time – a benefit to those with total loss of sight who, with a little practice, can use sound to move down a busy sidewalk.
To learn more about human echolocation and the above study, visit “Just in time for Halloween: Human Echolocation Allows Ears to “see” in the Dark” on Healthy Hearing.