Echolocation scores a resounding win for the blind

By Amie Ahn Apr. 3, 2024

In the deep, dark depths of the abyssal waters, nothing is visible—the world is pitch-black. Yet, whales have no problem finding their way around and catching prey. Similarly, bats thrive in dark caves, able to efficiently hunt during nighttime. Whales, bats and other nocturnal animals use echolocation, or acoustic location, to estimate the distance and size of nearby objects by releasing a sound wave and processing the returning echo. Gradually, this usage of sound waves is becoming a part of human technology.  

Different animals have different methods of echolocating. Dolphins produce clicks through their nasal passage, which are reflected off nearby organisms that could be potential food sources. The echoes are received by the dolphin in the acoustic window of the lower jaw and are ultimately transmitted to the brain, allowing them to easily locate prey. Bats produce a wide variety of high frequency sound pulses in their larynx and emit them into the air. The reflecting pulse waves are used to determine size, shape and texture of surrounding objects to avoid obstacles.  

Humans have never possessed echolocation as a natural trait. However, according to WebMD, 20% to 30% of blind people learn to echolocate thanks to neural plasticity—a phenomenon where the brain can adapt its structure and function to one’s experiences. The visual cortex, normally used for receiving visual information, can adapt its function to receive non-visual information and be used for echolocation in visually impaired people, explaining the notion that blind people have sharper hearing than non-blind people. To echolocate, humans can make clicking noises, tap their white canes or stomp their feet. This creates an echo that can be perceived by the ears and various parts of the brain, including the visual cortex and occipital place area.  

“People could make use of echolocation in investigations, like locating missing people. Echolocation technology could be used to more quickly and effectively search for missing people, especially in confined spaces and dark areas such as caves,” Freshman Melody Chong said. 

Contrary to animals like dolphins or bats, there are still many inherent barriers to authentic human echolocation. Human ears have a very limited range compared to echolocating animals. Due to these constraints, echolocating technologies are advancing to assist the visually impaired, including the Sunu Band and Lidar. The Sunu Band is a band worn on the wrist that uses echolocation and sonar to detect the objects around the person, and it emits vibrations to inform them of objects in their proximity. Lidar uses eye-safe laser beams to bounce off surrounding objects. The reflected light waves return to the sensor, where it calculates the distance of the objects from the person. 

“Echolocating devices are not safe to completely rely on yet—imperfections in the system could result in misjudging the distance from or completely missing oddly shaped objects. Due to this occasional inaccuracy, an individual relying solely on echolocation could be injured fatally such as by a moving car. However, making use of such technology alongside already existing guide techniques has the potential to make life much safer for visually impaired people,” Senior Matthew Rodrigues said. 

Echolocation technology has many challenges to overcome before it will be safe to function independently—even signals from sonar, which is not used by humans on a daily basis, have impacted the environment by interfering with the echolocation abilities of marine life like whales. Nevertheless, the human world will continue to see a growing role of echolocation in many aspects of human life—the ongoing study of echolocation has the potential to unlock new knowledge about the human brain. Ultimately, echolocation serves as a representation of how the understanding of human perception is constantly evolving.

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