The Boy Who Sees Without Eyes
Human Spirit and Human Echolocation



Different People - Mysterious World
The Boy Who Sees Without Eyes


In loving memory - Ben Underwood (January 26th 1992 - January 19th 2009). Ben Underwood taught himself to use echo location to navigate around the world. He was completely blind after having surgery to his eyes when he was only three years old due
to Bilateral Retnoblastoma (cancer in both eyes).

Diagnosed with retinal cancer at the age of two, American Ben Underwood had his eyes removed at the age of three. He discovered echolocation at the age of five.

He was able to detect the location of objects by making frequent clicking noises with his tongue. This case was explained in 20/20: Medical Mysteries.
He used it to accomplish such feats as running, basketball, rollerblading, playing foosball, and skateboarding.

Though at first resistant to using a cane for mobility, seeing it as a "handi-capped" device, and considering himself "not handicapped at all", Daniel Kish demonstrated to Underwood how he used his white cane combined with echolocation to further expand his mobility, though Underwood never adopted this method.

Ben Underwood lives with his family in the suburbs of Sacramento, California where he attends his local high school. Like any other 14-year-old boy, he loves to play with his friends and chat to girls his age, with whom he seems popular. He looks like any other boy, until he removes his $4,600, hand-crafted eyes.

Ben is blind and, like other blind people, relies on some specialist equipment to survive. He uses talking computer software and a Braille machine to help with his homework. Ben does not have a guide dog, uses no stick, and does not even use his hands to aid his mobility.

Instead, he has developed something of a super sense: he is the only person in the world who navigates using clicks. As he walks, he makes a continuous clicking noise with his tongue. As these clicks echo around him, he is able to draw up a detailed mental plan of his surroundings and adjust his direction accordingly.

So accurate is his technique that he is even able to go rollerblading on the street, negotiating narrow gaps between parked cars that even sighted children might find challenging. In fact, Ben’s mother, Aquanetta, insists that her son is far more attentive to the dangers of the road than his friends, always the first to move onto the pavement when a car approaches.

Ben first noticed his talent at the age of seven, when at summer camp. While it began as just a habit, Ben explains, he soon realized that it had potential benefits for navigation. He began to practice every day and developed the system to the point it is at today.

It is the fact that Ben is entirely self-taught that is perhaps most astonishing and has led people to use the term ‘genius’ when referring to the boy.


Mechanics of Human Echolocation


Vision and hearing are closely related in that they can process reflected waves of energy. Vision processes light waves as they travel from their source, bounce off surfaces throughout the environment and enter the eyes.

Similarly, the auditory system processes sound waves as they travel from their source, bounce off surfaces and enter the ears.

Both systems can extract a great deal of information about the environment by interpreting the complex patterns of reflected energy that they receive.

In the case of sound, these waves of reflected energy are called "echoes". Echoes and other sounds can convey spatial information that is comparable in many respects to that conveyed by light.

With echoes, a blind traveler can perceive very complex, detailed, and specific information from distances far beyond the reach of the longest cane or arm.

Echoes make information available about the nature and arrangement of objects and environmental features such as overhangs, walls, doorways and recesses, poles, ascending curbs and steps, planter boxes, pedestrians, fire hydrants, parked or moving vehicles, trees and other foliage, and much more.

Echoes can give detailed information about location (where objects are), dimension (how big they are and their general shape), and density (how solid they are). Location is generally broken down into distance from the observer and direction (left/right, front/back, high/low). Dimension refers to the object's height (tall or short) and breadth (wide or narrow).

By understanding the interrelationships of these qualities, much can be perceived about the nature of an object or multiple objects. For example, an object that is tall and narrow may be recognized quickly as a pole. An object that is tall and narrow near the bottom while broad near the top would be a tree.

Something that is tall and very broad registers as a wall or building. Something that is broad and tall in the middle, while being shorter at either end may be identified as a parked car. An object that is low and broad may be a planter, retaining wall, or curb. And finally, something that starts out close and very low but recedes into the distance as it gets higher is a set of steps.

Density refers to the solidity of the object (solid/sparse, hard/soft). Awareness of density adds richness and complexity to one's available information. For instance, an object that is low and solid may be recognized as a table, while something low and sparse sounds like a bush; but an object that is tall and broad and very sparse is probably a fence.


Ben Underwood & Human Echolocation

Human echolocation is the ability of humans to sense objects in their environment by hearing echoes from those objects.

This ability is used by some blind people to navigate within their environment.

They actively create sounds, such as by tapping their canes, lightly stomping their foot or by making clicking noises with their mouths.


Human echolocation is similar in principle to active sonar and to the animal echolocation employed by some animals, including bats and dolphins.


Underwood died on January 19th, 2009 at the age of 16, from the same cancer that took his vision. We can all learn some important things in life, and people like Ben Underwood help remind us of this.



Ben Underwood
In Loving Memory
(January 26th 1992 - January 19th 2009)