Echolocation: the brain "sees" with sound
How expert blind people build images of space from the echo of a click — and why science takes it seriously.
Image: Visioneers · World Access for the Blind
Some blind people cross streets, ride bikes or recognize a tree several meters away. They do it by making small clicks with the tongue and listening to how the echo bounces off surfaces. From those echoes, the brain reconstructs an "acoustic image" of the surroundings: where there's a wall, a gap, a person. It's the same principle bats and dolphins use, applied to humans.
World Access for the Blind has turned it into a teachable method called FlashSonar. Its co-founder, Daniel Kish —blind since infancy from retinal cancer— coined the term and was the first totally blind person certified as an Orientation & Mobility specialist. The organization has taught sonar perception to thousands of people in more than 40 countries since 2000.
And it isn't just experience: neuroimaging studies of expert echolocators show that echoes are processed in the brain's visual cortex —the region that processes sight in sighted people— and not only in the auditory cortex. In other words, the brain learns to "see" with sound. It's real perceptual training, measurable with the same rigor as any other skill.
That's why echolocation is one of the pieces Beyond Sight wants to share between schools. It doesn't replace the cane, the guide dog or orientation and mobility: it complements them, and widens what a blind person can perceive of the world.
In brief
- FlashSonar: tongue clicks whose echoes give the brain an image of space.
- Daniel Kish, co-founder, coined the term and was the first totally blind O&M specialist.
- Neuroimaging shows echoes activate the visual cortex, not only the auditory one.
- Taught to thousands of people in more than 40 countries since 2000.
World Access for the Blind
The science of SonarVision and human echolocation.
Read on visioneers.org →An explanatory summary written by Beyond Sight from public sources. For the full original content, visit the linked source's website.
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