A new study confirms how adept some blind people are at “echolocation”— tracking objects near them by making clicks and interpreting the echoes—and identifies the brain regions involved.
The skill is more typically associated with bats and dolphins.
A 43-year-old man who had been sightless since 13 months was able to locate a pole placed five feet away to within three degrees of its position, using oral clicks. He was tested along with a 27-year-old who’d been blind for 13 years, who had slightly lesser (yet still formidable) echolocation skills, and two control subjects, with no such ability.
Both blind subjects were able to tell when a panel placed 1.3 feet away from them was flat or concave, and whether it was 20 degrees to the right or left. Outdoors, they could say when they were standing in front of a car, tree, or light pole.
For the scanning part of the study, researchers first placed microphones in the subjects’ ears and recorded their clicks and echoes, in the lab and outdoors. Those sounds were later played back, through in-ear devices, as they lay in a scanner.
When listening to clicks and echoes, the blind subjects, but not the controls, displayed heightened activity in part of the brain associated with visual processing.