Most humans find their way through the world using a combination of senses, relying largely on sight and touch to avoid danger. Dolphins, however, map the ocean and find one another using echolocation, a sonar-based language. Bats use it too, and now some humans can as well.
Scientists at Ludwig-Maximilians-Universitaet in Munich have successfully trained a small group of sighted people to figure out the size of a room using echolocation, a first. The researchers wondered whether a human brain could adapt to using a complex skill like echolocation if it wasn’t essential for survival.
Blind people have been successful in learning to use tongue clicks to navigate their world, but since their brains have already learned to rely on non-visual forms of direction, scientists weren’t surprised.
“We thought, ‘If it’s sighted people, it’s not going to be something we’ve ever learned to do,’” Virginia Flanagin, lead author of the study, told The Atlantic. “’So probably we’re really bad at it.’”
They were wrong.
For the experiment, 11 sighted people and one blind person were first given a training session in echolocation. Subjects were placed in a padded, echo-less room and listened to clicks recorded in real-life buildings. This helped them learn to recognize the small differences between sounds made in larger versus smaller rooms.
The participants were then hooked up to an MRI machine to monitor brain activity and connected to a virtual, 3D model of a church, where researchers digitally shrunk or enlarged rooms, for the main experiment. Participants then clicked their tongues and listened to the echoes to judge the size of the virtual rooms they were in.
According to results, the person who became the most skilled at echolocation could detect as little as a four percent difference in the room sizes. The least skilled person could still detect a 16 percent difference.
Interestingly, the brain scans showed that the echolocation lit up sighted subjects’ motor cortex, while the visual cortex was activated in the blind participant. This study lays the groundwork for future research into echolocation, specifically what changes in a blind person’s brain that might allow them to do something a sighted person cannot.
The study was originally published in the Journal of Neuroscience in January.
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