The results were surprising. “We thought, ‘If it’s sighted people, it’s not going to be something we’ve ever learned to do,’” reflects Virginia Flanagin, a neuroscientist and first author of the study. “‘So probably we’re really bad at it.’” But the sighted subjects had little trouble figuring out the relative sizes of the spaces. The person who grew the most skilled at it could tell if there was as little as a 4 percent difference in the size of the room. Even the people who did less well could still often tell apart differences of 6 to 8 percent, with the least skilled bottoming out at a 16 percent difference. Overall, that actually is about the same level of acuity—ability to distinguish differences—that you find in some visual tests, says Flanagin.

Additionally, the brain scans showed something odd: The sound of the echoes was activating sighted subjects’ motor cortex, the part of the brain that handles movements. The researchers had the subjects make their echolocation sound—usually a click with their tongues—without playing them back any echoes, then subtracted that scan from the scans taken when they heard the noise reverberating in the church, to get rid of any motor cortex activation from moving the tongue. But it still lit up, even with the tongue movement removed. In fact, the brain region was more active with large versions of the church than smaller ones. “It seems like the motor cortex is somehow involved in the sensory processing,” says Flanagin. In the blind subject, the echoes caused the activation of the visual cortex instead.

These results lay the groundwork for future studies investigating whether sighted people can be trained to do more complicated kinds of echolocation, like navigating down a virtual hallway. The idea, Flanagin says, is to understand at what level of complexity blind people start being able to do things that sighted people can’t and what might have changed in their brains to allow them to do that. In general, the resilience of the human brain and the readiness with which we can learn new skills when circumstances demand it is impressive. Quoting the blind advocate Daniel Kish, who uses echol oc ation himself to walk around every day , Flanagin remarks, “The only reason sighted people can’t do it is they don’t have to.”

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