Four bikers headed off down a street in Southern California, safely navigating through traffic and past parked cars, and turned onto a narrow bike path leading up a steep hillside. None of them veered off the dirt path, and all safely avoided boulders along the way, always conscious of their surroundings and any possible obstacles.
It happens all the time, right? Well, not quite like this. Three of the four were blind.
"They had no problem whatsoever," said Lawrence Rosenblum, the only biker in the pack who could see. But the blind bikers could "see" about as well as Rosenblum, just not with their eyes. Like three bats in a dark cave, they knew where they were, and where they were going, because of echolocation, the sounds echoing from the trees and the dirt and the rocks around them as they sped along the path.
That may not seem all that surprising, since we've known for decades that people deprived of their eyes, or any of the five primary senses, compensate by enhancing their remaining senses. But here's what's new: Anybody can learn how to do it, because we all possess extraordinary powers when it comes to our perception of the world around us.
Rosenblum, a psychology professor at the University of California, Riverside, has spent 25 years studying how the human brain can rewire itself -- sometimes temporarily -- so we can better perceive the world around us and offset any deficiencies among our senses. In his new book, "See What I'm Saying," he describes how anyone wearing a blindfold can learn in about 10 minutes how to walk toward a wall and stop before hitting it.
Like the bikers on the path, it's through echolocation, learning how sound changes as the distance between an observer and an obstacle changes.
"We use it all the time, not just when we are blindfolded," Rosenblum said in a telephone interview. "When we walk into a room we get an idea of its space not only by looking around, but also from the way it reflects sound."
As part of his research, Rosenblum has had his grad students blindfolded, wearing sound-deadening headphones -- and crawling around on the lawn to see if they could track a smell just like a dog, using only their noses. They could.
It's all part of a growing field of research called neuroplasticity, or how the brain changes, sometimes reallocating its own resources, in response to experience or changes in the environment. The best known example is the natural ability of blind persons to enhance their auditory system, literally redirecting the neurons in the brain to "listen" instead of "look." But we all do it, to varying degrees, according to Rosenblum.
His interest in the field dates back to his early childhood. Both of his parents worked with sensory-impaired persons, as he put it.
"My dad ran an agency for the blind, and my mom worked with deaf kids," he said. When he visited their offices as a child, he added, he was intrigued with "the skills these folks acquired to compensate for their losses."