A new brain-imaging study of human echolocation is making headlines after 45-year-old Daniel Kish of Long Beach, Calif.—a man who can "see" what's around him by emitting clicks with his tongue —had his sonar ability tested in an MRI machine. According to Kish, the discovery that blind humans can navigate using echolocation could lead to improved training for people with vision problems. "Blind people should realize that this is an opportunity," said Melvyn Goodale, senior author on the new study.
Let's not get too excited. Human echolocation has been "discovered" many times over the past few decades, most famously in the 1960s by the experimental psychologist—and one-time parent to a chimpanzee—Winthrop Kellogg. You may remember a similar rash of news stories from 2006 touting the exploits of Ben Underwood, the blind teenager who gained minor celebrity for using a clicking method like Kish's. As it happens, Kish himself was quoted in those stories as an expert practitioner of the method, and a staunch advocate (then, as now) for teaching sonar to all blind people everywhere.
As I reported in a Slate column on Underwood, there's nothing new in the idea of helping blind people to navigate using reflected sound. Indeed, lessons in echolocation have been a part of orientation and mobility programs going back to those programs' development in the 1940s. When Kish and Goodale claim that sonar could be a tremendous boon for the blind, they're not merely restating the conventional wisdom. They're implying that the conventional training doesn't go far enough. Instead of having blind people learn echolocation as a nifty trick to be used in concert with conventional aids like guide dogs and canes, they'd like to see them being taught to employ clicks and bleeps as a primary mode of getting around. That's the goal of Kish's nonprofit, World Access for the Blind, which uses "sonar enhancement technology" to help people who can't see. Theirs may be a good system, but it's controversial—if not downright marginal—among specialists in orientation and mobility training. Many of Kish's colleagues believe that echolocation, if it's taught, should remain a secondary skill for the blind. And some disability advocates worry that all the hoopla over sonar makes blind people seem like superhuman freaks, with special powers that more than compensate for their problems.
I'm in no position to adjudicate the debate over whether and how to teach echolocation to the blind. But as a science journalist, I do wonder why certain types of discoveries tend to be made over and over again. (To be fair, Goodale and colleagues never claim to have unearthed a brand-new phenomenon, but that's how their story played out in the media.) It happened with human echolocation, and there are plenty more examples to choose from. Here's one from the last few weeks: According to a recent study, senior citizens are having more sex than you think. This salacious finding, hot off the presses in 2011, was also made in 2007, when I first wrote about it—and before that in 1999 and 1996 and 1993 and 1985 and I'm sure on many other occasions that didn't come up in a minute's Googling. Or to choose another subject near to my heart, the "myth of quicksand" was most recently debunked by scientists in 2005, despite the fact that we'd learned the same thing—mud can't really suck you under—from an episode of MythBusters in 2004, and also from science textbooks dating back to the 1960s, and from a 1946 academic journal article, among other sources. (Indeed, the scientific principle behind that debunking was established more than 2,000 years ago.)
What is it about certain stories that makes them so amenable to rehashing and rediscovery? I'm not sure, but here are a few ideas. First, they may include certain scientific facts that we'd rather not think about. Take the news, for example, that Grandpa is performing cunnilingus on Grandma: It's the kind of datum that would pull a lot of clicks as a Slate headline, but also one that you'd strive to expunge from your hippocampus as soon as you finished reading about it. If researchers have to keep reminding us that our grandparents are having sex, maybe it's because we don't like to think about our grandparents having sex.