Picture this: you’re in a classroom. Your teacher is at the blackboard. She has long, red nails. She reaches out—and scrapes her nails slowly down the blackboard from top to bottom.
Got the shivers? You’re not alone. Many people cringe at the mere thought of fingernails on a blackboard, even without hearing that horrible screeching sound. In fact, you might think it’s the most revolting sound in the world.
But is it? Scientists at the Acoustic Research Centre at Salford University in the U.K. have decided to find out.
They’ve set up a project called BadVibes whose centerpiece is a website, www.sound101.org, where people can listen to a collection of awful sounds and rate them as not bad, bad, awful, really awful, or horrible. (Right now, the leading contender for most revolting sound appears to be the sound of someone throwing up.)
It’s all done in a spirit of fun, as befits a project which is also going to become an exhibit for the Museum of Science and Industry in Manchester, and so the site also includes a horrible sound mixer, where you can mix up your own awful sound, and even a collection of horrible sound ringtones, because, really, wouldn’t you love to have your phone go off with the sound of someone throwing up while you’re at an important business lunch?
Still, there is a serious side to it, according to Professor Trevor Cox, who is leading the project. “By examining people’s voting patterns we will learn more about people’s perception of horrible sounds,” he says. “We hope to learn about what is the worst sound in the world, and maybe why it is the worst sound.”
Our reasons for reacting to some sounds the way we do seem obvious. We startle and become alert when we hear a threatening sound, such as a loud roar, because we have to be ready to flee possible danger. We are disgusted by the sound of someone throwing up or coughing because disgust is a powerful emotion we have evolved to protect ourselves from disease.
Annoyance at particular sounds is more complicated. The boom-boom-boom of a loud stereo at a party may annoy you if you’re living upstairs and trying to get to sleep, but not if you’re anticipating going to the party in a few minutes and having a good time.
And then there’s the aforementioned sound of fingernails on a blackboard. In a study carried out in the 1980s, researchers D. L. Halpern, R. Blake and J. Hillenbrand had 24 people rate a variety of sounds in terms of unpleasantness. Worst of the worst: a garden tool scraped across a piece of slate, the equivalent of nails on a blackboard.
Surprisingly, altering the sound by removing the screechy high frequencies did not make it any less unpleasant: that unpleasantness seems to reside in the middle frequencies. (Removing the low frequencies didn’t make any difference, either.)
The scientists found that the waveforms of the scraping noises resemble, in the way the volume varies with pitch, the warning cries of macaque monkeys. They suggested we dislike this sound because, deep in our brains, we think of it as a warning cry.
However, more recent research has found that cotton-top tamarins react the same to white noise as they do to fingernail-on-blackboard-screeches, whereas humans much prefer white noise. So if it’s a warning cry, it’s not one other species of monkeys recognize.
I’ve always thought I dislike the sound of fingernails on a blackboard because it reminds me of the feel of my fingernails on a blackboard. One of Professor Cox’s colleagues has suggested the same thing, but as yet, neither of us has any research to back up this notion.
(Suggested science project: identify a group of kids who have never scratched their fingernails on a blackboard or similar surface. Identify a second group of kids who have. Play them a selection of the sounds from the BadVibes website. See if the reaction to the sound of fingernails on a blackboard differs between the two groups. And then let me and Professor Cox know!)
Check out the BadVibes site, listen to (and vote one) as many of the sounds as you can stand to, and then spare a thought for poor Professor Cox.
“It’s been a lot of fund putting together the website,” he says, “but I’m glad I no longer have to edit horrible things like the sound of my snotty nose!”
