By Devin Powell
In a study that borders on painful, people who listened to the sounds of nails and squeaky chalk dragged across a chalkboard have helped scientists pinpoint which frequencies cause people to cringe.
Two scientists who study icky sounds have figured out why fingernails dragged across a chalkboard make people’s skin crawl. It’s not the highest or lowest sounds in the squeak that are so annoying, but rather tones that lie in the range of a piano keyboard.
This makes sense because the human ear has evolved to be sensitive to these frequencies, says Christoph Reuter of the University of Vienna’s Musicological Institute. His colleague, Michael Oehler of the Macromedia University for Media and Communication in Cologne, Germany, will present the findings in San Diego November 3 at a meeting of the Acoustical Society of America.
But sound waves alone can’t account for the excruciating experience. Knowing that a screech comes from a chalkboard instead of a piece of contemporary music increases a listener’s discomfort, the researchers found.