The sound of someone scraping their fingernails down a chalkboard is the worst thing ever. It's not even a contest. If you don't hate it, you're a masochist; if you like it, you should probably be locked away.
If you were in a room where one person was scraping their nails down a chalkboard and a TV was playing the scene in American History X where he curb stomps that guy, a black hole would appear and all of the world's joy would be sucked into a vacuum.
The sonic and visual horror would be too much for one dimension to take. Terrible images are easier to quantify, though. Sounds, on the other hand, seem a bit more benign. So why does a noise like nails on a chalkboard make your mouth grimace and your face disappear into your neck like this?
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It's a similar reaction to when someone drags their cutlery across a plate, and as with many things, the answer is science. Instead of curing cancer or making our jobs obsolete, researchers at the University of Cologne in Austria have answered this hugely important question.
Basically it's your ears' fault:
"Sounds in [a certain] range are amplified due to the anatomy of the ear canal; they are literally louder to us than other sounds are."
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Basically the shape of the ear amplifies the sound of fingernails running across a chalkboard, cutlery on a plate, and a nail file on your overgrown claws. You've really fucked us over there, God.
Explaining the situation further, the scientists said that the ear "may have evolved to amplify frequencies that are important for communication...[which] could have been advantageous for survival, allowing people to come to the rescue of their screaming infants quicker, and thus improve their offspring's chance of survival, or coordinate more effectively during a hunt."
So when we hear the awful sounds of nails scraping on a chalkboard or a knife across a plate, we react in a hugely dramatic way because the noise is hitting "right in the sweet spot of human hearing," TIFO reported.
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If just the thought of this has made you cringe, you're not alone.
In the same study, researchers found there are actual physical responses to unpleasant noises.
"They played back the...sounds for the participants, all the while monitoring certain indicators of stress, such as heart rate, blood pressure and the electrical conductivity of skin. They found that the offensive sounds changed the listeners' skin conductivity significantly, showing that they really do cause a measurable, physical reaction," Live Science reported.
Luckily by about the year 2020, everyone will be working on a computer and only old, creepy tutors will be the owners of a chalkboard. And you shouldn't be hanging around with them anyway.
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