It's so universal that it's become a cliché: nails on a chalkboard! When it comes to noises that bother everyone's ears, it's seemingly a given that scraping fingernails across a slate board is the one that everyone hates most. But when a group of neuroscientists decided to test which sounds most upset the human brain, they discovered that fingernails on a chalkboard isn't number one.
It's not even number two. As part of their research, published last week in the Journal of Neuroscience, they put 16 participants in an MRI machine, played them a range of 74 different sounds and asked them to rate which were most annoying.