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. Their top ten most irritating sounds, with links to audio files for the worst five (although we can’t imagine why you’d want to listen):


  1. A knife on a bottle
  2. A fork on a glass
  3. Chalk on a blackboard
  4. A ruler on a bottle
  5. Nails on a blackboard
  6. A female scream
  7. An anglegrinder (a power tool)
  8. Squealing brakes on a bicycle
  9. A baby crying
  10. An electric drill

They also played the participants a number of more pleasant noises. Here were the four they rated as the least irritating:


  1. Applause
  2. A baby laughing
  3. Thunder
  4. Water flowing

Even more interesting than the rankings were the parts of the brain that lit up with activity when the research participants heard the irritating noises. The MRI scans revealed that along with the auditory cortex (which processes sounds), activity in the amygdala—the region of the brain responsible for producing emotions—increased in direct proportion to the perceived unpleasantness of the sound. The researchers found that the amygdala interacted with signals coming from the auditory cortex, increasing the amount of unpleasantness conveyed by sounds at the top of the list, which all happen to occur in the frequency range between 2,000 and 5,000 Hz.


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Original citation: Kumar, S., von Kriegstein, K., Friston, K., Griffiths, T.D. (2012). Features versus Feelings: Dissociable Representations of the Acoustic Features and Valence of Aversive Sounds, The Journal of Neuroscience, 32 (41): p. 14184-14192; doi: 10.1523/​