Why Fingernails On a Chalkboard Sound Painful

Discussion in 'Off-topic Zone' started by Sam I Am, Nov 1, 2011.

  1. Sam I Am

    Sam I Am Unfriendly and Aloof!

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    Some sounds are excruciating. Take fingernails squeaking on a chalkboard. The noise makes many people shudder, but researchers never knew exactly why. A new study finds that there are two factors at work: the knowledge of where the sound is coming from and the unfortunate design of our ear canals.

    Previous research found that the painful parts of unpleasant sounds appear to be in the middle range of audible frequencies. But scientists didn’t nail down exactly which frequencies or explain why the sounds were painful. So musicologists Michael Oehler of the Macromedia University for Media and Communication in Cologne, Germany, and Christoph Reuter of the University of Vienna asked listeners to rank sounds in a listening test. Fingernails raking against a chalkboard and chalk squeaking against slate were the most unpleasant sounds from a family of recordings, which also included sounds such as Styrofoam squeaks and scraping a plate with a fork.

    The researchers then modified the recordings of fingernails and chalk, removing or attenuating various frequency ranges. They also modified the sounds by selectively extracting either the tonal, musical-pitch parts or the scraping, growling, noiselike parts of the sound. Some listeners were told the true source of the sounds, whereas others were told that the sounds were part of contemporary musical compositions. The same listeners then rated the pleasantness or unpleasantness of the sounds while the researchers measured physical indicators of distress: the listeners’ heart rate, blood pressure, and the electrical conductivity of their skin.

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  2. Reality

    Reality Administrator Staff Member

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    I am glad you posted this! I have always wondered something and I think I finally have an answer.

    Scraping fingernails on a chalkboard has never bothered me. In fact, I always enjoyed driving other people crazy with it when I was young :D I always wondered though why it didn't bother me.

    When I was young, my hearing was tested and the tests showed I had an overall hearing deficiency of 30-35% (that was when I was young, I believe it worse now). When I was in my late teens, some friends and I were in a car audio shop looking for new cars speakers. Like many car audio shops, they had one radio hooked to several speakers that could be toggled by pressing their associated buttons. When I tried the higher quality speakers, they sounded horrible and I made a comment on that to my friends. They all looked at me thinking I was kidding.

    That is when I learned all of my hearing problems are with mid-range frequencies. Listening to just those speakers alone (which were only mid-range) it sounded like 10 different songs all playing at the same time to me. I had never realized it before because usually speakers cover mid-range and high-range or just low-range and the high-range and low-range speakers compensated for the distortion.

    I also have the same problem with people whose voices operate at certain frequencies or that speak fast without enunciating their words. I see them talking and I hear sounds coming from their mouths but it is like they are speaking gibberish or another language entirely. The funny thing is that I almost always hear extremely low and extremely high sounds long before anyone else and I am sometimes the only one who can hear them.

    This article sheds some light on the fact that fingernails on a chalkboard doesn't bother me. The most likely reason now is that my lack of hearing in the annoying frequency ranges that bother most people such as those from fingernails on a chalkboard are blocked by my hearing problems.

  3. Sam I Am

    Sam I Am Unfriendly and Aloof!

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    Glad I could help. :)

    Interesting story btw.
  4. casmith07

    casmith07 Attorney-at-Zone

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    I read the title "fingernails on a chalkboard" and I got chills. Classical conditioning, haha.
  5. VietCowboy

    VietCowboy Be Realistic. Demand the Impossible.

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    styrofoam gets me more. I can barely touch it.
  6. Sam I Am

    Sam I Am Unfriendly and Aloof!

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    Just for you. ;)
  7. jubal

    jubal Active Member

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    Had a friend I drove crazy by rubbing the pages of a book between thumb and finger to separate the pages before turning them.
  8. Jenky

    Jenky Well-Known Member

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    This is the same for me!!!

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