• Question: Why do humans get irritated when nails go down on a chalkboard, or something really squeaky is heard.

    Asked by lani to Chris, Emily, Martin, Natalie, Tamsin on 16 Mar 2010 in Categories: .
    • Photo: Martin Coath

      Martin Coath answered on 16 Mar 2010:

      I honestly don’t know. I wonder if anyone knows. I will ask round my friends who are psychologists and see if anyone has an answer for you – OK

    • Photo: Emily Cook

      Emily Cook answered on 16 Mar 2010:

      Good question – nobody knows exactly.

      Some people have done experiements trying to work out what frequency of sound is so unpleasant but there isn’t a particular frequency that is especially bad. Its the combination of frequencies that most upsets our ears.

      The best theory I’ve heard is that the sound might be like some monster man eating predator from our past so we have evolved to hate the noise and want to run from it – just a theory though.

    • Photo: Chris Cooper

      Chris Cooper answered on 16 Mar 2010:

      Amazing question! I suspect it is one of those things that seems simple on the surface, but we really don’t know the answer to. So I am going to go away and research this myself and then edit my answer later. Thanks for giving me some interesting work to do!

    • Photo: Natalie Stanford

      Natalie Stanford answered on 17 Mar 2010:

      I don’t know the answer to this one so I had a little google and it seems like no one is 100% sure but some scientists think it is an evolutionary response. They think the pitch may have been similar to the vocal call of a predator in our past.

Comments

  • Photo: themaoman

    themaoman commented on :

    I think it’s just because people get squeemish! Everyone gets squeemish about something, like me. I’m pretty squeelish and don’t like nails on blackboards. I also don’t like achilles and other tendons etc.

  • Photo: Natalie

    Natalie commented on :

    Tendons freak me out a bit too, especially the thought of injuring or snapping them. Ewwwww.

  • Photo: Chris

    Chris commented on :

    I don’t think it is the same as being squeemish. I think it is more extreme and immediate. I suspect it does not have an evolutionary base and is just a quirk of the brain that has not been selected for or against. But we really don’t seem to know.

    In terms of sqeemish some people faint at the sight of blood. I can’t help but feel this is a bad thing to have evolved? I assume it is a pathological over-reaction to the blood = red = danger, which is a useful response.

  • Moderator - Craig commented on :

    Aaaaargh even thinking about nails going down a chalkboard freaks me out. Scientists, please sort this issue out!