Why does scratching a chalkboard hurt

Instead, when they removed frequencies from the middle or low spectrum of the sound, subjects gave more positive ratings than when all of the frequencies remained. Years later, in Austria and Germany in , musicologists Michael Oehler and Christoph Reuters found that frequencies causing the most aversion lay between and Hz, the range in which our ear amplifies sound the most.

Oehler and Reuters conducted a study with 24 subjects, none of whom were experts or professional musicians. Each of the eight sounds was a modified version of the sound of nails on a chalkboard—the scientists either removed frequencies or modified tones and pitches in each of the stimuli. Finally, they analyzed psychological factors, differentiating between subjects who had knowledge of sound origins and those who did not. Oehler and Reuter found that there was no significant difference in physiological reactions between the two groups during the study.

In the study, 13 participants listened to 74 sounds, including nails on a chalkboard and the whine of power tools, and rated them according to their pleasantness. Researchers used functional magnetic resonance imaging fMRI to examine how the participants' brains responded to the sounds.

When the participants heard an unpleasant sound, there was an interaction between the auditory cortex, which processes sound , and the amygdala, which processes negative emotions. Moreover, the more averse the sound, the greater the activity between these two brain regions, the researchers said.

Some of the most unpleasant sounds, according to the participants' ratings, included a knife on a bottle, a fork on a glass and chalk on a blackboard. The nicest sounds included flowing water, thunder and a laughing baby, they found. Frequencies between 2, and 5, Hertz were found to be unpleasant — roughly the same frequencies found by the research. The reason for such sensitivity is not exactly understood, but this range includes the sounds of screams, which people find intrinsically unpleasant, he said.

Then the researchers fiddled with the recording, removing the high, middle and low frequencies from different recordings. After playing the modified sounds to volunteers, the researchers found that removing the high frequencies didn't make the sounds more pleasant. Rather, eliminating the low and middle frequencies of the sound made the sounds more appealing, they learned, according to Medical Press.

In addition, the warning cry of a chimpanzee is similar to the sound of fingernails on a chalkboard, they found. Perhaps people have an unconscious reflex to this sound because of its uncanny resemblance to a warning call , the researchers told Medical Press.

Laura is an editor at Live Science. I have always been the one to cringe at the very thought of nails on a chalkboard. I even cringed at the picture in this blog. Although, it clearly seems as if the sound alone is causing us to feel unpleasant feelings, I am now more inclined to believing that we are just socialized to have these feelings. After reading your blog, I believe this is very likely.

I feel that a lot of things in our lives that spark unpleasant feelings are simply because we have always known them as being bad. What if we were raised to believe that this sound was pleasant? In my opinion, then we would enjoy the sound of the nails.

I absolutely hate the sound of of chalk on a chalk board. I also hate the feel of chalk, just reading the title of this blog post made me cringe. I think it is very interesting that the theory that our instincts may be the reason why many people find it to be such a horrible sound.

The thought that even though we have evolved and grown into the humans we are today and can still use our ancient instincts is remarkable. WHo would have that that even though we may not need to know or use some of our original instincts we still have them and could use them for everyday events. I do think that it is possible that as humans be both know it is an unpleasant sound and automatically do not enjoy it as well as having some instincts that cause us to not like the sound.

I do think that as people we can make ourselves believe that something or someone is more unpleasant or pleasant than they may actually be based on what we have been told or personally believe.

Psychology humans dominantly make their own decisions and can change the way they think about something purely by someones opinion. Who would have that that even though we may not need to know or use some of our original instincts we still have them and could use them for everyday events.

The power of opinion and speech can change anyone's view point on a situation even merely if one likes a certain sound or not. These two explanations both seem logical.