Few sounds make us feel so cringe like Nails scratching across a chalkboard, or a fork scraped on a plate, or a metal chair dragged across a tiled floor. We not only hear these types of sounds, but we can feel them, and they make us feel so cringe.
But what is so wrong with this kind of scraping that makes it offensive to our brain that many people say it’s actually painful for them?
According to a study that won a 2006 Ig Nobel Prize, in the sound of fingernails scraping chalkboards. The middle audio range frequencies were the most irritating, and these were similar to the chimpanzee’s warning cries. In the research, it’s speculated that human reactions to these sounds have roots in escape response feeling from our evolutionary past.
According to the University of Salford’s acoustic engineer Trevor Cox, he says the range that is in question is 2000-5000 Hz. This range resonates the ear canal, this makes the sound transmit very efficiently. This range of frequency hits us when our ears are particularly sensitive, and there we have a more robust response of cringer or painful feeling.
According to another study published in 2012, it was found that these sound frequencies activate the amygdala, part of the brain, which is involved in fear responses, this in return, creates intense reactions in the auditory cortex.
Another characteristic that triggers Grima or the cringe effect is roughness. When we scrape fingernails on a chalkboard, we have our nails cause roughness catching on the blackboard. It’s something similar to how violin bow works.
So, there are many studies done on this subject to find out why we feel cringe whenever we run our nails on the chalkboard. Many reasons have been cited, still to find the exact cause, there is more research needed on this topic.