There are many sounds that people hate, such as the sound coming from the barbecue stall downstairs late at night, the music of square dancing in the neighborhood square, and the sound of a train driving by is. These are the louder noise, there is another kind of sound, the sound is not big, but also very disgusting. That is the sound of scratching the blackboard with your fingernails, which reminds you of goosebumps when you hear it.
Different from the annoyance that loud noise brings to people. This kind of sound, which is not too loud in volume, brings people to the heart. Many people can imagine what that sound is like as soon as they see an image or text of a blackboard being scratched with their fingernails, even if the sound hasn't been scratched yet. And it's not just one person who dislikes the sound, it's almost everyone who dislikes the sound. Why do people loathe the sound so much?
It turns out that people hate the sound because of two parts of the brain. Before we talk about why people hate this sound, let's talk about the frequency of the sound that people can hear. The average person can hear sounds with frequencies between twenty hertz and twenty thousand hertz. If the sound is not within this range, people cannot hear it. The amount of sound that a normal person speaks is acceptable as long as it is not too loud. If the sound is as loud as the screams of a person who has encountered something frightening, then it is a bit offensive. This unpleasant sound is in the frequency of sound that we can hear. If it were below twenty hertz, or above twenty thousand hertz, then we wouldn't hear it. And not so many people would be afraid to hear the sound. Many people hear the sound of scratching the chalkboard and have a feeling of general discomfort, and a numbing discomfort of the scalp.
In our brain, there is a part that does the amygdala and another called the auditory cortex. The amygdala is very sensitive to high-frequency noise, and once this type of noise is present, it is stimulated. After the amygdala is stimulated, it in turn transmits this sensation to the auditory cortex. Therefore after hearing the sound made by the contact between the nail and the blackboard, these two parts of the brain react more. As soon as the two of them make contact, the person feels noticeable discomfort. Some people will experience a tingling and cold sensation in their scalp, while others will react more strongly and get goosebumps. And the sound of scratching the blackboard with fingernails is a high-frequency noise. In fact, there is a solution to the fear of this sound, but many people can't do it.
People can suggest to themselves that this sound is not unpleasant, and even as good as music. Once it is accepted mentally, it will improve physically as well. However, not many people should be able to use this method. When you hear this uncomfortable sound, it is better to cover your ears or stay away from the scene where this noise exists.