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Scratching the blackboard with your fingernail, rubbing Styrofoam against each other or slipping on the plate with a knife: these and other noises trigger discomfort in many people. Then a shiver runs down our spines, goosebumps stand up and sometimes it even pulls on our teeth when we are exposed to the noises.
- Many people react to sounds in a high frequency range.
- Goosebumps and tense neck muscles in response to the noises could be evolutionary
- violent reactions to chewing sounds, on the other hand, indicate misophonia.
- The sometimes severe intolerance to eating noises could have both acoustic and motor causes.
Goosebumps at certain sounds
In 2011, a team led by neurologist Sukhbinder Kumar researched these tormenting sounds at Newcastle University. The result of the study: These sounds activate the amygdala in the brain. This part of the limbic system in the brain processes emotions. If we associate a feeling with certain sounds, we are probably reproducing it. In addition, the researchers found that the acoustic properties are equally relevant for the reaction.
The test subjects reacted most clearly to sounds whose frequency is between 2000 and 5000 hertz. This range is high and easily noticeable to the human ear. One assumption is that these clear reactions are evolutionary. Alarm signals such as screaming babies or a frightened screech have a comparable frequency.
The brain associates sounds in this way with emergency situations and activates a series of physical reactions: We feel goosebumps and tense back muscles. This reflex is comparable to animals in dangerous situations. They hump and raise their fur to make them look more threatening to predators or attackers.
Misophonia: When sounds of chewing and swallowing are stressful
The technical term misophonia is often literally translated as “hatred of sounds”. Unlike the more typical reaction to selected sounds, misophonia is seen as a disorder. It often refers to sounds that emanate from people themselves, such as smacking, loud chewing or swallowing. These sounds are produced by orofacial movements – i.e. in the area of the face and mouth. They also usually sound randomly while eating or drinking.
Sukhbinder Kumar also conducted research on this with a team in 2021. The journal “Journal of Neuroscience” published the research article. It says: “Misophonia is a disorder of emotion processing in which everyday noises at normal volumes cause such strong discomfort that they severely impair the professional, social and domestic life of those affected.” Those affected are so irritated by the noises that they feel anger, irritation, disgust and fear. The confrontation with these sounds also leads to these people sometimes fleeing the situation. Since the noises usually emanate uncontrollably from fellow human beings, living together with others is not possible in extreme cases.
Intolerance to sounds is not only in the ear
However, the results of this study suggest that it is not only hearing that is responsible for the intolerance in misophonia. According to initial findings, it could be due to a pronounced connection to the insula. This area of the brain influences the motor and sensory functions of the organs. In the processing of pain, this area is also attributed the connection of cognitive elements and emotions.
In the study, the researchers observed that those affected did not only react to acoustic stimuli. Soundless depictions of chewing movements also caused discomfort. Some test subjects also imitated the movements when they were confronted with them. This suggests that the trigger sounds activate the brain area (motor cortex), which helps determine the movement that causes the sounds.
