Scientists have explained the aversion to the screeching of nails on glass
An international group of psychologists came to the conclusion that the sensation, which occurs when a person hears the screeching of nails on glass and other unpleasant sounds, is a separate emotion, verifiable.
The researchers also showed that reaction to such stimuli different from the response to other sounds aversive. The paper was published in the journal Frontiers in Psychology.
In Spanish there is a word grima, which describes the response to such sounds, like chalk squeaking on a blackboard or scratching a fork on a plate. Psychologists have spent many years trying to explain the nature of this feeling, but it is still not fully understood.
So, some works show that these sounds are in the range from 2000 to 4000 Hertz in which our ear is more sensitive of all, which causes a strong reaction. In the study, which received the IG Nobel prize in 2006, says that frequency, causing grima, is very similar to the frequencies of the alarm chimpanzees, so our reaction is due to the evolutionary. It is also known that such sounds increase the activity of the amygdala — a brain area often associated with the experience of fear.
The creators of the work decided to study how people characterize grima, and also to compare whether people’s reaction to sounds, causing grima and disgust. At first they asked 116 Hispanic students to tell what they mean grima. Among the most popular answers was “unpleasant feeling”, “shaking”, “sounds” and “disgust”, and the most popular incentive was the rasp of a knife or fork on glass, chalk squeaking on a blackboard and scratching things on the surface (such as sound and physical sensation). Nearest to grima emotion, according to participants, was disgust.
Then the psychologists asked 37 volunteers from the UK and Germany, whose language has no equivalent for grima and which relate to that feeling with disgust, to listen to several groups of sounds. Among them were those of disgust (vomiting), fun (laughter), unpleasant feeling (Creek) and grima.
It turned out that when listening to the grima-sounds of the heartbeat of the person is first slightly slowed down, then accelerated sharply, before returning to normal after six seconds. When listening to unpleasant or sickening records heart participants reacted differently: his pulse was slowing down more sharply and accelerated, on the contrary, slower. The conductivity of the skin, which is associated with emotional arousal, remained in all three cases the same.
According to scientists, these results show that grima is sounds unlike the sounds associated with disgust and dislike, to a lesser extent, motivates the defense, however, forced him to prepare for action.
After this experiment the volunteers were asked to monitor their reaction to the creaking of the plug which is rolled over the plate, and try to ignore the sound. While the participants tried to tell myself not to pay attention to him, he seemed to be less unpleasant. However, such “meditation” is not triggered when students tried it in a similar manner to suppress responses to other annoying sounds. According to the authors, this shows that grima is a special kind of emotional experience that involves certain cognitive processes and control.
Recently, researchers have tried to explain different phenomenon in the field of sound perception: why musicians prefer the sound of overloaded tube amps compared to solid state amplifiers. It turned out that tube amplifiers make the signal mostly even harmonics, and solid-state amplifiers, the advantage is given to odd harmonics that introduce dissonance. Other recent work by scientists has shown that sounds that are characterized as dissonant in Western countries, like the cultures, where preference is given to assonant or dissonant chords.
Christina Ulasovich