We’re sorry to start so fast, but imagine, right now, the sound that a piece of chalk makes or the very nails of our hands by pressing them hard against a blackboard. Rather, the noise of some chairs being dragged across the floor or the sensation that arises when sucking on something sour. What do you feel? set on edge, TRUE? Precisely one of the concepts that you have asked us about this week and that the Royal Spanish Academy (RAE) defines as a unpleasant sensation in the teeth and gums by eating sour or harsh substances to taste, hearing certain unpleasant noises, touching certain bodies or simply remembering any of these things.

The teething “is one of the most primitive brain reactions that exist”José Manuel Moltó, former member of the Spanish Society of Neurology (SEN), explained on Radio Aragón. It is a response to a fact that we find unpleasant, especially at the hearing levelalthough there may be other circumstances.


This is the case, for example, of flavors (such as citrus) or textures (Do you know someone who can’t stand peach skin?). The settee, according to the expert, is quite universal and should not be confused with phobias or situations of mere unpleasantness: “It’s different.” If we think about it, these situations do not produce the same consequences of the set of teeth, such as goosebumps or that sensation in the teeth and gums, which does cause the sound that a door makes when a pebble has stuck under it or that of the door. friction between two metals.

One of the curious things about teething is that, with just think about the situation that the cause, can be easily reproduce sensations that causes us “You think of someone running their fingers across the board and probably more than one, as I am commenting, is feeling their skin crawl. Not with the intensity with which it would happen when it is really happening, but also ”, indicated Moltó in the program.

As Moltó explained, the sounds that make us set our teeth on edge are quite similar to those emitted by our cousin brothers, the primates, when detecting a potential danger, and that they use as a generalized warning signal. That is why, when hearing something similar, “we are on guard, upsetlooking to see what can happen at that time”.


A study published in 1986 and winner of that year’s Ig Nobel Prize in 2006 points out that, in the context of our hearing range (between approximately 20 and 20,000 hertz), it’s the mid frequencies that irritate us the mostsince our hearing is more sensitive to them.

The sounds included in these medium frequencies (between 2,000 and 5,000 hertz) are very similar to these alarm cries of chimpanzees. Hence, the researchers hypothesize that our reaction to sounds that set our teeth on edge stems from the flight instinct of predators in the past. “We know that it is a group response that basically triggers all the organic alert responses. It prepares us for a possible escape”, indicated Moltó.

Also a 2012 study found that sounds within this range are capable of activating amygdalaa part of the brain involved in fear-related responses which, in turn, increases activity in the auditory cortex.


“Our speculation was that the reason the sound of fingernails on a blackboard has an almost universal aversive quality is that unleashes in us automatic and unconscious reflex that we are hearing a warning cry“, pointed out on the website of Vanderbilt University (Tennessee, United States) the main author of the first study, the psychologist Randolph Blake.

In the case of flavors and textures, the set on edge would work as a kind of suggestion of our body to warn us that the food could be in poor condition so that we at least consider the possibility.

Now, what is this sensation in the gums and teeth due to? Which part of our body is the ‘culprit’? Although we know that the ‘executive arm’ is the brain, the physiology of teething and all the situations that occur around it “are not well known”. According to Molto, “it’s not even the brain nuclei where this is likely to happen”: “It is possible that it is simply a primitive reaction in the oldest areas of our brain and it is very diffuse. They are not things that happen in a very specific nucleus”.


The reason for goosebumps and that specific sensation in the teeth and gums, therefore, remains a mystery.