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Author Topic: Teeth on the edge, the audioception theory  (Read 750 times)

Offline manuelbcd

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Teeth on the edge, the audioception theory
« on: 01/05/2016 23:30:51 »
Hello all people. Firstly I'm sorry for my poor English.
I have an hypothesis on the common experience of teeth on edge, shivers or what we
in Spain call "dentera", I mean when someone screetches his nails in a blackboard or the sensation
of someone hitting his teeths.  I have posted it on reddit but I would like also to discuss it here.
I copy paste my original texto below.

Origin of shivers or teeth on edge.

There are several experiences that make us feel shivers, like screeching nails against a blackboard. I have a personal theory built from an evolutive point of view. There are no consensus about the origin of these shivers. Some authors said it's a primary alert mechanism (fight or fly) developed to trigger a rapid response to some sounds. Something that seems to be clear and well documented is that the origin of that mechanism relies in our vegetative nervous system, the most primary area over which our mammal part was developed. Another doubtless fact is that shivers are perceived as negative feeling. No one likes to feel the shivers. In the best case one can be inmune to them, but people sensible to these sounds interrupts suddenly their normal behaviour and experiment a terrible feeling just for one moment. Thus, the shivers are uncomfortable feeling triggered by specific sounds or sensations, once we experiment them we only have one target: to stop feeling it as soon as possible.

From my point of view its not a "fight or fly" mechanism since tipical reactions of "survival" mechanisms usually include drastic metabolic changes like blood pressure raising, hormonal changes even some times sympatic reactions like shocking, jumping or realeasing any possible object we were carrying.

But if we introspect ourselves is easy to realize that the shivers feeling is different, and a common symptom is like a "teeth screeching" perception. Thus is why in some languages this feeling is called with expressions related with teeth ( I.e. Spanish "dentera").

Above facts lead me to the next theory: the shivers feeling are primary mechanism to protect us from damaging our teeth and nails (and may be also other unsensible body parts).

Why this "hear bassed mechanism" could be necessary? Since teeth and nails do not have nervous net or are poorly populated (teeth can perceive warm and cool but not discrete pressure). A rapid reaction mechanism would be useful to alert ourselves about possible damages if we try to bit hard stuff or to scratch strong with our nails. Another example could be squeaking teeth. It does not damage our teeth inmediatly but is strongly counter-productive in the long term. We cannot perceive teeth squeak from "tactile" nerves so the only mechanism able to alert us could be the ear system.

It makes sense to think in the long evolutive history any mechanism has been developed to make us aware of teeth / nails risks from our childhood. May be these feelings teach us from our early years (may be near our baby-teeth falen) to not performing potentially risky usage of our teeth and nails. Once in the adulthood we have strongly automatized correct behaviours but we still be able to feel these disgusting feelings.

This is the theory and I would be happy to discuss, discord or improve with the feedback of other evolutionary followers.

That was my "hear proprioception" theory.
« Last Edit: 02/05/2016 18:38:46 by manuelbcd »


 

Offline RD

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Re: Teeth on the edge, the audioception theory
« Reply #1 on: 02/05/2016 00:00:30 »
... to alert ourselves about possible damages if we try to bit hard stuff ...

+1

The squeak sound is like that of [dog] teeth-on-bone.
« Last Edit: 02/05/2016 00:04:17 by RD »
 
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Offline manuelbcd

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Re: Teeth on the edge, the audioception theory
« Reply #2 on: 02/05/2016 00:27:16 »
Yes, also try to imagine yourself as a dog digging the ground with your nails, suddenly you reach a big rock... If you continue with your compulsive nail-hitting your nails could become damaged. Imagine a brain mechanism that advices you that this sounds is not good and you might change your behaviour inmediately. However, there seems to exist a disgust-threshold (some people does not seems to be disgusted or not percieving same sensations).  This threshold, as other behaviour features, can act as decission factor (if we are escaping from a predator we will not mind to suffer shivers if we stay alive).

Why humans could have a low threshold level? Because our ancestor generations experimented a lack of evolutive pressure because they don't need to use nails and teeth for everything (just the opposite than other mammals).  That could explain why some humans do not feel that sensation.
 

Offline chiralSPO

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Re: Teeth on the edge, the audioception theory
« Reply #3 on: 02/05/2016 00:48:56 »
I would like to add that some people (myself included) are so sensitive to this effect that they get shivers and goosebumps from rubbing fuzzy surfaces (like peaches, velvet or Velour) or hearing other people handle these things nearby. I believe the term for this is "haptodysphoria" (though I suppose the literal definition of that word could be much broader...)

No idea what the evolutionary significance is, but your explanation seems reasonable...
 
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Offline RD

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Re: Teeth on the edge, the audioception theory
« Reply #4 on: 02/05/2016 08:17:36 »
The optimum squeak-frequency is about the same as the optimum for triggering the acoustic reflex : about 3kHz ...

http://www.freesound.org/people/Sirderf/sounds/332290/

So wincing being triggered in some when hearing that frequency could just be a resonance [side] effect : an [unintentional?] crossover* in the facial nerve ...


https://vula.uct.ac.za/Acoustic%20_stapedius_%20reflexes.pdf

[ * cf. photic-sneeze ]
« Last Edit: 02/05/2016 09:15:07 by RD »
 

Offline Colin2B

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Re: Teeth on the edge, the audioception theory
« Reply #5 on: 02/05/2016 11:26:05 »
The optimum squeak-frequency is about the same as the optimum for triggering the acoustic reflex : about 3kHz ...
The first significant resonance of the ear canal is around 4kHz and so we are very sensitive to sounds around that area. A lot of alarm triggers are fairly HF - snapping of twigs, baby cry,  etc - so it's not surprising we get a reaction.

But sensitivity to stroking fur, velvet, (smooth skin??), sounds like something else to me  ;)
 

Offline manuelbcd

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Re: Teeth on the edge, the audioception theory
« Reply #6 on: 02/05/2016 13:15:45 »
Yeah, velvet, polyspan and other tactile perceptions seems to be out of this theory. However if I may launch some thoughts just inventing, as a mindstorm,  I would say :

May be some tactile perceptions triggers the same alarm pathway to alert us about venomous animals like velvet worms, some aracnoids and or plants.

Could it be also a signar of "do not use this surface to climb, its not secure".

Something interesting is that these sensations are disgusting if you imagine them on teeth, fingers and Hands bit I cannot feel the same disgusting feeling on other body parts. Could it be a clue on where is our brain trying to advice us?

Thanks for your points of view, are simply amazing
 

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Re: Teeth on the edge, the audioception theory
« Reply #6 on: 02/05/2016 13:15:45 »

 

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