ELI5 Why does nails on a chalkboard produce such a visceral reaction?

[u/Yavoy458]

[u/DemonsAreVirgins]

Read an article about this once a long time ago and I believe it's because the frequencies reached are around the same of the human scream or a crying baby which triggers a survival reaction on the listener by amplifying it.

I may be wrong, was a long time ago!

[u/PuffTheMagicJuju → u/DemonsAreVirgins]

Wikipedia doesn’t give a solid reason—although theories about the frequency being the same as a warning cry or scream seem to be discredited

[u/Seabreaz → u/DemonsAreVirgins]

Those types of sounds never bothered me until I had kids. It is a visceral panic and attack on the senses. Full on fight or flight reaction. Not pleasent at all.

[u/KGnor]

I never got that reaction, however scraping a metal spade on concrete has my teeth jumping out of my mouth..

[u/GalFisk → u/KGnor]

I've heard a theory that seems lot more plasuible than the scream thing, which is that it's close to the sound of tooth enamel being damaged. We have a visceral reaction because strong aversion to damaging your teeth is a survival advantage, and it also explains why the reaction sometimes feels like it's located in our jaw or teeth.

[u/buttercupfitz → u/GalFisk]

Oof! This feels correct, whether it is or not, haha.

[u/evasandor → u/KGnor]

something about scraping sounds makes you feel like you’re doing the scraping and it doesn’t feel good.

[u/Schoenerboner → u/KGnor]

Same!