Why does hearing sounds like nails on a chalkboard and also imagining them, create such an irritating sensation?

Question

Why does hearing sounds like nails on a chalkboard and also imagining them, create such an irritating sensation?

In: Biology

Answer 1

I remember reading the theory that it could be an evolutionary reaction to our primate ancestors’ giant bird predators.

https://www.sciencedaily.com/releases/2006/08/060830005634.htm

(Edit: apparently that wasn’t clear: the sound of a chalkboard or plate scratch was posited to be similar to the screech of giant primate-eating raptors of our primordial ancestors)