Shivers

[GrahamT]

Why do some people get a "shiver" from grating noises - butchers sharpening knives, nails down blackboards etc.

[tigga]

I dont know sorry, but uuuurgh you only needed to mention the nails and blackboards for me !!!

[amarillis]

Apparently it is something to do with the frequency of the noise and the fact that it isn't a 'pure tone' that makes people react that way. This link explains it a bit:

http://www.madsci.org/posts/archives/aug98/902328462.Bp.r.html