[matxip]

I'll throw my hat in by saying I noticed I had this sort of reaction before I ever heard about it. Certain sounds would just cause a reaction I can best equate to getting a scalp massage. The sounds that trigger the effect are pretty widely varied.

It was actually pretty bizarre when I realized it wasn't a universal thing. In fact, I think the most interesting facets of the whole thing is this divide. It makes for one of those weird situation where if you don't experience it, you just have to take people's word that it's not something akin to a placebo effect. And I fully admit it sounds like it's made up, and I probably would be skeptical if I didn't have firsthand experience.