http://www.theblaze.com/stories/2013/07/11/a-fascinating-thing-happens-to-the-heartbeats-of-choir-members-when-they-sing/
 
I grew up singing in choirs.

I sang in a barbershop quartet quintet for a while, and I do remember a kind of weird spiritual out of body type feeling when everyone hit a harmony dead on. 

Definitely. I read even playing music together synchronizes your brain waves.

The Beatles when singing harmonies would sing into the same microphone using a figure 8 pattern.

I believe it goes back to our early human/pre-human wiring. We've only had the Internet since the 90s. Only had TV since the early part of the 20th century. But singing? That goes back to the early cave men... We were putting dye in our mouths and spitting on our hands on the wall (to leave the impression). Our brains were pretty much as they are today, but we hunted to eat (all of us...) Small groups, the concept of the village did not come about until we became farmers about 25,000 years ago. Before that? We killed it and grilled it. But we had song, and we had music of some kind. THAT is why music touches people in a way that other things cannot. It's in our DNA.
 
I wonder if the Neanderthal people had music before we killed them off?

Wow, it sounds like “Band19” is actually an alias for The Motor City Madman.
 
In the book “This is Your Brain on Music” the author has an interesting discussion about the idea of a musical expert (or musician) being a very modern western concept (not cowboy western).  For example, an individual brought up in a modern western tradition may decline to participate in a group sing-along because they are not a singer whereas the idea of NOT participating in the music would be foreign to somebody not raised in a modern western tradition.  Or in other words, in non-western traditions, music is an integral part of society that everybody participates in … not just the experts.