MMario, in the fifth post in this thread, recalled a child at a concert bouncing to the beat and singing, accompanied by the whole family singing, but presumably much more controlled body language.

This reminded me of a class I took with West Virginia Old-Time banjo guru Dwight Diller, a great if somewhat imperious banjo teacher. He said something like:

"Say you're playin' the banjo at one end of a room, and at a table at the other end are some people, talkin', not even listenin' to you play the music. They don't even know it, but their feet are tappin' in time with your music. THEN you know you've got the rhythm!"

Dave Oesterreich