[nollidge]

Is this true for everyone, though? I've sung in choirs and played various instruments over the years, so my experience of music is almost always one of deconstructing it, and so my unconscious motivation to hum along (or tap my fingers or beatbox) is to facilitate picking apart the different voices and instruments.

But not everyone has that musical background, so maybe not everyone is so compelled as you or me to sing along.