All of life is set to music -- or at least to a rhythm. From the graceful undulation of a jellyfish to the irresistible urge to bop along to our favorite songs, the urge to sway is hard-wired.  Dr. Laurel Trainor has found that our unconscious movements connect us in surprising ways, whether it's musicians playing in concert, a mother singing to her infant, or couples on a speed date.