How did the unique human ability to create and perceive music evolve? Why was it sustained to such a degree that every known culture – extant or extinct – has had music? Myriad theories have been proposed, but all of them treat music holistically.  In reality, music is the sum total of a number of separate but compatible elements. My research will explore the possibility that rhythm and melody evolved separately, eventually joining together to form what we now recognize as music. In particular, I will explore the evolution of rhythm, its connection with the brain’s mirror neuron system, and its role as an interpersonal social adhesive. Ethnomusicological fieldwork from the summer 2011 music festival season will inform my analysis.