Cooperation in sound and motion: Complexity matching in collaborative interaction

Complex behaviors are layered with processes across timescales that must be coordinated with each other to accomplish cooperative goals. Complexity matching is the coordination of nested layers of behaviors across individuals. We hypothesize that complexity matching extends across individuals and their respective layers of processes when cooperating in joint tasks. We measured coordination in a joint tower building task through the layers of sound and movement patterns produced by partners and found that partners built higher towers when their sound patterns fell into more similar relations with each other across timescales, as measured by complexity matching. Our findings shed light on the function of complexity matching and lead to new hypotheses about multiscale coordination and communication. We discuss how complexity matching encompasses flexible and complementary dynamics between partners that support complex acts of human coordination.