Inspired by the dynamic clamp of cellular neuroscience, this paper introduces VPI—Virtual Partner Interaction—a coupled
dynamical system for studying real time interaction between a human and a machine. In this proof of concept study, human
subjects coordinate hand movements with a virtual partner, an avatar of a hand whose movements are driven by a
computerized version of the Haken-Kelso-Bunz (HKB) equations that have been shown to govern basic forms of human
coordination. As a surrogate system for human social coordination, VPI allows one to examine regions of the parameter
space not typically explored during live interactions. A number of novel behaviors never previously observed are uncovered
and accounted for. Having its basis in an empirically derived theory of human coordination, VPI offers a principled approach
to human-machine interaction and opens up new ways to understand how humans interact with human-like machines
including identification of underlying neural mechanisms.