The problem of how the imitator knows what acts of their own ‘match’ those they see in others. What is the metric of equivalence? That is a question that still has to be resolved satisfactorily in studies of imitation, and solutions may be available in comparing the kinematics of the demonstrator and the imitator. Traditional theories in cognitive psychology assume that visual and motor systems are separate; this poses the correspondence problem.
See Common coding, Emulation, Imitation, Kinematics, Newborn imitation, Perception-action coupling