My research is aimed to explore how two players improvising jazz can co-ordinate the spectrum of their mental time patterns in such a way as to communicate their performances, and their self-expression, in a single musical narrative. It takes inspiration from studies of the natural history of human action and communication, and assumes that the ability to enter a shared frame of time is at the heart of our communicative nature. It also assumes that, that while time-sharing skills are certainly refined throughout our lives, they are with us from birth. Acoustic analysis of adult-infant interactions confirms that the social world of the infant is fabricated out of the rhythms of a sensitive innate “communicative musicality” (Malloch et al., 1997), as has been claimed by psychologists who have made micro-analytic studies in recent decades of film and video data of mother-infant play. As we develop in skill and knowledge, the intrinsic vital sense of time remains the basis for elaborate multi-layered systems of communication and interaction. The mature and practised musician is the subject of this investigation of temporal coordination, which employs analysis of “blind” improvisations — improvisations mediated by instrumental sound alone.