This chapter proposes a new way to approach the ontogenesis of symbol formation: the analysis of movement and its relation to the development of action. First, it highlights some of the essential traits of movement, both during the early adult-child dyad as well as in temporal arts. The chapter discusses the capacity that movement has to express vital affections and modes of temporal organization of movements: alternation, synchrony, and the repetition-variation form. It then suggests that the variations in the quality of movement, the attunements, and the repetition-variation forms that constitute the social circular reactions are elaborations, in the Dissanayake sense, which have the virtue to drive an ongoing flow of the vitality affects. Finally, the chapter proposes that the elaborations that compose the social circular reactions undergo a gradual externalization process beyond the dyad.