In this chapter, we summarize the findings of our quantitative and qualitative analysis of thirteen mother-infant dyads, observed weekly during free play with toy objects, across the developmental transition that marks the emergence of mother-infant-object play. In addition, we discuss the limitations and possibilities for the research methods used here. In the first section of this chapter we summarize the findings on the research propositions about the development of frames and transitions. In the second section, we address the propositions about the development of infant actions as they relate to frame development. In the third section, we address the limitations of our study.

Each of the different methods used – statistical modeling of developmental trajectories and their covariates in infant action, and the quantitative and qualitative analysis of four representative dyads – give different views on the process of developmental change. The quantitative analysis is developmental in the sense that we model the shape of developmental trajectories within dyads over twelve weekly observation sessions. The qualitative analysis is historical because it examines particular successions of events through time in order to understand how developed actions grow from their earlier forms and how these project themselves towards possible future pathways. Our approach is called relational-historical because, in addition to developmental analysis, we study historical process in the context of a developing relationship. The relationship – the unfolding of communication patterns over time – is the focus of the analysis rather than the individual infant.