ABSTRACT
What we have outlined so far highlights the importance of a two-person psychology in the context of a relational exchange where neither party can be considered to be entirely separate from the other. This does not mean that a one-person psychology is not relevant but it is the tension between the two that is signi®cant in the context of therapeutic work with its emphasis on self, other and interactive regulation. Trevarthen (1993, 2001) in particular highlights the importance of a shared mind postulating a preverbal intersubjectivity based in the reciprocal exchange of rhythmic communication processes, a position recognized and supported by other researchers and writers (see Beebe et al., 2005). The idea that the process is much more than one of `matching' responses is important. Matching can occur in the context of either positive or negative affective states and research studies have highlighted the negative affects of certain kinds of matching between mothers and infants, for example, where a depressed mother interacts with her baby (e.g. Field et al., 1990) or where the matching takes on an escalating quality (Beebe, 2000). Daniel Stern's work on affect attunement (Stern, 1985a) demonstrates both the importance of cross modal communication between mother and infant, as well as the role of perturbations in attunement and their importance for development.
