e., interpreting infants’ interests and goals and adapting her/his own behavior accordingly (Bornstein, 1989; Conner & Cross, 2003; Kochanska & Aksan, 2004). Following Fogel’s theory (1993), our interest was in how mothers and children jointly contribute to the interaction. Therefore, unlike Bakeman selleck compound and Adamson’s (1984), Adamson and Bakeman’s (1985), and Bakeman and Gottman’s (1986) (more recently, see Bigelow, Maclean, & Proctor, 2004) studies on social

play and unlike most research on social interaction (a recent example is Kochanska & Aksan, 2004), we chose the dyad as the unit of analysis rather than the individual (the infant or the mother). Accordingly, we coded that unit as a single entity, using an instrument which has been designed for the purpose of observing interaction per se, i.e., the Relational Coding System (Fogel & Lyra, 1997). Based on a corollary of Fogel’s (1993) relational theory, which posits that the Nutlin-3 mouse organized patterns of behavior are to be found in the whole system of communication rather than in one of its components, this instrument captures the ways in which the partners adjust to each other continuously while interacting. Different patterns of coregulation are identified that correspond to the nature of this adjustment: unilateral, when only one partner is paying attention to the other while the other is engaged in something else; asymmetrical, when there is a joint

focus of attention but only one partner is elaborating on the activity while the other only observes; and symmetrical, where both partners adapt to each other and together come up with innovative ways to take

part in an activity. Unlike previous studies that used the Relational Coding System to examine the first few months of life (Hsu & Fogel, 2001; Lavelli, 2005), our study focuses on a later period, from 10 to 24 months of age. It therefore contributes to extending the analysis of interpersonal coregulation from face-to-face interaction to mother–infant–object interaction. We also partly modified the original coding system according to the developmental changes in the content of interaction shown by previous studies. They found that in the first half of the second year of life infants use affective expressions (Bakeman Sorafenib manufacturer & Adamson, 1984) or manipulative actions (Bakeman & Adamson, 1984; Camaioni et al., 2003) to interact with their mother during social play; later, with the advancement of representational skills, infants begin to produce linguistic expressions related to shared activity, such as protowords and words (Adamson et al., 2004; Camaioni et al., 2003). To account for these possible changes during the observed period, we divided symmetrical coregulation into three subcategories, which, in line with the above results, aimed at coding episodes in which affect, action or language is shared. We expected to find a developmental sequence in the predominant patterns shared by the dyads to achieve coregulation.