The goal of this follow up study is to understand the development, stability and change of mother child interaction dynamics in the first two years of life and to stimulate research into the mechanisms underlying this developmental trajectories. Particularly it will be investigated how different aspects such as maternal state of mind, reflective functioning, maternal responsiveness to the child and sensitivity are carried out in the intersubjective experience of mother-child relationship and contribute to shape the child development. The innovative and relevant contribution of the project relies in the possibility to follow over time the interaction of the dimensions cited above. This, for two main reasons: first, for the importance of monitoring and evaluating, in crucial phases in the development of intersubjectivity, how specific indicators, individual and / or relational, emerge and interact within the mother-child relationship; secondly, a longitudinal survey would provide an opportunity to follow the long-term effects exercised on the cognitive, emotional and social development of the child by her mental representations of attachment and maternal behaviour. We will concentrate on regulatory factors internal to the relationship, and, especially, on risk factors - such as difficult disruptive affective regulation, infant temperament, maternal depression. All these factors are, in fact, considered as a possible source of impairments in the developmental path.