The fetus/infant - mother as a co-evolving dyadic system and the development of attachment styles: an active inference perspective.

The mother-fetus/infant dyad constitutes a uniquely asymmetric biological and psychological system whose co-evolutionary dynamics we propose are most coherently understood within the Active Inference Framework (AIF). We hypothesize that the development of attachment styles emerges from the progressive construction of a generative model in the fetus and infant, shaped by the precision and content of predictions learned through early dyadic interactions - beginning already during the gestational period. Drawing on the Free Energy Principle and its neuroscientific and mathematical foundations, we propose that internal working models (IWM), as originally conceived in attachment theory, are best reinterpreted as hierarchical generative models that develop through reciprocal inferential exchanges across the Markov blankets of two asymmetrically coupled agents: the mother and the fetus/infant. The quality and consistency of maternal caregiving determines the precision of the infant's predictions, which in turn organizes the attachment system along the axes of security and behavioral organization. This framework integrates neurobiological, epigenetic, cognitive, and developmental perspectives under a single first-principles account, offers novel testable predictions, and opens new directions for clinical translation, particularly regarding early intervention and intergenerational transmission of attachment.