A two-person neuroscience perspective on parent-infant dyadic expansion of consciousness.

Caregiver-infant interaction represents the space where development happens through time. According to the mutual regulation model (MRM) by Tronick, meaning-making, emotion regulation, and stress resilience all emerge from the complex fabric of caregiver-infant interaction. Within this model, the dyadic expansion of consciousness (DEC) identifies how adult caregivers and infants co-create an expanded state of consciousness characterized by greater complexity through reciprocal interactions of their individual states of consciousness and alternating phases of matching, mismatching, and reparation. The well-validated Face-to-Face Still-Face paradigm (FFSF), by introducing experimental manipulations of caregiver's interactive availability, represents a reliable procedure to investigate these early forms of socio-emotional and socio-cognitive exchanges. Nonetheless, there is a general lack of studies investigating and providing measures of DEC. Recent advancements in the developmental neuroscience field (i.e., hyperscanning protocols) hold promises to provide renewed interest in studying DEC by exploring the dyadic co-regulation of inter-brain coupling and uncoupling from a caregiver-infant perspective. By employing diverse emerging metrics of neural coupling, researchers can investigate, using unprecedented neuroscientific approaches, how the behavioral and neural activity of each interactive partner may lead to the emergence of a "two-brained system" capable of producing dyadic meanings through dynamically synchronized and resonating individual brain networks. In the present contribution, we highlight how developmental hyperscanning research can be beneficial to our comprehension of the early mutual regulation processes occurring in caregiver-infant dyads.