Fig. 1: Flexible biobehavioral synchrony enabled by the maturation of SOD over the lifespan.

Figure 1 depicts the trajectories of flexible biobehavioural synchrony and the development of SOD as dynamic processes indexing RF over the lifespan. Strongly coupled synchrony in early infancy, mediated by a blurring of the boundary between the infant (self) and their primary caregiver (other), enabled by sensitive caregiving and co-regulation, which in turn fosters the development of both the infant's stress-coping and interpersonal skills. Beginning in childhood and culminating in later adolescence (when necessary individuation processes take place), positive synchrony alternates increasingly with moments of significant misalignment and uncoupling. These moments of rupture and repair provide the necessary context-dependent experience for the TPJ to master flexible switching between representations of self and other, ultimately establishing the basis for the ability to align (synchronize) and retract (segregate) from another person’s mental, and behavioral and physiological arousal state in adulthood in a dynamic and context-sensitive manner.