The attachment system motivates a human infant to seek proximity to parents (and other primary caregivers) and to establish communication with them… attachment establishes an interpersonal relationship that helps the immature embodied brain to use the mature functions of the parent’s body and brain to organize its own processes.
Siegel defines the attachment system as an evolved motivational architecture that recruits the caregiver’s mature brain to regulate the infant’s immature neural processes, grounding the system in interpersonal neurobiology.
, The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020thesis